Volume-related and volume-independent effects of posture on esophageal and transpulmonary pressures in healthy subjects
Volume-related and volume-independent effects of posture on esophageal and transpulmonary pressures in healthy subjects
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DOI：
10.1152/japplphysiol.00697.2005
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发表时间：
2006-03-01
影响因子：
3.3
通讯作者：
Loring, SH
中科院分区：
文献类型：
--
作者：
Washko, GR;O'Donnell, CR;Loring, SH
了解患者的经肺压可以更好地了解急性肺损伤的呼吸机管理决策，这可以通过测量食管压来估计。食管测压术很少用于此，然而，部分原因是由于假定的仰卧位的姿势伪影。在这里，我们描述了健康受试者的姿势对食管压力影响的幅度和变异性，以更好地评估其在急性肺损伤患者中的意义。我们测量了10名健康受试者在直立、仰卧、俯卧和左侧侧卧四种姿势下的放松量和总肺活量的姿势相关变化。然后，在相同的受试者中，我们使用食道球囊导管测量了在不同姿势下肺容量范围内的静压-容积特征。舒张期肺压（PLrel）直立时平均3.7 (SD 2.0) cmH(2)，仰卧时平均-3.3 (SD 3.2) cmH(2)。在直立和仰卧姿势之间，大约58%的PLrel下降是由于相应的放松量减少。剩余的2.9cmH(2)O差异与假定的姿势伪影的报告值一致。俯卧位和侧卧位的松弛量和压力适中。为了校正估计的仰卧对肺压的影响，我们建议增加3cmh (2)O（95%可信区间：-1至+ 7cmh (2)O）。我们的结论是，与急性肺损伤患者PLrel的大范围相比，在给定肺容量下估计的经肺压的体位差异很小。
Ventilator management decisions in acute lung injury could be better informed with knowledge of the patient's transpulmonary pressure, which can be estimated using measurements of esophageal pressure. Esophageal manometry is seldom used for this, however, in part because of a presumed postural artifact in the supine position. Here, we characterize the magnitude and variability of postural effects on esophageal pressure in healthy subjects to better assess its significance in patients with acute lung injury. We measured the posture-related changes in relaxation volume and total lung capacity in 10 healthy subjects in four postures: upright, supine, prone, and left lateral decubitus. Then, in the same subjects, we measured static pressure-volume characteristics of the lung over a wide range of lung volumes in each posture by using an esophageal balloon catheter. Transpulmonary pressure during relaxation (PLrel) averaged 3.7 (SD 2.0) cmH(2)O upright and -3.3 (SD 3.2) cmH(2)O supine. Approximately 58% of the decrease in PLrel between the upright and supine postures was due to a corresponding decrease in relaxation volume. The remaining 2.9cmH(2)O difference is consistent with reported values of a presumed postural artifact. Relaxation volumes and pressures in prone and lateral postures were intermediate. To correct estimated transpulmonary pressure for the effect of lying supine, we suggest adding 3 cmH(2)O (95% confidence interval: -1 to +7 cmH(2)O). We conclude that postural differences in estimated transpulmonary pressure at a given lung volume are small compared with the substantial range of PLrel in patients with acute lung injury.