Rose D M, Downs J B, Heenan T J
Crit Care Med. 1981 Feb;9(2):79-82. doi: 10.1097/00003246-198102000-00001.
PEEP is widely accepted as a therapy for some forms of acute respiratory failure (ARF). PEEP increases functional residual capacity (FRC), decreases intrapulmonary shunt fraction, and improves arterial oxygenation. The time required for FRC and arterial oxygen tension (PaO2) to stabilize after an adjustment in the level of PEEP is not clearly established. Therefore, to determine the temporal relationship between PEEP, FRC, and PaO2 after adjusting the level of PEEP, aspiration pneumonitis was produced in swine. The FRC and the PaO2 decreased within seconds after intratracheal instillation of 0.1 N HCl; FRC of all animals was restored to its control value after the application of PEEP, 5 cm H2O, but PaO2 remained low. It was necessary to increase PEEP to 20 cm H2O and FRC to twice the control value to return arterial oxygenation to control levels. After PEEP was applied, an average of 15 sec was required to increase FRC; the less compliant the lung, the more rapid the change. After PEEP was removed, FRC stabilized within an average of 22 sec. When PEEP, 25 cm H2O, was removed, arterial oxygenation decreased suddenly and substantially which suggests that PEEP, especially at higher levels, should not be discontinued, even momentarily, for nonessential maneuvers.
呼气末正压通气（PEEP）作为治疗某些形式急性呼吸衰竭（ARF）的方法已被广泛接受。PEEP可增加功能残气量（FRC），降低肺内分流分数，并改善动脉氧合。在调整PEEP水平后，FRC和动脉血氧张力（PaO2）达到稳定所需的时间尚未明确确定。因此，为了确定调整PEEP水平后PEEP、FRC和PaO2之间的时间关系，在猪身上诱发了吸入性肺炎。气管内滴注0.1N盐酸后数秒内，FRC和PaO2下降；应用5cmH2O的PEEP后，所有动物的FRC恢复到对照值，但PaO2仍较低。有必要将PEEP增加到20cmH2O，并将FRC增加到对照值的两倍，以使动脉氧合恢复到对照水平。应用PEEP后，平均需要15秒来增加FRC；肺顺应性越低，变化越快。去除PEEP后，FRC平均在22秒内稳定。当去除25cmH2O的PEEP时，动脉氧合突然大幅下降，这表明PEEP，尤其是较高水平的PEEP，即使是暂时的，也不应因非必要操作而中断。
