Urban accidental hypothermia: 135 cases.

We retrospectively reviewed 135 presentations (114 patients) of urban hypothermia treated at the discretion of the emergency department staff over a nine-year period from February 1971 to March 1980. Rewarming treatment options included passive external, active external, and heated oxygen aerosol administered by mask or intubation. The rates of rewarming were statistically similar for passive external (0.71 C/hr) and heated aerosol via mask (0.74 C/hr). The rate of rewarming for active external methods was 0.90 C/hr. Heated oxygen aerosol using intubation rewarmed the patient at a significantly greater rate than the passive external method (1.22 C/hr) (P < 0.01). The overall mortality rate for the series was 11.9%, but 47.9% when serious underlying disease was present. Individual mortality rates were 64.3% for active external (9/14), 7.67% for active core with a mask (1/13), 5.2% for passive external (4/68), and 5.0% for active core with a nasotracheal tube (2/40). Active core rewarming using intubation was selected more frequently with moderate and severe hypothermia (P < 0.001). The group of survivors had a higher mean arrival temperature (31.33 C) than did the non-survivors (27.55 C) (P = 0.01). Active core rewarming with heated aerosolized oygen via nasotraheal tube is a safe technique for the rapid rewarming of selected hypothermic patients. The arrival temperature and the presence of serious underlying disease, in addition to the method of rewarming, appear to be major determinants of prognosis.