Poh Paula Y S, Gagnon Daniel, Romero Steven A, Convertino Victor A, Adams-Huet Beverley, Crandall Craig G
*Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital and UT Southwestern Medical Center, Dallas, Texas †Tactical Combat Casualty Care, U.S. Army Institute for Surgical Research, Fort Sam Houston, Texas ‡Departments of Clinical Sciences and Internal Medicine, UT Southwestern Medical Center, Dallas, Texas.
Shock. 2016 Sep;46(3 Suppl 1):42-9. doi: 10.1097/SHK.0000000000000661.
One in 10 deaths worldwide is caused by traumatic injury, and 30% to 40% of those trauma-related deaths are due to hemorrhage. Currently, warming a bleeding victim is the standard of care due to the adverse effects of combined hemorrhage and hypothermia on survival. We tested the hypothesis that heating is detrimental to the maintenance of arterial pressure and cerebral perfusion during hemorrhage, while cooling is beneficial to victims who are otherwise normothermic. Twenty-one men (31 ± 9 y) were examined under two separate protocols designed to produce central hypovolemia similar to hemorrhage. Following 15 min of supine rest, 10 min of 30 mm Hg of lower body negative pressure (LBNP) was applied. On separate randomized days, subjects were then exposed to skin surface cooling (COOL), warming (WARM), or remained thermoneutral (NEUT), while LBNP continued. Subjects remained in these thermal conditions for either 40 min of 30 mm Hg LBNP (N = 9), or underwent a continuous LBNP ramp until hemodynamic decompensation (N = 12). Arterial blood pressure during LBNP was dependent on the thermal perturbation as blood pressure was greater during COOL (P >0.001) relative to NEUT and WARM for both protocols. Middle cerebral artery blood velocity decreased (P <0.001) from baseline throughout sustained and continuous LBNP, but the magnitude of reduction did not differ between thermal conditions. Contrary to our hypothesis, WARM did not reduce cerebral blood velocity or LBNP tolerance relative to COOL and NEUT in normothermic individuals. While COOL increased blood pressure, cerebral perfusion and time to presyncope were not different relative to NEUT or WARM during sustained or continuous LBNP. Warming an otherwise normothermic hemorrhaging victim is not detrimental to hemodynamic stability, nor is this stability improved with cooling.
全球十分之一的死亡是由创伤性损伤导致的，其中30%至40%的创伤相关死亡是由出血引起的。目前，由于出血合并体温过低对生存有不利影响，给出血患者升温是护理标准。我们检验了这样一个假设：在出血期间加热不利于维持动脉血压和脑灌注，而对于体温正常的患者，降温则有益。21名男性（31±9岁）按照两个单独的方案接受检查，这两个方案旨在产生与出血相似的中心血容量减少。在仰卧休息15分钟后，施加10分钟30毫米汞柱的下体负压（LBNP）。在不同的随机日期，受试者随后分别接受皮肤表面冷却（COOL）、加热（WARM）或保持体温中性（NEUT），同时LBNP持续进行。受试者在这些热条件下保持40分钟的30毫米汞柱LBNP（N = 9），或经历连续的LBNP斜坡直至血流动力学失代偿（N = 12）。在两种方案中，LBNP期间的动脉血压都依赖于热扰动，因为相对于NEUT和WARM，COOL期间的血压更高（P>0.001）。在持续和连续的LBNP过程中，大脑中动脉血流速度从基线开始下降（P<0.001），但热条件之间下降的幅度没有差异。与我们的假设相反，在体温正常的个体中，相对于COOL和NEUT，WARM并没有降低脑血流速度或LBNP耐受性。虽然COOL增加了血压，但在持续或连续的LBNP期间，相对于NEUT或WARM，脑灌注和接近晕厥的时间没有差异。给原本体温正常的出血患者升温对血流动力学稳定性没有不利影响，降温也不会改善这种稳定性。
