E.C.G. CHANGES DURING POSTHÆMORRHAGIC HYPOTENSION IN PRECOOLED DOGS

D. Panteli ¹, E. Vajs ¹, and R. Debijadji ¹

¹ Institute of Pathophysiology, Military Medical Academy, Belgrade, Yugoslavia

E.C.G. changes were recorded in the course of twenty-nine experiments on dogs which were bled during either light (30-32° C.) or deep (26-28° C.) hypothermia. After being maintained with a blood pressure of 40 mm. Hg for 2 hr., sixteen dogs received a 6 per cent solution of dextran in amounts equal to the total blood loss. The survival rate in this group was 87·5 per cent. The majority of dogs in the control group without administration of dextran died some hours after termination of the bleeding.

It was impossible to pick out any E.C.G. changes which are characteristic for the state of prolonged posthæmorrhagic hypotension in hypothermia. In fact, excluding the effects of hypothermia itself, the E.C.G. changes were very similar to that described for dogs bled at normal body temperature. The less the hypothermia, the greater was the similarity.

It is our opinion that the described E.C.G. changes do not explain the greater tolerance of cooled dogs to the posthæmorrhagic hypotension. Also, none of the described E.C.G. changes, including "Osborn's wave", in the course of cooling and during posthæmorrhagic hypotension could be taken as a bad prognostic sign.