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Farnebo, Simon
Publications (10 of 22) Show all publications
Elmasry, M., Mirdell, R., Tesselaar, E., Farnebo, S., Sjöberg, F. & Steinvall, I. (2019). Laser speckle contrast imaging in children with scalds: Its influence on timing of intervention, duration of healing and care, and costs. Burns, 45(4), 798-804
Open this publication in new window or tab >>Laser speckle contrast imaging in children with scalds: Its influence on timing of intervention, duration of healing and care, and costs
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2019 (English)In: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 45, no 4, p. 798-804Article in journal (Refereed) Published
Abstract [sv]

Background

Scalds are the most common type of burn injury in children, and the initial evaluation of burn depth is a problem. Early identification of deep dermal areas that need excision and grafting would save unnecessary visits and stays in hospital. Laser speckle contrast imaging (LSCI) shows promise for the evaluation of this type of burn. The aim of this study was to find out whether perfusion measured with LSCI has an influence on the decision for operation, duration of healing and care period, and costs, in children with scalds.

Methods

We studied a group of children with scalds whose wounds were evaluated with LSCI on day 3–4 after injury during the period 2012–2015. Regression (adjustment for percentage total body surface area burned (TBSA%), age, and sex) was used to analyse the significance of associations between degree of perfusion and clinical outcome.

Results

We studied 33 children with a mean TBSA% of 6.0 (95% CI 4.4–7.7)%. Lower perfusion values were associated with operation (area under the receiver-operating characteristic curve 0.86, 95% CI 0.73–1.00). The perfusion cut-off with 100% specificity for not undergoing an operation was ≥191 PU units (66.7% sensitivity and 72.7% accurately classified). Multivariable analyses showed that perfusion was independently associated with duration of healing and care period.

Conclusion

Lower perfusion values, as measured with LSCI, are associated with longer healing time and longer care period. By earlier identification of burns that will be operated, perfusion measurements may further decrease the duration of care of burns in children with scalds.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Laser speckle contrast imaging; Burns; Scalds; Perfusion; Outcome; Children
National Category
Other Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-154872 (URN)10.1016/j.burns.2019.02.001 (DOI)000467914900006 ()30827850 (PubMedID)2-s2.0-85062153561 (Scopus ID)
Note

Funding agencies: Linkoping University, Linkoping, Sweden; Burn Centre, Department of Hand Surgery, Plastic Surgery, and Burns

Available from: 2019-03-02 Created: 2019-03-02 Last updated: 2019-07-01Bibliographically approved
Tesselaar, E., Nezirevic Dernroth, D. & Farnebo, S. (2017). Acute effects of coffee on skin blood flow and microvascular function. Microvascular Research, 114, 58-64
Open this publication in new window or tab >>Acute effects of coffee on skin blood flow and microvascular function
2017 (English)In: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 114, p. 58-64Article in journal (Refereed) Published
Abstract [en]

Objective

Studies on the acute effects of coffee on the microcirculation have shown contradicting results. This study aimed to investigate if intake of caffeine-containing coffee changes blood flow and microvascular reactivity in the skin.

Methods

We measured acute changes in cutaneous vascular conductance (CVC) in the forearm and the tip of the finger, the microvascular response to transdermaliontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) and post-occlusive reactive hyperemia (PORH) in the skin, after intake of caffeinated or decaffeinated coffee.

Results

Vasodilatation during iontophoresis of ACh was significantly stronger after intake of caffeinated coffee compared to after intake of decaffeinated coffee (1.26 ± 0.20 PU/mm Hg vs. 1.13 ± 0.38 PU/mm Hg, P < 0.001). Forearm CVC before and after PORH were not affected by caffeinated and decaffeinated coffee. After intake of caffeinated coffee, a more pronounced decrease in CVC in the fingertip was observed compared to after intake of decaffeinated coffee (− 1.36 PU/mm Hg vs. − 0.52 PU/mm Hg, P = 0.002).

