Safety of 65 °C intravenous fluid for the treatment of hypothermia

To demonstrate the safety and efficacy of 65°C (149°F) centrally administered intravenous fluid (CIVF) compared to conventional 40°C (104°F) CIVF in the treatment of hypothermia. Ten beagles (9–13 kg) were prospectively randomized to receive 65°C or 40°C CIVF. They were anesthetized and data were collected at baseline, during hypothermia, and after 1 and 2 hours of rewarming. The plasma free/total hemoglobin (PFHb/THb) was measured to detect hemolysis. Each subject was cooled to 30°C (86°F) and then received either 65 C or 40°C CIVF through a specialized catheter in the superior vena cava for 2 hours in addition to conventional rewarming techniques. All subjects survived 7 days, after which they were sacrificed and a complete autopsy was performed. The rewarming rate was 3.7°C/hr in the 65°C CIVF group and 1.75°C/hr in the 40°C CIVF group. Core temperatures were significantly different after 1 hour (33.4° ± 0.77° versus 31.7° ±0.57°, P < 0.01) and 2 hours (37° ± 1.03° versus 33.4° ± 0.89°, P < 0.001). PFHb/THb was not different. Two intimai injuries occurred in each group but these were remote from the infusion site. Blinded examination by two pathologists could not differentiate the etiology of these injuries from mechanical trauma. CIVF at 65°C is a safe and effective means of treating hypothermia.