Death by hyperventilation: a common and life-threatening problem during cardiopulmonary resuscitation.
Death by hyperventilation: a common and life-threatening problem during cardiopulmonary resuscitation.
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DOI：
10.1097/01.ccm.0000134335.46859.09
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发表时间：
2004-09-01
影响因子：
8.8
通讯作者：
Lurie, Keith G
中科院分区：
文献类型：
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作者：
Aufderheide, Tom P;Lurie, Keith G
背景：这项转化研究的重点是心肺复苏(CPR)的生理学，这项研究是由一项临床观察发起的，即专业救援者在院外心脏骤停时持续过度换气。这一观察产生了只能在动物实验室进行伦理检验的科学假设。目的：检验过度热情但训练有素的救援人员在实施CPR期间过度通气率会显著降低冠脉灌注压和增加死亡可能性的假设。设计和背景：在活体人体方面，我们在一项前瞻性临床试验中，以客观和电子的方式记录训练有素的专业救援人员在进行CPR期间的通气率和持续时间，该试验针对院外心脏骤停的成年插管式患者。在活体动物方面，为了模拟临床观察到的过度换气，9只心跳骤停的猪以随机顺序以12、20或30次/分钟的呼吸速度进行呼吸，并评估生理变量。接下来，三组7只心脏骤停的猪分别以12次/分钟的100%氧气、30次/分钟的100%氧气或30次/分钟的5%二氧化碳/95%氧气进行呼吸，并评估其存活率。结果：在连续13例(平均年龄63+/-5.8岁)接受CPR的成人(7名男性)中，平均通气率为30+/-3.2次/分(15~49次/分)，平均每次呼吸时间为1.0+/-0.07秒。肺内记录到正压的平均时间百分比为47.3+/-4.3%。无一人生还。在呼吸速度分别为12、20和30次/min的动物中，平均气管内压和冠脉灌注压分别为7.1+/-0.7、11.6+/-0.7、17.5+/-1.0 mm Hg/min(p<；分别为23.4+/-1.0、19.5+/-1.8、16.9+/-1.8 mm Hg(p=0.03)和23.4+/-1.0、19.5+/-1.8、16.9+/-1.8 mm Hg(p=0.03)(p=12次/分钟与30次/分钟的平均气管内压和冠脉灌注压的比较)。每分钟二氧化碳呼吸次数分别为12次、30次和30次的患者存活率分别为6/7、1/7和1/7(p=0.006)。结论：尽管似乎有足够的培训，但专业救援者在院外心肺复苏期间始终会使患者过度换气。随后在猪身上进行的血流动力学和存活率研究表明，尽管补充二氧化碳可以预防低碳酸血症，但过度的通气率显著降低了冠脉灌注压和存活率。这项转化性研究表明，心肺复苏期间，平均气管内压和冠脉灌注压之间呈负比例关系。迫切需要对心肺复苏提供者进行更多的教育，以减少心肺复苏期间过度换气的这些新发现的致命后果。这些发现还对复苏研究、CPR指南、教育、生物医疗设备的开发、紧急医疗服务质量保证和临床实践的解释和设计具有重要意义。
CONTEXT: This translational research initiative focused on the physiology of cardiopulmonary resuscitation (CPR) initiated by a clinical observation of consistent hyperventilation by professional rescuers in out-of-hospital cardiac arrest. This observation generated scientific hypotheses that could only ethically be tested in the animal laboratory.OBJECTIVE: To examine the hypothesis that excessive ventilation rates during performance of CPR by overzealous but well-trained rescue personnel causes a significant decrease in coronary perfusion pressure and an increased likelihood of death.DESIGN AND SETTING: In the in vivo human aspect of the study, we set out to objectively and electronically record rate and duration of ventilation during performance of CPR by trained professional rescue personnel in a prospective clinical trial in intubated, adult patients with out-of-hospital cardiac arrest. In the in vivo animal aspect of the study, to simulate the clinically observed hyperventilation, nine pigs in cardiac arrest were ventilated in a random order with 12, 20, or 30 breaths/min, and physiologic variables were assessed. Next, three groups of seven pigs in cardiac arrest were ventilated at 12 breaths/min with 100% oxygen, 30 breaths/min with 100% oxygen, or 30 breaths/min with 5% CO2/95% oxygen, and survival was assessed.MAIN OUTCOME MEASURES: Ventilation rate and duration in humans; mean intratracheal pressure, coronary perfusion pressure, and survival rates in animals.RESULTS: In 13 consecutive adults (average age, 63 +/- 5.8 yrs) receiving CPR (seven men) the average ventilation rate was 30 +/- 3.2 breaths/min (range, 15 to 49 breaths/min) and the average duration of each breath was 1.0 +/- 0.07 sec. The average percentage of time in which a positive pressure was recorded in the lungs was 47.3 +/- 4.3%. No patient survived. In animals treated with 12, 20, and 30 breaths/min, the mean intratracheal pressures and coronary perfusion pressures were 7.1 +/- 0.7, 11.6 +/- 0.7, 17.5 +/- 1.0 mm Hg/min (p < .0001) and 23.4 +/- 1.0, 19.5 +/- 1.8, 16.9 +/- 1.8 mm Hg (p = .03) with each of the different ventilation rates, respectively (p = comparison of 12 breaths/min vs. 30 breaths/min for mean intratracheal pressure and coronary perfusion pressure). Survival rates were six of seven, one of seven, and one of seven with 12, 30, and 30 + CO2 breaths/min, respectively (p = .006).CONCLUSIONS: Despite seemingly adequate training, professional rescuers consistently hyperventilated patients during out-of-hospital CPR. Subsequent hemodynamic and survival studies in pigs demonstrated that excessive ventilation rates significantly decreased coronary perfusion pressures and survival rates, despite supplemental CO2 to prevent hypocapnia. This translational research initiative demonstrates an inversely proportional relationship between mean intratracheal pressure and coronary perfusion pressure during CPR. Additional education of CPR providers is urgently needed to reduce these newly identified and deadly consequences of hyperventilation during CPR. These findings also have significant implications for interpretation and design of resuscitation research, CPR guidelines, education, the development of biomedical devices, emergency medical services quality assurance, and clinical practice.