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Introduction: While previous studies have shown a significant impact of extreme hypo- and hyperthermia on coagulation, effects of much more frequently occurring perioperative mild hypothermia are largely unknown. This study therefore aimed to analyze the effects of mild hypothermia using rotational thromboelastometry in vitro. Materials and Methods: Twelve healthy volunteers were included in this study. Standard thromboelastometric tests (EXTEM, INTEM, FIBTEM) were used to evaluate coagulation in vitro at 39, 37, 35.5, 35, and 33°C. Beyond standard thromboelastometric tests, we also evaluated the effects of mild hypothermia on the TPA-test (ClotPro, Enicor GmbH, Munich, Germany), a new test which aims to detect fibrinolytic capacity by adding tissue plasminogen activator to the sample. Data are presented as the median with 25/75th percentiles. Results: Extrinsically activated coagulation (measured by EXTEM) showed a significant increase in clot formation time (CFT; 37°C: 90 s [81/105] vs. 35°C: 109 s [99/126]; p = 0.0002), while maximum clot firmness (MCF) was not significantly reduced. Intrinsically activated coagulation (measured by INTEM) also showed a significant increase in CFT (37°C: 80 s [72/88] vs. 35°C: 94 s [86/109]; p = 0.0002) without significant effects on MCF. Mild hypothermia significantly increased both the lysis onset time (136 s [132/151; 37°C] vs. 162 s [141/228; 35°C], p = 0.0223) and lysis time (208 s [184/297; 37°C] vs. 249 s [215/358; 35°C]; p = 0.0259). Conclusion: This demonstrates that even under mild hypothermia coagulation is significantly altered in vitro. Perioperative temperature monitoring and management are greatly important and can help to prevent mild hypothermia and its adverse effects. Further investigation and in vivo testing of coagulation under mild hypothermia is needed. [ABSTRACT FROM AUTHOR]

Introduction: Fibrinogen concentrates are widely used to restore clot stability in situations of bleeding. Fibrinogen preparations are produced using different production methods, resulting in different compounds. Thus, different preparations might have a distinct impact on blood coagulation. We tested the effect of fibrinogen concentrates Haemocomplettan® (CSL Behring, Marburg, Germany) and fibryga® (Octapharma GmbH, Langenfeld, Germany) on the impairments induced by 60% dilutional coagulopathy in vitro. Materials and Methods: The influence of the fibrinogen concentrates fibryga® and Haemocomplettan® on colloid (gelatine, hydroxyethyl starch [HES], albumin)-induced or crystalloid (Ringer's acetate)-induced dilutional coagulopathy was analysed using rotational thromboelastometry (ROTEM®) and standard laboratory tests. The following experimental conditions were analysed in vitro: whole blood, 60% dilution (40% blood and 60% diluent) ± 50 or 100 mg/kg–1 fibryga® or Haemocomplettan®, respectively. Results: Dilution with either diluent resulted in prolonged clotting time (CT) in an extrinsic activated test (CTEXTEM) and decreased maximum clot firmness (MCFFIBTEM) as expressed, e.g., by gelatine: (59.5 s [62/54.8] vs. 95 s [102.8/86.8]; p < 0.001 and 14 mm [16/10.5] vs. 3 mm [4–3]; p < 0.001). Substitution after 60% dilution with HES resulted in no difference between the preparations, except for shorter thrombin time with fibryga® (14 s [15/14] vs. 18 s [18.8/17]; p = 0.0093; low dose). CTEXTEM was higher with Haemocomplettan® in a gelatine-induced dilution (51 s [54.5/47.5] vs. 63 s [71/60.3]; p = 0.0202; low dose) whereas thrombin time was lower with fibryga® (19.5 s [20.8/19] vs. 27 s [29/25.3]; p = 0.0017). In dilution with albumin, differences in CTEXTEM (69 s [76.5/66] vs. 56 s [57/53.3]; p = 0.0114; low dose) and thrombin time (18 s [18/17] vs. 24.5 s [25.8/24]; p = 0.0202; low dose) were seen. In dilution with crystalloid solution, again differences in CTEXTEM (53.5 s [57.8/53] vs. 45 s [47/43]; p = 0.035; low dose) and thrombin time (17 s [17/16] vs. 23.5 s [24/23]; p = 0.0014; low dose) were seen. Fibrinogen levels were more increased by high-dose substitution of both preparations. Conclusion: Based on this data it can be stated that both fibryga® and Haemocomplettan® had the same performance in our in vitro model except for CTEXTEM and thrombin time. [ABSTRACT FROM AUTHOR]