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  • 1.
    Berlin, Gösta
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Hammar, Mats
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    Tapper, Linus
    Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine. Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Tynngård, Nahreen
    Linköping University, Department of Clinical and Experimental Medicine, Division of Hematopoiesis and Developmental Biology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Effects of age, gender and menstrual cycle on platelet function assessed by impedance aggregometry2019In: Platelets, ISSN 0953-7104, E-ISSN 1369-1635, Vol. 30, no 4, p. 473-479Article in journal (Refereed)
    Abstract [en]

    Platelets are needed to prevent or arrest bleeding and aggregate at the site of injury upon vascular damage. Platelets express receptors for estrogens which might affect the function of the platelets and their hemostatic ability. The aim was to identify possible differences in platelet function related to age, gender, and phases of the menstrual cycle by use of impedance aggregometry with Multiplate. In the first part of the study, platelet function was assessed in 60 healthy individuals (30 men and 30 women) in each of three age groups (20-25, 40-45, and 60-65 years). In the second part of the study, the platelet function was analyzed on four occasions during the menstrual cycle in women without oral contraceptives (OCs) (n = 17) and compared to 19 women on OCs and 18 men of similar age (20-40 years). For the women on OCs, aggregation was analyzed once during the tablet-free week and once late during the period with OCs. The men were sampled once. Women of younger age (amp;lt;45 years) had significantly higher agonist-induced aggregation response than both men and post-menopausal women (60-65 years). The agonist-induced aggregation response did not differ between phases of the menstrual cycle or OC use. The results suggest that estradiol and/or progesterone affect spontaneous aggregation since it was found to be lowest in the mid-luteal phase. Spontaneous aggregation was significantly lower in women on OCs than in both men and women without OCs. Our findings indicate that fertile age is associated with higher aggregation response capacity of the platelets, possibly to prevent excessive bleeding during menstruation, but this response capacity is not altered during the menstrual cycle or by use of OCs.

  • 2.
    Kander, Thomas
    et al.
    Lund University, Sweden; Skåne University Hospital Lund, Sweden.
    Larsson, Anna
    Lund University, Sweden.
    Taune, Victor
    Lund University, Sweden.
    Schott, Ulf
    Lund University, Sweden; Skåne University Hospital Lund, Sweden.
    Tynngård, Nahreen
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Assessment of Haemostasis in Disseminated Intravascular Coagulation by Use of Point-of-Care Assays and Routine Coagulation Tests, in Critically Ill Patients; A Prospective Observational Study2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 3, p. e0151202-Article in journal (Refereed)
    Abstract [en]

    Background Disseminated intravascular coagulopathy (DIC) relates to the consumption of coagulation factors and platelets with bleeding and micro thrombosis events. Aim The aim of this study was to compare haemostasis parameters in critically ill patients with DIC versus patients without DIC, and in survivors versus non-survivors over time. Correlations between the DIC-score, the degree of organ failure and the haemostasis were assessed. Method Patients admitted to the intensive care unit with a condition known to be associated with DIC and with an expected length of stay of >3 days were included. Routine laboratory tests, prothrombin time, activated partial thromboplastin time, platelet count, fibrinogen concentration and D-dimer were measured. Coagulation and platelet function were assessed with two point-of-care devices; Multiplate and ROTEM. DIC scores were calculated according to the International Society on Thrombosis and Haemostasis and Japanese Association for Acute Medicine. Results Blood was sampled on days 0-1, 2-3 and 4-10 from 136 patients with mixed diagnoses during 290 sampling events. The point-of-care assays indicated a hypocoagulative response (decreased platelet aggregation and reduced clot strength) in patients with DIC and, over time, in non-survivors compared to survivors. Patients with DIC as well as non-survivors had decreased fibrinolysis as shown by ROTEM. DIC scores were higher in non-survivors than in survivors. Conclusions Patients with DIC displayed signs of a hypocoagulative response and impaired fibrinolysis, which was also evident over time in non-survivors. Patients with DIC had a higher mortality rate than non-DIC patients, and DIC scores were higher in non-survivors than in survivors.

  • 3.
    Larsson, A.
    et al.
    Lund University, Sweden.
    Tynngård, Nahreen
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Kander, T.
    Lund University, Sweden; Skåne University Hospital Lund, Sweden.
    Bonnevier, J.
    Lund University, Sweden; Skåne University Hospital Lund, Sweden.
    Schott, U.
    Lund University, Sweden; Skåne University Hospital Lund, Sweden.
    Comparison of point-of-care hemostatic assays, routine coagulation tests, and outcome scores in critically ill patients2015In: Journal of critical care, ISSN 0883-9441, E-ISSN 1557-8615, Vol. 30, no 5, p. 1032-1038Article in journal (Refereed)
    Abstract [en]

    Purpose: The purposes of the study are to compare point-of-care (POC) hemostatic devices in critically ill patients with routine laboratory tests and intensive care unit (ICU) outcome scoring assessments and to describe the time course of these variables in relation to mortality rate. Materials and methods: Patients admitted to the ICU with a prognosis of more than 3 days of stay were included. The POC devices, Multiplate platelet aggregometry, rotational thromboelastometry, and ReoRox viscoelastic tests, were used. All variables were compared between survivors and nonsurvivors. Point-of-care results were compared to prothrombin time, activated partial thromboplastin time, platelet count, fibrinogen concentration, and Sequential Organ Failure Assessment score and Simplified Acute Physiology Score 3. Results: Blood was sampled on days 0 to 1, 2 to 3, and 4 to 10 from 114 patients with mixed diagnoses during 237 sampling events. Nonsurvivors showed POC and laboratory signs of hypocoagulation and decreased fibrinolysis over time compared to survivors. ReoRox detected differences between survivors and nonsurvivors better than ROTEM and Multiplate. Conclusions: All POC and routine laboratory tests showed a hypocoagulative response in nonsurvivors compared to survivors. ReoRox was better than ROTEM and Multiplate at detecting differences between surviving and nonsurviving ICU patients. However, Simplified Acute Physiology Score 3 showed the best association to mortality outcome.

  • 4.
    Nilsson, Caroline U.
    et al.
    Lund University, Sweden .
    Tynngård, Nahreen
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Reinstrup, Peter
    Lund University, Sweden .
    Engstrom, Martin
    Lund University, Sweden .
    Monitoring fibrinolysis in whole blood by viscoelastic instruments: A comparison of ROTEM and ReoRox2013In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 73, no 6, p. 457-465Article in journal (Refereed)
    Abstract [en]

    Objective. Increased fibrinolysis with the risk of bleeding is a consequence of thrombolytic therapy and can also be seen in clinical situations such as acute trauma. Thrombelastography and thrombelastometry are viscoelastic coagulation instruments that can detect higher degrees of fibrinolysis; hyperfibrinolysis. A newer viscoelastic instrument is the ReoRox, which uses free oscillation rheometry to detect clot formation, strength and fibrinolysis. The ReoRox has a new test for detection of fibrinolysis, called ReoLyse. The aim of this study was to compare ReoRox with its new ReoLyse test with rotational thrombelastometry (ROTEM) in the monitoring of in vitro-induced fibrinolysis. Methods. Whole blood from 10 healthy volunteers was mixed with tissue plasminogen activator (t-PA) to obtain seven different plasma concentrations (0, 0.25, 0.5, 0.75, 1, 3 and 5 mu g/mL). Whole blood samples with the different t-PA plasma concentrations were analyzed with ROTEM EXTEM and FIBTEM tests, ReoRox standard test Fib1 (clot formation/strength) and ReoLyse (fibrinolysis) tests. Results. The fibrinolysis variables with the best dose-response effect were the ReoRox ReoLyse lysis variables and ROTEM EXTEM Time to complete lysis. However, these variables only detected high t-PA levels (andgt;1 mu g/mL). Conclusions. The new ReoRox ReoLyse test provides more information on fibrinolysis compared to the ReoRox Fib1 program. Neither ReoRox nor ROTEM could detect lower degrees of fibrinolysis. ReoRox is a valuable alternative to ROTEM to study high degrees of fibrinolysis and should be evaluated in clinical situations with increased fibrinolysis and during therapeutic thrombolysis.

