Influence of mild therapeutic hypothermia after cardiac arrest on hospital mortality.
OBJECTIVE
Following two randomized controlled trials that demonstrated reduced mortality and better neurological outcome in cardiac arrest patients, mild therapeutic hypothermia was implemented in many intensive care units. Up to now, no large observational studies have confirmed the beneficial effects of mild therapeutic hypothermia.


METHODS
Internet-based survey combined with a retrospective, observational study.


METHODS
All patients admitted to an intensive care unit in The Netherlands after cardiac arrest from January 1, 1999 until January 1, 2009.


METHODS
Dutch National Intensive Care Evaluation database.


METHODS
The moment of implementation of mild therapeutic hypothermia for each hospital participating in the Dutch National Intensive Care Evaluation database was determined with an Internet survey. To compare mortality before and after implementation of mild therapeutic hypothermia, the odds ratio adjusted for Simplified Acute Physiology Score II score, age, gender, propensity score, and in- or out-of-hospital cardiac arrest was calculated. Patients were excluded if 1) they were admitted to an intensive care unit that did not respond to the survey, 2) they were admitted within 3 months after implementation of mild therapeutic hypothermia, 3) they had a Glasgow Coma Scale score of >8, or 4) they did not satisfy the Simplified Acute Physiology Score II inclusion criteria.


METHODS
None.


RESULTS
A total of 13,962 patients were admitted to an intensive care unit following cardiac arrest. In total 8,645 patients were excluded, 5,544 because of a Glasgow Coma Scale score of >8. Of the resultant 5,317 patients, 1,547 patients were treated before and 3,770 patients after implementation of mild therapeutic hypothermia. Patients admitted after implementation of mild therapeutic hypothermia had lower minimal and maximal temperatures (p < .0001) during the first 24 hrs on the intensive care unit compared to patients admitted before implementation of mild therapeutic hypothermia. The adjusted odds ratio of the hospital mortality of patients treated after implementation of mild therapeutic hypothermia was 0.80 (95% confidence interval of 0.65-0.98, p = .029).


CONCLUSIONS
The results of this retrospective, observational survey suggest that implementation of mild therapeutic hypothermia in Dutch intensive care units is associated with a 20% relative reduction of hospital mortality in cardiac arrest patients.
van der Wal
Greetje
G
Department of Intensive Care Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Brinkman
Sylvia
S
Bisschops
Laurens L A
LL
Hoedemaekers
Cornelia W
CW
van der Hoeven
Johannes G
JG
de Lange
Dylan W
DW
de Keizer
Nicolette F
NF
Pickkers
Peter
P
D000368:Aged; D000369:Aged, 80 and over; D016001:Confidence Intervals; D016638:Critical Illness / Q000401:mortality / Q000628:therapy*; D016208:Databases, Factual; D005260:Female; D006323:Heart Arrest / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy*; D017052:Hospital Mortality; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods*; D007362:Intensive Care Units; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome