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  • 51.
    Hahn, Robert G.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Clinical Fluid Therapy in the Perioperative Setting2011Collection (editor) (Other academic)
    Abstract [en]

    Clinical Fluid Therapy in the Peri-Operative Setting brings together some of the world's leading clinical experts in fluid management to explain what you should know when providing infusion fluids to surgical and critical care patients. Current evidence-based knowledge, essential basic science and modern clinical practice are explained in 25 focused and authoritative chapters. Each chapter guides the reader in the use of fluid therapy in all aspects of peri-operative patient care. Guidance is given on the correct selection, quantity and composition of fluids required as a consequence of the underlying pathology and state of hydration of the patient, and the type and duration of surgery. Edited by Robert G. Hahn, a highly experienced clinician and award-winning researcher in fluid therapy, this is essential reading for all anaesthetists, intensivists and surgeons.

  • 52.
    Hahn, Robert G.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Surgery.
    Clinical pharmacology of infusion fluids2012In: Acta Medica Lituanica, ISSN 1392-0138, Vol. 19, no 3, p. 210-212Article in journal (Refereed)
    Abstract [en]

    Fluids are used for intravenous infusion during practically all surgeries, but several different compositions are available on the market.

    Crystalloid fluids comprise lactated or acetated Ringer solutions, normal saline, Plasma-Lyte, hypertonic saline, and glucose. They lack allergic properties but are prone to cause peripheral tissue oedema. Their turn­ over is governed by physiological factors such as dehydration and drug effects.

    Colloid fluids include hydroxyethyl starch, albumin, dextran, and gelatin. These fluids have various degrees of allergic properties and do not promote peripheral oedema. Their half-life is usually about hours. Factors increasing the turnover rate are poorly known but might include inflammatory states.

    Current debates include the widespread use of normal saline, which should be replaced by Ringer’s or Plasma-Lyte in most situations, and the kidney damage associated with the use of starch in septic patients. New studies show that hypertonic saline does not improve survival or neurological damage in prehospital care.

  • 53.
    Hahn, Robert G
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Fluid therapy in uncontrolled hemorrhage - what experimental models have taught us2013In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 57, no 1, p. 16-28Article, review/survey (Refereed)
    Abstract [en]

    Intravenous fluid is life-saving in hypovolemic shock, but fluid sometimes aggravates the bleeding. During the past 25 years, animal models have helped our understanding of the mechanisms involved in this unexpected effect. A key issue is that vasoconstriction is insufficient to arrest the bleeding when damage is made to a major blood vessel. ‘Uncontrolled hemorrhage’ is rather stopped by a blood clot formed at the outside surface of the vessel, and the immature clot is sensitive to mechanical and chemical interactions. The mortality increases if rebleeding occurs. In the aortic tear model in swine, hemorrhage volume and the mortality increase from effective restoration of the arterial pressure. The mortality vs. amount of fluid curve is U-shaped with higher mortality at either end. Without any fluid at all, irreversible shock causes death provided the hemorrhage is sufficiently large. Crystalloid fluid administered in a 3 : 1 proportion to the amount of lost blood initiates serious rebleeding. Hypertonic saline 7.5% in 6% dextran 70 (HSD) also provokes rebleeding resulting in higher mortality in the recommended dosage of 4 ml/kg. Uncontrolled hemorrhage models in rats, except for the ‘cut-tail’ model, confirm the results from swine. To avoid rebleeding, fluid programs should not aim to fully restore the arterial pressure, blood flow rates, or blood volume. For a hemorrhage of 1000 ml, computer simulations show that deliberate hypovolemia (−300 ml) would be achieved by infusing 600–750 ml crystalloid fluid over 20–30 min or 100 ml of HSD over 10–20 min in an adult male.

  • 54.
    Hahn, Robert G
    Östergötlands Läns Landsting, Anaesthesiology and Surgical Centre, Department of Anaesthesiology and Intensive Care VHN. Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Anesthesiology.
    Volume Kinetics for Infusion Fluids2010In: Anesthesiology, ISSN 0003-3022, E-ISSN 1528-1175, Vol. 113, no 2, p. 470-481Article, review/survey (Refereed)
    Abstract [en]

    Volume kinetics is a method for analyzing and simulating the distribution and elimination of infusion fluids. Approximately 50 studies describe the disposition of 0.9% saline, acetated and lactated Ringer´s solution, based on repeated measurements of the hemoglobin concentration and (sometimes) the urinary excretion.

    The slow distribution to the peripheral compartment results in a 50-75% larger plasma dilution during an infusion of crystalloid fluid than would be expected if distribution had been immediate. A drop in the arterial pressure during induction of anesthesia reduces the rate of distribution even further.

    The renal clearance of the infused fluid during surgery is only 10-20% compared to conscious volunteers. Some of this temporary decrease can be attributed to the anesthesia and probably also to preoperative psychological stress and/or dehydration. 

    Crystalloid fluid might be allocated to “non-functional” fluid spaces where it is unavailable for excretion. This amounts to approximately 20-25% during minor (thyroid) surgery.

  • 55.
    Hahn, Robert
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Surgery.
    Li, Yuhong
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Zdolsek, Joachim
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Surgery.
    Non-invasive monitoring of blood haemoglobin for analysis of fluid volume kinetics2010In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 54, no 10, p. 1233-1240Article in journal (Refereed)
    Abstract [en]

    Background: A commercially available pulse oximeter that reports blood haemoglobin (Hb) concentration is evaluated. This study considers whether this device can provide serial Hb data that would be sufficiently reliable for volume kinetic analysis of infusion fluids.

    Methods: Forty infusions of 5 or 10 ml/kg of acetated Ringer's solution were given over 15 min in 10 healthy volunteers. Hb was measured on 17 different occasions over 120 min using the Radical 7 pulse oximeter and compared with the result of invasive blood sampling (control). A one-volume kinetic model was applied to each data series. The pulse oximeter also reported the perfusion index (PI).

    Results: The median deviation between the 680 invasive and non-invasive Hb samples (the accuracy) was 1.6% and the absolute median deviation (precision) was 4.6%. Between-subject factors explained half of the variation in the difference between non-invasive vs. invasive sampling.

    Ten of the 40 non-invasive series of Hb values were discarded from kinetic analysis due to poor quality. The remaining 30 series showed a smaller distribution volume for the infused fluid when kinetic analysis was based on the non-invasive method (3.0 vs. 5.3 l; P<0.001). This was due to co-variance with the PI, which exaggerated the decrease in Hb caused by the infusions. The non-invasive method might provide useful kinetic data at the group level, but individual curves deviated too much from the invasive data to be reliable.

    Conclusions: Non-invasive measurement of the Hb concentration during volume loading could not provide useful kinetic data for individuals.

  • 56.
    Hahn, Robert
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Lindahl, C C
    Karolinska University Hospital.
    Drobin, D
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Volume kinetics of acetated Ringer's solution during experimental spinal anaesthesia2011In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 55, no 8, p. 987-994Article in journal (Refereed)
    Abstract [en]

    Background:

    General anaesthesia lowers the clearance of crystalloid fluid, but the volume kinetics of such fluid throughout the duration of spinal anaesthesia has not been studied.

    Methods:

    Ten female volunteers (mean age 29 years) received an intravenous infusion of 25 ml/kg of acetated Ringer's solution with and without spinal anaesthesia. A volume kinetic model was fitted to serial measurements of the haemoglobin concentration over 240 min based on arterial, cubital vein, and femoral vein blood. The measured urine flow was compared to the model-predicted elimination.

    Results:

    The arterial pressure remained stable, although the block reached to Th3-Th5 in half of the volunteers. There were no differences in fluid kinetics between the spinal anaesthesia and the control experiments. The administered volume was well confined to the kinetic system, which consisted of two communicating fluid spaces that were 2.8 l and approximately 7 l in size at baseline. The arteriovenous difference in plasma dilution remained positive for 30 min post-infusion in those having analgesia reaching to Th3-Th5, which differed significantly from low-level analgesia (Th12-L2, P < 0.03) when venous plasma was sampled from the leg. The urinary excretion averaged 1.13 l and 1.01 l for the spinal and control experiments, respectively. Volume kinetics predicted the urinary excretion at 5- to 10-min intervals with an overall bias of 52 ml.

    Conclusion:

    Acetated Ringer's solution showed the same kinetics during experimental spinal anaesthesia as when the fluid was infused alone. Hence, spinal anaesthesia is not associated with the reduced fluid clearance reported for general anaesthesia.

  • 57.
    Hahn, Robert
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Ljunggren, Stefan
    Södertalje Hospital.
    Larsen, Filip
    Karolinska Institute.
    Nystrom, Thomas
    Karolinska Institute.
    A simple intravenous glucose tolerance test for assessment of insulin sensitivity2011In: Theoretical Biology Medical Modelling, ISSN 1742-4682, E-ISSN 1742-4682, Vol. 8, no 12Article in journal (Refereed)
    Abstract [en]

    Background

    The aim of the study was to find a simple intravenous glucose tolerance test (IVGTT) that can be used to estimate insulin sensitivity.

    Methods

    In 20 healthy volunteers aged between 18 and 51 years (mean, 28) comparisons were made between kinetic parameters derived from a 12-sample, 75-min IVGTT and the Mbw (glucose uptake) obtained during a hyperinsulinemic euglycemic glucose clamp. Plasma glucose was used to calculate the volume of distribution (Vd) and the clearance (CL) of the injected glucose bolus. The plasma insulin response was quantified by the area under the curve (AUCins). Uptake of glucose during the clamp was corrected for body weight (Mbw).

    Results

    There was a 7-fold variation in Mbw. Algorithms based on the slope of the glucose-elimination curve (CL/Vd) in combination with AUCins obtained during the IVGTT showed statistically significant correlations with Mbw, the linearity being r2 = 0.63-0.83. The best algorithms were associated with a 25-75th prediction error ranging from -10% to +10%. Sampling could be shortened to 30-40 min without loss of linearity or precision.

    Conclusion

    Simple measures of glucose and insulin kinetics during an IVGTT can predict between 2/3 and 4/5 of the insulin sensitivity.

  • 58.
    Hahn, Robert
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Nystrom, Thomas
    Karolinska Institute.
    Plasma Volume Expansion Resulting from Intravenous Glucose Tolerance Test2011In: Computational & Mathematical Methods in Medicine, ISSN 1748-670X, E-ISSN 1748-6718, Vol. 2011, no 965075Article in journal (Refereed)
    Abstract [en]

    Objective. To quantify the degree of plasma volume expansion that occurs during an intravenous glucose tolerance test (IVGTT). Methods. Twenty healthy volunteers (mean age, 28 years) underwent IVGTTs in which 0.3 g/kg of glucose 30% was injected as a bolus over 1 min. Twelve blood samples were collected over 75 min. The plasma glucose and blood hemoglobin concentrations were used to calculate the volume distribution (𝑉𝑑) and the clearance (𝐶𝐿) of both the exogenous glucose and the injected fluid volume. Results. The IVGTT caused a virtually instant plasma volume expansion of 10%. The half-life of the glucose averaged 15 min and the plasma volume expansion 16 min. Correction of the fluid kinetic model for osmotic effects after injection reduced 𝐶𝐿 for the infused volume by 85%, which illustrates the strength of osmosis in allocating fluid back to the intracellular fluid space. Simulations indicated that plasma volume expansion can be reduced to 60% by increasing the injection time from 1 to 5 min and reducing the glucose load from 0.3 to 0.2 g/kg. Conclusion. A regular IVGTT induced an acute plasma volume expansion that peaked at 10% despite the fact that only 50–80 mL of fluid were administered.                                    

