Effects of pulmonary gas emoblism on circulation and respiration in the dog. VI. Influence of body position on the effects of pulmonary gas embolism.

In the present study the influence of body position on the effects of venous gas infusion was examined. The body position of anesthetized dogs ventilated artifically varied between supine, right-side-down and left-side-down position. Without venous gas infusion the change of body position hardly affected pulmonary arterial pressure (Pap) and alveolar CO2 fractional concentration (FACO2). However, during venous gas infusion a change of body position immediately elicited a rapid increase Pap and a decrease in FACO2 completed within a few seconds. Thereafter both variables gradually returned to their initial levels as before the change of body position. The extent of change in Pap and FACO2 due to alteration of body position depended on the initial embolic level (determined by the rate of infusion and the nature of the gas used) and on the change of body position.