title: Pre-hospital cooling of patients following cardiac arrest is effective using even low volumes of cold saline.
abstract: BACKGROUND
  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.
  
  
  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 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.
  
  
  RESULTS
  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).
  
  
  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 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.
  
  
  BACKGROUND
  ClinicalTrials (NCT): NCT00915421.
authors.affiliation: Emergency Medical Service of the Central Bohemian Region, Prof, Veseleho 461, Beroun 266 01, Czech Republic. skulec@email.cz
authors.forename: Roman
authors.initials: R
authors.lastname: Skulec
authors.forename: Anatolij
authors.initials: A
authors.lastname: Truhlár
authors.forename: Jana
authors.initials: J
authors.lastname: Seblová
authors.forename: Pavel
authors.initials: P
authors.lastname: Dostál
authors.forename: Vladimír
authors.initials: V
authors.lastname: Cerný
mesh_terms: D000328:Adult; D000368:Aged; D003080:Cold Temperature; D004305:Dose-Response Relationship, Drug; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D006323:Heart Arrest / Q000175:diagnosis / Q000628:therapy*; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010952:Plasma Substitutes / Q000008:administration & dosage*; D011446:Prospective Studies; D012189:Retrospective Studies; D012965:Sodium Chloride / Q000008:administration & dosage*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D010952:Plasma Substitutes; D012965:Sodium Chloride