  • 59.
    Heinius, Goran
    et al.
    Karolinska Institute.
    Hahn, Robert
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Sonden, Anders
    Karolinska Institute.
    HYPOTHERMIA INCREASES REBLEEDING DURING UNCONTROLLED HEMORRHAGE IN THE RAT2011In: Shock, ISSN 1073-2322, E-ISSN 1540-0514, Vol. 36, no 1, p. 60-66Article in journal (Refereed)
    Abstract [en]

    Trauma registers show that hypothermia (HT) is an independent risk factor for death during hemorrhagic shock, although experimental animal studies indicate that HT may be beneficial during these conditions. However, the animal models were not designed to detect the expected increase in bleeding caused by HT. In a new model for uncontrolled bleeding, 40 Sprague-Dawley rats were exposed to a standardized femoral artery injury and randomized to either normothermia or HT. Ketamine/midazolam was used to minimize hemodynamic changes due to the anesthesia. The hypothermic rats were cooled to 30 degrees C and rewarmed again at 90 min. The study period was 3 h. The incidence, onset time, duration, and volume of bleedings as well as hemodynamic and metabolic changes were recorded. There was no difference between groups with respect to the initial bleeding. Rebleedings occurred among 60% of the animals in both groups. Hypothermic rebleeders had more, larger, and longer rebleedings, resulting in a total rebleeding volume amounting to 41% of their estimated blood volume. The corresponding figure for the normothermic rebleeders was 3% (P less than 0.001). Total rebleeding volume was significantly larger in the hypothermic group, even at body temperatures greater than 35 degrees C. We conclude that the risk of rebleeding from a femoral injury is greater in the presence of cooling and HT. The larger rebleeding volumes seen even at body temperatures greater than 35 degrees C indicate that factors other than temperature-induced coagulopathy also contributed to the increased hemorrhage.

  • 60.
    Heinius, Göran
    et al.
    Section of Surgery, Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden.
    Sondén, Anders
    Section of Surgery, Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden.
    Hahn, Robert G
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Effects of Different Fluid Regimes and Desmopressin on Uncontrolled Hemorrhage During Hypothermia in the Rat2012In: Therapeutic Hypothermia and Temperature Management, ISSN 2153-7658, E-ISSN 2153-7933, Vol. 2, no 2, p. 53-60Article in journal (Refereed)
    Abstract [en]

    Resuscitation with large volumes of crystalloids during traumatic hemorrhagic shock might increase the mortality by inducing rebleeding. However, few studies have addressed this problem during hypothermic conditions. Sixty-eight Sprague-Dawley rats were exposed to a standardized femoral artery injury and resuscitated with low (LRe), medium (MRe), or high (HRe) intensity using lactated Ringer's solution after being cooled to 30°C. An additional MRe group was also given desmopressin since this drug might reverse hypothermic-induced impairment of the primary hemostasis. The rats were rewarmed after 90 minutes and observed for 3 hours. The incidence, on-set time, duration, and volume of bleedings and hemodynamic changes were recorded. Rebleedings occurred in 60% of all animals and were more voluminous in the HRe group than in the LRe group (p=0.01). The total rebleeding volume per animal increased with the rate of fluid administration (r=0.50, p=0.01) and the duration of each rebleeding episode was longer in the HRe group than in the LRe group (p<0.001). However, the mortality tended to be higher in the LRe group (LRe=6/15, MRe=1/15, HRe=2/15, p=0.07). Desmopressin did not change the bled volume or the mortality. Overall, the mortality increased if rebleeding occurred (10/35 rebleeders died vs. 1/25 nonrebleeders, p=0.015). Liberal fluid administration increased the rebleeding volume while a trend toward higher mortality was seen with the restrictive fluid program. Desmopressin had no effect on the studied parameters.

  • 61.
    Holm, Jonas
    et al.
    Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Thoracic and Vascular Surgery in Östergötland. Linköping University, Department of Medical and Health Sciences, Thoracic Surgery. Linköping University, Faculty of Health Sciences.
    Håkanson, Erik
    Linköping University, Department of Medical and Health Sciences, Cardiothoracic Anaesthesia and Intensive care. Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Vánky, Farkas
    Linköping University, Department of Medical and Health Sciences, Thoracic Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Thoracic and Vascular Surgery in Östergötland.
    Svedjeholm, Rolf
    Linköping University, Department of Medical and Health Sciences, Thoracic Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Thoracic and Vascular Surgery in Östergötland.
    Mixed venous oxygen saturation predicts short- and long-term outcome after coronary artery bypass grafting surgery: a retrospective cohort analysis2011In: British Journal of Anaesthesia, ISSN 0007-0912, E-ISSN 1471-6771, Vol. 107, no 3, p. 344-350Article in journal (Refereed)
    Abstract [en]

    Background. Complications of an inadequate haemodynamic state are a leading cause of morbidity and mortality after cardiac surgery. Unfortunately, commonly used methods to assess haemodynamic status are not well documented with respect to outcome. The aim of this study was to investigate SV(O2) as a prognostic marker for short-and long-term outcome in a large unselected coronary artery bypass grafting (CABG) cohort and in subgroups with or without treatment for intraoperative heart failure. less thanbrgreater than less thanbrgreater thanMethods. Two thousand seven hundred and fifty-five consecutive CABG patients and subgroups comprising 344 patients with and 2411 patients without intraoperative heart failure, respectively, were investigated. SV(O2) was routinely measured on admission to the intensive care unit (ICU). The mean (SD) follow-up was 10.2 (1.5) yr. less thanbrgreater than less thanbrgreater thanResults. The best cut-off for 30 day mortality related to heart failure based on receiver-operating characteristic analysis was SV(O2) 60.1%. Patients with SV(O2) andlt;60% had higher 30 day mortality (5.4% vs 1.0%; P andlt; 0.0001) and lower 5 yr survival (81.4% vs 90.5%; P andlt; 0.0001). The incidences of perioperative myocardial infarction, renal failure, and stroke were also significantly higher, leading to a longer ICU stay. Similar prognostic information was obtained in the subgroups that were admitted to ICU with or without treatment for intraoperative heart failure. In patients admitted to ICU without treatment for intraoperative heart failure and SV(O2) andgt;= 60%, 30 day mortality was 0.5% and 5 yr survival 92.1%. less thanbrgreater than less thanbrgreater thanConclusions. SV(O2) andlt;60% on admission to ICU was related to worse short- and long-term outcome after CABG, regardless of whether the patients were admitted to ICU with or without treatment for intraoperative heart failure.

  • 62.
    Hong Li, Yu
    et al.
    Zhejiang University, China.
    Bin Zhu, Hai
    Zhejiang University, China.
    Zheng, Xiaozhu
    Zhejiang Hospital, China.
    Jian Chen, Han
    Zhejiang University, China.
    Shao, Liang
    Yuhuan County Peoples Hospital, China.
    Hahn, Robert G
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Low doses of esmolol and phenylephrine act as diuretics during intravenous anesthesia2012In: Critical Care, ISSN 1364-8535, E-ISSN 1466-609X, Vol. 16, no 1Article in journal (Refereed)
    Abstract [en]

    Introduction

    The renal clearance of infused crystalloid fluid is very low during anaesthesia and surgery, but experiments in conscious sheep indicate that the renal fluid clearance might approach a normal rate when the adrenergic balance is modified.

    Methods

    Sixty females (mean age, 32 years) undergoing laparoscopic gynecological surgery were randomized to control group and received only the conventional anesthetic drugs and 20 ml/kg of lactated Ringer's over 30 mins. The others were also given an infusion of 50 μg/kg/min of esmolol (beta1-receptor blocker) or 0.01 μg/kg/min of phenylephrine (alpha1-adrenergic agonist) over 3 hours. The distribution and elimination of infused fluid were studied by volume kinetic analysis based on urinary excretion and blood hemoglobin level.

    Results

    Both drugs significantly increased urinary excretion while heart rate and arterial pressure remained largely unaffected. The urine flows during non-surgery were 43, 147, and 176 ml in the control, esmolol, and phenylephrine groups, respectively (medians, P < 0.03). When surgery had started the corresponding values were 34, 65 and 61 ml (P < 0.04). At 3 hours, averages of 9%, 20%, and 25% of the infused volume had been excreted in the three groups (P < 0.01). The kinetic analyses indicated that both treatments slowed down the distribution of fluid from the plasma to the interstitial fluid space, thereby preventing hypovolemia.

    Conclusions

    Esmolol doubled and phenylephrine almost tripled urinary excretion during anesthesia-induced depression of renal fluid clearance.

  • 63.
    Hult, Peter
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Fjällbrant, Tore
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Engdahl, O.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Ask, Per
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    An improved bioacoustic method for monitoring of respiration2004In: Technology and Health Care, ISSN 0928-7329, E-ISSN 1878-7401, Vol. 12, no 4, p. 323-332Article in journal (Refereed)
    Abstract [en]

    Reliable monitoring of respiration plays an important role in a broad spectrum of applications. Today, there are several methods for monitoring respiration, but none of them has proved to be satisfactory in all respects. We have recently developed a bioacoustic method that can accurately time respiration from tracheal sounds. The aim of this study is to tailor this bioacoustic method for monitoring purposes by introducing dedicated signal processing. The method was developed on a material of ten patients and then tested in another ten patients treated in an intensive care unit. By studying the differences in the variation of the spectral content between the different phases of respiration, the described method can distinguish between inspiration and expiration and can extract respiration frequency, and respiration pause periods. The system detected 98% of the inspirations and 99% of the expirations. This method for respiration monitoring has the advantage of being simple, robust and the sensor does not need to be placed closed to the face. A commercial heart microphone was used and we anticipate that further improvement in performance can be achieved trough optimization of sensor design.

  • 64.
    Hyllienmark, Lars
    et al.
    Department of Clinical Neurophysiology, Karolinska Hospital, Stockholm, Sweden.
    Golster, Helena
    Linköping University, Department of Neuroscience and Locomotion, Clinical Neurophysiology. Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Samuelsson, Ulf
    Linköping University, Department of Molecular and Clinical Medicine, Pediatrics. Linköping University, Faculty of Health Sciences.
    Ludvigsson, Johnny
    Linköping University, Department of Molecular and Clinical Medicine, Pediatrics. Linköping University, Faculty of Health Sciences.
    Nerve conduction defects are retarded by tight metabolic control in type I diabetes2001In: Muscle and Nerve, ISSN 0148-639X, E-ISSN 1097-4598, Vol. 24, no 2, p. 240-246Article in journal (Refereed)
    Abstract [en]

    This follow-up study examines whether the development of nerve dysfunction is retarded by tight metabolic control in patients with type I diabetes mellitus. Seventy-one patients and 115 age-matched healthy control subjects underwent studies of nerve conduction in peroneal and sural nerves. The presence of diabetes was associated with a reduction in peroneal motor nerve conduction velocity (MCV) by 5.9 m/s, sural sensory nerve conduction velocity (SCV) by 3.4 m/s, and sural sensory nerve action potential (SNAP) amplitude by 22%. Dysfunction in peroneal MCV, sural SCV, and sural SNAP were related to long-term poor metabolic control. Eleven of 12 patients with HbA1c <6.5% had normal nerve conduction or abnormality in only one nerve as compared to 2 of 15 patients with HbA1c >8.0%. It is concluded that tight long-term metabolic control (HbA1c <6.5%) can retard nerve dysfunction in patients with type I diabetes mellitus and a mean disease duration of 12 years.

