TOPICAL ICE SLURRY PREVENTS BRAIN REWARMING DURING DEEP HYPOTHERMIC CIRCULATORY ARREST IN NEWBORN SHEEP

Objectives: To measure the effect of ice slurry topical cooling on bra in surface temperature during deep hypothermic circulatory arrest. Des ign: This was a prospective, controlled experiment, Setting: Animal la boratory at a university hospital. Participants: Five control lambs, f ive treatment (ice slurry) lambs. Interventions: Animals were studied in two groups: the study group had topical cooling of the head with ic e slurry started immediately before circulatory arrest and continued t hroughout the period of circulatory arrest; control group lambs receiv ed no supplemental topical cooling. Measurements and Main Results: Bra in surface temperature, scalp, nasopharyngeal, and rectal temperatures were measured at 5-minute intervals during 45 minutes of circulatory arrest. Lambs receiving topical cooling of the head with ice slurry ha d a statistically significant decrease in brain surface temperature of 2.2 +/- 1.2 degrees C during circulatory arrest, whereas brain surfac e temperature increased 1.2 +/- 0.3 degrees C, in control lambs. Equil ibration of temperature between the scalp and brain in control lambs p roduced rewarming of the brain surface, Conclusions: Topical cooling o f the head with ice slurry in newborn lambs lowers brain surface tempe rature during deep hypothermic circulatory arrest, Surrogate temperatu re monitoring locations such as nasopharyngeal and rectal temperatures varied significantly and do not accurately reflect changes in brain s urface temperature. Copyright (C) 1997 by W.B. Saunders Company.