  • 5.
    Ramström, Sofia
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Södergren, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Tynngård, Nahreen
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Lindahl, Tomas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Platelet Function Determined by Flow Cytometry: New Perspectives?2016In: Seminars in Thrombosis and Hemostasis, ISSN 0094-6176, E-ISSN 1098-9064, Vol. 42, no 3, p. 268-281Article in journal (Refereed)
    Abstract [en]

    Flow cytometry enables studies of several different aspects of platelet function in response to a variety of platelet agonists. This can be done using only a small volume of whole blood, and also in blood with low platelet counts. These properties, together with the increasing number of flow cytometers available in hospitals worldwide, make flow cytometry an interesting option for laboratories interested in studies of platelet function in different clinical settings. This review focuses on practical issues regarding the use of flow cytometry for platelet function testing. It provides an overview of available activation markers, platelet agonists, and experimental setup issues. The review summarizes previous experience and factors important to consider to perform high-quality platelet function testing by flow cytometry. It also discusses its current use and possibilities and challenges for future use of flow cytometry in clinical settings

  • 6.
    Sandgren, Per
    et al.
    Karolinska University Hospital, Sweden; Karolinska Institute, Sweden.
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Tynngård, Nahreen
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Treatment of platelet concentrates with ultraviolet C light for pathogen reduction increases cytokine accumulation2016In: Transfusion, ISSN 0041-1132, E-ISSN 1537-2995, Vol. 56, no 6, p. 1377-1383Article in journal (Refereed)
    Abstract [en]

    BACKGROUNDPathogen reduction technologies use photoactive substances in combination with ultraviolet (UV) light to inactivate pathogens. A new method uses only UVC light for pathogen reduction. This study assesses the effects of UVC light treatment on cytokine release in platelet (PLT) concentrates (PCs). STUDY DESIGN AND METHODSA PC with 35% plasma and 65% PLT additive solution (SSP+) was prepared from five buffy coats. Three such PCs were pooled and divided into 3 units. One unit was used as a nonirradiated control, the second was a gamma-irradiated control, and the third unit was treated with UVC light technology. Ten units of each type were investigated. Cytokine release was analyzed on Days 1, 5, and 7 of storage. Correlation between cytokines, PLT surface markers, and hemostatic properties was investigated. RESULTSSwirling was well preserved and pH was above the reference limit of 6.4 during storage of PLTs in all groups. Cytokine levels increased during storage in all groups but to a larger degree in PCs treated with UVC light. Only weak correlation was found between cytokines and PLT surface markers (ramp;lt;0.5). However, several cytokines showed strong correlation (ramp;gt;0.6) with the PLTs ability to promote clot retraction. CONCLUSIONUVC treatment resulted in increased release from PLT alpha granules as evident by a higher cytokine release compared to nonirradiated and gamma-irradiated PCs. The clinical relevance of these findings needs to be further evaluated.

  • 7.
    Södergren, Anna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Tynngård, Nahreen
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Ramström, Sofia
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Responsiveness of platelets during storage studied with flow cytometry - formation of platelet subpopulations and LAMP-1 as new markers for the platelet storage lesion2016In: Vox Sanguinis, ISSN 0042-9007, E-ISSN 1423-0410, Vol. 110, no 2, p. 116-125Article in journal (Refereed)
    Abstract [en]

    Background and ObjectivesStorage lesions may prevent transfused platelets to respond to agonists and arrest bleeding. The aim of this study was to evaluate and quantify the capacity of platelet activation during storage using flow cytometry and new markers of platelet activation. Materials and MethodsActivation responses of platelets prepared by apheresis were measured on days 1, 5, 7 and 12. In addition, comparisons were made for platelet concentrates stored until swirling was affected. Lysosome-associated membrane protein-1 (LAMP-1), P-selectin and phosphatidylserine (PS) exposure were assessed by flow cytometry on platelets in different subpopulations in resting state or following stimulation with platelet agonists (cross-linked collagen-related peptide (CRP-XL), PAR1- and PAR4-activating peptides). ResultsThe ability to form subpopulations upon activation was significantly decreased already at day 5 for some agonist combinations. The agonist-induced exposure of PS and LAMP-1 also gradually decreased with time. Spontaneous exposure of P-selectin and PS increased with time, while spontaneous LAMP-1 exposure was unchanged. In addition, agonist-induced LAMP-1 expression clearly discriminated platelet concentrates with reduced swirling from those with retained swirling. This suggests that LAMP-1 could be a good marker to capture changes in activation capacity in stored platelets. ConclusionThe platelet activation potential seen as LAMP-1 exposure and fragmentation into platelet subpopulations is potential sensitive markers for the platelet storage lesion.

  • 8.
    Thomas, Owain
    et al.
    Lund University, Sweden; SUS Lund University Hospital, Sweden.
    Larsson, Anna
    Lund University, Sweden.
    Tynngård, Nahreen
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Schott, Ulf
    Lund University, Sweden; SUS Lund University Hospital, Sweden.
    Thromboelastometry versus free-oscillation rheometry and enoxaparin versus tinzaparin: an in-vitro study comparing two viscoelastic haemostatic tests dose-responses to two low molecular weight heparins at the time of withdrawing epidural catheters from ten patients after major surgery2015In: BMC Anesthesiology, ISSN 1471-2253, E-ISSN 1471-2253, Vol. 15Article in journal (Refereed)
    Abstract [en]