  • 65.
    Jildenstal, Pether K
    et al.
    Örebro University Hospital .
    Hallen, Jan L
    Örebro University Hospital .
    Rawal, Narinder
    Örebro University Hospital .
    Gupta, Anil
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Berggren, Lars
    Örebro University Hospital .
    Effect of Auditory Evoked Potential-Guided Anaesthesia on Consumption of Anaesthetics and Early Postoperative Cognitive Dysfunction: a randomised controlled trial2011In: EUROPEAN JOURNAL OF ANAESTHESIOLOGY, ISSN 0265-0215, Vol. 28, no 3, p. 213-219Article in journal (Refereed)
    Abstract [en]

    Background Post-operative cognitive dysfunction (POCD) after non-cardiac surgery is a well known problem in some categories of patients. This study aims to evaluate the influence of auditory evoked potential (AEP)-guided anaesthesia on the requirement for anaesthetic drugs and their influence on POCD. Methods Four hundred and fifty patients aged between 18 and 92 years scheduled for ophthalmic surgery under general anaesthesia were assigned randomly to one of two groups. In group A (AEP group), the depth of anaesthesia (DoA) was aimed at an AEP index (AAI) between 15 and 25. In group C (control group), DoA was guided by clinical signs. Hypotension was treated with fluids and vasopressors using a standardised algorithm. A mini-mental test and the Cognitive Failure Questionnaire were used to evaluate cognitive function. Results Anaesthetic drug requirements were significantly lower in group A than in group C: propofol 92.5 +/- 26.5 vs. 103.8 +/- 39.5 mg (P = andlt;0.001) and desflurane end-tidal concentration 2.5 +/- 0.58 vs. 3.3 +/- 0.79% (P andlt; 0.001). In group A, 36 patients (16%) received additional fluids and vasopressors compared to 65 patients (29%) in group C (P andlt; 0.01). AAI values differed significantly between the groups: 18 (11-21) in group A vs. 12 (10-19) in group C (P andlt; 0.001). The number of patients with POCD was 16 in group C compared to two in group A (P andlt; 0.001) at day 1 post-operation. Conclusion AEP monitoring allows dose reduction of anaesthetic agents, leading to better cardiovascular stability and decreased requirements for intra-operative fluids and vasopressors. Cognitive decline seen following minor ophthalmic surgery, even when anaesthesia is assessed clinically, is short-lived with no long-term sequelae.

  • 66.
    Johansson, Robert
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Holmdahl, Johanna
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Rydell, Marie
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Rousseau, Andréas
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Andersson, Gerhard
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    An open study of the effectiveness of a tailored Internet-delivered cognitive behaviour therapy treatment for symptoms of depression and anxiety in a primary care setting2011Conference paper (Other academic)
  • 67.
    Johansson, Robert
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Sjöberg, Elin
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Sjögren, Magnus
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Johnsson, Erik
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Carlbring, Per
    Umeå University, Sweden .
    Andersson, Therese
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Rousseau, Andreas
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Andersson, Gerhard
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Tailored vs. Standardized Internet-Based Cognitive Behavior Therapy for Depression and Comorbid Symptoms: A Randomized Controlled Trial2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 5Article in journal (Refereed)
    Abstract [en]

    Background and Aims: Major depression can be treated by means of cognitive behavior therapy, delivered via the Internet as guided self-help. Individually tailored guided self-help treatments have shown promising results in the treatment of anxiety disorders. This randomized controlled trial tested the efficacy of an Internet-based individually tailored guided self-help treatment which specifically targeted depression with comorbid symptoms. The treatment was compared both to standardized (non-tailored) Internet-based treatment and to an active control group in the form of a monitored online discussion group. Both guided self-help treatments were based on cognitive behavior therapy and lasted for 10 weeks. The discussion group consisted of weekly discussion themes related to depression and the treatment of depression. Methods: A total of 121 participants with diagnosed major depressive disorder and with a range of comorbid symptoms were randomized to three groups. The tailored treatment consisted of a prescribed set of modules targeting depression as well as comorbid problems. The standardized treatment was a previously tested guided self-help program for depression. Results: From pre-treatment to post-treatment, both treatment groups improved on measures of depression, anxiety and quality of life. The results were maintained at a 6-month follow-up. Subgroup analyses showed that the tailored treatment was more effective than the standardized treatment among participants with higher levels of depression at baseline and more comorbidity, both in terms of reduction of depressive symptoms and on recovery rates. In the subgroup with lower baseline scores of depression, few differences were seen between treatments and the discussion group. Conclusions: This study shows that tailored Internet-based treatment for depression is effective and that addressing comorbidity by tailoring may be one way of making guided self-help treatments more effective than standardized approaches in the treatment of more severe depression.

  • 68.
    Johansson, Torsten
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine . Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Engquist, M.
    Department of Orthopaedic Surgery, Ryhov Central Hospital, Jönköping, Sweden.
    Pettersson, L.-G.
    Department of Orthopaedic Surgery, Kalmar Central Hospital, Kalmar, Sweden.
    Lisander, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Anesthesiology .
    Blood loss after total hip replacement: A prospective randomized study between wound compression and drainage2005In: The Journal of Arthroplasty, ISSN 0883-5403, E-ISSN 1532-8406, Vol. 20, no 8, p. 967-971Article in journal (Refereed)
    Abstract [en]

    A randomized, controlled study compared the effects of wound compression with drainage after primary total hip arthroplasty. In 51 patients, an inflatable cuff was placed over the wound underneath a girdle (System Calmed, Calmed AB, Askim, Sweden). Control patients had wound drainage (n = 54). Preoperative and intraoperative variables did not differ between groups. Total blood loss was calculated using hemoglobin balance, with compression it was 1510 ± 656 mL (mean ± SD) and in controls 1695 ± 712 mL (P = .13). However, less blood was transfused in the compression group (P = .05). Wound infection was seen in 2 patients with compression and in 3 controls. Deep venous thrombosis occurred in 3 controls. Wound discharge was more frequent in controls (19/54 vs 8/51, P = .04). Thus, wound compression had no obvious negative effects and reduced wound discharge and need for transfusion. It may replace drainage after total hip arthroplasty. © 2005 Elsevier Inc. All rights reserved.

  • 69.
    Johansson, Torsten
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Pettersson, L.-G.
    Department of Orthopedic Surgery, Kalmar Central Hospital, Kalmar, Sweden.
    Lisander, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Anesthesiology.
    Tranexamic acid in total hip arthroplasty saves blood and money: A randomized, double-blind study in 100 patients2005In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 76, no 3, p. 314-319Article in journal (Refereed)
    Abstract [en]

    Background: A blood transfusion is a costly transplantation of tissue that may endanger the health for the recipient. Blood transfusions are common after total hip arthroplasty. The total saving potential is substantial if the blood loss could be reduced. Studies on the use of tranexamic acid have shown interesting results, but its benefits in total hip arthroplasty have not yet been resolved. Patients and methods: 100 patients receiving a total hip arthroplasty (THA) got a single injection of tranexamic acid (15 mg/kg) or placebo intravenously before the start of the operation. The study was double-blind and randomized. Total blood loss was calculated from the hemoglobin (Hb) balance. Volume and Hb concentration of the drainage was measured 24 h after the operation. Intraoperative blood loss was estimated volumetrically and visually. Results: The patients who received tranexamic acid (TA) bled less. The total blood loss was on average 0.97 L in the TA group and 1.3 L in the placebo group (p < 0.001). 8/47 (0.2) in the TA group were given blood transfusion versus 23/53 (0.4) in the placebo group (p = 0.009). Drainage volume and drainage Hb concentration were less in the TA group (p < 0.001 and p = 0.001). No thromboembolic complications occurred. Interpretation: Considering the cost of blood and tranexamic acid only, use of the drug would save EUR 47 Euro per patient. We recommend a preoperative single dose of tranexamic acid for standard use in THA. Copyright © Taylor & Francis 2005.

  • 70.
    Kimme, Peter
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Fridriksson, Steen
    Linköping University, Department of Neuroscience and Locomotion, Neurosurgery. Linköping University, Faculty of Health Sciences.
    Engdahl, O.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Hillman, Jan
    Linköping University, Department of Neuroscience and Locomotion, Neurosurgery. Linköping University, Faculty of Health Sciences.
    Vegfors, Magnus
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Sjöberg, Folke
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Moderate hypothermia for 359 operations to clip cerebral aneurysms2004In: British Journal of Anaesthesia, ISSN 0007-0912, E-ISSN 1471-6771, Vol. 93, no 3, p. 343-347Article in journal (Refereed)
    Abstract [en]

    Background. Experimental data have suggested that hypothermia (32–34°C) may improve outcome after cerebral ischaemia, but its efficacy has not yet been established conclusively in humans. In this study we examined the feasibility and safety of deliberate moderate perioperative hypothermia during operations for subarachnoid aneurysms.

    Methods. A total of 359 operations for intracranial cerebral aneurysms were included in this prospective study. By using cold intravenous infusions (4°C) and convective cooling our aim was to reduce the patient's core temperature to more than 34°C within 1 h before operation. The protocol assessed postoperative complications such as infections, prolonged mechanical ventilation, pulmonary complications and coagulopathies.

    Results. During surgery, the body temperature was reduced to a mean of 32.5 (sd 0.4) °C. Cooling was accomplished at a rate of 4.0 (sd 0.4) °C h−1. All patients were normothermic at 5 (sd 2) h postoperatively. Peri/postoperative complications included circulatory instability (n=36, 10%), arrhythmias (n=17, 5%) coagulation abnormalities and blood transfusion (n=169, 47%), infections (n=29, 8%) and pulmonary complications (infiltrate or oedema while on ventilatory support) (n=97, 27%). Eighteen patients died within 30 days (5%). There was no significant correlation between the extent of hypothermia and any of the complications. However, there was a strong correlation between the occurrence of complications and the severity of the underlying neurological disease as assessed by the Hunt and Hess score.

    Conclusion. Moderate hypothermia accomplished within 1 h of induction of anaesthesia and maintained during surgery for subarachnoid aneurysms appears to be a safe method as far as the risks of peri/postoperative complications such as circulatory instability, coagulation abnormalities and infections are concerned.

  • 71.
    Kimme, Peter
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Gustafsson, U.
    Linköping University, Faculty of Health Sciences.
    Sollev, A.
    Department of Anaesthesiology, Karolinska Hospital, Stockholm, Sweden.
    Nilsson, G.
    Department of Biomedical Engineering, Linköping University, Sweden.
    Sjöberg, Folke
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Department of Biomedicine and Surgery, Plastic Surgery, Hand Surgery and Burns. Linköping University, Faculty of Health Sciences.
    Cerebral blood flow of the exposed brain surface measured by laser Doppler perfusion imaging1997In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 159, no 1, p. 15-22Article in journal (Refereed)
    Abstract [en]

    A novel application of laser Doppler flowmetry (LDF), laser Doppler perfusion imaging (LDPI), was used to study cerebral cortical blood flow (CBFcortex). In contrast to the conventional laser Doppler perfusion monitor, LDPI creates two-dimensional maps of the tissue perfusion in a well defined area of up to 120×120 mm comprising 4096 measurement points. Measurements of CBFcortex were made through an optically transparent polyester film applied to a cranial window preparation in ventilated anaesthetized pigs. Temporal and spatial heterogeneity in CBFcortex were visualized by LDPI during provocations which are known to alter CBF (varying arterial PCO2 or MABP, or infusion of adenosine at constant MABP (concomitant angiotensin administration) or by hyperoxemia). During hypercapnia the recorded CBFcortex increased homogeneously. The adenosine-mediated increase in recorded CBFcortex was concentrated on the lower flow interval, as was the hyperoxemia-caused decline. At decreasing MABP the autoregulatory threshold was found to vary locally within the cortex. The results suggest that LDPI, apart from detecting localized changes in CBFcortex, also visualizes flow changes within different vascular segments. Together with the practical advantages of the system, i.e. not necessitating direct contact with the tissues, this feature makes the technique suitable for studies of CBFcortex distributions.

