Topography of esophageal pressure as a function of posture in man

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Abstract
Esophageal and mouth pressures were determined at various fixed lung volumes in seven normal subjects in various postures. Esophageal pressure was obtained from balloons placed at various levels of the esophagus. The balloons contained a volume of gas small enough to render its effect on the pressure recorded negligible. In approximately the upper third of the esophagus changes in mouth pressure, head posture, and external pressure on the trachea produced pressure variations which were unrelated to variations in pleural pressure and were probably the result of traction on, or compression of, the esophagus by the trachea. These artifacts were absent in the lower two-thirds of the esophagus. In the lower third of the esophagus, pressures were found to vary markedly from point to point and with body posture. In approximately the middle third of the esophagus pressures were relatively uniform from point to point, did not vary markedly with body posture, and probably more closely reflect local pleural pressures. It is concluded that in studies of respiratory mechanics esophageal pressure should be measured in the middle third of the esophagus. pleural pressure; lung volume-pressure curves; esophageal balloons Submitted on August 13, 1963