    Background: Monitoring low molecular weight heparins (LMWHs) in the perioperative period is prudent in patients at high risk of coagulative complications, especially when the patient has an epidural catheter requiring withdrawal, which is associated with the risk of spinal haematoma. The aim of this study was to evaluate the in vitro dose-responses of two different LMWHs on two different viscoelastic haemostatic tests, using blood sampled from patients with normal routine coagulation parameters, on the day after major surgery when their epidural catheters were due to be withdrawn. Methods: Enoxaparin or tinzaparin were added in vitro to blood from ten patients who had undergone oesophageal resection, to obtain plasma concentrations of approximately 0, 0.5, 1.0 and 1.5 IU/mL. Coagulation was monitored using thromboelastometry (ROTEM (R)) using the InTEM (R) activating reagent; and free oscillation rheometry (FOR: ReoRox (R)), activated using thromboplastin. Clot initiation was measured using ROTEM-CT, ReoRox-COT1 and ReoRox-COT2. Clot propagation was measured using ROTEM-CFT, ROTEM-Alpha Angle and ReoRox-Slope. Clot stability was measured using ROTEM-MCF and ReoRox-Gmax, and clot lysis was measured using ROTEM-ML and ReoRox-ClotSR. Results: Clot initiation time assessed by thromboelastometry and FOR was prolonged by increasing concentrations of both LMWHs (P < 0.01). Equivalent doses of tinzaparin in international units (anti FXa units) per millilitre prolonged clot initiation more than enoxaparin (P < 0.05). There was significant inter-individual variation - the ranges of CT and COT1 at LMWH-concentrations of 0 and 1.5 IU/mL overlapped. None of the tests reflecting clot formation rate or stability showed a dose-response to either LMWH but clot lysis showed a tentative negative dose-response to the LMWHs. Conclusions: Clot initiation times dose-dependent prolongation by LMWHs in this study agrees with previous research, as does tinzaparins stronger anti-coagulative effect than enoxaparin at equivalent levels of anti-FXa activity. This casts doubt on the validity of using anti-FXa assays alone to guide dosage of LMWHs. The significant inter-individual variation in dose-response suggests that the relationship between dose and effect in the postoperative period is complicated. While both ROTEM and FOR may have some role in postoperative monitoring, more research is needed before any conclusion can be made about their clinical usefulness.

  • 9.
    Thomas, Owain
    et al.
    Lund University, Sweden; SUS Lund University Hospital, Sweden.
    Lybeck, Emanuel
    Lund University, Sweden.
    Strandberg, Karin
    Lund University, Sweden; Skåne University Hospital, Sweden.
    Tynngård, Nahreen
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Schott, Ulf
    Lund University, Sweden; SUS Lund University Hospital, Sweden.
    Monitoring Low Molecular Weight Heparins at Therapeutic Levels: Dose-Responses of, and Correlations and Differences between aPTT, Anti-Factor Xa and Thrombin Generation Assays2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 1, article id e0116835Article in journal (Refereed)
    Abstract [en]

    Background Low molecular weight heparins (LMWHs) are used to prevent and treat thrombosis. Tests for monitoring LMWHs include anti-factor Xa (anti-FXa), activated partial thromboplastin time (aPTT) and thrombin generation. Anti-FXa is the current gold standard despite LMWHs varying affinities for FXa and thrombin. Aim To examine the effects of two different LMWHs on the results of 4 different aPTT-tests, anti-FXa activity and thrombin generation and to assess the tests concordance. Method Enoxaparin and tinzaparin were added ex-vivo in concentrations of 0.0, 0.5, 1.0 and 1.5 anti-FXa international units (IU)/mL, to blood from 10 volunteers. aPTT was measured using two whole blood methods (Free oscillation rheometry (FOR) and Hemochron Jr (HCJ)) and an optical plasma method using two different reagents (ActinFSL and PTT-Automat). Anti-FXa activity was quantified using a chromogenic assay. Thrombin generation (Endogenous Thrombin Potential, ETP) was measured on a Ceveron Alpha instrument using the TGA RB and more tissue-factor rich TGA RC reagents. Results Methods mean aPTT at 1.0 IU/mL LMWH varied between 54s (SD 11) and 69s (SD 14) for enoxaparin and between 101s (SD 21) and 140s (SD 28) for tinzaparin. ActinFSL gave significantly shorter aPTT results. aPTT and anti-FXa generally correlated well. ETP as measured with the TGA RC reagent but not the TGA RB reagent showed an inverse exponential relationship to the concentration of LMWH. The HCJ-aPTT results had the weakest correlation to anti-FXa and thrombin generation (R(s)0.62-0.87), whereas the other aPTT methods had similar correlation coefficients (R(s)0.80-0.92). Conclusions aPTT displays a linear dose-respone to LMWH. There is variation between aPTT assays. Tinzaparin increases aPTT and decreases thrombin generation more than enoxaparin at any given level of anti-FXa activity, casting doubt on anti-FXas present gold standard status. Thrombin generation with tissue factor-rich activator is a promising method for monitoring LMWHs.

  • 10.
    Tynngård, Nahreen
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Immunology and Transfusion Medicine.
    Free oscillation rheometry in the assessment of platelet quality2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Platelets play an important role in the haemostatic process in order to seal damaged blood vessels. The platelets form a platelet plug at the damaged area and prevent blood loss. Once the damage to the vessel wall has been covered, the platelets retract the coagulum, to allow the blood to flow freely in the vessel. Free oscillation rheometry (FOR) can be used for analysis of coagulation as measured by clotting time and changes in clot elasticity (G'). Clot G' provides information about the fibrin network in the coagulum and the platelets’ ability to retract the coagulum. FOR analysis is performed using the ReoRox® 4 instrument. The blood sample is added to a cylindrical sample cup, which is set into free oscillation. The frequency and damping of the oscillation is recorded over time as the blood coagulates. The change in G' is calculated from the frequency and damping measured. Patients with malignant haematological diseases are often thrombocytopaenic and require platelet transfusions to prevent or stop bleeding. To ensure good haemostatic function in the recipient it is important that the quality of the platelets used for transfusion is well preserved. The aim of this thesis was to determine the quality of platelet concentrates (PCs), during storage, using various in vitro methods, including FOR, and to investigate how various preparation processes affect the quality. We also investigated whether FOR can be used to evaluate the haemostatic status in subjects at risk for thrombosis or bleeding as well as how the haemostatic status was affected by a platelet transfusion.

    We show that FOR can provide information about the coagulation properties in subjects at risk of thrombosis (pregnant women) or bleeding (thrombocytopaenic patients). We also show that the coagulation as measured by FOR is influenced by red blood cells and the fibrinogen concentration. However, the presence of functional platelets accounted for 90% of the G'. Furthermore we present data that FOR can provide information on the haemostatic effect of platelet transfusions and on the function of the transfused platelets.

    PCs produced by two different cell separators showed similar quality during storage for 7 days as assessed by FOR analysis. Leukocytes in the PCs can cause transfusion-associated graft-versus-host disease which can be prevented by gamma irradiation of the PCs. Gamma irradiation did not affect the quality of PCs during 7 days of storage as analysed by FOR. The clotting time was unchanged during the storage period. The capacity of platelets to retract the coagulum was reduced from days 1 to 5 of storage as seen by a prolonged time to reach maximum G' and the reduced mean change in G' per minute. However, if sufficient time is allowed for the platelets to regain their function, the clot will be fully retracted (as seen by a well maintained maximum G'). The FOR parameters were similar for 5- and 7-day old PCs, which, combined with other in vitro tests (e.g. hypotonic shock response, changes in pH, swirling, lactate and glucose), support the prolongation of the platelet storage period to 7 days. Intercept treatment of PCs can be performed to inhibit replication of contaminating bacteria in PCs. Intercept treatment of PCs did not diminish the clot-promoting capacity of the platelets as assessed by FOR clotting time.

    In conclusion, FOR is a promising method for assessing hyper- and hypocoagulability. It can provide information on the haemostatic effect of platelet transfusions and the function of the transfused platelets. FOR was also shown to be useful for analysing PC quality during different preparation and storage conditions.