  • 72.
    Kimme, Peter
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Jannsen, Bengt
    Västerviks Hospital, Västervik, Sweden.
    Ledin, Torbjörn
    Linköping University, Department of Neuroscience and Locomotion, Oto-Rhiono-Laryngology and Head & Neck Surgery. Linköping University, Faculty of Health Sciences.
    Gupta, Anil
    Örebro Hospital, Örebro, Sweden.
    Vegfors, Magnus
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    High incidence of pruritus after large doses of hydroxyethyl starch (HES) infusions2001In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 45, no 6, p. 686-689Article in journal (Refereed)
    Abstract [en]

    Background: There are several studies indicating a correlation between treatment with hydroxyethyl starch (HES) and pruritus. In order to see whether there is a possible dose–response relationship between HES and pruritus, we retrospectively studied 50 patients who had received HES in varying doses (cumulative dose 500–19500 ml) as hemodilution therapy after subarachnoid hemorrhage.

    Methods: Of 50 consecutive patients, 6 were excluded due to severe neurological sequelae. A questionnaire was sent to the remaining 44 patients at 6 months (5–12 months) median (range) after the end of HES treatment.

    Results: We received answers from 37 patients, of whom 54% reported pruritus. On average pruritus lasted for 15 weeks. There was significantly more pruritus in patients who received more than 5000 ml of HES versus those who received less than 5000 ml (P=0.023). Pruritus had a delayed onset and appeared as pruritic crises lasting for 2–30 min. It had a patchy distribution in most patients and no predilected locations. In 4 patients (20%) the pruritus lasted longer than 21 weeks.

    Conclusion: Our study indicates that there is a dose-dependency for the incidence of HES-induced pruritus, and that in some cases the pruritus may be severe and long-lasting.

  • 73.
    Kimme, Peter
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Ledin, Torbjörn
    Linköping University, Department of Neuroscience and Locomotion, Oto-Rhiono-Laryngology and Head & Neck Surgery. Linköping University, Faculty of Health Sciences.
    Sjöberg, Folke
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Department of Biomedicine and Surgery, Plastic Surgery, Hand Surgery and Burns. Linköping University, Faculty of Health Sciences.
    Cortical blood flow autoregulation revisited using laser Doppler perfusion imaging2002In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 176, no 4, p. 255-262Article in journal (Refereed)
    Abstract [en]

    Methods of laser Doppler perfusion monitoring (LDPM) and imaging (LDPI) have been validated and found useful for measurements of brain blood flow in several studies. The present work was undertaken to examine the cortical blood flow autoregulatory phenomenon as it has lately been questioned and claimed to be method-dependent and related to sample volume. Spatial variations in cerebral cortical blood flow (CBFcortex) in the pressure range 20–140 mmHg (static cerebral autoregulation; caval block/angiotensin infusion) were studied in six mechanically ventilated (hypocapnic, normocapnic and hypercapnic) pigs anaesthetized with propofol and fentanyl. Although the cortical blood flow values sampled were highly heterogeneously distributed, they were strongly pressure-dependent as well as CO2-dependent (P < 0.001). A cumulative cerebral blood flow (CBF)–pressure (MAP) plot comprising all values obtained indicated a pressure range between 70 and 120 mmHg where CBF remained almost constant. However, at the local level in the cortex (mm2) the same type of ‘classic’ autoregulatory flow : pressure graphs (FPG) were found in only a few of the cases of the cortical areas examined (n = 96). Alterations in blood PaCO2 saturation did not affect the pressure : flow relationship at low perfusion pressures, whereas at normal or above normal values, and as anticipated, hypercapnia considerably increased CBF (P < 0.001). ‘Classic’ autoregulatory FPGs were found only when all values sampled were clustered together, whereas, as a new finding, data are presented indicating that autoregulatory capacity is lacking at the local level at some cortical surface areas.

  • 74.
    Kimme, Peter
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Ledin, Torbjörn
    Linköping University, Department of Neuroscience and Locomotion, Oto-Rhiono-Laryngology and Head & Neck Surgery. Linköping University, Faculty of Health Sciences.
    Sjöberg, Folke
    Linköping University, Department of Biomedicine and Surgery, Plastic Surgery, Hand Surgery and Burns. Linköping University, Faculty of Health Sciences.
    Dose effect of sevoflurane and isoflurane anesthetics on cortical blood flow during controlled hypotension in the pig2007In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 51, no 5, p. 607-613Article in journal (Refereed)
    Abstract [en]

    Background:  The ability of the brain to preserve adequate cerebral blood flow (CBF) during alterations in systemic perfusion pressure is of fundamental importance. At increasing concentrations, isoflurane and sevoflurane have been known to alter CBF, which may be disadvantageous for patients with increased intracranial pressure. The aim was to examine the effects of isoflurane and sevoflurane at increasing minimum alveolar concentrations (MAC) on CBF, during controlled hypotension.

    Methods:  We studied eight pigs during variations in perfusion pressure induced by caval block (100, 60, 50, and 40 mmHg) under normocapnia. CBF was measured locally in a defined area (4 × 5 measurement points covering 1 cm2) of the motor cortex using laser Doppler perfusion imaging. Physiological variables, assessed by analysis of arterial O2 and CO2, hemoglobin and hematocrit, were controlled. CBF was measured during propofol (10 mg × kg−1× h−1) and fentanyl (0.002 mg × kg−1× h−1) anesthesia, and then during anesthesia with either isoflurane or sevoflurane (given in random order) at increasing MAC (0.3–1.2). After a washout period, the measurements were repeated with the other gas.

    Results:  CBF was significantly higher in the cortex during normotensive (control) settings, MAP ∼100 mmHg, compared with during hypotension (MAP 40–60 mmHg). Neither different anesthetic nor MAC or local measurement sites were found to influence CBF at any perfusion pressure.

    Conclusion:  In this experimental model, the effect of hypotension on CBF was not altered by the anesthetics used [isoflurane, sevoflurane (MAC 0.3–1.2) or propofol (10 mg × kg−1× h−1)]. In this aspect (cortical tissue perspective), these volatile agents appear as suitable as propofol for neurosurgical anesthesia for patients at risk.

  • 75.
    Kjölhede, Preben
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    Borendal Wodlin, Ninnie
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Nilsson, Lena
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    Fredrikson, Mats
    Linköping University, Department of Clinical and Experimental Medicine, Occupational and Environmental Medicine. Linköping University, Faculty of Health Sciences.
    Wijma, Klaas
    Linköping University, Department of Clinical and Experimental Medicine, Gender and medicine. Linköping University, Faculty of Health Sciences.
    Impact of stress coping capacity on recovery from abdominal hysterectomy in a fast-track programme: a prospective longitudinal study2012In: British Journal of Obstetrics and Gynecology, ISSN 1470-0328, E-ISSN 1471-0528, Vol. 119, no 8, p. 998-1007Article in journal (Refereed)
    Abstract [en]

    Objective To evaluate the effect of stress coping capacity in combination with mode of anaesthesia on postoperative recovery in fast-track abdominal hysterectomy. Design Prospective longitudinal study. Setting Five hospitals in the south-east of Sweden. Population A cohort of 162 women undergoing fast-track abdominal hysterectomy for benign conditions. Methods Self-administered questionnaires, the Stress Coping Inventory (SCI) and the Swedish Postoperative Symptom Questionnaire (SPSQ), and clinical information were collected prospectively. Stress coping capacity was categorised as high or low according to the summed score of the SCI. Comparisons of effect variables were adjusted using a propensity score-matching model. Main outcome measures Associations between stress coping capacity and hospital stay, sick leave, use of analgesic and self-reported postoperative symptoms. Results Women with high stress coping capacity had a significantly shorter sick leave, experienced postoperative symptoms significantly less often, and with lower intensity, than women with low stress coping capacity. With the exception of symptom intensity, these findings were related to having had the operation under spinal anaesthesia as opposed to general anaesthesia. Hospital stay, use of analgesics and abdominal pain were not related to stress coping capacity. Conclusions In patients for whom spinal anaesthesia was applied, high stress coping seems to be a quality that helps patients manage the burden of surgery. It is desirable for the individual, as well as for the healthcare system, to enhance recovery by using intervention programmes designed to improve or manage stress coping, particularly for individuals with low stress coping capacity. This recommendation merits further investigation.

  • 76.
    Kjölhede, Preben
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    Langström, Petra
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    Nilsson, Pernilla
    Östergötlands Läns Landsting, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping. Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences.
    Borendal Wodlin, Ninnie
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Nilsson, Lena
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    Quality of sleep the night after surgery, does it matter? A prospective cohort study of women undergoing fast track abdominal hysterectomy in ACTA OBSTETRICIA ET GYNECOLOGICA SCANDINAVICA, vol 91, issue SI, pp 18-182012In: ACTA OBSTETRICIA ET GYNECOLOGICA SCANDINAVICA, Informa Healthcare / Wiley-Blackwell , 2012, Vol. 91, no SI, p. 18-18Conference paper (Refereed)
    Abstract [en]

    n/a

  • 77.
    Kjölhede, Preben
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    Langström, Petra
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences.
    Nilsson, Pernilla
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences.
    Borendal Wodlin, Ninnie
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Nilsson, Lena
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    The Impact of Quality of Sleep on Recovery from Fast-Track Abdominal Hysterectomy2012In: Journal of Clinical Sleep Medicine (JCSM), ISSN 1550-9389, E-ISSN 1550-9397, Vol. 8, no 4, p. 395-402Article in journal (Refereed)
    Abstract [en]

    Study Objectives: To examine the impact of mode of anesthesia on perceived quality of sleep and to analyze the perceived quality of sleep in affecting recovery from surgery. less thanbrgreater than less thanbrgreater thanMethods: A randomized, controlled, open multicenter trial was conducted in 5 hospitals in Southeast Sweden. One-hundred eighty women scheduled for fast-track abdominal hysterectomy for benign conditions were randomized to spinal anesthesia or general anesthesia; 162 women completed the trial; 82 allocated to spinal anesthesia and 80 to general anesthesia. Symptoms and perceived quality of sleep after surgery were registered daily in the Swedish Postoperative Symptoms Questionnaire. less thanbrgreater than less thanbrgreater thanResults: Women in the general anesthesia group experienced bad quality of sleep the night after surgery significantly more often than the women who had spinal anesthesia (odds ratio [OR] 2.45; p = 0.03). This was almost exclusively attributed to a significantly higher consumption of opioids postoperatively in the general anesthesia group. Risk factors for bad quality of sleep during the first night postoperatively were: opioids (OR 1.07; p = 0.03); rescue antiemetics (OR 2.45; p = 0.05); relative weight gain (OR 1.47; p = 0.04); summary score of postoperative symptoms (OR 1.13; p = 0.02); and stress coping capacity (OR 0.98; p = 0.01). A longer hospital stay was strongly associated with a poorer quality of sleep the first night postoperatively (p = 0.002). less thanbrgreater than less thanbrgreater thanConclusions: The quality of sleep the first night after abdominal hysterectomy is an important factor for recovery. In fast-track abdominal hysterectomy, it seems important to use anesthesia and multimodal analgesia reducing the need for opioids postoperatively and to use strategies that diminish other factors that may interfere negatively with sleep. Efforts to enhance quality of sleep postoperatively by means of preventive measures and treatment of sleep disturbances should be included in fast-track programs.

