Rapid Infusion of Cold Hartmanns - RICH
The goal of the trial was to evaluate prehospital cooling compared with initiation of cooling in the hospital among patients who suffered an out-of-hospital cardiac arrest.
Induction of hypothermia by paramedics would be more effective at improving the proportion of patients discharged to home or a rehabilitation facility.
Patients at least 15 years of age resuscitated from an out-of-hospital cardiac arrest due to ventricular fibrillation
Systolic blood pressure >90 mm Hg
Cardiac arrest time >10 minutes
Number of screened applicants: 842
Number of enrollees: 234
Duration of follow-up: hospital discharge
Age: mean 63 years
Percentage female: 14%
Nonintubated patients, dependency on others for activities of daily living, or pre-existing hypothermia
Discharge to home or rehabilitation facility at hospital discharge
Core temperature at hospital arrival
Prehospital pulmonary edema
Recurrent prehospital cardiac arrest
Patients resuscitated from an out-of-hospital cardiac arrest were randomized to initiation of cooling by paramedics prior to hospitalization (n = 118) versus initiation of cooling in the hospital (n = 116). Target temperature was 33°C.
In the prehospital cooling group, patients received midazolam, pancuronium, and up to 2 liters of ice-cold lactated Ringer’s solution at 100 cc/minute.
In the hospital cooling group, patients received rapid infusion of 40 cc/kg of ice-cold lactated Ringer’s solution, and midazolam/pancuronium if necessary.
After induction of hypothermia, all patients received surface cooling with specialized cooling machines or ice packs.
Overall, 234 patients were randomized. In the prehospital cooling group, the mean age was 63 years, 17% were women, and 69% received bystander cardiopulmonary resuscitation. The initial temperature was 35.9°C in the prehospital cooling group and 35.8°C in the hospital cooling group (p = 0.63). Upon arrival in the emergency department, temperature was lower in the prehospital cooling group: 34.4°C versus 35.2°C (p = 0.001), although temperature was similar by 60 minutes: 34.7°C versus 34.7°C (p = 0.70).
A favorable outcome occurred in 47.5% of the prehospital cooling group versus 52.6% of the hospital cooling group (p = 0.43). Deaths occurred in 52.5% versus 46.6%, discharge to home was 20.3% versus 29.3%, and discharge to a rehabilitation facility was 27.1% versus 23.3%, respectively.
Among patients who suffered an out-of-hospital cardiac arrest, induction of cooling by paramedics was not superior to cooling in the hospital. A similar proportion of patients was discharged to home or a rehabilitation facility with either cooling strategy. The inability to detect a difference in the primary outcome might have been due to a modest difference in temperature between groups at hospital arrival; however, maintaining hypothermia for 12-24 hours might be more important than rapid induction prior to hospital arrival. In fact, the first trial on the topic demonstrated benefit from cooling despite a very slow reduction in core body temperature.
Bernard SA, Smith K, Cameron P, et al. Induction of therapeutic hypothermia by paramedics after resuscitation from out-of-hospital ventricular fibrillation cardiac arrest: a randomized controlled trial. Circulation 2010;122:737-42.
Keywords: Midazolam, Pancuronium, Resuscitation, Out-of-Hospital Cardiac Arrest, Hypothermia, Cardiopulmonary Resuscitation, Ventricular Fibrillation, Emergency Service, Hospital, Isotonic Solutions, Cold Temperature
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