Conclusions

Caffeine, as ingested by drinking caffeinated coffee acutely improves endothelium-dependent microvascular responses in the forearm skin, while endothelium-independent responses to PORH and SNP iontophoresis are not affected. Blood flow in the fingertip decreases markedly during the first hour after drinking caffeinated coffee compared to decaffeinated coffee.

Place, publisher, year, edition, pages
Academic Press, 2017
Keywords
Coffee, Caffeine, Skin, Microcirculation, Laser Doppler flowmetry, Laser speckle contrast imaging
National Category
Anesthesiology and Intensive Care
Identifiers
urn:nbn:se:liu:diva-145382 (URN)10.1016/j.mvr.2017.06.006 (DOI)000431155100009 ()28625890 (PubMedID)2-s2.0-85020924088 (Scopus ID)
Available from: 2018-02-27 Created: 2018-02-27 Last updated: 2019-01-11Bibliographically approved
Droog Tesselaar, E., Flejmer, A. M., Farnebo, S. & Dasu, A. (2017). Changes in skin microcirculation during radiation therapy for breast cancer. Acta Oncologica, 56(8), 1072-1080
Open this publication in new window or tab >>Changes in skin microcirculation during radiation therapy for breast cancer
2017 (English)In: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 56, no 8, p. 1072-1080Article in journal (Refereed) Published
Abstract [en]

Abstract:

Background: The majority of breast cancer patients who receive radiation treatment are affected by acute radiation-induced skin changes. The assessment of these changes is usually done by subjective methods, which complicates the comparison between different treatments or patient groups. This study investigates the feasibility of new robust methods for monitoring skin microcirculation to objectively assess and quantify acute skin reactions during radiation treatment.

Material and methods: Laser Doppler flowmetry, laser speckle contrast imaging, and polarized light spectroscopy imaging were used to measure radiation-induced changes in microvascular perfusion and red blood cell concentration (RBC) in the skin of 15 patients undergoing adjuvant radiation therapy for breast cancer. Measurements were made before treatment, once a week during treatment, and directly after the last fraction.

Results: In the treated breast, perfusion and RBC concentration were increased after 1–5 fractions (2.66–13.3 Gy) compared to baseline. The largest effects were seen in the areola and the medial area. No changes in perfusion and RBC concentration were seen in the untreated breast. In contrast, Radiation Therapy Oncology Group (RTOG) scores were increased only after 2 weeks of treatment, which demonstrates the potential of the proposed methods for early assessment of skin changes. Also, there was a moderate to good correlation between the perfusion (r = 0.52) and RBC concentration (r = 0.59) and the RTOG score given a week later.

Conclusion: We conclude that radiation-induced microvascular changes in the skin can be objectively measured using novel camera-based techniques before visual changes in the skin are apparent. Objective measurement of microvascular changes in the skin may be valuable in the comparison of skin reactions between different radiation treatments and possibly in predicting acute skin effects at an earlier stage.

Place, publisher, year, edition, pages
Oxfordshire: Taylor & Francis, 2017
National Category
Cancer and Oncology
Identifiers
urn:nbn:se:liu:diva-134594 (URN)10.1080/0284186X.2017.1299220 (DOI)000402609100006 ()28281359 (PubMedID)
Available from: 2017-02-20 Created: 2017-02-20 Last updated: 2018-05-03Bibliographically approved
Farnebo, S. & Gerber Ekblom, A. (2017). Hand surgery in Sweden. Journal of Hand Surgery, European Volume, 42(5), 537-539
Open this publication in new window or tab >>Hand surgery in Sweden
2017 (English)In: Journal of Hand Surgery, European Volume, ISSN 1753-1934, E-ISSN 2043-6289, Vol. 42, no 5, p. 537-539Article in journal, Editorial material (Other academic) Published
Abstract [en]