    List of papers
    1. Effects of different blood components on clot retraction analysed by measuring elasticity with a free oscillating rheometer
    Open this publication in new window or tab >>Effects of different blood components on clot retraction analysed by measuring elasticity with a free oscillating rheometer
    2006 (English)In: Platelets, ISSN 0953-7104, Vol. 17, no 8, p. 545-554Article in journal (Refereed) Published
    Abstract [en]

    Free oscillation rheometry (FOR) using the ReoRox® 4 instrument makes it possible, at bedside, to study the coagulation process in blood over time and gives information on clotting time and coagulum elastic properties. In order to find out how various factors influence the FOR analysis we studied the coagulation process and change of elasticity over time in non-anticoagulated and citrated blood samples, plasma samples with various platelet concentrations (0-200 109/l) and blood samples with various haematocrit (0-40%). Blood samples supplemented with fibrinogen were analysed to elucidate the importance of fibrinogen on elasticity. The importance of the GPIIb/IIIa receptor on platelets was investigated by comparing the elasticity development in blood samples in presence and absence of a GPIIb/IIIa receptor inhibitor, abciximab. Anticoagulation with citrate did not have major influence on the viscoelastic properties of the coagulum. Increasing number of platelets and increasing fibrinogen concentration resulted in higher elasticity while increasing haematocrit gave lower elasticity. Blood samples with GPIIb/IIIa receptor inhibitor had very low elasticity indicating the importance of functional GPIIb/IIIa receptors. In conclusion we consider FOR to be a useful method to study the elastic properties of the coagulum. Various factors such as the number of red blood cells and platelets as well as the fibrinogen concentration should be taken into consideration when evaluating the results. The ReoRox® 4 instrument had excellent measuring range and unusually small artefactual effects on clot elasticity induced by the instrument in comparison with published results on other instruments.

    Keywords
    Coagulation; clot retraction; elasticity; platelets; rheology
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13164 (URN)10.1080/09537100600759238 (DOI)
    Available from: 2008-04-14 Created: 2008-04-14 Last updated: 2015-03-13
    2. Free oscillation rheometry detects changes in clot properties in pregnancy and thrombocytopaenia
    Open this publication in new window or tab >>Free oscillation rheometry detects changes in clot properties in pregnancy and thrombocytopaenia
    Show others...
    2008 (English)In: Platelets, ISSN 0953-7104, Vol. 19, no 5, p. 373-378Article in journal (Refereed) Published
    Abstract [en]

    Improved methods are needed to identify patients at risk for thrombotic or bleeding events. Free oscillation rheometry (FOR) is a technique that offers information on coagulation, based on contributions of all blood components, by measurement of clotting time and changes in clot elasticity. This is the first study that evaluates FOR parameters in subjects likely to represent hypercoagulability (pregnant women) and hypocoagulability (thrombocytopenic patients). Clotting time and blood clot elasticity were measured by FOR in blood samples obtained from women in different pregnancy trimesters (n = 58), in thrombocytopenic patients before and after a platelet transfusion (n = 20) and in healthy blood donors (n = 60). The clotting time was shorter and the clot elasticity higher in pregnant women compared to the non-pregnant female blood donors. The elasticity was higher in late pregnancy compared to early pregnancy. Compared to the blood donors, the thrombocytopenic patients had lower elasticity, which was increased by a platelet transfusion, but there was no difference in clotting time. The results suggest that FOR can provide new information on the haemostatic status of patients at risk of thrombotic or bleeding events as well as information on the haemostatic effect of a platelet transfusion.

    Keywords
    Clot elasticity, clot retraction, coagulation, platelets
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13165 (URN)10.1080/09537100802082264 (DOI)
    Available from: 2008-04-14 Created: 2008-04-14 Last updated: 2015-03-13
    3. The quality of platelet concentrates produced by COBE Spectra and Trima Accel during storage for 7 days as assessed by in vitro methods
    Open this publication in new window or tab >>The quality of platelet concentrates produced by COBE Spectra and Trima Accel during storage for 7 days as assessed by in vitro methods
    Show others...
    2008 (English)In: Transfusion, ISSN 0041-1132, E-ISSN 1537-2995, Vol. 48, no 4, p. 715-722Article in journal (Refereed) Published
    Abstract [en]

    Background: The quality of PLT concentrates (PCs) can be evaluated using various in vitro methods. A new technique, free oscillation rheometry (FOR), can be used to monitor coagulation properties of PCs and gives information on clotting time and coagulum elasticity. This study compared the quality of apheresis PCs produced by COBE Spectra and Trima Accel during storage for 7 days using in vitro tests including FOR.

    Study design and methods: Apheresis PCs were collected with the COBE Spectra (n=10) and Trima Accel (n=10) cell separators. Swirling, blood gases and metabolic parameters were analyzed on day 0. Samples taken on day 1, 5 and 7 were also analyzed for hypotonic shock response (HSR), P-selectin and GPIb expression and evaluation of coagulation by FOR.

    Results: Swirling, HSR and percent GPIb expressing PLTs were well maintained for 7 days whereas glucose decreased and lactate increased significantly during storage for both Spectra and Trima PCs. Percent P-selectin expressing cells increased to the same extent in both types of PCs during storage. pH increased between day 0 and 1 but then decreased. The clotting time remained constant throughout the storage period whereas the development of elasticity was reduced on day 5 and 7 compared to day 1 (p<0.05) for both types of PCs.

    Conclusion: The results indicate that the PLT quality after storage for 7 days is well preserved although activation of PLTs occurs during storage as assessed by in vitro tests. No difference in platelet quality was observed between Spectra and Trima produced PCs.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-12533 (URN)10.1111/j.1537-2995.2007.01610.x (DOI)
    Note
    The definitive version is available at www.blackwell-synergy.com: Nahreen Tynngård, Tomas L. Lindahl, Marie Trinks, Monika Studer and Gösta Berlin, The quality of platelet concentrates produced by COBE Spectra and Trima Accel during storage for 7 days as assessed by in vitro methods, 2008, Transfusion, (48), 4, 715-722. Copyright: Blackwell Publishing www.blackwell-synergy.comAvailable from: 2008-09-08 Created: 2008-09-12 Last updated: 2017-12-08Bibliographically approved
    4. The effect of gamma irradiation on the quality of apheresis platelets during storage for 7 days
    Open this publication in new window or tab >>The effect of gamma irradiation on the quality of apheresis platelets during storage for 7 days
    Show others...
    2008 (English)In: Transfusion, ISSN 0041-1132, E-ISSN 1537-2995, Transfusion, Vol. 48, no 8, p. 1669-1675Article in journal (Refereed) Published
    Abstract [en]

    Background:This study compares the quality of gamma-irradiated versus nonirradiated platelet (PLT) concentrates (PCs) during storage for 7 days as assessed by various in vitro methods. A new technique, free oscillation rheometry (FOR), which measures clotting time and coagulum elasticity, was also used to evaluate the PLT function.

    Study design and methods: Single-donor PLTs were collected by apheresis technique (n = 20). The PLTs from each donor were divided into two PCs, one gamma-irradiated with 25 Gy and the other used as a nonirradiated control. Blood gases, metabolic variables, and swirling were analyzed from Day 0. Samples taken on Days 1, 5, and 7 were also analyzed for hypotonic shock response (HSR), P-selectin, and glycoprotein (GP)Ib expression by flow cytometry and coagulation by FOR.

