Hypothermia from prolonged immersion: biophysical parameters of a survivor

We report a case of survival following prolonged immersion and hypothermia. The patient survived for over 9 h in open water, after his vessel capsized and sank in the Pacific Ocean off the coast of Northern California. Water temperature on the day of the sinking was 14.4°C (58.0°F). Although he did have adequate flotation, the patient did not wear a survival suit. On initial physical examination in the Emergency Department (ED), the patient’s rectal temperature was 30.0°C (86.0°F). With active rewarming, his temperature returned to normal (37.0°C {98.6°F}) within 5 h. Body fat of the patient was 19.6%, near the 50th percentile for his age (19.0%). Surface/volume ratio of the patient (.0228 m2/L) was 19% smaller than a predicted average (.0282 m2/L). We believe that the patient’s large body habitus contributed to survival and that surface/volume ratio was likely the biophysical variable most closely associated with decreased cooling.