n/a

Place, publisher, year, edition, pages
SAGE PUBLICATIONS LTD, 2017
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-138219 (URN)10.1177/1753193417698866 (DOI)000401720500024 ()28516812 (PubMedID)
Available from: 2017-06-14 Created: 2017-06-14 Last updated: 2018-05-02
Zötterman, J., Mirdell, R., Horsten, S., Farnebo, S. & Tesselaar, E. (2017). Methodological concerns with laser speckle contrast imaging in clinical evaluation of microcirculation. PLoS ONE, 12(3), Article ID e0174703.
Open this publication in new window or tab >>Methodological concerns with laser speckle contrast imaging in clinical evaluation of microcirculation
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2017 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 3, article id e0174703Article in journal (Refereed) Published
Abstract [en]

Background Laser Speckle Contrast Imaging (LSCI) is a non-invasive and fast technique for measuring microvascular blood flow that recently has found clinical use for burn assessment and evaluation of flaps. Tissue motion caused by for example breathing or patient movements may however affect the measurements in these clinical applications, as may distance between the camera and the skin and tissue curvature. Therefore, the aims of this study were to investigate the effect of frame rate, number of frames/image, movement of the tissue, measuring distance and tissue curvature on the measured perfusion. Methods Methyl nicotinate-induced vasodilation in the forearm skin was measured using LSCI during controlled motion at different speeds, using different combinations of frame rate and number of frames/image, and at varying camera angles and distances. Experiments were made on healthy volunteers and on a cloth soaked in a colloidal suspension of polystyrene microspheres. Results Measured perfusion increased with tissue motion speed. The relation was independent of the absolute perfusion in the skin and of frame rate and number of frames/image. The measured perfusion decreased with increasing angles (16% at 60, p = 0.01). Measured perfusion did not vary significantly between measurement distances from 15 to 40 cm (p = 0.77, %CV 0.9%). Conclusion Tissue motion increases and measurement angles beyond 45 decrease the measured perfusion in LSCI. These findings have to be taken into account when LSCI is used to assess moving or curved tissue surfaces, which is common in clinical applications.

Place, publisher, year, edition, pages
PUBLIC LIBRARY SCIENCE, 2017
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-137098 (URN)10.1371/journal.pone.0174703 (DOI)000399174800074 ()28358906 (PubMedID)
Note

Funding Agencies|ALF grants, Region Ostergotland

Available from: 2017-05-05 Created: 2017-05-05 Last updated: 2018-05-02
Bergkvist, M., Zötterman, J., Henricson, J., Iredahl, F., Tesselaar, E. & Farnebo, S. (2017). Vascular Occlusion in a Porcine Flap Model: Effects on Blood Cell Concentration and Oxygenation.. Plastic and reconstructive surgery. Global open, 5(11), Article ID e1531.
Open this publication in new window or tab >>Vascular Occlusion in a Porcine Flap Model: Effects on Blood Cell Concentration and Oxygenation.
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2017 (English)In: Plastic and reconstructive surgery. Global open, ISSN 2169-7574, Vol. 5, no 11, article id e1531Article in journal (Refereed) Published
Abstract [en]

Background: Venous congestion in skin flaps is difficult to detect. This study evaluated the ability of tissue viability imaging (TiVi) to measure changes in the concentration of red blood cells (CRBC), oxygenation, and heterogeneity during vascular provocations in a porcine fasciocutaneous flap model.

Methods: In 5 pigs, cranial gluteal artery perforator flaps were raised (8 flaps in 5 pigs). The arterial and venous blood flow was monitored with ultrasonic flow probes. CRBC, tissue oxygenation, and heterogeneity in the skin were monitored with TiVi during baseline, 50% and 100% venous occlusion, recovery, 100% arterial occlusion and final recovery, thereby simulating venous and arterial occlusion of a free fasciocutaneous flap. A laser Doppler probe was used as a reference for microvascular perfusion in the flap.

