Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Taucher, A.
The Seasonal Variation in the Effects of Central Hypovolemia Induced by Lower Body Negative Pressure (LBNP) on Coagulation.
Humanmedizin; [ Diplomarbeit ] Graz Medical University; 2020. pp. 56
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Cvirn Gerhard
- Goswami Nandu
- Altmetrics:
- Abstract:
- Introduction: LBNP is a method to stimulate an artificial state similar to orthostatic stress and/or bleeding, reducing the central venous pressure by applying a vacuum at the lower body. This thesis aims to compare coagulation related baseline values as well as their response to LBNP in cold versus warm seasons. Methods: LBNP was applied gradually (-10mmHg, -20mm Hg, -30mmHg, -40mmHg) in a controlled setting with a room temperature of 23°C-24°C. During the experiment three blood samples, one for baseline parameters, one at the point of applied LBNP, and one after a 10min recovery-phase were sampled and subsequently evaluated. Results: The subjects were 18-35 years old, 160-180cm tall, non-smokers without known abnormalities in the coagulation system. The baseline values of FII, TF and the markers for thrombin-generation TAT and F1+2 were increased during summer when compared to winter. Factor VIII, F1+2, TAT and CT showed a significant rise in response to LBNP. In summer some variables measured via CAT (Lag, ttPeak, Peak) shifted in a procoagulant manner during applied LBNP. Hct showed an initial decrease with a subsequent rise in recovery phase accompanied by RBC, Hb and WBC. In the examined subjects LBNP application reduced INR in winter and aPTT in summer. Discussion: The higher baseline values of FII, TF, F1+2, TAT as well as the greater response to LBNP by thrombin-generation markers F1+2, TAT, Lag, ttPeak and Peak imply a higher plasmatic coagulation activity of the subjects during summer as. These results stand in contrast to the available literature describing incidents of VTE accumulating during winter. The room temperature of the testing facility, the in comparison to other sources relatively young sample group, as well as individual contributing factors such as potential inflammatory processes could possibly explain this discrepancy and could imply that factors such as those mentioned above may influence the coagulation more profoundly than seasonal tendencies, overruling their possible effects in young adults.