心肺复苏中通气的研究进展

Advances of ventilation during cardiopulmonary resuscitation

作为现代心肺复苏（CPR）的基石之一，通气在过去十几年中受到争议和挑战。2000年至2015年美国心脏协会（AHA）CPR指南的变化显示通气相对于心脏按压地位在逐渐下降。近年来单纯胸外按压CPR得到了大力提倡，特别是对于有目击者的心源性心搏骤停（CA）患者。被动给氧、心脑复苏（CCR）在心源性CA复苏早期亦显示出良好的疗效，但仍需在更大范围内进行临床验证。阻力阀（ITD）装置在按压放松期阻止气流进入肺部，降低胸腔压力，从而促进静脉回流，增加冠状动脉（冠脉）血流，但目前有关ITD的研究结论并不一致，因此指南不推荐常规应用。正压通气可升高胸腔压力，从而影响冠脉灌注压（CPP）和脑灌注，因而在CPR最初几分钟内被认为可能不仅无用，还会产生不良结果。这种观点被许多学者所接受。然而在延迟开始的CPR、延长CPR及非心源性CA等情况下，通气是必不可少的。机械通气特别是针对CPR的特殊通气模式显示出一定的发展前景。目前正压通气仍是标准CPR的重要组成部分。现有的研究表明，过度通气可明显降低复苏成功率，因而避免过度通气已成为共识。但目前关于CPR时通气研究的数量非常有限，且研究结论并不一致。故未来仍需要更多的高质量研究来进一步阐明通气在CPR中的应用。

As one of the cornerstones of modern cardiopulmonary resuscitation （CPR）, ventilation received controversy and challenges in the past two decades. From 2000 to 2015, the changes in CPR guidelines of American Heart Association （AHA） showed that the position of ventilation declined gradually as compared to chest compressions. Chest compressions only CPR has been strongly advocated in recent years, especially in witnessed cardiogenic cardiac arrest （CA）. Passive oxygenation and cardiocerebral resuscitation （CCR） also showed good effect in the early stage of cardiogenic CA. However, clinical validation in a larger context is still needed. An impedance threshold device （ITD） transiently blocks air from entering the lungs during recoil, decreases the intrathoracic pressure, facilitates venous return to the chest and increases coronary blood flow. However, the relevant research findings are not consistent, and the guidelines do not recommend routine use of ITD. Positive-pressure ventilation, which can increases intrathoracic pressure, affects the coronary perfusion pressure （CPP） and cerebral perfusion, is thought to be not only useless, but also has adverse effects within the first few minutes of CPR. This view is accepted by many scholars, however, ventilation is essential in late-start CPR, prolonged CPR and non-cardiogenic CA. Mechanical ventilation, especially special ventilation modes for CPR showed some prospects. Positive-pressure ventilation remains the gold standard in CPR in clinical practice at present. It was shown by existing research that hyperventilation significantly reduce the success rate of resuscitation, thus a consensus had been reached about avoiding hyperventilation. Currently, the number of studies on ventilation during CPR is very limited, and many of the conclusions are not consistent among studies. Therefore, more high-quality studies are needed in future to further clarify the application of ventilation during CPR.