Hyperthermic resuscitation is safe and effective after hemorrhagic shock in dogs

Objective: To show that resuscitation from hypothermic, hemorrhagic shock u sing 65 degrees C intravenous fluid results in a more rapid return to euthe rmia compared with 40 degrees C intravenous fluid, without significant endo thelial or hemolytic injury. Design: Fourteen anesthetized beagles (10-12 kg) were cooled to a core temp erature of 30 degrees C and hemorrhaged to a mean arterial pressure of 40 t o 45 mm Hg for 30 minutes. The animals were randomized to receive either 65 degrees C or 10 degrees C intravenous fluid through a specially designed c atheter at a rate of 80% of their blood volume per hour until euthermic (37 degrees C) or for 2 hours. Materials and Methods: Blood pressure, pulmonary artery pressure, heart rat e, and core temperature were continuously monitored. Blood samples were col lected at baseline, after hemorrhage, 2 hours of resuscitation, and at post mortem examination after 7 days of survival. Laboratory measurements includ ed complete blood count, plasma-free hemoglobin, and osmotic fragility. Val ues were compared using the Student's paired or unpaired t test with p simi lar to 0.05 indicating significance. Postmortem examination included light microscopy of the proximal superior vena cava or right atrium, Results: Animals receiving 65 degrees C intravenous fluid warmed 3.6 degree s C/hour, significantly faster than the 40 degrees C animals (1,9 degrees C /hour), There were no significant differences in plasma-free hemoglobin or osmotic fragility. Endothelial injuries were found in two animals in each g roup, These defects occurred along the path of catheter insertion and not a t the infusion site, Conclusions: Central intravenous fluid at 65 degrees C is a more rapid mean s of treating hypothermia than standard 40 degrees C intravenous fluid, It is safe even in hypothermia animals.