    Results: Swirling, HSR, and the percentage of GPIb-expressing cells were well maintained for 7 days of storage. pH was always within accepted range (6.4-7.4). Glucose decreased and lactate increased during the storage period (p < 0.05). P-selectin expression increased during storage (p < 0.05). The FOR clotting time remained constant, whereas the build-up of elasticity was slower after storage (p < 0.05). No difference was found between irradiated and nonirradiated PCs.

    Conclusion: The results indicate a well-preserved quality of gamma-irradiated apheresis PLTs during storage for 7 days as assessed by in vitro methods, with no difference compared to nonirradiated PLTs.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13167 (URN)10.1111/j.1537-2995.2008.01746.x (DOI)
    Available from: 2008-04-14 Created: 2008-04-14 Last updated: 2017-12-13
    5. Effects of intercept pathogen inactivation on platelet function as analysed by free oscillation rheometry
    Open this publication in new window or tab >>Effects of intercept pathogen inactivation on platelet function as analysed by free oscillation rheometry
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    2008 (English)In: Transfusion and apheresis science, ISSN 1473-0502, E-ISSN 1878-1683, Vol. 38, no 1, p. 85-88Article in journal (Refereed) Published
    Abstract [en]

    Introduction: The Intercept Blood System, using InterSol as additive solution, is used for inactivation of contaminating pathogens in PCs, thus reducing the risk for transfusion transmitted infection and making it possible to prolong the storage period. This study aimed at investigating the ability of Intercept treated platelets to induce clot formation, as measured by coagulation time using free oscillation rheometry (FOR), and to compare with that of platelets in concentrates with the additive solution T-Sol or plasma.

    Methods: Seventy-four single-donor platelet units were diluted in InterSol (n = 27) or T-Sol (n = 47) to a mean plasma concentration of 38%. The Intercept treatment was performed by addition of amotosalen HCl to the InterSol PCs followed by UVA irradiation and treatment with a compound adsorption device (CAD). Forty-six units were collected and stored in 100% plasma for comparison. Clotting time was measured by FOR in fresh PCs (within 26 h after collection) after stimulation by a platelet activator. Soluble P-selectin was analysed as a marker of platelet activation in the Intercept and T-Sol PCs.

    Results: The clotting time was shorter for Intercept treated platelets compared to platelets in T-Sol and plasma (p < 0.05). There was no difference in clotting time between T-Sol and plasma PCs. Soluble P-selectin was higher for Intercept platelets than platelets in T-Sol (p < 0.05).

    Conclusions: The platelets treated with the Intercept procedure had good clot promoting capacity.

    Keywords
    Apheresis, Pathogen inactivation, Platelet concentrates, Platelet function
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13168 (URN)10.1016/j.transci.2007.12.012 (DOI)
    Available from: 2008-04-14 Created: 2008-04-14 Last updated: 2017-12-13
  • 11.
    Tynngård, Nahreen
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Immunology and Transfusion Medicine.
    Preparation, storage and quality control of platelet concentrates.2009In: Transfusion and apheresis science, ISSN 1473-0502, E-ISSN 1878-1683, Vol. 41, no 2, p. 97-104Article, review/survey (Refereed)
    Abstract [en]

    Patients with thrombocytopaenia need transfusions of platelet concentrates to prevent or stop bleeding. A platelet transfusion should provide platelets with good functionality. The quality of platelet concentrates (PCs) is affected by the preparation method and the storage conditions including duration of storage, type of storage container, and storage solution (plasma or an additive solution). Different in vivo and in vitro techniques can be used to analyse PCs. Platelets can be collected by apheresis technique, and from whole blood using either the buffy-coat or the platelet-rich plasma method. PCs can be gamma irradiated to prevent occurrence of graft-versus-host disease in the recipient. Pathogen inactivation procedures have been developed to prevent transmission of bacteraemia.

  • 12.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Samuelsson, Anders
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    Berg, Sören
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Low dose of hydroxyethyl starch impairs clot formation as assessed by viscoelastic devices2014In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 74, no 4, p. 344-350Article in journal (Refereed)
    Abstract [en]

    Objective. High doses of the synthetic colloid hydroxyethyl starch (HES) used for plasma expansion have been associated with impaired haemostasis and hypocoagulation. Less is known about effects on clot formation in the low haemodilutional range (less than 40%). This study evaluated the effects of low haemodilution with HES and albumin on coagulation using two different viscoelastic methods. Methods. Clot formation was studied in vitro in healthy donor blood after 10% and 30% haemodilution with 60 g/L HES 130/0.4 or 50 g/L albumin with free oscillation rheometry (FOR) and rotational thromboelastography. Results. Clotting time was not significantly affected at 10% haemodilution but was prolonged with both substances at 30% dilution (p less than 0.01-0.001). The effect was significantly more pronounced with HES than with albumin. The elasticity of the clot was slightly reduced at 10% dilution with albumin, more pronounced at 10% dilution with HES (p less than 0.05), further reduced at 30% dilution with albumin and to a still greater extent at 30% dilution with HES (p less than 0.05). With albumin the functional activity of fibrinogen was not reduced in excess of the dilutional effect. HES in contrast produced a further reduction in clot elasticity than caused by mere dilution at both 10% and 30% dilutions (p less than 0.001). Conclusions. There is an adverse effect on clot formation even at low grade haemodilution with both albumin and HES. The effect on coagulation is significantly more pronounced with HES than with albumin.

  • 13.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Regional Board, Research and Development Unit.
    Boknäs, Niklas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Haematology.
    Trinks, Marie
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Dreimane, Arta
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Haematology.
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Storage-induced change in platelet transfusion response evaluated by serial transfusions from one donor to one patient2019In: Transfusion, ISSN 0041-1132, E-ISSN 1537-2995, Vol. 59, no 2, p. 723-728Article in journal (Refereed)
    Abstract [en]

    BACKGROUND

    Storage of platelet concentrates (PCs) results in storage lesions with possible detrimental effects on platelet recovery after transfusion, which might affect their ability to prevent or arrest bleeding. The aim of this study was to compare the quality of PCs stored for 1 to 3 or 5 to 7 days by assessing the corrected count increment (CCI) after transfusion. To isolate the effects of storage time, we studied serial transfusions of PCs obtained from one donor and one donation, and transfused to one single recipient after storage for 1 to 3 days and 5 to 7 days.

    STUDY DESIGN AND METHODS

    Platelets were obtained from one donor by apheresis, divided into two units (>240 × 109platelets/unit) and stored for 1 to 3 and 5 to 7 days, respectively, before transfusion. The PCs were transfused on normal indications to patients undergoing treatment at the hematology ward. Platelet count was measured before and after transfusion.

    RESULTS

    Thirty patients concluded the study according to the protocol. The mean storage time was 2.4 ± 0.7 and 5.7 ± 0.8 days for platelets transfused on Days 1 to 3 and 5 to 7, respectively. Storage for 5 to 7 days decreased the 1‐hour transfusion response as compared to platelets stored 1 to 3 days, from a CCI of 17 ± 7 to 13 ± 5. Despite this decrease, 86% of the 5 to 7 days stored PCs resulted in a CCI above the cutoff value for a successful transfusion of 7.5, which was not significantly different to PCs stored for 1 to 3 days.

    CONCLUSION

    Storage of PCs for 5 to 7 days only slightly altered the transfusion response.

