EFFECTS OF HYPOTHERMIC EXTRACORPOREAL LUNG AND HEART ASSIST (ECLHA) ON CARDIOPULMONARY AND CEREBRAL RESUSCITATION

背景和目的：虽然恒温体外心肺辅助（ECLHA）可改善心脏预后，但患者不能从低温介导的脑保护中获益。本研究评估了长期ECLHA伴轻至中度低温（33℃）对延长心脏骤停犬模型的影响。方法：15只狗分为低温组（7只，33℃）和常温组（8只，37.5℃）。所有狗均诱导常温心室颤动（VF） 15 min，然后进行24 h的ECLHA和72 h的重症监护。低温组从复苏开始将核心（肺动脉）温度保持在33℃20 h，然后再加热28 h。死亡率,2。儿茶酚胺剂量3。4.拔管时间；坏死的心肌团块(g), 5。神经缺损评分（NDS）。结果：常温组4只狗死于心源性休克，1只狗死于缺氧。2只存活犬仍处于昏迷状态（NDS为60.5±4.9%），坏死心肌肿块14.5±3.5 g。低温组1只死于肺功能障碍，6只存活。幸存犬出现脑损伤（29.8±2.5%），但有一定的脑保护作用。低温组坏死心肌体积为4.2±1.3 g，比常温组小3.4倍。低温组成活率显著高于常温组（P<0.01）。低温组儿茶酚胺需要量低于常温组（P<0.05）。结论：心脏骤停后立即诱导ECLHA的长期轻度至中度低温可改善生存以及脑和心脏预后。

Background and purpose : Although normothermic extracorporeal lung and heart assist (ECLHA) improves cardiac outcomes, patients can not benefit from hypothermia-mediated brain protection. The present study evaluated the effects of long-term ECLHA with mild to moderate hypothermia (33℃) in a canine model of prolonged cardiac arrest.Methods : Fifteen dogs were assigned to either the hypothermic (7 dogs, 33℃) or normothermic group (8 dogs, 37.5℃). All dogs were induced to normothermic ventricular fibrillation (VF) for 15 min, followed by 24 h of ECLHA and 72 h of intensive care. The hypothermia group maintained core (pulmonary artery) temperature at 33℃ for 20 h starting from resuscitation, then were rewarmed by 28 h. Outcome evaluations included : 1. mortality, 2. catecholamine dose, 3. time to extubation, 4. necrotic myocardial mass (g), 5. Neurological Deficits Score (NDS).Results : In the normothermic group 4 dogs died of cardiogenic shock and 1 dog succumbed to poor oxygenation. The 2 surviving dogs remained comatose (NDS 60.5 ± 4.9%) with necrotic myocardial mass of 14.5 ± 3.5 g. In the hypothermic group, one dog died from pulmonary dysfunction, the other 6 dogs survived. The surviving dogs showed brain damage (29.8 ± 2.5%), but there was evidence of some brain-protective effect. The mass of necrotic myocardium was 4.2 ± 1.3 g in the hypothermic group or 3.4 times smaller than in the normothermic group. The survival rate was significantly higher in the hypothermic than in the normothermic group (P<0.01). The catecholamine requirement was also lower in the hypothermic than in the normothermic dogs (P<0.05).Conclusions : Long-term mild to moderate hypothermia with ECLHA induced immediately after cardiac arrest improved survival as well as cerebral and cardiac outcomes.