Beijing Key Laboratory of Cardiopulmonary-Cerebral Resuscitation, Department of Emergency Medicine, Beijing Chaoyang Hospital, Capital Medical University, 100020, Beijing, China.
Department of Emergency Medicine, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
Neurocrit Care. 2017 Oct;27(2):297-303. doi: 10.1007/s12028-017-0395-6.
The effect of mild hypothermia (MH) on microcirculation after resuscitation from cardiac arrest is controversial. The aim of this study was to determine whether MH improves or aggravates the disturbance of cerebral microcirculation.
Twenty domestic male pigs were randomized into the MH group (n = 8), non-hypothermia (NH) group (n = 8) or sham operation group (n = 4). In the MH group, the animals were initiated rapid intravascular cooling at 1 h after return of spontaneous circulation (ROSC) from 8 min ventricular fibrillation, and the core temperature was reduced to 33 °C for 12 h and then rewarmed to 37 °C. In the NH group, animals did not receive hypothermia treatment after ROSC. In the sham operation group, the same surgical procedure was performed, but without inducing ventricular fibrillation and hypothermia treatment. The cerebral microvascular flow index (MFI) of large microvessel (diameter > 20 μm) and small microvessel (diameter < 20 μm) was measured after ROSC. Cerebral oxygen extraction ratio, internal jugular venous-artery lactate difference, and CO difference were also calculated.
Cerebral MFI dramatically reduced after ROSC, and MH further aggravated the decrease in MFI of small microvessel compared with NH (p < 0.05). Internal jugular venous-arterial lactate difference and CO difference, and oxygen extraction ratio were all significantly increased after ROSC. MH significantly decreased the values compared with NH (p < 0.05).
MH decreases cerebral small microvessel blood flow and cerebral metabolism after ROSC compared with NH. However, the total effect is that cerebral oxygen supply-demand relationship is improved during hypothermia.
心脏骤停复苏后亚低温（MH）对微循环的影响存在争议。本研究旨在确定 MH 是否改善或加重脑微循环的紊乱。
20 头国内雄性猪随机分为 MH 组（n=8）、非低温组（NH 组，n=8）或假手术组（n=4）。在 MH 组，动物在自主循环恢复（ROSC）后 1 小时开始快速血管内冷却，从 8 分钟心室颤动开始，核心温度降至 33°C 持续 12 小时，然后复温至 37°C。在 NH 组，ROSC 后动物未接受低温治疗。在假手术组，进行相同的手术操作，但不诱发心室颤动和低温治疗。ROSC 后测量大脑大微血管（直径>20μm）和小微血管（直径<20μm）的脑微血管血流指数（MFI）。还计算了脑氧摄取率、颈内静脉-动脉乳酸差和 CO 差。
ROSC 后大脑 MFI 明显降低，MH 进一步加重了与 NH 相比小微血管 MFI 的降低（p<0.05）。ROSC 后颈内静脉-动脉乳酸差和 CO 差以及氧摄取率均显著增加。MH 与 NH 相比显著降低了这些值（p<0.05）。
与 NH 相比，MH 降低了 ROSC 后脑小血管血流和脑代谢。然而，总的来说，低温期间改善了脑氧供需关系。