  • 14.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Immunology and Transfusion Medicine.
    Johansson, Britt-Marie
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas L
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Immunology and Transfusion Medicine.
    Hansson, Mona
    Karolinska University Hospital and Karolinska Institute.
    Effects of intercept pathogen inactivation on platelet function as analysed by free oscillation rheometry2008In: Transfusion and apheresis science, ISSN 1473-0502, E-ISSN 1878-1683, Vol. 38, no 1, p. 85-88Article in journal (Refereed)
    Abstract [en]

    Introduction: The Intercept Blood System, using InterSol as additive solution, is used for inactivation of contaminating pathogens in PCs, thus reducing the risk for transfusion transmitted infection and making it possible to prolong the storage period. This study aimed at investigating the ability of Intercept treated platelets to induce clot formation, as measured by coagulation time using free oscillation rheometry (FOR), and to compare with that of platelets in concentrates with the additive solution T-Sol or plasma.

    Methods: Seventy-four single-donor platelet units were diluted in InterSol (n = 27) or T-Sol (n = 47) to a mean plasma concentration of 38%. The Intercept treatment was performed by addition of amotosalen HCl to the InterSol PCs followed by UVA irradiation and treatment with a compound adsorption device (CAD). Forty-six units were collected and stored in 100% plasma for comparison. Clotting time was measured by FOR in fresh PCs (within 26 h after collection) after stimulation by a platelet activator. Soluble P-selectin was analysed as a marker of platelet activation in the Intercept and T-Sol PCs.

    Results: The clotting time was shorter for Intercept treated platelets compared to platelets in T-Sol and plasma (p < 0.05). There was no difference in clotting time between T-Sol and plasma PCs. Soluble P-selectin was higher for Intercept platelets than platelets in T-Sol (p < 0.05).

    Conclusions: The platelets treated with the Intercept procedure had good clot promoting capacity.

  • 15.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine . Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas L
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Ramström, Sofia
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine . Linköping University, Faculty of Health Sciences.
    Effects of different blood components on clot retraction analysed by measuring elasticity with a free oscillating rheometer2006In: Platelets, ISSN 0953-7104, Vol. 17, no 8, p. 545-554Article in journal (Refereed)
    Abstract [en]

    Free oscillation rheometry (FOR) using the ReoRox® 4 instrument makes it possible, at bedside, to study the coagulation process in blood over time and gives information on clotting time and coagulum elastic properties. In order to find out how various factors influence the FOR analysis we studied the coagulation process and change of elasticity over time in non-anticoagulated and citrated blood samples, plasma samples with various platelet concentrations (0-200 109/l) and blood samples with various haematocrit (0-40%). Blood samples supplemented with fibrinogen were analysed to elucidate the importance of fibrinogen on elasticity. The importance of the GPIIb/IIIa receptor on platelets was investigated by comparing the elasticity development in blood samples in presence and absence of a GPIIb/IIIa receptor inhibitor, abciximab. Anticoagulation with citrate did not have major influence on the viscoelastic properties of the coagulum. Increasing number of platelets and increasing fibrinogen concentration resulted in higher elasticity while increasing haematocrit gave lower elasticity. Blood samples with GPIIb/IIIa receptor inhibitor had very low elasticity indicating the importance of functional GPIIb/IIIa receptors. In conclusion we consider FOR to be a useful method to study the elastic properties of the coagulum. Various factors such as the number of red blood cells and platelets as well as the fibrinogen concentration should be taken into consideration when evaluating the results. The ReoRox® 4 instrument had excellent measuring range and unusually small artefactual effects on clot elasticity induced by the instrument in comparison with published results on other instruments.

  • 16.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas L
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Ramström, Sofia
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Räf, Tuulia
    Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Rugarn, Olof
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences.
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences.
    Free oscillation rheometry detects changes in clot properties in pregnancy and thrombocytopaenia2008In: Platelets, ISSN 0953-7104, Vol. 19, no 5, p. 373-378Article in journal (Refereed)
    Abstract [en]

    Improved methods are needed to identify patients at risk for thrombotic or bleeding events. Free oscillation rheometry (FOR) is a technique that offers information on coagulation, based on contributions of all blood components, by measurement of clotting time and changes in clot elasticity. This is the first study that evaluates FOR parameters in subjects likely to represent hypercoagulability (pregnant women) and hypocoagulability (thrombocytopenic patients). Clotting time and blood clot elasticity were measured by FOR in blood samples obtained from women in different pregnancy trimesters (n = 58), in thrombocytopenic patients before and after a platelet transfusion (n = 20) and in healthy blood donors (n = 60). The clotting time was shorter and the clot elasticity higher in pregnant women compared to the non-pregnant female blood donors. The elasticity was higher in late pregnancy compared to early pregnancy. Compared to the blood donors, the thrombocytopenic patients had lower elasticity, which was increased by a platelet transfusion, but there was no difference in clotting time. The results suggest that FOR can provide new information on the haemostatic status of patients at risk of thrombotic or bleeding events as well as information on the haemostatic effect of a platelet transfusion.

  • 17.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Immunology and Transfusion Medicine.
    Lindahl, Tomas
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Trinks, Marie
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Studer, Monika
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Immunology and Transfusion Medicine.
    The quality of platelet concentrates produced by COBE Spectra and Trima Accel during storage for 7 days as assessed by in vitro methods2008In: Transfusion, ISSN 0041-1132, E-ISSN 1537-2995, Vol. 48, no 4, p. 715-722Article in journal (Refereed)
    Abstract [en]

    Background: The quality of PLT concentrates (PCs) can be evaluated using various in vitro methods. A new technique, free oscillation rheometry (FOR), can be used to monitor coagulation properties of PCs and gives information on clotting time and coagulum elasticity. This study compared the quality of apheresis PCs produced by COBE Spectra and Trima Accel during storage for 7 days using in vitro tests including FOR.

    Study design and methods: Apheresis PCs were collected with the COBE Spectra (n=10) and Trima Accel (n=10) cell separators. Swirling, blood gases and metabolic parameters were analyzed on day 0. Samples taken on day 1, 5 and 7 were also analyzed for hypotonic shock response (HSR), P-selectin and GPIb expression and evaluation of coagulation by FOR.

    Results: Swirling, HSR and percent GPIb expressing PLTs were well maintained for 7 days whereas glucose decreased and lactate increased significantly during storage for both Spectra and Trima PCs. Percent P-selectin expressing cells increased to the same extent in both types of PCs during storage. pH increased between day 0 and 1 but then decreased. The clotting time remained constant throughout the storage period whereas the development of elasticity was reduced on day 5 and 7 compared to day 1 (p<0.05) for both types of PCs.

    Conclusion: The results indicate that the PLT quality after storage for 7 days is well preserved although activation of PLTs occurs during storage as assessed by in vitro tests. No difference in platelet quality was observed between Spectra and Trima produced PCs.

  • 18.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine . Linköping University, Faculty of Health Sciences.
    Studer, Monika
    Lindahl, Tomas L
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Trinks, Marie
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    The effect of gamma irradiation on the quality of apheresis platelets during storage for 7 days2008In: Transfusion, ISSN 0041-1132, E-ISSN 1537-2995, Transfusion, Vol. 48, no 8, p. 1669-1675Article in journal (Refereed)
    Abstract [en]

    Background:This study compares the quality of gamma-irradiated versus nonirradiated platelet (PLT) concentrates (PCs) during storage for 7 days as assessed by various in vitro methods. A new technique, free oscillation rheometry (FOR), which measures clotting time and coagulum elasticity, was also used to evaluate the PLT function.

