Prognostic Signs in Experimental Hemorrhagic Shock
OTTO GLASSER, Ph.D.
IRVINE H. PAGE, M.D.
Despite a large amount of investigation, criteria have not been found which indicate with certainty the death or survival of animals in secondary hemorrhagic shock. This has handicapped efforts to ascertain the value of various treatments. It was, therefore, the purpose of this investigation to study still other manifestations of shock in the hope that their quantitative measurement would lead to better prognosis.Methods
Dogs were anesthetized by subcutaneous injection of 5 mg./kg. of morphine sulphate and intraperitoneal injection of 30 mg./kg. of sodium pentobarbital. The animals were bled rapidly from the femoral artery until, within a few minutes, an arterial pressure of 50 mm. Hg was established. This level was maintained for ninety minutes, after which it was lowered to 30 mm. Hg by further withdrawal of blood. This was maintained for forty-five minutes or more, making the total period of hypotension at least one hundred and thirty-five minutes, the average period being one hundred and forty-seven minutes. The withdrawn blood was stored in a bottle-reservoir under controlled pressure and remained connected with the arterial circulation for the duration of the experiment. The quantities of blood removed to produce the desired state of hypotension ranged from 2.6 to 7.7 per cent body weight. Ten to 15 mg. of heparin was used as anticoagulant in the reservoir and connecting tubing in each experiment.
After the hypotensive period, all or part of the blood was reinfused through the same femoral artery at an average rate of 30 ml. per minute, until. . .