Journal of Applied Physiology, Vol 38, Issue 5 896-899, Copyright © 1975 by American Physiological Society
Positive airway pressure and vertical transpulmonary pressure gradient in man
K. Rehder, N. Abboud, J. R. Rodarte and R. E. Hyatt
Static transpulmonary pressure (Pao-Pes) and the vertical gradient of
transpulmonary pressure were determined in five sitting conscious normal
subjects at mean airway pressures of 0 (ambient), 11, and 21 cmH2O. All
subjects exhibited a nonuniform transpulmonary pressure gradient down the
esophagus. The vertical pressure gradient was consistently larger in the
lower (8-20cm below esophageal artifact) than in the middle region (0-8cm)
of the esophagus. The gradient was not significantly altered by continuous
positive airway pressure (11 and 21 cmH2O) or by changes in lung volume
(60, 70, and 80% of total lung capacity (TLC)). Continuous positive airway
pressure also did not result in a consistent change of the overall static
pressure-volume curve of the lung. There was a small but statistically
significant increase in TLC with each increase in airway pressure.
