Intra-Arrest Induction of Hypothermia via Large-Volume Ice-Cold Saline for Sudden Cardiac Arrest: The New York City Project Hypothermia Experience

Abstract

Therapeutic hypothermia, the standard for post-resuscitation care of out-of-hospital sudden cardiac arrest (SCA), is an area that the most recent resuscitation guidelines note ''has not been studied adequately.'' We conducted a two-phase study examining the role of intra-arrest hypothermia for out-of-hospital SCA, first standardizing the resuscitation and transport of patients to resuscitation centers where post-resuscitation hypothermia was required and then initiating hypothermia during out-of-hospital resuscitation efforts. The primary end points were return of spontaneous circulation (ROSC), sustained ROSC, survival to hospital admission, and survival to discharge. Comparing the cohort of standard hospital-initiated hypothermia (Phase I) with the prehospital-initiated hypothermia via large-volume ice-cold saline (LVICS) infusion (Phase II), no difference was noted for any end point: ROSC (56.4% vs. 53.4%, p = 0.51; 95% confidence interval [CI]:-5.7 to 11.4), sustained ROSC (46.9% vs. 42.8%, p = 0.38; 95% CI:-4.7 to 12.4), hospital admission (44.7% vs. 37.7%, p = 0.13; 95% CI:-1.9 to 15.4), hospital discharge among those surviving to admission (40.0% vs. 28.0%, p = 0.08; 95% CI:-1.5 to 27.8), or neurological outcome among those surviving to discharge (76.0% vs. 71.4%, p = 0.73; 95% CI:-26.9 to 38.7). Patients presenting in ventricular fibrillation were more likely to survive to hospital discharge in both phases, although a trend toward worsened early outcomes (ROSC, sustained ROSC, and survival to admission) with intra-arrest hypothermia was noted in this subgroup. Multivariable regression analyses failed to demonstrate any survival benefit associated with the intra-arrest initiation of hypothermia via LVICS. Our study, the largest study of intra-arrest initiation of hypothermia published to date, failed to demonstrate any effect on survival for out-of-hospital SCA patients, confirming findings of previously published smaller studies. We therefore do not recommend the use of intra-arrest cooling via LVICS infusion as part of routine out-of-hospital SCA resuscitative efforts.

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).…”

“…The ROB for RCTs was low in three studies [10,12,16] and showed some concerns in one [14] ( Table 2). For all non-RCTs, the ROB was high [9,11,13,15] (Table 3). All selected studies included only patients after OHCA.…”

“…All selected studies included only patients after OHCA. In ve studies, IATH was induced using intravenous cold uids [11][12][13][14][15], whereas two studies used TNEC [10,16] and one selective cranial cooling [9].…”

“…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.…”