Wright J, Gong H
Department of Respiratory Therapy, University of California, Los Angeles Medical Center 90024-1658.
Heart Lung. 1990 Jul;19(4):352-7.
In patients receiving mechanical ventilation there occasionally occurs an unintentional positive end-expiratory pressure, known as auto-PEEP, a phenomenon that can easily go undetected. Potential adverse effects of auto-PEEP include misleading hemodynamic information, cardiopulmonary morbidity, or both. Our study was designed to evaluate the incidence of auto-PEEP, its magnitude, and factors influencing it in a university hospital. Every patient receiving ventilation was evaluated for controlled ventilation and auto-PEEP in medical and surgical intensive care units during a 3-month period. Expiration was stopped at the instant that the next inspiration would have been delivered. At this moment, when the pressures in the lung and the ventilator circuit had equilibrated, the level of auto-PEEP was systematically measured. Of 57 patients undergoing controlled mechanical ventilation, 27 (47%) had 1 to 6 cm H2O of auto-PEEP. The incidence of auto-PEEP increased significantly when the minute ventilation exceeded 18.4 L/min, the respiratory rate was higher than 27 breaths/min, or the set PEEP was greater than or equal to 10 cm H2O. Therefore, auto-PEEP is the result of several ventilator-related factors. Because auto-PEEP occurred in 47% of the patients in the study, routine monitoring for auto-PEEP in patients receiving controlled ventilation is recommended. Further studies of auto-PEEP and its clinical impact are warranted.
在接受机械通气的患者中，偶尔会出现一种无意的呼气末正压，称为内源性呼气末正压（auto-PEEP），这是一种很容易被忽视的现象。内源性呼气末正压的潜在不良影响包括误导血流动力学信息、心肺疾病发生率增加，或两者兼而有之。我们的研究旨在评估一所大学医院内源性呼气末正压的发生率、其大小以及影响它的因素。在3个月的时间里，对医疗和外科重症监护病房中每一位接受通气的患者进行了控制通气和内源性呼气末正压评估。在下一次吸气即将开始的瞬间停止呼气。此时，当肺内和通气回路中的压力达到平衡时，系统地测量内源性呼气末正压水平。在57例接受控制性机械通气的患者中，27例（47%）存在1至$6 cmH_2O$的内源性呼气末正压。当分钟通气量超过18.4 L/min、呼吸频率高于27次/分钟或设定的呼气末正压大于或等于$10 cmH_2O$时，内源性呼气末正压的发生率显著增加。因此，内源性呼气末正压是多种与通气机相关因素的结果。由于本研究中47%的患者出现了内源性呼气末正压，建议对接受控制通气的患者进行内源性呼气末正压的常规监测。有必要对内源性呼气末正压及其临床影响进行进一步研究。