    Study design and methods: Single-donor PLTs were collected by apheresis technique (n = 20). The PLTs from each donor were divided into two PCs, one gamma-irradiated with 25 Gy and the other used as a nonirradiated control. Blood gases, metabolic variables, and swirling were analyzed from Day 0. Samples taken on Days 1, 5, and 7 were also analyzed for hypotonic shock response (HSR), P-selectin, and glycoprotein (GP)Ib expression by flow cytometry and coagulation by FOR.

    Results: Swirling, HSR, and the percentage of GPIb-expressing cells were well maintained for 7 days of storage. pH was always within accepted range (6.4-7.4). Glucose decreased and lactate increased during the storage period (p < 0.05). P-selectin expression increased during storage (p < 0.05). The FOR clotting time remained constant, whereas the build-up of elasticity was slower after storage (p < 0.05). No difference was found between irradiated and nonirradiated PCs.

    Conclusion: The results indicate a well-preserved quality of gamma-irradiated apheresis PLTs during storage for 7 days as assessed by in vitro methods, with no difference compared to nonirradiated PLTs.

  • 19.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Trinks, M.
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    In vitro quality of platelets during prolonged storage after washing with three platelet additive solutions2012In: Vox Sanguinis, ISSN 0042-9007, E-ISSN 1423-0410, Vol. 102, no 1, p. 32-39Article in journal (Refereed)
    Abstract [en]

    Background and Objectives Patients with anaphylactic transfusion reactions require washed platelet concentrates (PCs) for subsequent platelet (PLT) transfusions. New PLT additive solutions (PASs) contain substances that might be beneficial for the preservation of PLT function during storage. This study compares the quality of PLTs washed and stored with T-Sol, Composol or SSP+. Study Design and Methods Fifteen buffy coats were pooled and divided into three parts. PCs with 30% plasma and 70% PAS (T-Sol, Composol or SSP+) were prepared. Washing was performed on day 5 of storage. Ten PCs were prepared and washed with each PAS. In vitro variables including haemostatic function (clotting time and clot retraction) were analysed on day 5 before, directly after and up to 2days after washing. Results Swirling was well preserved, and pH was within acceptable limits (6·4-7·4) during storage for all PASs. The PLT number was reduced by washing for all PASs, and T-Sol PCs had a further decrease during storage. PLTs in T-Sol were spontaneously more activated and had lower capacity to respond to an agonist than Composol or SSP+ PLTs. The haemostatic function was only slightly changed by washing and during postwashing storage. Conclusion PLTs washed with T-Sol, Composol or SSP+ had good in vitro quality for two days after washing despite absence of glucose. PLTs in T-Sol were more affected by the washing procedure and subsequent storage than Composol or SSP+ PLTs as judged by higher spontaneous activation. © 2011 The Author(s). Vox Sanguinis © 2011 International Society of Blood Transfusion.

  • 20.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Trinks, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Berlin, Gosta
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Platelet quality after washing: the effect of storage time before washing2010In: TRANSFUSION, ISSN 0041-1132, Vol. 50, no 12, p. 2745-2752Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Patients who have experienced anaphylactic transfusion reactions receive washed platelet (PLT) concentrates (PCs) where the plasma has been substituted with a PLT additive solution. This study compares the in vitro quality of PCs washed at the beginning of the storage period (Day 1) to PCs washed at the end of storage (Day 7). STUDY DESIGN AND METHODS: PLTs were prepared by the buffy coat procedure. Two concentrates were pooled and then split to obtain an identical pair of PCs. One of the PCs was washed with T-Sol on Day 1 and the other on Day 7 of storage. Swirling, blood gases, and metabolic variables were analyzed before washing. Analyses of surface expression of CD62P and coagulation by free oscillation rheometry (FOR) were performed before and after washing. RESULTS: pH was acceptable in all PCs. Washing on Days 1 and 7 increased the CD62P surface expression. The FOR variables clotting time and clot retraction were not influenced by washing on either day. Washing resulted in a decrease in the number of PLTs and the decrease was larger on Day 7 compared to Day 1. CONCLUSIONS: PLTs washed on Days 1 and 7 of storage are effected by washing in a similar manner. However, a larger loss of PLTs occurred during washing on Day 7.

  • 21.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Trinks, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Berlin, Gosta
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    QUALITY OF PLATELETS IN CONCENTRATES DURING STORAGE IN THREE ADDITIVE SOLUTIONS: T-SOL, COMPOSOL AND SSP in VOX SANGUINIS, vol 99, issue , pp 214-2142010In: VOX SANGUINIS, Blackwell Publishing Ltd , 2010, Vol. 99, p. 214-214Conference paper (Refereed)
    Abstract [en]

    n/a

  • 22.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Trinks, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Berlin, Gosta
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    THE INFLUENCE OF DIFFERENT PLATELET ADDITIVE SOLUTIONS ON THE QUALITY OF PLATELETS AFTER WASHING in VOX SANGUINIS, vol 99, issue , pp 214-2142010In: VOX SANGUINIS, Blackwell Publishing Ltd , 2010, Vol. 99, p. 214-214Conference paper (Refereed)
    Abstract [en]

    n/a

  • 23.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Trinks, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    In vitro function of platelets treated with ultraviolet C light for pathogen inactivation: a comparative study with nonirradiated and gamma-irradiated platelets2015In: Transfusion, ISSN 0041-1132, E-ISSN 1537-2995, Vol. 55, no 6, p. 1169-1177Article in journal (Refereed)
    Abstract [en]

    BackgroundDuring storage of platelet concentrates (PCs) replication of contaminating pathogens might occur, which can be prevented by various pathogen inactivation (PI) methods using photoactive substances in combination with ultraviolet (UV) light. A new method uses only UVC light for PI without photoactive substances. This study evaluates the in vitro function, including hemostatic properties (clot formation and elasticity), of platelets (PLTs) treated with UVC light. Study Design and MethodsA PC with 35% plasma and 65% PLT additive solution (SSP+) was prepared from five buffy coats. Three PCs were pooled and divided into 3units. One unit was used as a nonirradiated control, the second was a gamma-irradiated control, and the third unit was treated with UVC light. In vitro variables including analysis of coagulation by free oscillation rheometry were analyzed on Days 1, 5, and 7 of storage. Ten units in each group were investigated. ResultsSwirling was well preserved, and the pH level was higher than the reference limit (6.4) during storage of PLTs in all groups. Glycolysis and PLT activation were higher for UVC-treated PLTs but the clot-forming capacity was unaffected. However, immediately after UVC treatment, the clot elastic properties were slightly affected. Hypotonic shock response decreased immediately after UVC treatment but recovered partly during the storage period. ConclusionUVC treatment affected the in vitro properties, but PLT quality and storage stability were well preserved for up to 7 days, and the in vitro hemostatic capacity of UVC-treated PLTs was only minimally altered. The clinical relevance of these changes needs to be evaluated in controlled trials.