  • 78.
    Källström, Reidar
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Surgery . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Urology in Östergötland.
    Rousseau, Andreas
    Linköping University, Department of Medicine and Health Sciences, Anesthesiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Bengtsson, Andreas
    Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Hjertberg, Hans
    Linköping University, Department of Clinical and Experimental Medicine, Surgery . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Urology in Östergötland.
    Svanvik, Joar
    Linköping University, Department of Clinical and Experimental Medicine, Surgery . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Simulator performance, psychometrics and personality testing guiding the choice of clinical disciplineManuscript (preprint) (Other academic)
    Abstract [en]

    The complexity of surgical training has increased and surgery put high demands on personal abilities that cannot be met by all even after training. Selection of personnel is critical to many professions, including surgery, but the selection procedure of surgical apprenticeship is not well developed. It would be of value to get an early assessment of important personal features like the ability to learn complex procedures. Further, individuals learn in different ways and the personality may influence this ability. Other important aspects are visuospatial abilities, working memory and executive functioning. These variables are measured in the present study by: learning curves in a TURP VR-simulator, scores from the personality test TCI-R, Rey complex figure and recognition trial, Tower of London (dx) and tests from WAISIII.

    Twenty-four residents in urology performed three real TUR-P procedures and their performances were analyzed with OSATS and video-recordings. The learning curves from the OR were compared with the results from the simulation practice, personality tests and psychometrics using multiple linear regression. The findings from personality and psychometric data were also compared with the general population to see if there are any indications of a “surgical personality”. The urology residents in this sample have a welldeveloped character (effective, mature, reliable, goal-oriented, empathetic, tolerant, supportive, cooperative) and with high reward dependence (tender-hearted, dedicated, sociable) together with better executive planning abilities and better verbal working memory than normal.

    The connections between the operation learning curves and the variables above indicate that a better learning score is associated with a good learning score in a simulated environment, goal-directedness, a high level of impulse control, anticipation of harmful events and responsibility, a balanced attachment style and a good visual spatial memory.

  • 79.
    Lennmarken, Claes
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Anesthesiology . Östergötlands Läns Landsting, Anaesthesiology and Surgical Centre, Department of Intensive Care UHL.
    Sandin, R
    Neuromonitoring for awareness during surgery2004In: The Lancet, ISSN 0140-6736, E-ISSN 1474-547X, Vol. 363, no 9423, p. 1747-1748Other (Other academic)
  • 80.
    Lindfors, Sara
    et al.
    Karolinska Institutet.
    Eintrei, Christina
    Linköping University, Department of Medicine and Health Sciences, Anesthesiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthesiology and Surgical Centre, Department of Intensive Care UHL.
    Alexanderson, Kristina
    Karolinska Institutet.
    Stress factors affecting academic physicians at a university hospital.2009In: Work (Reading, Mass.), ISSN 1875-9270, Vol. 34, no 3, p. 305-13Article in journal (Refereed)
    Abstract [en]

    Research is limited regarding occupational stress in academic physicians; professionals whose work situation includes the three areas of clinical practice, research, and teaching. The aim of this study was to gain knowledge of factors experienced as stressful by academic physicians employed by a university hospital. A questionnaire assessing the frequency and intensity of 36 potentially stressful factors was sent to all 157 academic physicians who were employed at the Linköping University Hospital, Sweden. The response rate was 77%. Both a high frequency and intensity of stress was experienced by 66% of the academic physicians in relation to "time pressure" and by almost 50% in connection with both "find time for research" and having "conflict of interest between different work assignments". Moreover, physicians in the higher age group and those who had attained a higher academic position experienced less stress. The female participants experienced more stress than the males due to gender-related problems and to variables associated with relationships at work. More knowledge is needed to determine the consequences of this finding and to identify coping strategies used for handling such stress.

  • 81.
    Lindgren, Margareta
    et al.
    Linköping University, Department of Medicine and Care, Nursing Science. Linköping University, Faculty of Health Sciences.
    Malmqvist, Lars-Åke
    Linköping University, Department of Medicine and Care, Nursing Science. Linköping University, Faculty of Health Sciences.
    Sjöberg, Folke
    Linköping University, Department of Biomedicine and Surgery, Plastic Surgery, Hand Surgery and Burns. Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Ek, Anna-Christina
    Linköping University, Department of Medicine and Care, Nursing Science. Linköping University, Faculty of Health Sciences.
    Altered skin blood perfusion in areas with non blanchable erythema: an explorative study2006In: International Wound Journal, ISSN 1742-4801, E-ISSN 1742-481X, Vol. 3, no 3, p. 215-223Article in journal (Refereed)
    Abstract [en]

    Non blanchable erythema, i.e. stage I pressure ulcer, is common in patients in acute and geriatric care and in nursing homes. Research has shown that this type of lesions is prone to develop into more severe pressure ulcers. The peripheral skin blood perfusion is of major importance for the development of pressure ulcers. The aim of this study was to explore the peripheral skin blood perfusion over time, in areas with non blanchable erythema and in corresponding undamaged areas on the opposite side of the body. A total of 19 measurements were performed, over time, using a laser Doppler perfusion imager. The blood flow distribution profiles over areas with non blanchable erythema and undamaged skin were found to be different. As the area of the non blanchable erythema decreased, the blood perfusion distribution profiles gradually became more heterogeneous; an area of high blood perfusion in the centre of the lesions was seen and the perfusion successively decreased closer to the edge. These results indicate that there are differences in blood perfusion between skin areas of non blanchable erythema and undamaged skin. The results also indicate that the visible redness in areas with non blanchable erythema is related to altered blood perfusion. The skin blood perfusion also seems to increase in relation to the size of the non blanchable erythema.

  • 82.
    Lindholm, Maj-Lis
    et al.
    Karolinska Institute.
    Traff, Stefan
    Östergötlands Läns Landsting, Anaesthesiology and Surgical Centre, Department of Anaesthesiology and Intensive Care VHN.
    Granath, Fredrik
    Karolinska Institute.
    Greenwald, Scott D
    Aspect Medical Systems.
    Ekbom, Anders
    Karolinska Institute.
    Lennmarken, Claes
    Linköping University, Department of Medicine and Health Sciences, Anesthesiology . Linköping University, Faculty of Health Sciences.
    Sandin, Rolf H
    Karolinska Institute.
    Mortality Within 2 Years After Surgery in Relation to Low Intraoperative Bispectral Index Values and Preexisting Malignant Disease2009In: ANESTHESIA AND ANALGESIA, ISSN 0003-2999, Vol. 108, no 2, p. 508-512Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: A correlation between deep anesthesia (defined as time with Bispectral Index (BIS) &lt;45; T-BIS &lt;45 and death within 1. yr after surgery has previously been reported. In order to confirm or refute these findings, we evaluated T-BIS (&lt;45) as an independent risk factor for death within I and 2 yr after surgery and also the impact of malignancy, the predominant cause of death in the previous report.

    METHODS: Mortality within 2 yr after surgery, causes of death and the occurrence of malignant disease at the time of surgery were identified in a cohort of 4087 BIS-monitored patients. Statistically significant univariate predictors of mortality were identified. In order to allow for comparison with previous data, the following multivariate analysis was first done without, and thereafter with, preexisting malignancy status, the predominant cause of death.

    RESULTS: One-hundred-seventy-four (4.3%) patients died within I yr and another 92 during the second year (totaling 6.5% in 2 yr). T-BIS &lt;45 was a significant predictor of 1- and 2-yr mortality when preexisting malignant disease was not among the co-variates (hazard ratio [HR] 113 [1.01-1.27] and 1.18 [1.08-1.29], respectively). Further exploration confined the significant relation between postoperative mortality and T-BIS &lt;45 to Patients with preexisting malignant diagnoses associated with extensive Surgery and less favorable prognosis. The most powerful predictors of 2-yr mortality in the model, including preexisting malignancy, were ASA physical score class IV (HR 19.3 [7.31-51.1]), age &gt;80 yr (HR 2.93 [1.79-4.79]), and preexisting malignancy associated with less favorable prognosis (HR 9.30 [6.60-13.1]). When the initial multivariate regression was repeated using preexisting malignancy status among the co-variates in the model, the previously significant relation between 1, and 2-yr mortality and T-BIS &lt;45 did not reach statistical significance.

    CONCLUSION: Using a similar set of co-variates as in previous work, we confirmed the statistical relation between 1-yr mortality and T-BIS &lt;45, and we extended this observation to 2-yr mortality. However, this relation is sensitive to the selection of co-variates in the statistical model, and a randomized study is required to demonstrate that there really is a causal impact from and T-BIS (&lt;45) on postoperative mortality and, if it does, the effect is probably very weak in comparison with co-morbidity as assessed by ASA physical score, the preexisting malignancy status at surgery and age.

  • 83.
    Lindén, Maria
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Health Sciences.
    Golster, Helena
    Linköping University, Department of Biomedicine and Surgery, Plastic Surgery, Hand Surgery and Burns. Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Bertuglia, Silvia
    CNR Institute of Clinical Physiology, Via Trieste, Pisa, Italy.
    Colantuoni, Antonio
    CNR Institute of Clinical Physiology, Via Trieste, Pisa, Italy.
    Sjöberg, Folke
    Linköping University, Department of Biomedicine and Surgery, Plastic Surgery, Hand Surgery and Burns. Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Nilsson, Gert
    Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Health Sciences.
    Evaluation of Enhanced High-Resolution Laser Doppler Imaging in an in Vitro Tube Model with the Aim of Assessing Blood Flow in Separate Microvessels1998In: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 56, no 3, p. 261-270Article in journal (Refereed)
    Abstract [en]

    An enhanced high-resolution laser Doppler imaging (EHR-LDI) technique intended for visualization of separate microvessels was evaluated by use ofin vitroflow models. In EHR-LDI, a laser beam focused to a half-power diameter less than 40 μm successively scans the tissue under study in steps of 25 μm. Spatial blood flow variations within microvascular structures of 1.5 × 1.5 mm are rendered by 64 × 64 measurement sites. Individual microvessel diameters could be estimated and an average difference of 11 μm compared to microscopic measurements was obtained. For the flow algorithm used, the LDI output signal was found to scale linearly with average velocity (0–3.5 mm/s) when a plastic tube of inner diameter 175 μm was perfused with human blood (correlation coefficient 0.99). The LDI output signal was further found insensitive to hematocrit variations in the range 16–44%. Due to the limited laser light penetration in blood, a reduction in the LDI output signal was observed as the inner tube diameters were successively changed from 280 to 1400 μm.

  • 84.
    Lisander, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Anesthesiology .
    Hahn, R
    Linkoping Univ Hosp, Dept Anesthesia, S-58185 Linkoping, Sweden Karolinska Inst, Stockholm, Sweden.
    Hemostasis in patients of different ABO blood groups2002In: Anesthesia and Analgesia, ISSN 0003-2999, E-ISSN 1526-7598, Vol. 95, no 1, p. 254-255Other (Other academic)
  • 85.
    Ljunggren, Stefan
    et al.
    Södertalje Hospital, Sweden Karolinska Institute, Sweden.
    Hahn, Robert G
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Oral nutrition or water loading before hip replacement surgery; a randomized clinical trial2012In: Trials, ISSN 1745-6215, E-ISSN 1745-6215, Vol. 13, no 97Article in journal (Refereed)
    Abstract [en]

    Background

    Surgery induces insulin resistance that might be alleviated by a nutritional drink given preoperatively. The authors hypothesized that some of the beneficial effects of the drink could be attributed to the volume component (approximately 1 L) rather than to the nutrients.

