Topical ice slurry prevents brain rewarming during deep hypothermic circulatory arrest in newborn sheep.
OBJECTIVE
To measure the effect of ice slurry topical cooling on brain surface temperature during deep hypothermic circulatory arrest.


METHODS
This was a prospective, controlled experiment.


METHODS
Animal laboratory at a university hospital.


METHODS
Five control lambs, five treatment (ice slurry) lambs.


METHODS
Animals were studied in two groups: the study group had topical cooling of the head with ice slurry started immediately before circulatory arrest and continued throughout the period of circulatory arrest; control group lambs received no supplemental topical cooling.


RESULTS
Brain 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 had a statistically significant decrease in brain surface temperature of 2.2 +/- 1.2 degrees C during circulatory arrest, whereas brain surface temperature increased 1.2 +/- 0.3 degrees C, in control lambs. Equilibration of temperature between the scalp and brain in control lambs produced rewarming of the brain surface.


CONCLUSIONS
Topical cooling of the head with ice slurry in newborn lambs lowers brain surface temperature during deep hypothermic circulatory arrest. Surrogate temperature monitoring locations such as nasopharyngeal and rectal temperatures varied significantly and do not accurately reflect changes in brain surface temperature.
Brooker
R F
RF
Department of Anesthesia, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27157-1009, USA.
Zvara
D A
DA
Velvis
H
H
Prielipp
R C
RC
D000818:Animals; D000831:Animals, Newborn; D001831:Body Temperature; D001921:Brain / Q000502:physiology*; D003080:Cold Temperature; D006324:Heart Arrest, Induced; D010101:Oxygen Consumption; D012756:Sheep