Putensen C, Lingnau W, Hörmann C, Putensen-Himmer G, Baum M
Department of Anaesthesia and Intensive Care Medicine, University of Innsbruck, Austria.
Crit Care Med. 1994 Jan;22(1):67-73. doi: 10.1097/00003246-199401000-00015.
To examine the glottic function in extubated patients recovering from acute lung injury by simultaneous measurement of airway opening and subglottic airway pressures while patients are breathing at ambient pressure and receiving continuous positive airway pressure by a face mask.
Descriptive, prospective study.
Intensive care unit at a university hospital.
Ten patients who required continuous positive airway pressure of at least 7 cm H2O in order to restore gas exchange after mechanical ventilation for acute lung injury.
Spontaneous breathing at ambient airway pressure and with continuous positive airway pressures of 5 and 10 cm H2O via face mask.
Intratracheal pressure, airway opening pressure, and airflow at the airway opening were measured. Breathing at ambient pressure resulted in significantly higher end-expiratory intratracheal pressure than end-expiratory airway opening pressure (p < .01). No significant differences between end-expiratory intratracheal pressure and end-expiratory airway opening pressure were observed during breathing with continuous positive airway pressures of 5 and 10 cm H2O. A significant end-expiratory airflow at the airway opening (p < .01), observed during ambient pressure breathing, was not detectable while the patient received mask continuous positive airway pressure. The partial pressure of oxygen in the arterial blood (Pao2) increased significantly while patients breathed with 10 cm H2O, but not while patients breathed 5 cm H2O continuous positive airway pressure compared with breathing at ambient pressure (p < .05).
Our data imply that patients recovering from acute lung injury create an intratracheal positive end-expiratory pressure by braking the expiratory airflow, probably by glottic narrowing. Despite compensatory glottic narrowing, extubated patients with reduced lung function may benefit from higher levels of continuous positive airway pressure.
通过在患者常压呼吸并通过面罩接受持续气道正压通气时，同时测量气道开口压力和声门下气道压力，来检查急性肺损伤拔管患者的声门功能。
描述性前瞻性研究。
大学医院重症监护病房。
10例急性肺损伤机械通气后需要至少7 cm H₂O持续气道正压通气以恢复气体交换的患者。
在常压气道压力下自主呼吸，并通过面罩给予5 cm H₂O和10 cm H₂O的持续气道正压通气。
测量气管内压力、气道开口压力和气道开口处气流。常压呼吸时，呼气末气管内压力显著高于呼气末气道开口压力（p < 0.01）。在给予5 cm H₂O和10 cm H₂O持续气道正压通气时，呼气末气管内压力与呼气末气道开口压力之间未观察到显著差异。常压呼吸时观察到气道开口处有显著的呼气末气流（p < 0.01），而患者接受面罩持续气道正压通气时未检测到。与常压呼吸相比，患者在10 cm H₂O持续气道正压通气下呼吸时动脉血氧分压（Pao₂）显著升高，但在5 cm H₂O持续气道正压通气时未升高（p < 0.05）。
我们的数据表明，急性肺损伤恢复过程中的患者可能通过声门变窄来制动呼气气流，从而产生气管内呼气末正压。尽管有声门变窄的代偿作用，但肺功能降低的拔管患者可能从更高水平的持续气道正压通气中获益。
