Roman Skulec, Anatolij Truhlar, Jana Seblova, Pavel Dostal, Vladimir Cerny; Critical Care 2010, 14:R231
Introduction: Pre-hospital induction of therapeutic mild hypothermia (TH) may reduce post-cardiac arrest brain injury in patients resuscitated from out-of-hospital cardiac arrest. Most often, it is induced by a rapid intravenous administration of as much as 30 ml/kg of cold crystalloids. We decided to assess the pre-hospital cooling effectivity of this approach; using a target dose of 15-20 ml/kg of 4degrees C cold normal saline in the setting of the physician staffed Emergency Medical Service. The safety and impact on the clinical outcome have also been analyzed.
Methods: We performed a prospective observational study with a retrospective control group. A total of 40 patients were cooled by an intravenous administration of 15-20 ml/kg of 4degreesC cold normal saline during transport to the hospital (TH group). The pre-hospital decrease of tympanic temperature (TT) was analysed as the primary endpoint. Patients in the control group did not undergo any pre-hospital cooling.
Results: In the TH group, administration of 12.6+/-6.4 ml/kg of 4degreesC cold normal saline was followed by a pre-hospital decrease of TT of 1.4+/-0.8degreesC in 42.8+/-19.6 min (p<0.001). The most effective cooling was associated with a transport time duration of 38-60 min and with an infusion of 17 ml/kg of cold saline. In the TH group, a trend toward a reduced need for catecholamines during transport was detected (35.0 vs. 52.5%, p=0.115). There were no differences in demographic variables, comorbidities, parameters of the cardiopulmonary resuscitation and in other post-resuscitation characteristics. The coupling of pre-hospital cooling with subsequent in-hospital TH predicted a favourable neurological outcome at hospital discharge (OR 4.1, CI95% 1.1-18.2, p=0.046).
Conclusions: Pre-hospital induction of TH by the rapid intravenous administration of cold normal saline has been shown to be efficient even with a lower dose of coolant than reported in previous studies. This dose can be associated with a favourable impact on circulatory stability early after the return of spontaneous circulation and, when coupled with in-hospital continuation of cooling, it can potentially improve the prognosis of patients.
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