Cold-induced hypercoagulability in vitro: a trauma connection?

Injury severity score and hypothermia can lead to a high level of mortality when combined clinically. In acute trauma, the presence of a coagulopathy is difficult to treat and the aim is prevention. Aliquots of whole blood from healthy human volunteers (n = 9) were added to saline (control) and saline plus endotoxin (activated). The control and activated groups were divided and subjected to 60 minutes of normothermia (24 degrees C) or hypothermia (0 degrees C). The samples were returned to 37 degrees C; then the recalcification times were determined using fibrin formation and the viscous drag as the determining factors. The activated hypothermic group showed a decreased recalcification time of 345 (+/- 48.9) seconds compared to 405 (+/- 60.8) for the activated normothermic group (P less than 0.001). When the normothermic and hypothermic groups were compared without endotoxin added, the differences were not significant. The authors conclude that the effects of endotoxin on clotting time are worsened by hypothermia in vitro and act synergistically to possibly cause the coagulopathy seen in trauma patients.