Pre-hospital cooling of patients following cardiac arrest is effective using even low volumes of cold saline
1 Emergency Medical Service of the Central Bohemian Region, Prof. Veseleho 461, Beroun 266 01, Czech Republic
2 Department of Anesthesiology and Intensive Care, Charles University in Prague, Faculty of Medicine in Hradec Kralove, University Hospital Hradec Kralove, Hradec Kralove 500 05, Czech Republic
3 Beroun City Hospital, Jessenia a.s., Prof. Veseleho 451, Beroun 266 01, Czech Republic
4 Hradec Kralove Region Emergency Medical Services, Hradecka 1690/2A, Hradec Kralove 500 12, Czech Republic
5 Emergency Medical Service of the Central Bohemian Region, Vančurova 1544, Kladno 272 01, Czech Republic
6 Department of Anesthesia, Dalhousie University, 1276 South Park Street, 10 West, Victoria Building, Halifax, NS, B3H 2Y9, Canada
Critical Care 2010, 14:R231 doi:10.1186/cc9386Published: 22 December 2010
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 by using a target dose of 15-20 ml/kg of 4°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.
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 4°C cold normal saline during transport to the hospital (TH group). The pre-hospital decrease of tympanic temperature (TT) was analyzed as the primary endpoint. Patients in the control group did not undergo any pre-hospital cooling.
In the TH group, administration of 12.6 ± 6.4 ml/kg of 4°C cold normal saline was followed by a pre-hospital decrease of TT of 1.4 ± 0.8°C 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 favorable neurological outcome at hospital discharge (OR 4.1, CI95% 1.1-18.2, p = 0.046).
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 favorable impact on circulatory stability early after the return of spontaneous circulation and, when coupled with in-hospital continuation of cooling, can potentially improve the prognosis of patients.
ClinicalTrials (NCT): NCT00915421