Hospital course and body temperature. The patient demonstrated progressive heat loss despite standard rewarming measures, and his temperature fell to 32.4°C. Also, severe acidosis (pH 7.08, base excess (BE) –13.8 mmol/L) was observed. The intravascular balloon catheter system was used for aggressive rewarming. His core temperature reached 36.0°C after 125 min of intravascular rewarming, and the severe acidosis was normalized.