COMPARISON STUDIES OF PASSIVE AND ACTIVE SHUNTING DURING CROSS-CLAMPING OF THE DESCENDING THORACIC AORTA

The effects of passive (no pump) and active (using centrifugal pump) s hunting on hemodynamics and metabolisms during cross-clamping of the d escending thoracic aorta were compared in mongrel dogs. In Group I (co ntrol), the aorta was cross-clamped for 2 hours without shunting; in G roup II (passive), a temporary shunt was placed between the left commo n carotid and left femoral arteries during cross-clamping; and in Grou p III (active), left heart by-pass, matching flow to that in group II, was performed. Hemodynamic and metabolic parameters were recorded pri or to cross-clamping and following every 30 min for 4 hours. All anima ls in Group I suffered from hemodynamic instability, metabolic abnorma l and neurologic injury and died within 12 hours. Hemodynamic changes were unstable in Group III than II, and three dogs in Group III, but n one in Group II, suffered from neurologic injury. Metabolic changes be tween Group II and III were not significant. We conclude that passive shunting is superior to active shunting for aortic by-pass.