Effect of prehospital initiation of therapeutic hypothermia in adults with cardiac arrest on time-to-target temperature

Abstract

Objective: Despite growing adoption, the impact of prehospital initiation of therapeutic hypothermia on outcomes of cardiac arrest patients is unknown. The objective of this study was to determine if prehospital administration of cold intravenous fluids improved the time-to-target temperature. Methods: All patients enrolled in an institutional postcardiac arrest treatment pathway were prospectively registered into a quality assurance database. Patients undergoing cooling induction on hospital arrival were compared to those receiving a new treatment protocol initiated during the study period involving prehospital cooling with 4uC (39.2uF) normal saline. The primary outcome was the time-to-target temperature. Secondary outcomes included emergency medicine system transport time metrics, mortality, and neurologic status at discharge and 1 year. Results: One hundred thirty-two patients were enrolled during the study period. The initial rhythm was ventricular fibrillation/tachycardia in 63% and asystole/pulseless electrical activity in 36%. Eighty patients received prehospital cooling and 52 patients did not and comprised the historical control group. Time-to-target temperatures were not significantly different between prehospital and hospital cooled groups (256 v. 271 minutes, respectively, p 5 0.64), nor was there any improvement in hospital survival (54% v. 50%, p 5 0.67), good neurologic outcome (49% v. 44%, p 5 0.61), or 1-year survival (49% v. 42%, p 5 0.46) between the two groups. Transport times were longer in the prehospital cooled group. Conclusions: Out-of-hospital cardiac arrest patients treated with prehospital cooling before arrival at our urban hospital did not have faster time-to-target temperature or improvement in outcomes compared to patients cooled immediately on emergency department arrival. Further research is needed to determine if any benefits exist from prehospital cooling prior to its widespread adoption. RÉ SUMÉObjectif: Bien que l'amorce de l'hypothermie thé rapeutique en phase pré hospitaliè re soit de plus en plus ré pandue, on n'en connaît pas l'effet sur les ré sultats, chez les patients victimes d'un arrê t cardiaque. L'é tude visait à dé terminer si l'administration intraveineuse de liquides froids, en phase pré hospitaliè re, permettait d'atteindre plus rapidement la tempé rature cible. Mé thode: Tous les patients soumis à un parcours de traitement, en é tablissement, pour un arrê t cardiaque ont é té inscrits de maniè re prospective dans une base de donné es sur l'assurance de la qualité. Les patients soumis au refroidissement à leur arrivé e à l'hô pital ont é té comparé s avec ceux soumis au nouveau protocole de traitement mis en oeuvre durant la pé riode à l'é tude, comportant un refroidissement pré hospitalier à l'aide de l'administration d'une solution physiologique salé e maintenue à 4uC (39.2uF). Le principal critè re d'é valuation é tait le temps né cessaire à l'atteinte de la tempé rature cible. Les critè res d'é valuation secondaires comprenaient les mesures du tem...

Emergency medical service treated out-of-hospital cardiac arrest: Identification of weak links in the chain-of-survival through an epidemiological study

“…Temperature management in comatose survivors of OHCA is largely recommended 34 but the benefits of prehospital initiation of TH are still undefined. 35 In our population, only a minority of potential candidates underwent TH and none started cooling on scene; initial rhythm and age of patients did not influence the decision to start TH. Table 3.…”

Impact of therapeutic hypothermia during cardiopulmonary resuscitation on neurologic outcome: A systematic review and meta-analysis

“…After the rst screening procedure, 43 studies were assessed for eligibility. Of those, 35 did not t inclusion criteria, as reported in Figure 1; a total of 8 studies [9][10][11][12][13][14][15][16], including 3493 patients, were then included for meta-analysis.…”

“…The characteristics of the selected studies are summarized in Table 1. We identi ed 4 RCTs (high quality of evidence for two [12,16] and moderate for two [10,14]), two prospective studies (low level of evidence in one [9] and very low quality of evidence [15] in the other, which compared a prospective cohort with historical controls) and two retrospective studies (very low quality of evidence [11,13]). The ROB for RCTs was low in three studies [10,12,16] and showed some concerns in one [14] ( Table 2).…”

“…either during cardiopulmonary resuscitation (CPR) or immediately after ROSC prior to hospital arrival. This very early approach, which has been identi ed as "intra-arrest therapeutic hypothermia" (IATH), has been administered by different cooling methods, including selective brain cooling, rapid infusion of cold uids and trans-nasal evaporative cooling (TNEC) [9][10][11][12][13][14][15][16]. However, despite some preliminary encouraging ndings [10], variable results in RCTs have suggested either a potential bene t (i.e.…”

Prehospital initiation of mild therapeutic hypothermia for out-of-hospital cardiac arrest (OHCA): where are we now?

“…In this CJEM issue, Schenfeld et al report a pragmatic observational study examining the effectiveness of prehospital MTH in decreasing the time-to-target temperature among those who survived to intensive care unit (ICU) admission and were treated with a MTH protocol, in comparison to historical controls who had MTH initiated upon emergency department arrival. 50 Due to the study's restrictive and subjective inclusion criteria and observational design, conclusions of the intervention's effectiveness on survival and neurological outcomes cannot be drawn. However, this study provides insight into the real-world application of prehospital MTH.…”