Rapid Infusion of Cold Hartmanns - RICH
Description:
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.
Hypothesis:
Induction of hypothermia by paramedics would be more effective at improving the proportion of patients discharged to home or a rehabilitation facility.
Study Design
- Parallel
- Randomized
Patient Populations:
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Patients at least 15 years of age resuscitated from an out-of-hospital cardiac arrest due to ventricular fibrillation
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Systolic blood pressure >90 mm Hg
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Cardiac arrest time >10 minutes
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Intravenous access
Number of screened applicants: 842
Number of enrollees: 234
Duration of follow-up: hospital discharge
Age: mean 63 years
Percentage female: 14%
Exclusions:
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Pregnancy
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Nonintubated patients, dependency on others for activities of daily living, or pre-existing hypothermia
Primary Endpoints:
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Discharge to home or rehabilitation facility at hospital discharge
Secondary Endpoints:
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Core temperature at hospital arrival
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Prehospital pulmonary edema
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Recurrent prehospital cardiac arrest
Drug/Procedures Used:
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.
Principal Findings:
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.
Interpretation:
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.
References:
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.
Clinical Topics: Arrhythmias and Clinical EP, SCD/Ventricular Arrhythmias, Novel Agents
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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