Is aortic occlusion advisable in the management of massive hemorrhage? Experimental study in dogs.

Occlusion of the thoracic aorta is meant to improve cerebral and cardiac perfusion in the moribund, exsanguinating trauma patient. Yet clinical and experimental experience shows no evident benefit from this critical maneuver, and hind limb paralysis (HLP) is a feared complication. Our study is intended to verify whether aortic occlusion can decrease further blood loss and therefore be useful during treatment of hemorrhagic shock. Four groups of 10 dogs were submitted to hemorrhagic shock and treated with blood (40 mL/kg) and saline (35 mL/kg). Group I was then submitted to intermittent intra-aortic occlusion (IIAO), Groups II and III to IIAO and to a second bleeding (rebleeding), and Group IV to rebleeding only, without IIAO. All dogs received volume replacement during this rebleeding phase and were kept alive for 8 days. Five dogs died and seven had HLP in the three groups submitted to IIAO. Death and HLP occurred even in the dogs of Group I, which were not submitted to a second bleeding. IIAO reduced blood loss from 139 mL/kg to 48 mL/kg. There were no complications or deaths among the 10 dogs in Group IV. Although efficient in reducing blood loss, IIAO was associated with a 16% mortality and 23% of HLP, whereas volume replacement alone was tolerated without complications or death. We conclude that IIAO is dangerous while treating severe hemorrhagic shock even after volume replacement and hemodynamic stabilization.