Prehospital induction of moderate hypothermia after cardiac resuscitation can increase survival without increasing neurologic impairment: a case-control study

Corral Torres E, Fernández Avilés F, López De Sa E, Martín Benítez JC, Montejo JC, Martín Reyes R, Saavedra Cervantes R

Objectives: To assess the effect of early prehospital emergency responder implementation

of moderate hypothermia on neurologic outcome in patients recovering from cardiac

arrest.

Methods: Case-control comparative study. The cases were the first 40 patients in

cardiorespiratory arrest in whom hypothermia was induced in the ambulance after

resuscitation by responders from the Citizen Protection Emergency Service of Madrid

(SAMUR); hypothermia was also later used in the hospital. The controls were the last 40

patients in cardiorespiratory arrest who were resuscitated by the SAMUR responders

before the prehospital hypothermia protocol had been established; hypothermia was

later induced after the control patients’ arrival at the hospital. Patients whose

cardiorespiratory arrest had neurologic causes were excluded given that the effect on

neurologic outcome was under evaluation. The Cerebral Performance Category scale

was used to assess impairment. A grade 1 or 2 assessment was considered to indicate a

good neurologic outcome.

Results: Neurologic outcome was good for 50% of the patients in whom hypothermia was

induced early; outcome was good for 27.5% of the control patients (P=.039). The

significant difference between cases and controls was maintained regardless of whether the

initial heart rhythm was shockable (58.3% of such cases had good neurologic outcomes

with early hypothermia vs 37.5% of the controls with shockable rhythm) or not (42.8% of

such cases had good outcomes vs 14.2% of the controls with nonshockable rhythm).

Conclusions: Our findings show a significant relationship between prehospital induction

of moderate hypothermia and a higher probability of neurologic recovery (performance

categories 1 and 2). If moderate hypothermia is initiated before arrival at the hospital, the

likelihood of good neurologic recovery is 2.6-times greater.

Corral Torres E, Fernández Avilés F, López De Sa E, Martín Benítez JC, Martín Reyes R, Montejo JC, Saavedra Cervantes R