Morphologic alterations in brain, blood and viscera following use of cardiopulmonary bypass to induce prolonged deep hypothermic circulatory arrest after hemorrhagic shock in dogs

The feasibility of using cardiopulmonary bypass (CPB) as a rapid method to induce deep hypothermic circulatory arrest during intractable hemorrhagic shock to allow repair of otherwise lethal injuries in a bloodless field is investigated. Rapid [13-37 min.] cooling to 15°C and later rewarming were accomplished using the heater/cooler unit of a cardiopulmonary bypass system (centrifugal pump, hollow fiber membrane oxygenator). Fifteen lightly anesthetized spontaneously breathing dogs were subjected to a 30-min. period of hemorrhagic shock (mean arterial pressure of 40 mm Hg) followed by cooling to 15°C and 60, 90, or 120 min. of circulatory arrest. Two additional dogs (shams) had hypothermic CPB without a period of circulatory arrest (one with and one without a period of hemorrhagic shock). Alterations in blood parameters, brain, and visceral organs are discussed