TIME COURSE AND MECHANISMS OF LUNG-VOLUME INCREASE WITH PEEP IN ACUTE PULMONARY FAILURE
TIME COURSE AND MECHANISMS OF LUNG-VOLUME INCREASE WITH PEEP IN ACUTE PULMONARY FAILURE
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DOI：
10.1097/00000542-198101000-00003
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发表时间：
1981-01-01
期刊：
影响因子：
8.8
通讯作者：
FAIRLEY, HB
中科院分区：
文献类型：
--
作者：
KATZ, JA;OZANNE, GM;FAIRLEY, HB
为探讨呼气末压力阶跃变化对肺功能残气量（FRC）和肺胸顺应性（CLT）的影响，对8例急性肺功能衰竭需机械通气的患者应用10 cm H2O呼气末正压（PEEP）。在FRC的总变化中，66 .+-. 5.3%（平均值±）SEM [平均值的标准误差]）在下一次呼吸内完成，并且在4.6 . ±. 1.4呼吸（24 .+-. 6.4 s）。应用PEEP和去除PEEP时，达到90% FRC变化的时间无统计学显著差异。另13例患者PEEP从3 ~ 18 cm H2O以5cm H2O为步长递增。3 cm H2O PEEP时的平均FRC为1.51 ±。0.20 1（55 .+-. 7.0%预测仰卧位值）。平均CLT在达到18 cm H2O PEEP时无显著变化，此时降低（P < 0.005）。与初始水平相比，由FRC变化导出的静态顺应性（Δ FRC/Δ PEEP）随着PEEP的增加而增加（P < 0.05）。在PEEP水平为8和13 cm H2O时，平均FRC大于平均CLT预测值（P < 0.005），但在3 cm H2O PEEP时无显著差异。肺成分占62 . ±. 3.7%的肺胸顺应性差异。这些数据定义了一个时间依赖性的肺容量增加，类似于正常人的压力-容量滞后。可能的机制包括表面张力的变化，非通气肺的募集和肺和胸壁的应力松弛。这项研究可以解释PEEP与大潮气量通气相比在增加急性肺衰竭患者的PaO 2 [动脉O2压]方面更有效。
To determine the effects of a step change in end-expiratory pressure on functional residual capacity (FRC) and lung-thorax compliance (CLT), 10 cm H2O positive end-expiratory pressure (PEEP) was applied in 8 patients who needed mechanical ventilation for acute pulmonary failure. Of the total change in FRC, 66 .+-. 5.3% (mean .+-. SEM [standard error of the mean]) was complete within the next breath, and 90% change was achieved in 4.6 .+-. 1.4 breaths (24 .+-. 6.4 s). There was no statistically singificant difference between times to 90% FRC change with application and with removal of PEEP. In another 13 patients PEEP was increased in 5 cm H2O steps from 3 to 18 cm H2O. Mean FRC at 3 cm H2O PEEP was 1.51 .+-. 0.20 1 (55 .+-. 7.0% predicted supine value). Mean CLT did not change significantly until 18 cm H2O PEEP was reached, at which point it decreased (P < 0.005). The static compliance derived from change in FRC (.DELTA.FRC/.DELTA.PEEP) increased with increments of PEEP (P < 0.05) compared to the initial level. At PEEP levels of 8 and 13 cm H2O, mean FRC was larger than would be predicted from mean CLT (P < 0.005), but it was not significantly different at 3 cm H2O PEEP. The lung component accounted for 62 .+-. 3.7% of the lung-thorax compliance difference. These data define a time-dependent increase in lung volume that resembles pressure-volume hysteresis in normal man. Possible mechanisms include surface tension changes, recruitment of nonventilated lung and stress relaxation of lung and chest wall. This study may explain the greater efficiency of PEEP compared to large tidal-volume ventilation in increasing PaO2 [arterial O2 pressure] in patients with acute pulmonary failure.