Abstract: [Abstract] Objective To study effects of environmental hypothermia on hemodynamics and oxygen dynamics in hemorrhagic shock (HS) pigs. Methods sixteen healthy Bama miniature pigs were randomly divided into 2 groups (n = 8): normal temperature group (group C) and environmental hypothermia exposure group (group H). Blood of all pigs were withdrawn by 30 ml•kg-1 in 15min at equal pace to achieved capacity controlled hemorrhagic shock. Record all models’ heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), mean pulmonary artery pressure (MPAP), pulmonary artery wedge pressure (PAWP) and cardiac output (CO) consecutively, and calculated stroke volume (SV) and systemic vascular resistance (SVR); and blood gas analysis through the artery, pulmonary artery blood for monitoring blood lactate (LA), mixed venous oxygen saturation (SmvO2), and calculating the oxygen uptake (Ca-vO2) , oxygen delivery (DO2),oxygen consumption(VO2), oxygen extraction ratio(O2ER)and ΔPCO2 at time of pro-bleed (T0) and different time points in 4h (T1~T10) of post-bleed, record survive time of all pigs. Results Compared with group C, at time of T1, HR was slower ( P <0.05), in the time of T3~T9, MAP was higher ( P <0.05), at time of T10, CO was lower ( P <0.05), in the time of T7~T10, SV was lower ( P <0.05), in the time of T3~T10, SVR was higher ( P <0.05) in group H. When in the time of T7~T10, compare with group C, SmvO2 was lower (P <0.05), Ca-vO2 and O2ER was higher ( P <0.05) in group H, other indexes have no significant comparison statistically (P> 0.05). Kaplan-Meier survival analysis showed that the living conditions in group C was better than group H (Log-rank test P = 0.025). Conclusion Compared with normal temperature group, vascular resistance was higher, cardiac output was lower and oxygen metabolism was more complex when HS body was exposed in environmental hypothermia. Environmental hypothermia can overwhelm HS body, the natural progression of the HS body was accelerated and its short-term mortality was increased.
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