Evaporation versus iced peritoneal lavage treatment of heatstroke: comparative efficacy in a canine model

The authors compared the speed of cooling and treatment efficacy for evaporative cooling versus iced peritoneal lavage in a canine heatstroke model. Nine random-source, mongrel dogs were anesthetized, shaved, and internally heated until the core temperature reached 43.0 degrees C. The animals were then randomly assigned to be cooled to 37 degrees C either by sterile normal saline (6 degrees C) continuous peritoneal lavage at 250 mL/min (n = 4), or by spraying with tap water (15 degrees C, 12 L/min) before a large fan blowing room temperature air (23 degrees C) across the dog at 0.5 m/sec from a height of 50 cm (n = 5). Temperatures were monitored by thermocouples in both tympanic membranes. Electrocardiogram, blood pressure, and pulse were continuously monitored. Evaporative cooling was as rapid as iced peritoneal lavage (0.18 +/- .03 versus 0.17 +/- .07 degrees C/min/m2, P = NS). All animals survived, although one animal in each treatment group demonstrated a moderate neurologic deficit when measured 48 hours following resuscitation. A simple noninvasive evaporative cooling technique, readily available in the emergency department, appears to be as rapid readily available in the emergency department, appears to be as rapid and effective as aggressive peritoneal lavage for cooling and treating heatstroke in the dog.