VERY HOT INTRAVENOUS FLUID IN THE TREATMENT OF HYPOTHERMIA

The efficacy and safety of very hot (65-degrees-C/149-degrees-F) intravenous fluid (IVF) were compared with those of conventional warm (38-degrees-C/100.4-degrees-F) IVF in the treatment of hypothermia. Eight anesthetized beagles (11-20 kg) were studied. Blood pressure (BP), pulse (P), and core temperature (cT-degrees) were recorded at baseline, during hypothermia, and during rewarming. The plasma free hemoglobin (PFHg) was measured to assess hemolysis. Each subject was cooled to 32-degrees-C/89.6-degrees-F and assigned to receive either 65-degrees-C or 38-degrees-C IVF via a specially designed multiport balloon-tipped catheter in the superior vena cava (SVC). The IV fluid rate was 80% of the blood volume per hour. Conventional rewarming methods were used in all subjects. After 2 hours the subjects were killed and the SVC was examined for injury. The rate of rewarming was 2.9-degrees-C/hour in the 65-degrees-C IVF group and 1.25-degrees-C/hour in the 38-degrees-C IVF group. The cT-degrees was significantly different in all subjects after 1 (35.2-degrees +/-1.03-degrees-C vs. 33.2-degrees +/- 0.5-degrees-C; p < 0.006) and 2 (37.6-degrees +/- 1.17-degrees-C vs. 34.3-degrees +/- 0.9-degrees-C; p < 0.004) hours of rewarming. The BP, P, and PFHg were not different. Visual examination of the SVC revealed two lesions in the 65-degrees-C IVF group and one in the 38-degrees-C group. Mechanical or thermal injury could not be differentiated. We conclude that 65-degrees-C IVF is more effective than 38-degrees-C IVF in the treatment of hypothermia. In addition, 65-degrees-C IVF did not uniformly cause hemolysis or injure the SVC.