Taylor N A, Morrison J B
Faculty of Physical Education, University of Otago, Dunedin, New Zealand.
Undersea Biomed Res. 1989 Jan;16(1):3-19.
Upright immersion imposes a pressure imbalance between alveolar and mean external thoracic pressure. Lung centroid pressure (PLC) is defined as the breathing pressure required to remove this imbalance. Static transrespiratory pressure-volume relationships were determined in subjects immersed in upright (n = 17) and prone (n = 13) postures. Compliances measured during immersion (1.87 +/- 0.15 liter.kPa-1 upright, 1.87 +/- 0.17 liter.kPa-1) prone) were compared with compliances, obtained over the same volume range, while upright in air (1.84 +/- 0.17 liter.kPa-1). PLC was determined by the horizontal (pressure) displacement of immersed compliance curves. PLC was calculated to be +1.33 +/- 0.11 kPa (+13.6 cmH2O) relative to the sternal notch when upright and -0.69 +/- 0.12 kPa (-7.0 cmH2O) relative to the sternal plane when prone (mean +/- SEM). Upright PLC did not support the widely used value of +19 cmH2O (Jarrett AS. J Appl Physiol 1965;20:1261-1266). Analysis shows that when data from earlier investigations were adjusted for differences in reference pressure, the collective PLC supports the present results.
直立浸入会导致肺泡压力与胸廓平均外部压力之间出现压力失衡。肺质心压力（PLC）被定义为消除这种失衡所需的呼吸压力。在直立姿势（n = 17）和俯卧姿势（n = 13）下浸入水中的受试者中测定了静态跨呼吸压力-容积关系。将浸入过程中测量的顺应性（直立时为1.87±0.15升·千帕-1，俯卧时为1.87±0.17升·千帕-1）与在相同体积范围内在空气中直立时获得的顺应性（1.84±0.17升·千帕-1）进行比较。PLC通过浸入顺应性曲线的水平（压力）位移来确定。计算得出，直立时相对于胸骨切迹的PLC为+1.33±0.11千帕（+13.6厘米水柱），俯卧时相对于胸骨平面的PLC为-0.69±0.12千帕（-7.0厘米水柱）（平均值±标准误）。直立时的PLC不支持广泛使用的+19厘米水柱这一数值（贾勒特AS。《应用生理学杂志》1965年；20：1261 - 1266）。分析表明，当对早期研究数据的参考压力差异进行调整后，总体PLC支持当前结果。
