Intravenous fluid flow beneath inflated antishock trousers in a canine hemorrhagic shock model

A study was performed to determine the percentage of fluid that enters the central circulation following infusion in a peripheral vein beneath an inflated pneumatic antishock garment (PASG) during hemorrhagic shock in a canine model. Seven mongrel dogs were bled acutely to a systolic blood pressure of 50 to 60 mm Hg. The PASG then was inflated. One to two microcuries of Technetium-99-labeled macroaggregated albumin was infused into a peripheral vein in the hind leg, followed by a 10-mL/kg fluid bolus. The albumin particles that reached the central circulation were trapped in the pulmonary capillary bed. Following infusion, a full body scan was performed. The percentage of injected fluid entering the central circulation was calculated by comparing the total body counts to counts localized to the thorax. Average mean arterial pressure was 111 mm Hg prior to bleeding, 47 mm Hg prior to shock trouser inflation, and 66 mm Hg after inflation. The percentage of injected Technetium-99-labeled albumin that reached the central circulation ranged from 80.5% to 99.6%, with a mean of 91.3%. We conclude that a significant percentage of IV fluids infused beneath inflated PASG will reach the central circulation.