Simultaneous determination of blood volume with Cr⁵¹ and T-1824 during hypothermia and rewarming

¹ Department of Surgery, Section of Experimental Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania

Dogs lightly anesthetized with ether, maintained between 23–24°C for 2 hours and rewarmed, were subjected to simultaneous determinations of red cell volume (Cr⁵¹) and plasma volume (T-1824). Red cell volume values were unchanged during the course of the experiment. Plasma volumes were significantly decreased during hypothermia and were transiently elevated during rewarming. Twenty-four hours after rewarming, total blood volume and plasma volume values were not significantly different from control values. It would seem that circulatory failure (‘rewarming shock’) is not a usual feature of rewarming following hypothermia of 2 hours duration.