Effect of antishock trouser inflation on plasma renin activity during hemorrhagic shock.

The effect of antishock trouser inflation on plasma renin activity during hypovolemic shock was studied in dogs. Following anesthesia, six dogs were bled to a systolic blood pressure of 60 mm Hg. Antishock trousers were inflated to 40 to 100 mm Hg for 20 minutes each. Plasma renin activity was measured before phlebotomy, after phlebotomy, and after each 20-minute period of antishock trouser inflation. Three dogs without antishock trousers served as controls. Experimental animals had a significant rise in blood pressure when the antishock trousers were inflated to 100 mm Hg. Plasma renin activity showed a marked increase following phlebotomy (experimental, 1.55 ng/mL/h to 13.63 ng/mL/h; control, 2.71 ng/mL/h to 19.7 ng/mL/h). Both groups had a continued small, statistically insignificant rise in plasma renin levels throughout the remainder of the experiment. Plasma renin level changes did not explain the observed rise in blood pressure following antishock trouser inflation. Plasma renin levels remained elevated in spite of improvement of blood pressure after application of antishock trousers.