Heating pad for the bleeding: external warming during hemorrhage improves survival.

Background: Hypothermia is common during hemorrhagic shock. To warm the victims or not has been controversial. This study aims to investigate the effect of warming during the initial time of hemorrhage on body temperature, blood pressure, and survival in rat hemorrhagic shock models.

Methods: Forty anesthetized rats were divided into control group (n = 20) and warming group (n = 20). The rats of control group were placed on a wooden pad without heating, and the rats of warming group were placed on a heating pad maintained at 37°C ± 0.1°C. Blood withdrawal reached 40% of the total blood volume within 60 minutes. Numbers of survival rats, rectal temperature, and mean arterial pressure (MAP) were recorded when blood loss reached 0 (T0), 20% (T20), 30% (T30), and 40% (T40) of the total blood volume, respectively.

Results: Rectal temperature and MAP decrease gradually in both groups during hemorrhage. Warming continuously makes the rectal temperature of the warming group (36.68°C ± 0.63°C) slightly higher than that of the control group (36.17°C ± 0.69°C) at T0. The rectal temperature and MAP of the warming group are higher than that of the control group at T20, T30, and T40 (p < 0.05). Survival rates of the warming group are higher than that of the control group (p < 0.01).

Conclusions: Warming during hemorrhage may prevent exacerbation of hypothermia and hypotension and therefore improve survival.