Cooling methods of targeted temperature management and neurological recovery after out-of-hospital cardiac arrest: A nationwide multicenter multi-level analysis

Abstract

Objective: The purpose of this study was to determine whether the cooling method used for target temperature management (TTM) was associated with neurological recovery after out-of-hospital cardiac arrest (OHCA).

Methods: From January 2008 to December 2016, adult OHCA patients who survived to hospitalization without any traumatic etiology and who received TTM were included. Patients who did not have information about neurological status at hospital discharge or who did not have information on target temperature management were excluded. Cooling methods were classified into four groups: (1) external device cooling (EDC) using a pad with cooling device, (2) external conventional cooling (ECC) such as ice water, fans, and simple blankets, (3) Intravascular cooling (IVC) using an intravascular cooling catheter, and (4) intracavitary cooling (ICC) using ice water for washing cavitary organ. The outcomes were good cerebral performance scale (CPC) score 1 or 2 and survival to discharge. In multivariate logistic regression analysis, the adjusted odds ratios (AORs) and the 95% confidence intervals (CIs) were calculated (reference = ECC). Finally, we used a GLIMMIX procedure with group-level variables (hospitals) to create a multilevel model for adjusting the clustering factor of patients being treated in the same hospital.

Results: The final analysis included a total of 4246 eligible patients (ECC 1386, EDC 2107, IVC 376, ICC 377). Good neurologic recovery was 20.7% for all (ECC 17.4, EDC 23.1%, IVC 26.9%, and ICC 13.3%, p < .001). The survival rate was 46.4% for all (ECC 45.4%, EDC 48.5%, IVC 50.5%, ICC 34.2%, p < .001). There were no significant differences (AOR and 95% CI) in the multi-level analysis for good neurological recovery between cooling methods compared with ECC; EDC 1.20 (0.95-1.52), IVC 1.43 (0.90-2.27), and ICC 0.71 (0.46-1.10). The ICC group had a lower survival to discharge rate compared with ECC; EDC 0.97 (0.83-1.15), IVC 0.96 (0.78-1.19), and ICC 0.63 (0.43-0.85).

Conclusion: The cooling methods for TTM did not show any significant difference in neurological recovery in multi-level logistic regression analysis. Only intracavitary cooling resulted in a lower survival to discharge than external surface cooling.

Keywords: Cardiac arrest; Cooling method; Outcome; Targeted temperature management.