Department of Paediatric Research, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway.
Resuscitation. 2010 Nov;81(11):1571-6. doi: 10.1016/j.resuscitation.2010.06.007. Epub 2010 Jul 17.
The rationale for a compression to ventilation ratio of 3:1 in neonates with primary hypoxic, hypercapnic cardiac arrest is to emphasize the importance of ventilation; however, there are no published studies testing this approach against alternative methods. An extended series of cardiac compressions offers the theoretical advantage of improving coronary perfusion pressures and hence, we aimed to explore the impact of compression cycles of two different durations.
Newborn swine (n = 32, age 12-36 h, weight 2.0-2.7 kg) were progressively asphyxiated until asystole occurred. Animals were randomized to receive compressions:ventilations 3:1 (n=16) or 9:3 (n=16). Return of spontaneous circulation (ROSC) was defined as a heart rate ≥ 100 beats min⁻¹.
All animals except one in the 9:3 group achieved ROSC. One animal in the 3:1 group suffered bradycardia at baseline, and was excluded, leaving us with 15 animals in each group surviving to completion of protocol. Time to ROSC (median and interquartile range) was 150 s (115-180) vs. 148 s (116-195) for 3:1 and 9:3, respectively (P = 0.74). There were no differences in diastolic blood pressure during compression cycles or in markers of hypoxia and inflammation. The temporal changes in mean arterial blood pressure, heart rate, arterial blood gas parameters, and systemic and regional oxygen saturation were comparable between groups.
Neonatal pigs with asphyxia-induced cardiac arrest did not respond to a compression:ventilation ratio of 9:3 better than to 3:1. Future research should address if alternative compression:ventilation ratios offer advantages over the current gold standard of 3:1.
在原发性低氧高碳酸血症性心脏骤停的新生儿中，采用 3:1 的按压通气比的基本原理是强调通气的重要性；然而，目前尚无研究对这种方法与替代方法进行测试。延长的心脏按压周期提供了改善冠状动脉灌注压的理论优势，因此，我们旨在探讨两种不同持续时间的按压周期的影响。
新生猪（n=32，年龄 12-36 小时，体重 2.0-2.7 千克）逐渐窒息，直至发生心搏骤停。动物随机接受以下两种通气模式的按压：3:1（n=16）或 9:3（n=16）。自主循环恢复（ROSC）定义为心率≥100 次/分钟。
除 9:3 组中的一只动物在基线时出现心动过缓而被排除在外，其余所有动物均实现了 ROSC。3:1 组中有一只动物在基线时出现心动过缓，被排除在外，每组有 15 只动物存活至完成方案。ROSC 时间（中位数和四分位间距）分别为 150 s（115-180）和 148 s（116-195），3:1 组和 9:3 组之间无差异（P=0.74）。两组间在心脏按压期间的舒张压或缺氧和炎症标志物均无差异。平均动脉压、心率、动脉血气参数以及全身和局部氧饱和度的时间变化在两组之间相似。
患有窒息性心脏骤停的新生猪对 9:3 的按压通气比的反应并不优于 3:1。未来的研究应该探讨替代的按压通气比是否比目前的 3:1 金标准具有优势。