Results: During partial and complete venous occlusion, increases in CRBC were seen in different regions of the flap. They were more pronounced in the distal part. During complete arterial occlusion, CRBC decreased in all but the most distal parts of the flap. There were also increases in tissue oxygenation and heterogeneity during venous occlusion.

Conclusions: TiVi measures regional changes in CRBC in the skin of the flap during arterial and venous occlusion, as well as an increase in oxygenated hemoglobin during venous occlusion that may be the result of reduced metabolism and impaired delivery of oxygen to the tissue. TiVi may provide a promising method for measuring flap viability because it is hand-held, easy to-use, and provides spatial information on venous congestion.

Place, publisher, year, edition, pages
Wolters Kluwer, 2017
National Category
Radiology, Nuclear Medicine and Medical Imaging Surgery
Identifiers
urn:nbn:se:liu:diva-145391 (URN)10.1097/GOX.0000000000001531 (DOI)29263951 (PubMedID)2-s2.0-85038559789 (Scopus ID)
Available from: 2018-02-27 Created: 2018-02-27 Last updated: 2019-07-23Bibliographically approved
Mirdell, R., Iredahl, F., Sjöberg, F., Farnebo, S. & Tesselaar, E. (2016). Microvascular blood flow in scalds in children and its relation to duration of wound healing: A study using laser speckle contrast imaging. Burns, 42(3), 648-654
Open this publication in new window or tab >>Microvascular blood flow in scalds in children and its relation to duration of wound healing: A study using laser speckle contrast imaging
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2016 (English)In: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 42, no 3, p. 648-654Article in journal (Refereed) Published
Abstract [en]

Background: Microvascular perfusion changes in scalds in children during the first weeks after injury is related to the outcome of healing, and measurements of perfusion, based on laser Doppler imaging, have been used successfully to predict the need for excision and grafting. However, the day-to-day changes in perfusion during the first weeks after injury have not to our knowledge been studied in detail. The aim of this study, based on a conservative treatment model where excision and grafting decisions were delayed to day 14 after injury, was to measure changes in perfusion in scalds using laser speckle contrast imaging (LSCI) during the first three weeks after injury. Methods: We measured perfusion with LSCI in 34 patients at regular intervals between 6 h after injury until complete reepithelialization or surgery. Duration of healing was defined as the time to complete reepithelialization. Results: Less perfusion, between 6 and 96 h after injury, was associated with longer duration of healing with the strongest association occurring between 72 and 96 h. Burns that healed within 14 days had relatively high initial perfusion, followed by a peak and subsequent slow decrease. Both the maximum perfusion and the time-to-peak were dependent on the severity of the burn. Burns that needed excision and grafting had less initial perfusion and a gradual reduction over time. Conclusion: The perfusion in scalds in children shows characteristic patterns during the first weeks after injury depending on the duration of wound healing, the greatest difference between wounds of different severity being on the 4th day. Perfusion should therefore preferably be measured on the fourth day if it is to be used in the assessment of burn depth. (c) 2015 Elsevier Ltd and ISBI. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2016
Keywords
Scalds; Burns; Perfusion; Laser speckle contrast imaging
National Category
Anesthesiology and Intensive Care
Identifiers
urn:nbn:se:liu:diva-129497 (URN)10.1016/j.burns.2015.12.005 (DOI)000376507500023 ()26810445 (PubMedID)
Available from: 2016-06-20 Created: 2016-06-20 Last updated: 2019-02-11
Zötterman, J., Bergkvist, M., Iredahl, F., Tesselaar, E. & Farnebo, S. (2016). Monitoring of partial and full venous outflow obstruction in a porcine flap model using laser speckle contrast imaging. Journal of Plastic, Reconstructive & Aesthetic Surgery, 69(7), 936-943
Open this publication in new window or tab >>Monitoring of partial and full venous outflow obstruction in a porcine flap model using laser speckle contrast imaging
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2016 (English)In: Journal of Plastic, Reconstructive & Aesthetic Surgery, ISSN 1748-6815, E-ISSN 1532-1959, Vol. 69, no 7, p. 936-943Article in journal (Refereed) Published
Abstract [en]

