Pressure-volume curves and compliance in acute lung injury - Evidence of recruitment above the lower inflection point
Pressure-volume curves and compliance in acute lung injury - Evidence of recruitment above the lower inflection point
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DOI：
10.1164/ajrccm.159.4.9801088
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发表时间：
1999-04-01
影响因子：
24.7
通讯作者：
Brochard, L
中科院分区：
文献类型：
--
作者：
Jonson, B;Richard, JC;Brochard, L
测量呼吸系统的弹性压力-容积（Pel-V）曲线和呼气末正压（PEEP）恢复的容积，可以研究急性肺损伤（ALI）时恢复的压力范围，并解释恢复如何影响顺应性。采用低流量充气技术测量了11例机械通气患者的Pel-V曲线。曲线I是在呼气过程中记录的，从呼气后在呼气末压力（9.0 +/- 2.2 cm H2O）下延长呼气后（6 s）达到的容积，曲线II是呼气后在零呼气末压力（ZEEP）下的弹性平衡容积。通过使用呼气末容积，曲线在一个共同的容积轴上对齐，以确定单次完全呼气的效果。在每个患者中，曲线II（来自ZEEP）向比曲线i更低的体积移动，可能是由于招募的原因，体积t在15 cm H2O时为205 +/- 100 ml (p < 0.01)，在30 cm H2O时为78 +/- 93 ml (p < 0.09)；因此，在ZEEP膨胀过程中，在至少30 cm H2O的压力范围内，体积赤字陆续恢复。在任何压力下，ZEEP的曲线顺应性都高于PEEP，在15 cm H2O时高出10.0 +/- 8.7 ml/cm H2O (p < 0.01)，在30 cm H2O时高出5.4 +/- 5.5 ml/cm H2O （p < 0.01）。结论：在ALI中，单次呼气到ZEEP就意味着肺萎陷。ZEEP灌注时的高顺应性表明肺再募集发生在远高于Pel-V曲线下拐点的位置。
Measuring elastic pressure-volume (Pel-V) curves of the respiratory system and the volume recruited by a positive end-expiratory pressure (PEEP) allows one to study the pressure range over which recruitment occurs in acute lung injury (ALI), and to explain how recruitment affects the compliance. Pel-V curves were measured with the low flow inflation technique in 11 patients mechanically ventilated for ALI. Curve I was recorded during inflation from the volume attained after a prolonged expiration (6 s) at PEEP (9.0 +/- 2.2 cm H2O), and Curve II after expiration to the elastic equilibrium volume at zero end-expiratory pressure (ZEEP), By using the end-expiratory volume of the breaths, the curves were aligned on a common volume axis to determine the effect of a single complete expiration. In each patient, Curve II (from ZEEP) was shifted toward lower volumes than Curve I. The volume shirt, probably due to derecruitment, was 205 +/- 100 ml at 15 cm H2O (p < 0.01) and 78 +/- 93 ml at 30 cm H2O (p < 0.09); thus, during inflation from ZEEP, the volume deficit was successively regained over a pressure range up to at least 30 cm H2O. At any pressure, compliance was higher on the curve from ZEEP than from PEEP, by 10.0 +/- 8.7 ml/cm H2O at 15 cm H2O (p < 0.01), and by 5.4 +/- 5.5 at 30 cm H2O (p < 0.01). It is concluded that in ALI, a single expiration to ZEEP reads to lung collapse. High compliance during insufflation from ZEEP indicates that lung recruitment happens far above the lower inflection point of the Pel-V curve.