Postural effect on ventilatory control

Abstract

Minute ventilation, alveolar CO2 tension (Paco2), and arterial CO2 tension (Pacoco2) were studied in human subjects during passive tilt from the supine to the erect position. These measurements showed that the erect position was associated with relative alveolar hyperventilation. The hyperventilation of the erect position was found to be almost entirely reversible if hydrostatic effects were removed by water immersion to the level of the xiphoid. Postural changes in ventilation correlated with circulatory changes, suggesting a causal relationship. However, the possibility of a gravity-sensitive abdominal receptor which influences ventilation was not eliminated. ventilation; alveolar ventilation; posture; alveolar gas tension Submitted on April 27, 1964