Effect of prehospital induction of mild hypothermia on survival and neurological status among adults with cardiac arrest: a randomized clinical trial.
OBJECTIVE
Hospital cooling improves outcome after cardiac arrest, but prehospital cooling immediately after return of spontaneous circulation may result in better outcomes.


OBJECTIVE
To determine whether prehospital cooling improves outcomes after resuscitation from cardiac arrest in patients with ventricular fibrillation (VF) and without VF.


METHODS
A randomized clinical trial that assigned adults with prehospital cardiac arrest to standard care with or without prehospital cooling, accomplished by infusing up to 2 L of 4°C normal saline as soon as possible following return of spontaneous circulation. Adults in King County, Washington, with prehospital cardiac arrest and resuscitated by paramedics were eligible and 1359 patients (583 with VF and 776 without VF) were randomized between December 15, 2007, and December 7, 2012. Patient follow-up was completed by May 1, 2013. Nearly all of the patients resuscitated from VF and admitted to the hospital received hospital cooling regardless of their randomization.


METHODS
The primary outcomes were survival to hospital discharge and neurological status at discharge.


RESULTS
The intervention decreased mean core temperature by 1.20°C (95% CI, -1.33°C to -1.07°C) in patients with VF and by 1.30°C (95% CI, -1.40°C to -1.20°C) in patients without VF by hospital arrival and reduced the time to achieve a temperature of less than 34°C by about 1 hour compared with the control group. However, survival to hospital discharge was similar among the intervention and control groups among patients with VF (62.7% [95% CI, 57.0%-68.0%] vs 64.3% [95% CI, 58.6%-69.5%], respectively; P = .69) and among patients without VF (19.2% [95% CI, 15.6%-23.4%] vs 16.3% [95% CI, 12.9%-20.4%], respectively; P = .30). The intervention was also not associated with improved neurological status of full recovery or mild impairment at discharge for either patients with VF (57.5% [95% CI, 51.8%-63.1%] of cases had full recovery or mild impairment vs 61.9% [95% CI, 56.2%-67.2%] of controls; P = .69) or those without VF (14.4% [95% CI, 11.3%-18.2%] of cases vs 13.4% [95% CI,10.4%-17.2%] of controls; P = .30). Overall, the intervention group experienced rearrest in the field more than the control group (26% [95% CI, 22%-29%] vs 21% [95% CI, 18%-24%], respectively; P = .008), as well as increased diuretic use and pulmonary edema on first chest x-ray, which resolved within 24 hours after admission.


CONCLUSIONS
Although use of prehospital cooling reduced core temperature by hospital arrival and reduced the time to reach a temperature of 34°C, it did not improve survival or neurological status among patients resuscitated from prehospital VF or those without VF.


BACKGROUND
clinicaltrials.gov Identifier: NCT00391469.
Department of Medicine, School of Medicine, University of Washington, Seattle.
Francis
F
Kim
Department of Medicine, School of Medicine, University of Washington, Seattle.
Graham
G
Nichol
Department of Health Services, School of Public Health, University of Washington, Seattle.
Charles
C
Maynard
Department of Biostatistics, School of Public Health, University of Washington, Seattle.
Al
A
Hallstrom
Department of Medicine, School of Medicine, University of Washington, Seattle.
Peter J
PJ
Kudenchuk
Department of Medicine, School of Medicine, University of Washington, Seattle.
Thomas
T
Rea
Department of Neurology, School of Medicine, University of Washington, Seattle.
Michael K
MK
Copass
Department of Medicine, School of Medicine, University of Washington, Seattle.
David
D
Carlbom
Department of Anesthesiology, School of Medicine, University of Washington, Seattle.
Steven
S
Deem
Department of Neurology, School of Medicine, University of Washington, Seattle6Department of Epidemiology, School of Public Health, University of Washington, Seattle.
W T
WT
Longstreth
Department of Medicine, School of Medicine, University of Washington, Seattle.
Michele
M
Olsufka
Department of Medicine, School of Medicine, University of Washington, Seattle.
Leonard A
LA
Cobb
D000368:Aged; D001831:Body Temperature; D001930:Brain Injuries / Q000150:complications / Q000209:etiology; D016887:Cardiopulmonary Resuscitation; D003072:Cognition Disorders / Q000209:etiology / Q000517:prevention & control; D004632:Emergency Medical Services; D005260:Female; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000503:physiopathology* / Q000628:therapy*; D012965:Sodium Chloride / Q000008:administration & dosage; D016019:Survival Analysis; D014693:Ventricular Fibrillation / Q000150:complications / Q000628:therapy
D012965:Sodium Chloride