    Methods

    Sixty patients scheduled for elective total hip replacement under spinal anesthesia were recruited to a clinical trial, and randomly allocated to preoperative fasting, to oral ingestion of tap water, or to oral ingestion of a carbohydrate drink. An intravenous glucose tolerance test calculated glucose clearance and insulin sensitivity on the day before surgery, in the postoperative ward, and on the day after surgery. Other parameters were stress (cortisol in plasma and urine), muscle catabolism (urinary 3-methylhistidine), and wellbeing.

    Results

    Fifty-seven patients completed the study. In the postoperative ward, the glucose clearance and the insulin response had decreased from the previous day by 23% and 36%, respectively. Insulin sensitivity did not decrease until the next morning (−48%) and was due to an increased insulin response (+51%). Cortisol excretion was highest on the day of surgery, while 3-methylhistidine increased 1 day later. Follow-up on the third postoperative day showed an average of 1.5 complications per patient. Wellbeing was better 2 weeks after than before the surgery. None of the measured parameters differed significantly between the study groups.

    Conclusions

    Preoperative ingestion of tap water or a nutritional drink had no statistically significant effect on glucose clearance, insulin sensitivity, postoperative complications, or wellbeing in patients undergoing elective hip surgery.

  • 86.
    Marion, E K
    et al.
    Karolinska Institute, Department of Clinical Science and Education, Department of Obstetrics and Gynecology, Södersjukhuset, Stockholm, Sweden.
    Hansen, Krystyna
    Karolinska Institute, Department of Clinical Science and Education, Department of Obstetrics and Gynecology, Södersjukhuset, Stockholm, Sweden.
    Tegerstedt, Gunilla E
    Karolinska Institute, Department of Clinical Science and Education, Department of Obstetrics and Gynecology, Södersjukhuset, Stockholm, Sweden.
    Svensen, Christer H.
    Head, Research and Education, Karolinska Institute, Department of Clinical Science and Education, Section of Anesthesiology and Intensive Care, Södersjukhuset, Stockholm, Sweden.
    Andrijauskas, Andrius
    Vilnius University Hospital, Section of Anaesthesiology and Intensive Care.
    Drobin, Dan
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Surgery.
    Spinal blocks with and without morphine in women undergoing hysterectomies: a randomized study2010In: Sri Lankan Journal of Anaesthesiology, ISSN 1391-8834, Vol. 18, no 1, p. 23-28Article in journal (Refereed)
    Abstract [en]

    Objective: To study whether a group of patients going through abdominal hysterectomies under general anesthesia could reduce their time of discharge and consumption of parenteral opioids by adding morphine to an intrathecal block. Methods: Sixty seven healthy women, undergoing abdominal hysterectomies. Patients had general anesthesia in combination with spinal blocks. Randomization between intrathecal blocks with morphine (group 1) and without morphine (group 2), in combination with either postoperative intermittent (group 1) or patient controlled analgesia (group 2). Results: The median time to discharge in group 1 was 53 hours and in group two 69 hours. Time of discharge was not statistically significant (p = 0.51). The patients in group 2 had significantly higher visual analogue scores for pain postoperatively. More postoperative opioids were also consumed in that group (p Conclusion: In summary, we conclude that intrathecal block with morphine in combination with postoperative nurse administered opioids did not show a difference in time to discharge compared to intratechal block without morphine in combination with PCA. However, there was a significant reduction in the level of pain and nausea as well as consumption of postoperative opioids. Based on the questionnaire, significantly more patients suffered from major nausea in the group without intrathecal morphine.

  • 87.
    Metcalf, Kerstin
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Berg, Anna
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Ericson, Ann-Charlott
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Lisander, Björn
    Linköping University, Department of Medicine and Care, Anaesthesiology. Linköping University, Faculty of Health Sciences.
    Nitric oxide does not cause extravasation in endotoxemic rats2005In: Journal of Trauma, ISSN 0022-5282, E-ISSN 1529-8809, Vol. 58, no 5, p. 1047-1054Article in journal (Refereed)
    Abstract [en]

    Background: Nitric oxide (NO) formed from inducible NO synthase (iNOS) is assumed to promote vascular permeability in sepsis and endotoxemia.

    Methods: Thirty-seven anesthetized rats were examined for the effects of endotoxin. After randomization, 17 animals had lipopolysaccharide (LPS) administered and 20 rats served as controls and were given the corresponding volume of saline. The observation period was 5 hours after administration of endotoxin. Mean arterial blood pressure, heart rate, and hematocrit were recorded in all animals, and transcapillary exchange of albumin, tissue water content, immunohistochemistry for nitric oxide synthase, and blood gases were investigated in subsets of animals.

    Results: When anesthetized rats were studied for 5 hours after endotoxin (LPS), the sequestration of albumin decreased in the intestine (double-isotope method) and there was no increased water content (freeze-drying technique) when the elevated tissue plasma volume of the LPS-treated rats was corrected for. Immunohistochemical methods showed a similar distribution and intensity of staining for endothelial NOS and neuronal NOS in LPS and control groups. In the lung of the LPS-treated rats, there was a significantly larger number of infiltrating, inflammatory cells staining for iNOS. There was no iNOS demonstrated in vascular structures or heart.

    Conclusion: At 5 hours after LPS, there was no increased loss of water or albumin from the circulation. This challenges the notion that NO causes vascular damage in endotoxemia and extravasation as an obligatory sequela to endotoxemia.

  • 88.
    Metcalf, Kerstin
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Jungersten, L.
    Department of Clinical Pharmacology, Sahlgrenska University Hospital, Sweden.
    Lisander, Björn
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Effective inhibition of nitric oxide production by aminoguanidine does not reverse hypotension in endotoxaemic rats2002In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 46, no 1, p. 17-23Article in journal (Refereed)
    Abstract [en]

    Background: Excess production of nitric oxide (NO) by the inducible NO synthase (iNOS) has been implicated in the pathophysiology of septic shock. Using methaemoglobin (metHb) and the stable NO metabolite nitrate as markers of NO formation, we assessed the effect of iNOS blockade by aminoguanidine (AG) on hypotension and NO formation in endotoxaemic rats.

    Methods: In 32 male Wistar rats under chloralose anaesthesia, MetHb (at 15 and 330 min, respectively) and plasma nitrate (at 330 min) were determined. Mean arterial pressure, heart rate and haematocrit were monitored. The LPS group (n=8) received bacterial endotoxin (LPS), 3 mg kg−1 i.v. and was subsequently monitored for 5 h. At 2 h after LPS, the LPS+AG20 group (n=8) received AG, 5 mg kg−1, and 5 mg kg−1 h−1 for the remaining 3 h. The LPS+AG100 group (n=8) instead received 25 mg kg−1, followed by 25 mg kg−1 h−1. The NaCl group (n=8) was given corresponding volumes of isotonic saline.

    Results: AG decreased the LPS-induced rise in plasma nitrate by about 50% in the LPS+AG20 group. MetHb levels, however, were not appreciably reduced by this dose. Both NO metabolites reached control levels after the higher dose of AG. LPS caused a progressive decrease in haematocrit. AG did not influence the LPS-induced hypotension, tachycardia or haemodilution.

    Conclusion: AG inhibited NO formation in a dose-dependent way. Yet, AG had no haemodynamic effects, suggesting a minor cardiovascular influence of iNOS in this endotoxin model, in parallel to what has been found in microbial sepsis.

  • 89.
    Metcalf, Kerstin
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Lisander, Björn
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Aminoguanidine does not influence tissue extravasation of albumin in endotoxaemic rats2001In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 45, no 1, p. 112-118Article in journal (Refereed)
    Abstract [en]

    Background: It is generally maintained that protein and fluid are lost from the circulation under septic conditions. The role played by an increased production of nitric oxide, by the inducible nitric oxide synthase (iNOS), in this process is unclear.

    Methods: Chloralose anaesthetised male Wistar rats received E. coli lipopolysaccharide (LPS), 3 mg kg−1 i.v., and were studied for 5 h. Mean arterial pressure (MAP) and heart rate (HR) were monitored and haematocrit (Hct) was determined intermittently. Tissue plasma volume and tissue clearances of radiolabelled albumin over the last 2 h of the experiment were determined by a double-isotope method. In 8 rats, 2 h after LPS, aminoguanidine, an iNOS selective blocker, was given i.v. at a dose of 5 mg kg−1. This was followed by a continuous infusion for the duration of the experiment; altogether 20 mg kg−1 was administered. In the control group (n=8), a corresponding volume of saline was infused.

    Results: Aminoguanidine did not significantly influence Hct, MAP and HR, as evidenced by inter-group comparisons (Mann-Whitney test). Tissue plasma clearances of albumin and tissue plasma volume were similar in both groups.

    Conclusion: Aminoguanidine at 20 mg kg−1 did not reverse the haemodynamic changes induced by LPS. Neither did the drug affect the tissue plasma clearance of albumin or the tissue plasma volume.

  • 90.
    Metcalf, Kerstin
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Sundkvist, T.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lisander, Björn
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Intravenous endotoxin does not increase tissue extravasation of albumin in rats1998In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 42, no 8, p. 966-973Article in journal (Refereed)
    Abstract [en]

    Background: It is unclear whether activation of the inducible nitric oxide synthase (iNOS) increases or decreases the extravasation of plasma.

    Methods: Chloralose anaesthetised male Wistar rats received E. coli lipopolysacharide (LPS), 3 mg kg-1 i.v., or the corresponding volume of saline, 3 or 5 h before the end of the experiment. Mean arterial pressure (MAP) and heart rate (HR) were recorded. Tissue clearance of radio-labelled albumin, during the last 2 h of each experiment, was determined by a double-isotope method. In separate animals, the serum concentration of nitrite and nitrate was determined, 5 h after LPS or the solvent.

    Main Results: LPS initially decreased MAP and lastingly increased HR. In the 3-h LPS animals (n=8), tissue plasma clearance was lower in the heart and calf muscle and increased only in diaphragm, compared to corresponding control animals (n=8). In the 5-h LPS rats, clearance was lowered (n=8) in the entire gastrointestinal tract and in testes, compared to controls (n=8). The serum nitrite/nitrate concentration was higher in animals given LPS (n=6) than in controls (n=6).

    Conclusion: After LPS, tissue clearance of albumin was not increased in any major tissue, in spite of increased serum levels of NO end products. Apparently, after activation of iNOS, the augmented release of NO is not necessarily associated with increased albumin extravasation.

  • 91.
    Meunier, Andreas
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Lisander, Björn
    Linköping University, Department of Medicine and Health Sciences, Anesthesiology . Linköping University, Faculty of Health Sciences.
    Good, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine . Linköping University, Faculty of Health Sciences.
    Effects of celecoxib on blood loss, pain, and recovery of function after total knee replacement: A randomized placebo-controlled trial2007In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 78, no 5, p. 661-667Article in journal (Refereed)
    Abstract [en]

    Background: Pain management after surgery has been used as a sales argument for the use of COX-2 inhibitors, but their potential positive and negative effects have not been fully investigated. We thus conducted a controlled evaluation of the effect of celecoxib on perioperative blood loss, pain relief and consumption of analgesics, range of motion, and subjective outcome in conjunction with total knee replacement (TKR).

    Method: 50 patients were randomized to either placebo or celecoxib (200 mg) preoperatively and then twice daily. Total blood loss was calculated by the Hb balance method, taking the patient's pre- and postoperative hemoglobin and blood volume into account. Pain scores (VAS), range of motion, and subjective outcome (KOOS) were monitored postoperatively and during the first year after surgery.

    Results: No differences in total, hidden, or drainage blood loss were found between the groups. There were 30% lower pain scores during the first 4 weeks after surgery and lower morphine consumption after surgery in the celecoxib group, while no effect was seen on pain, range of motion, and subjective outcome at the 1 year follow-up.

    Interpretation: Celecoxib does not increase perioperative blood loss but reduces pain during the postoperative period after TKR. It is not necessary to discontinue celecoxib before surgery. The postoperative use of celecoxib did not increase range of motion or subjective outcome 1 year after TKR.

  • 92.
    Naredi, S.
    et al.
    Dept. Anaesthesia and Intensive Care.
    Koskinen, L.-O.
    Department of Neurosurgery, Umeå University Hospital, Sweden.
    Grande, P.-O.
    Grände, P.-O., Dept. Anaesthesia and Intensive Care.
    Nordstrom, C.-H.
    Nordström, C.-H., Department of Neurosurgery, Lund University Hospital, Sweden.
    Nellgard, B.
    Nellgård, B., Dept. Anaesthesia and Intensive Care.
    Rydenhag, B.
    Department of Neurosurgery, Shalgrens University Hospital, Gothenbourg, Sweden.
    Vegfors, Magnus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Anesthesiology . Östergötlands Läns Landsting, Anaesthesiology and Surgical Centre, Department of Anaesthesiology and Intensive Care VHN.
    Treatment of Traumatic Head Injury - U.S./European Guidelines or the Lund Concept [1]2003In: Critical Care Medicine, ISSN 0090-3493, E-ISSN 1530-0293, Vol. 31, no 11, p. 2713-2714Other (Other academic)
    Abstract [en]

    [No abstract available]

  • 93.
    Nilsson, Andreas
    et al.
    Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL. Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Kalman, Sigga
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Intensive Care VHN.
    Arvidsson, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Plastic Surgery, Hand surgery UHL.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Plastic Surgery, Hand surgery UHL. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Difficulties in Controlling Mobilization Pain Using a Standardized Patient-Controlled Analgesia Protocol in Burns2011In: JOURNAL OF BURN CARE and RESEARCH, ISSN 1559-047X, Vol. 32, no 1, p. 166-171Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to evaluate pain relief for patients with burns during rest and mobilization with morphine according to a standard protocol for patient-controlled analgesia (PCA). Eighteen patients with a mean (SD) burned TBSA% of 26 (20) were studied for 10 days. Using a numeric rating scale (NRS, 0 = no pain and 10 = unbearable pain), patients were asked to estimate their acceptable and worst experienced pain by specifying a number on a scale and at what point they would like additional analgesics. Patients were allowed free access to morphine with a PCA pump device. Bolus doses were set according to age, (100 - age)/24 = bolus dose (mg), and 6 minutes lockout time. Degrees of pain, morphine requirements, doses delivered and demanded, oral intake of food, and antiemetics given were used as endpoints. Acceptable pain (mean [SD]) was estimated to be 3.8 (1.3) on the NRS, and additional treatment was considered necessary at scores of 4.3 (1.6) or more. NRS at rest was 2.7 (2.2) and during mobilization 4.7 (2.6). Required mean morphine per day was 81 (15) mg, and the number of doses requested increased during the first 6 days after the burn. The authors found no correlation between dose of morphine required and any other variables. Background pain can be controlled adequately with a standard PCA protocol. During mobilization, the pain experienced was too intense, despite having the already high doses of morphine increased. The present protocol must be refined further to provide analgesia adequate to cover mobilization as well.

  • 94.
    Nilsson, Andreas
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    Nilsson, Lena
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Surgery.
    Uustal, Eva
    Östergötlands Läns Landsting, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Surgery.
    Alfentanil and patient-controlled propofol sedation – facilitate gynaecological outpatient surgery with increased risk of respiratory events2012In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 56, no 9, p. 1123-1129Article in journal (Refereed)
    Abstract [en]

    Background

    Widespread use of patient-controlled sedation (PCS) demands simplicity and a predictable outcome. We evaluated patients’ safety and ease of use of PCS for gynaecological outpatient procedures.

    Methods

    In a prospective double-blind study, 165 patients were randomized to use propofol or propofol with alfentanil as PCS combined with local anaesthetic for pain control. Data on cardiopulmonary function, consciousness, and need for interventions were collected at baseline and every fifth minute. The surgeons’ evaluation of the ease and the duration of the procedure were recorded.

    Results

    One hundred and fifty-five patients used PCS for the entire procedure, 76 patients propofol, and 79 patients propofol/alfentanil. Fifteen procedures in the propofol group were limited or could not be done, compared with four in the propofol/alfentanil group (P = 0.02). The duration of surgery was not affected. The addition of alfentanil affected respiratory function compared with the propofol group: five patients compared with none were manually ventilated (P = 0.03), and two thirds, compared with a quarter, were given supplementary oxygen as their saturation decreased below 90% (P <0.001). Overall cardiovascular stability was maintained. The propofol group had deeper conscious sedation as measured by the bispectral index (P  = 0.03), but all patients could be roused. In the propofol/alfentanil group, five patients became apnoeic and could not be roused.

    Conclusions

    PCS using propofol alone supports patients’ safety, as the addition of alfentanil increased the need for specific interventions to maintain respiratory stability. However, alfentanil increases the feasibility of the procedure, as complementary doses of propofol were not required.

  • 95.
    Nilsson, Andreas
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Öster, Susanne
    Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    Bek-Jensen, Hanne
    Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Urology in Östergötland.
    Lennmarken, Claes
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    Patient-Controlled Sedation and Analgesia with Propofol and Alfentanil: A Preliminary Safety Evaluation Prior to Use of Non-Anaesthesiology Doctors2012In: Open Journal of Anesthesiology, ISSN 2164-5558, Vol. 2, no 2, p. 47-52Article in journal (Refereed)
    Abstract [en]

    Background: The aim was to evaluate safety aspects of patient-controlled sedation and analgesia (PCS) for extracor-poreal shockwave lithotripsy (ESWL) and PCS to be handled by non-anaesthesiology doctors. Methods: Thirty-four ASA I-III patients used PCS with propofol and alfentanil for ESWL in this interventional study. Strict safety limits were defined regarding respiratory rate (RR), heart rate (HR), mean arterial blood pressure (MAP), oxygen saturation from pulse oximetry (SpO2), and transcutaneous partial pressures of oxygen (PtcO2) and carbon dioxide (PtcCO2). The pa-tients’ levels of consciousness was graded on a five-point scale and monitored with Bispectral Index (BIS). A nurse anaesthetist was supervising the procedure but was instructed to intervene only if safety limits were breached. No sup-plementary oxygen was given. Results: All patients responded to verbal stimuli during treatment. Cardiovascular sta-bility was maintained, but respiratory variables were affected. Two patients with SpO2 < 90% and two cases of RR ≤ 8 were diagnosed, and seven patients became hypercarbic (PtcCO2 ≥ 6.5 kPa). In 18 patients hypoxaemia was indicated as PtcO2 ≤ 8.0 kPa. All these 18 patients were given supplementary oxygen. There was no correlation between dose of drugs, age, weight or any vital variable. The 34 patients would use PCS again in the case of future treatment. Conclu-sions: During ESWL treatment PCS can be used with good patients’ satisfaction, and maintained cardiovascular stabil-ity, but PCS had an indisputable effect on pulmonary function with hypoxemia (resulting in need for supplementary oxygen) or hypercarbia. The person in charge of PCS must therefore be trained to perform according to the guidelines for sedation and/or analgesia by non-anaesthesiology doctors.

  • 96.
    Nilsson, Andreas
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    Steinvall, Ingrid
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Bak, Zoltan
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Surgery in Linköping. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Surgery.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Surgery.
    Letter: Patient controlled sedation using a standard protocol for dressing changes in burns: Patients preference, procedural details and a preliminary safety evaluation. Are studies always adequately powered and analyzed? Response2010In: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 36, no 6, p. 948-950Article in journal (Other academic)
    Abstract [en]

    n/a

  • 97.
    Nilsson, Andreas
    et al.
    Department of Anesthesiology and Intensive Care Liköping University hospital.
    Steinvall, Ingrid
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Bak, Zoltan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Anesthesiology . Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Sjöberg, Folke
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Burn Unit . Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Patient controlled sedation using a standard protocol for dressing changes in burns: Patients' preference, procedural details and a preliminary safety evaluation2008In: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 34, no 7, p. 929-934Article in journal (Refereed)
    Abstract [en]

    Background: Patient controlled sedation (PCS) enables patients to titrate doses of drugs by themselves during different procedures involving pain or discomfort. Methods: We studied it in a prospective crossover design using a fixed protocol without lockout time to examine it as an alternative method of sedation for changing dressings in burned patients. Eleven patients with >10% total burn surface area (TBSA) had their dressings changed, starting with sedation by an anaesthetist (ACS). The second dressing change was done with PCS (propofol/alfentanil) and the third time the patients had to choose ACS or PCS. During the procedures, data on cardiopulmonary variables, sedation (bispectral index), pain intensity (VAS), procedural details, doses of drugs, and patients' preferences were collected to compare the two sedation techniques. Results: The study data indicated that wound care in burned patients is feasible with a standardized PCS protocol. The patients preferred PCS to ACS on the basis of self-control, and because they had less discomfort during the recovery period. Wound care was also considered adequate by the staff during PCS. No respiratory (respiratory rate/transcutaneous PCO2) or cardiovascular (heart rate/blood pressure) adverse events were recorded at any time during any of the PCS procedures. The doses of propofol and alfentanil and BIS index decrease were less during PCS than ACS. Procedural pain was higher during PCS but lower after the procedure. Conclusion: We suggest that PCS using a standard protocol is an interesting alternative to anaesthetist-provided sedation during dressing changes. It seems effective, saves resources, is safe, and at same time is preferred by the patients. The strength of these conclusions is, however, hampered by the small size of this investigation and therefore further studies are warranted. © 2008 Elsevier Ltd and ISBI.

  • 98.
    Nilsson, Lena
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    Respiration Signals from Photoplethysmography2013In: Anesthesia and Analgesia, ISSN 0003-2999, E-ISSN 1526-7598, Vol. 117, no 4, p. 859-865Article in journal (Refereed)
    Abstract [en]

    Pulse oximetry is based on the technique of photoplethysmography (PPG) wherein light transmitted through tissues is modulated by the pulse. In addition to variations in light modulation by the cardiac cycle, the PPG signal contains a respiratory modulation and variations associated with changing tissue blood volume of other origins. Cardiovascular, respiratory, and neural fluctuations in the PPG signal are of different frequencies and can all be characterized according to their sinusoidal components. PPG was described in 1937 to measure blood volume changes. The technique is today increasingly used, in part because of developments in semiconductor technology during recent decades that have resulted in considerable advances in PPG probe design. Artificial neural networks help to detect complex nonlinear relationships and are extensively used in electronic signal analysis, including PPG. Patient and/or probe-tissue movement artifacts are sources of signal interference. Physiologic variations such as vasoconstriction, a deep gasp, or yawn also affect the signal. Monitoring respiratory rates from PPG are often based on respiratory-induced intensity variations (RIIVs) contained in the baseline of the PPG signal. Qualitative RIIV signals may be used for monitoring purposes regardless of age, gender, anesthesia, and mode of ventilation. Detection of breaths in adult volunteers had a maximal error of 8%, and in infants the rates of overdetected and missed breaths using PPG were 1.5% and 2.7%, respectively. During central apnea, the rhythmic RIIV signals caused by variations in intrathoracic pressure disappear. PPG has been evaluated for detecting airway obstruction with a sensitivity of 75% and a specificity of 85%. The RIIV and the pulse synchronous PPG waveform are sensitive for detecting hypovolemia. The respiratory synchronous variation of the PPG pulse amplitude is an accurate predictor of fluid responsiveness. Pleth variability index is a continuous measure of the respiratory modulation of the pulse oximeter waveform and has been shown to predict fluid responsiveness in mechanically ventilated patients including infants. The pleth variability index value depends on the size of the tidal volume and on positive end-expiratory pressure. In conclusion, the respiration modulation of the PPG signal can be used to monitor respiratory rate. It is probable that improvements in neural network technology will increase sensitivity and specificity for detecting both central and obstructive apnea. The size of the PPG respiration variation can predict fluid responsiveness in mechanically ventilated patients.