Background: In microsurgery, there is a demand for more reliable methods of postoperative monitoring of free flaps, especially with regard to tissue-threatening obstructions of the feeding arteries and draining veins. In this study, we evaluated laser speckle contrast imaging (LSCI) and laser Doppler flowmetry (LDF) to assess their possibilities to detect partial and full venous outflow obstruction, as well as full arterial occlusion, in a porcine flap model. Methods: Cranial gluteal artery perforator flaps (CGAPs) were raised, and arterial and venous blood flow to and from the flaps was monitored using ultrasonic flow probes. The venous flow was altered with an inflatable cuff to simulate partial and full (50% and 100%) venous obstruction, and arterial flow was completely obstructed using clamps. The flap microcirculation was monitored using LSCI and LDF. Results: Both LDF and the LSCI detected significant changes in flap perfusion. After partial (50%) venous occlusion, perfusion decreased from baseline, LSCI: 63.5 +/- 12.9 PU (p = 0.01), LDF 31.3 +/- 15.7 (p = 0.64). After 100% venous occlusion, a further decrease in perfusion was observed: LSCI 54.6 +/- 14.2 PU (p amp;lt; 0.001) and LDF 16.7 +/- 12.8 PU (p amp;lt; 0.001). After release of the venous cuff, LSCI detected a return of the perfusion to a level slightly, but not significantly, below the baseline level 70.1 +/- 11.5 PU (p=0.39), while the LDF signal returned to a level not significant from the baseline 36.1 +/- 17.9 PU (p amp;gt; 0.99). Perfusion during 100% arterial occlusion decreased significantly as measured with both methods, LSCI: 48.3 +/- 7.7 (PU, pamp;lt;0.001) and LDF: 8.5 +/- 4.0 PU (pamp;lt;0.001). During 50% and 100% venous occlusion, LSCI showed a 20% and 26% inter-subject variability (CV%), respectively, compared to 50% and 77% for LDF. Conclusions: LSCI offers sensitive and reproducible measurements of flap microcirculation and seems more reliable in detecting decreases in blood perfusion caused by venous obstruction. It also allows for perfusion measurements in a relatively large area of flap tissue. This may be useful in identifying areas of the flap with compromised microcirculation during and after surgery. (C) 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2016
Keywords
Free flaps; Venous occlusion; Arterial occlusion; Laser Doppler; Laser speckle contrast imaging
National Category
Surgery
Identifiers
urn:nbn:se:liu:diva-130059 (URN)10.1016/j.bjps.2016.02.015 (DOI)000377698600010 ()27026039 (PubMedID)
Note

Funding Agencies|county of Ostergotland

Available from: 2016-07-06 Created: 2016-07-06 Last updated: 2017-06-21
Bergkvist, M., Henricson, J., Iredahl, F., Tesselaar, E., Sjöberg, F. & Farnebo, S. (2015). Assessment of microcirculation of the skin using Tissue Viability Imaging: A promising technique for detecting venous stasis in the skin. Microvascular Research, 101, 20-25
Open this publication in new window or tab >>Assessment of microcirculation of the skin using Tissue Viability Imaging: A promising technique for detecting venous stasis in the skin
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2015 (English)In: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 101, p. 20-25Article in journal (Refereed) Published
Abstract [en]

