THE EFFECT OF NEGATIVE PRESSURE BREATHING ON URINE FLOW

Abstract

Expts. were guided by the hypothesis that the vasosensitive areas within the pulmonary circulation, the great veins, and/or the chambers of the heart (Nonidez) represent the sensitive part of a regulatory mechanism which induces diuresis with increased blood vol. and oliguria with a decrease of blood vol. for the control of plasma vol. Accordingly a local engorgement of the intrathoracic circulation by negative pressure breathing in the order of -10 cm. H2O for 30 min. should cause a diuresis. In dogs under light chloralose anesthesia urine flow increased consistently from an average of 0.030 cc./kg./min. to 0.066 cc./kg./min. This increase of urine flow could not be attributed to physiol. factors such as mean arterial pressure, heart rate, cardiac output, venous pressure, and respiration, which may be affected by negative pressure breathing.