  • 24.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Trinks, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    In vitro properties of platelets stored in a small container for pediatric transfusion2014In: Transfusion, ISSN 0041-1132, E-ISSN 1537-2995, Vol. 54, no 6, p. 1562-1568Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    The quality of a platelet (PLT) concentrate (PC) is affected by the number of PLTs in relation to the size and gas permeability of the container. This study evaluates the in vitro function, including hemostatic properties (clot formation and elasticity), of PLTs stored in a container of standard or small size.

    STUDY DESIGN AND METHODS:

    PCs with 30% plasma and 70% PLT additive solution were prepared from buffy coats. Two PCs were pooled and divided into the following containers: 1 unit and ½ a unit into a 1.8-L container (reference container) and ½ a unit into a 0.45-L container (test container). In a second set of experiments ¼ of a unit was stored in the reference and test containers. Swirling, PLT count, blood gases, metabolic variables, PLT activation markers, hypotonic shock response (HSR), and coagulation by free oscillation rheometry were analyzed during 7 days of storage.

    RESULTS:

    Swirling was well preserved and pH was acceptable (6.4-7.4) during storage of PLTs in both containers. Glycolysis and PLT activation were higher when storing ½ and ¼ of a unit in the reference container and storage of ¼ of a unit in the reference container resulted in the largest decrease in HSR. The clotting time was similar whereas the clot elasticity was slightly lower for PLTs when stored as ½ and ¼ of a unit in the reference container.

    CONCLUSION:

    Storage of a low number of PLTs benefits by storage in a small container in terms of better maintained in vitro properties.

  • 25.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Trinks, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Berlin, Gösta
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    In vitro properties of platelets stored in three different additive solutions2012In: Transfusion, ISSN 0041-1132, E-ISSN 1537-2995, Vol. 52, no 5, p. 1003-1009Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: New platelet (PLT) additive solutions (PASs) contain compounds that might improve the storage conditions for PLTs. This study compares the in vitro function, including hemostatic properties (clot formation and elasticity), of PLTs in T-Sol, Composol, or SSP+ during storage for 5 days. STUDY DESIGN AND METHODS: Fifteen buffy coats were pooled and divided into three parts. PLT concentrates (PCs) with 30% plasma and 70% PAS (T-Sol, Composol, or SSP+) were prepared (n = 10). Swirling, PLT count, blood gases, metabolic variables, PLT activation markers, and coagulation by free oscillation rheometry (FOR) were analyzed on Days 1 and 5. RESULTS: Swirling was well preserved and pH acceptable (6.4-7.4) during storage for all PASs. Storage of PLTs in T-Sol led to a decrease in PLT count whereas the number of PLTs was unchanged in Composol or SSP+ PCs. PLTs in T-Sol showed higher glucose metabolism than PLTs in Composol or in SSP+. At the end of storage PLTs in T-Sol had higher spontaneous activation and lower ability to respond to an agonist than PLTs in Composol or SSP+. PLTs in all the PASs had a similar ability to promote clot formation and clot elasticity. CONCLUSION: Storage of PLTs in Composol or in SSP+ improved the quality of PCs in terms of better maintained PLT count, lower glucose metabolism, lower spontaneous activation, and improved response to a PLT agonist compared to PLTs in T-Sol. PLTs stored in the various PASs had similar hemostatic properties. These findings make Composol and SSP+ interesting alternatives as PASs.

  • 26.
    Tynngård, Nahreen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Wallstedt, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Södergren, Anna L
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Faxälv, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Ramström, Sofia
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Platelet adhesion changes during storage studied with a novel method using flow cytometry and protein-coated beads2015In: Platelets, ISSN 0953-7104, E-ISSN 1369-1635, Vol. 26, no 2, p. 177-185Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to set up and evaluate a novel method for studies of platelet adhesion and activation in blood and platelet suspensions such as platelet concentrate (PC) samples using protein-coated polystyrene beads and flow cytometry. To demonstrate its usefulness, we studied PCs during storage. PCs were prepared by aphaeresis technique (n = 7). Metabolic variables and platelet function was measured on day 1, 5, 7 and 12 of storage. Spontaneous and TRAP-6-induced adhesion to fibrinogen- and collagen-coated beads was analyzed by flow cytometry. P-selectin and phosphatidyl serine (PS) expression was assessed on platelets bound to beads as well as on non-adherent platelets. Platelet adhesion to fibrinogen beads had increased by day 12 and adhesion to collagen beads at day 7 of storage (p < 0.05). TRAP-6 stimulation significantly increased the platelet adhesion to fibrinogen beads (p < 0.05) as well as the P-selectin and PS exposure on platelets bound to beads (p < 0.01) during the first 7 days of storage, but by day 12, significant changes were no longer induced by TRAP-6 stimulation. We demonstrate that our adhesion assay using protein-coated polystyrene beads can be used to assess the adhesion properties of platelets during storage without the addition of red blood cells. Therefore it may offer a useful tool for future studies of platelet adhesive capacity in transfusion medicine and other settings.

  • 27.
    Winstedt, Dag
    et al.
    Lund University, Sweden.
    Tynngård, Nahreen
    Linköping University, Department of Clinical and Experimental Medicine, Transfusion Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Olanders, Knut
    Lund University, Sweden.
    Schott, Ulf
    Lund University, Sweden.
    Free oscillation rheometry monitoring of haemodilution and hypothermia and correction with fibrinogen and factor XIII concentrates2013In: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, ISSN 1757-7241, E-ISSN 1757-7241, Vol. 21Article in journal (Refereed)
    Abstract [en]

    Background

    Haemodilution and hypothermia induce coagulopathy separately, but their combined effect on coagulation has not been widely studied. Fibrinogen concentrate can correct dilutional coagulopathy and has an additional effect when combined with factor XIII concentrate. However, their effect on dilutional coagulopathy concomitant with hypothermia has not been studied previously. Free oscillation rheometry – FOR (Reorox®) – is a novel viscoelastic haemostatic assay that has not been studied in this context before.

    Methods

    Blood from 10 healthy volunteers was diluted by 33% with hydroxyethyl starch or Ringer’s acetate solutions. Effects of fibrinogen added in vitro with and without factor XIII were studied at 33°C and 37°C. Coagulation velocity (coagulation time) and clot strength (elasticity) were assessed with FOR. Coagulation was initiated in vitro with thromboplastin alone, or thromboplastin plus a platelet inhibitor.

    Results

    Hydroxyethyl starch increased the coagulation time and decreased clot strength significantly more than Ringer’s acetate solution, both in the presence and absence of a platelet inhibitor. There was a significant interaction between haemodilution with hydroxyethyl starch and hypothermia, resulting in increased coagulation time. After addition of fibrinogen, coagulation time shortened and elasticity increased, with the exception of fibrinogen-dependent clot strength (i.e., elasticity in the presence of a platelet inhibitor) after hydroxyethyl starch haemodilution. Factor XIII had an additional effect with fibrinogen on fibrinogen-dependent clot strength in blood diluted with Ringer’s acetate solution. Hypothermia did not influence any of the coagulation factor effects.

    Conclusions

    Both haemodilution and mild hypothermia impaired coagulation. Coagulopathy was more pronounced after haemodilution with hydroxyethyl starch than with Ringer’s acetate. Addition of fibrinogen with factor XIII was unable to reverse hydroxyethyl starch induced clot instability, but improved coagulation in blood diluted with Ringer’s acetate solution. Fibrinogen improved coagulation irrespective of hypothermia.

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