  • 99.
    Nilsson, Lena
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Respiratory monitoring using reflection mode photoplethysmography: clinical and physiological aspects2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Photoplethysmography (PPG) is a non-invasive optical technique for monitoring variations in blood volume and blood flow in skin and other tissues. Light from a light-emitting diode is absorbed, scattered and reflected from the skin, and detected by a photodetector as a plethysmogram. The plethysmogram contains variations of different frequencies. The most clinically utilised is the pulse synchronous variation in the PPG application pulse oximetry, but there is also a respiratory rate synchronous variation (PPGt).

    The aims of this work were to evaluate PPG as a clinical method for detection of breaths during anaesthesia, postoperative and intensive care, and to investigate possible circulatory factors in the physiological background of the respiratory synchronous part of the reflection mode PPG signal.

    It was concluded that respiratory variations in reflection mode PPG derived from the forearm could be detected with high sensitivity and specificity. PPG, was not significantly affected by awake or anaesthetised state, though indirect signs of reduced sympathetic tone in the anaesthetic state were present, or by spontaneous or positive pressure ventilation. There were no significant differences between men and women or between young and old subjects. Circulatory pressure variations in phase with respiration were present on both the arterial and venous side and they showed the same degree of variation, as did PPG when provoking respiration. Squared coherence, cross-correlation and visual techniques for evaluating time differences were equally good.

    Respiratory monitoring in the clinical setting is challenging and no golden standard exists. Methods based on airflow are mostly considered advantageous in detecting apnoea, but are less well tolerated by patients. The results indicate that PPG has a potential as a tool for monitoring respiratory rate. It is non-invasive, well tolerated and can be used for continuous monitoring.

    List of papers
    1. Monitoring of respiratory rate in postoperative care using a new photoplethysmographic technique
    Open this publication in new window or tab >>Monitoring of respiratory rate in postoperative care using a new photoplethysmographic technique
    2000 (English)In: Journal of clinical monitoring and computing, ISSN 1387-1307, E-ISSN 1573-2614, Vol. 16, no 4, p. 309-315Article in journal (Refereed) Published
    Abstract [en]

    Objective.Photoplethysmography (PPG) is a non-invasive optical technique that measures variations in skin blood volume and perfusion. The PPG signal contains components that are synchronous with respiratory and cardiacrhythms. We undertook this study to evaluate PPG for monitoring patients' respiratory rate in the postoperative care unit, using a new prototype device. We compared it with the established technique, transthoracic impedance (TTI).

    Methods.PPG signals from 16 patients(ASA classes 1–2, mean age 43 years) who were recovering from general anaesthesia after routine operations were recorded continuously for 60minutes/patient. The respiratory synchronous part of the PPG signal was extracted by using a band pass filter. Detection of breaths in the filtered PPG signals was done both visually and by using an automated algorithm. In both procedures, the detected breaths were compared with the breaths detected in the TTI reference.

    Results.A total of 10.661 breaths were recorded, and the mean ± SD respiratory rate was 12.3 ± 3.5breaths/minute. When compared with TTI, the rates of false positive and false negative breaths detected by PPG (visual procedure) were 4.6 ±4.5% and 5.8 ± 6.5%, respectively. When using the algorithm for breath detection from PPG, the rates of false positive andfalse negative breaths were 11.1 ± 9.7% and 3.7 ±3.8%, respectively, when compared to TTI. Lower respiratory rates increased the occurrence of false-positive breaths that were detected by the PPG using visual identification (p< 0.05). The same tendency was seen with the automated PPG procedure (p< 0.10).

    Conclusions.Our results indicate that PPG has the potential to be useful for monitoring respiratory rate in the postoperative period.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26704 (URN)10.1023/A:1011424732717 (DOI)11296 (Local ID)11296 (Archive number)11296 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    2. Respiratory variations in the reflection mode photoplethysmographic signal: relationships to peripheral venous pressure
    Open this publication in new window or tab >>Respiratory variations in the reflection mode photoplethysmographic signal: relationships to peripheral venous pressure
    2003 (English)In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 41, no 3, p. 249-254Article in journal (Refereed) Published
    Abstract [en]

    Photoplethysmography (PPG) is a non-invasive optical way of measuring variations in blood volume and perfusion in the tissue, used in pulse oximetry for instance. Respiratory-induced intensity variations (RIIVs) in the PPG signal exist, but the physiological background is not fully understood. Respiration causes variations in the blood volume in the peripheral vascular bed. It was hypothesised that the filling of peripheral veins is one of the important factors involved. In 16 healthy subjects, the respiratory synchronous variations from a PPG reflection mode signal and the peripheral venous pressure (PVP) were recorded. Variations of tidal volume, respiratory rate and contribution from abdominal and thoracic muscles gave significant and similar amplitude changes in both RIIV and the respiratory variation of PVP (p<0.01). The highest amplitudes of both signals were found at the largest tidal volume, lowest respiratory rate and during mainly thoracic breathing, respectively. The coherence between PVP and RIIV signals was high, the median (quartile range) being 0.78 (0.42). Phase analysis showed that RIIV was usually leading PVP, but variations between subjects were large. Although respiratory-induced variations in PVP and PPG showed a close correlation in amplitude variation, a causal relationship between the signals could not be demonstrated.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26703 (URN)10.1007/BF02348428 (DOI)11295 (Local ID)11295 (Archive number)11295 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    3. Macrocirculation is not the sole determinant of respiratory induced variations in the reflection mode photoplethysmographic signal
    Open this publication in new window or tab >>Macrocirculation is not the sole determinant of respiratory induced variations in the reflection mode photoplethysmographic signal
    2003 (English)In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 24, no 4, p. 925-937Article in journal (Refereed) Published
    Abstract [en]

    Photoplethysmography (PPG) is a non-invasive optical technique sensitive to variations in blood volume and perfusion in the tissue. Reflection mode PPG may have clinical advantages over transmission mode PPG. To improve clinical usefulness and further development of the reflection mode PPG, studies on factors that modify the signal are warranted. We studied the coherence between the respiratory induced intensity variations (RIIV) of the PPG signal and respiratory synchronous pressure variations in central venous pressure (CVP), peripheral venous pressure (PVP) and arterial blood pressure (ABP) during positive pressure ventilation on 12 patients under anaesthesia and on 12 patients with spontaneous breathing. During positive pressure ventilation the coherence between all signals was high. Inspiration was followed first by an increase in CVP, then by increases in ABP and PVP and lastly by RIIV indicating less back-scattered light. In spontaneously breathing patients the coherence was high, but the phases between the signals were changed. During inspiration, ABP decreased slightly before CVP, followed by a decrease in RIIV and PVP. The phase relation between RIIV and respiratory induced variation in macrocirculation changed with ventilatory mode, but not in a uniform way, indicating the influence of mechanisms other than macrocirculation involved in generating the RIIV signal.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26705 (URN)10.1088/0967-3334/24/4/009 (DOI)11297 (Local ID)11297 (Archive number)11297 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    4. Respiration can be monitored by photoplethysmography with high sensitivity and specificity regardless of anaesthesia and ventilatory mode
    Open this publication in new window or tab >>Respiration can be monitored by photoplethysmography with high sensitivity and specificity regardless of anaesthesia and ventilatory mode
    2005 (English)In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 49, no 8, p. 1157-1162Article in journal (Refereed) Published
    Abstract [en]

    Background:  Photoplethysmography (PPG) is a non-invasive optical technique used, for instance, in pulse oximetry. Beside the pulse synchronous component, PPG has a respiratory synchronous variation (PPGr). Efforts have been made to utilize this component for indirect monitoring of respiratory rate and volume. Assessment of the clinical usefulness as well as of the physiological background of PPGr is required. We evaluated if anaesthesia and positive-pressure ventilation would affect PPGr.

    Methods:  We recorded reflection mode PPGr, at the forearm, and the respiratory synchronous changes in central venous pressure (CVP), peripheral venous pressure (PVP) and arterial blood pressure (ABP) in 12 patients. Recordings for each patient were made on three occasions: awake with spontaneous breathing; anaesthetized with spontaneous breathing; and anaesthetized with positive-pressure ventilation. We analyzed the sensitivity, specificity, coherence and time relationship between the signals.

    Results:  PPGr sensitivity for breath detection was [mean (SD)] >86(21)% and specificity >96(12)%. Respiratory detection in the macrocirculation (CVP, PVP and ABP) showed a sensitivity >83(29)% and specificity >93(12)%. The coherence between signals was high (0.75–0.99). The three measurement situations did not significantly influence sensitivity, specificity or time shifts between the PPGr, PVP, ABP, and the reference CVP signal despite changes in physiological data between measurements.

    Conclusion:  A respiratory synchronous variation in PPG and all invasive pressure signals was detected. The reflection mode PPGr signal seemed to be a constant phenomenon related to respiration regardless of whether or not the subject was awake, anaesthetized or ventilated, which increases its clinical usefulness in respiratory monitoring.

    Keywords
    general anaesthesia, monitoring, photoplethysmography, positive-pressure ventilation, respiration
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-31542 (URN)10.1111/j.1399-6576.2005.00721.x (DOI)17342 (Local ID)17342 (Archive number)17342 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2017-12-13Bibliographically approved
    5. Age and gender do not influence the ability to detect respiration by photoplethysmography
    Open this publication in new window or tab >>Age and gender do not influence the ability to detect respiration by photoplethysmography
    Show others...
    2006 (English)In: Journal of clinical monitoring and computing, ISSN 1387-1307, E-ISSN 1573-2614, Vol. 20, no 6, p. 431-436Article in journal (Refereed) Published
    Abstract [en]

    Objective  The non-invasive technique photopl- ethysmography (PPG) can detect changes in blood volume and perfusion in a tissue. Respiration causes variations in the peripheral circulation, making it possible to monitor breaths using an optical sensor attached to the skin. The respiratory-synchronous part of the PPG signal (PPGr) has been used to monitor respiration during anaesthesia, and in postoperative and neonatal care. Studies addressing possible differences in PPGr signal characteristics depending on gender or age are lacking.

    Methods  We studied three groups of 16 healthy subjects each during normal breathing; young males, old males and young females, and calculated the concordance between PPGr, derived from a reflection mode PPG sensor on the forearm, and a reference CO2 signal. The concordance was quantified by using a squared coherence analysis. Time delay between the two signals was calculated. In this process, we compared three different methods for calculating time delay.

    Results  Coherence values ≥0.92 were seen for all three groups without any significant differences depending on age or gender (p = 0.67). Comparison between the three different methods for calculating time delay showed a correlation r = 0.93.

    Conclusions  These results demonstrate clinically important information implying the possibility to register qualitative PPGr signals for respiration monitoring, regardless of age and gender.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-37154 (URN)10.1007/s10877-006-9050-z (DOI)33808 (Local ID)33808 (Archive number)33808 (OAI)
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2018-03-23Bibliographically approved
  • 100.
    Nilsson, Lena
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences.
    Respiratory monitoring using reflection mode photoplethysmography: clinical and physiological aspects2007In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 51, no 1, p. 130-Article, review/survey (Refereed)
    Abstract [en]

    No abstract available.

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