Background: : Venous occlusion in the skin is difficult to detect by existing measurement techniques. Our aim was to find out whether Tissue Viability Imaging (TiVi) was better at detecting venous occlusion by comparing it with results of laser Doppler flowmetry (LDF) during graded arterial and venous stasis in human forearm skin. Methods: : Arterial and venous occlusions were simulated in 10 healthy volunteers by inflating a blood pressure cuff around the upper right arm. Changes in the concentration of red blood cells (RBC) were measured using TiVi, while skin perfusion and concentration of moving red blood cells (CMBC) were measured using static indices of LDF during exsanguination and subsequent arterial occlusion, postocclusive reactive hyperaemia, and graded increasing and decreasing venous stasis. Results: : During arterial occlusion there was a significant reduction in the mean concentration of RBC from baseline, as well as in perfusion and CMBC (p less than 0.008). Venous occlusion resulted in a significant 28% increase in the concentration of RBC (p = 0.002), but no significant change in perfusion (mean change -14%) while CMBC decreased significantly by 24% (p = 0.02). With stepwise increasing occlusion pressures there was a significant rise in the TiVi index and reduction in perfusion (p = 0.008), while the reverse was seen when venous flow was gradually restored. Conclusion: : The concentration of RBC measured with TiVi changes rapidly and consistently during both total and partial arterial and venous occlusions, while the changes in perfusion, measured by LDF, were less consistent This suggests that TiVi could be a more useful, non-invasive clinical monitoring tool for detecting venous stasis in the skin than LDF.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Tissue viability imaging; Laser Doppler flowmetry; Post-occusive hyperaemia; Venous occlusion; Arterial occlusion
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-121302 (URN)10.1016/j.mvr.2015.06.002 (DOI)000360028500004 ()26092681 (PubMedID)
Note

Funding Agencies|County Council of Ostergotland, Sweden [2014JZ0004]

Available from: 2015-09-16 Created: 2015-09-14 Last updated: 2019-07-23Bibliographically approved
Iredahl, F., Sadda, V., Ward, L., Hackethal, J., Farnebo, S., Tesselaar, E. & Sjöberg, F. (2015). Modeling Perfusion Dynamics in the Skin During Iontophoresis of Vasoactive Drugs Using Single-Pulse and Multiple-Pulse Protocols. Microcirculation, 22(6), 446-453
Open this publication in new window or tab >>Modeling Perfusion Dynamics in the Skin During Iontophoresis of Vasoactive Drugs Using Single-Pulse and Multiple-Pulse Protocols
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2015 (English)In: Microcirculation, ISSN 1073-9688, E-ISSN 1549-8719, Vol. 22, no 6, p. 446-453Article in journal (Refereed) Published
Abstract [en]

Objective: After iontophoresis of vasoactive drugs into the skin, a decrease in perfusion is commonly observed. We delivered vasoactive drugs by iontophoresis using different delivery protocols to study how these affect this decrease in perfusion as measured using LDF. Methods: We measured skin perfusion during iontophoresis of (ACh), MCh, andNAusing a single pulse or separate pulses at different skin sites, and during repeated delivery of ACh at the same site. Results: Perfusion half-life was 6.1 (5.6-6.6) minutes for ACh and 41 (29-69) minutes for MCh (p less than 0.001). The maximum response with multiple pulses of ACh iontophoresis was lower than with a single pulse, 30 (22-37) PU vs. 43 (36-50) PU, p less than 0.001. Vasoconstriction to NA was more rapid with a single pulse than with multiple pulses. The perfusion half-life of ACh decreased with repeated delivery of ACh at the same site-first 16 (14-18), second 5.9 (5.1-6-9) and third 3.2 (2.9-3.5) minutes, p less than 0.001. Conclusions: The drug delivery protocol affects microvascular responses to iontophoresis, possibly as a result of differences in the dynamics of local drug concentrations. Perfusion half-life may be used as a measure to quantify the rate of perfusion recovery after iontophoresis of vasoactive drugs.

Place, publisher, year, edition, pages
Informa Healthcare / Wiley: 12 months, 2015
Keywords
microcirculation; iontophoresis; acetylcholine; metha choline; noradrenaline; skin
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-121138 (URN)10.1111/micc.12211 (DOI)000359676500002 ()26016387 (PubMedID)
Available from: 2015-09-08 Created: 2015-09-08 Last updated: 2017-12-04
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