Therapeutic hypothermia after cardiac arrest: unintentional overcooling is common using ice packs and conventional cooling blankets.
OBJECTIVE
Although therapeutic hypothermia for cardiac arrest survivors has been shown to improve neurologically intact survival, optimal methods to ensure controlled induction and maintenance of cooling are not clearly established. Precise temperature control is important to evaluate because unintentional overcooling below the consensus target range of 32-34 degrees C may place the patient at risk for serious complications. We sought to measure the prevalence of overcooling (<32 degrees C) in postarrest survivors receiving primarily noninvasive cooling.


METHODS
Retrospective chart review of postarrest patients.


METHODS
Three large teaching hospitals.


METHODS
Cardiac arrest survivors receiving therapeutic hypothermia.


METHODS
Charts were reviewed if primarily surface cooling was used with a target temperature goal between 32 degrees C and 34 degrees C.


RESULTS
Of the 32 cases reviewed, overcooling lasting for >1 hr was identified as follows: 20 of 32 patients (63%) reached temperatures of <32 degrees C, 9 of 32 (28%) reached temperatures of <31 degrees C, and 4 of 32 (13%) reached temperatures of <30 degrees C. Of those with overcooling of <32 degrees C, 6 of 20 (30%) survived to hospital discharge, whereas of those without overcooling, 7 of 12 (58%) survived to hospital discharge (p = not significant).


CONCLUSIONS
The majority of the cases reviewed demonstrated unintentional overcooling below target temperature. Improved mechanisms for temperature control are required to prevent potentially deleterious complications of more profound hypothermia.
Merchant
Raina M
RM
Section of Emergency Medicine, University of Chicago Hospitals Emergency Resuscitation Center, Chicago, Illinois, USA.
Abella
Benjamin S
BS
Peberdy
Mary Ann
MA
Soar
Jasmeet
J
Ong
Marcus E H
ME
Schmidt
Gregory A
GA
Becker
Lance B
LB
Vanden Hoek
Terry L
TL
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001831:Body Temperature; D005260:Female; D006323:Heart Arrest / Q000628:therapy*; D006784:Hospitals, Teaching; D006801:Humans; D007036:Hypothermia, Induced / Q000009:adverse effects* / Q000379:methods*; D007053:Ice; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
D007053:Ice