Neuromuscular blockade during therapeutic hypothermia after cardiac arrest: observational study of neurological and infectious outcomes

Abstract

Introduction: Neuromuscular blockade (NMB) is widely used during therapeutic hypothermia (TH) after cardiac arrest but its effect on patient outcomes is unclear. We compared the effects of NMB on neurological outcomes and frequency of early-onset pneumonia in cardiac-arrest survivors managed with TH.

Methods: We retrospectively studied consecutive adult cardiac-arrest survivors managed with TH in a tertiary-level intensive care unit between January 2008 and July 2013. Patients given continuous NMB for persistent shivering were compared to those managed without NMB. Cases of early-onset pneumonia and vital status at ICU discharge were recorded. To avoid bias due to between-group baseline differences, we adjusted the analysis on a propensity score.

Results: Of 311 cardiac-arrest survivors, 144 received TH, including 117 with continuous NMB and 27 without NMBs. ICU mortality was lower with NMB (hazard ratio [HR], 0.54 [0.32; 0.89], p=0.016) but the difference was not significant after adjustment on the propensity score (HR, 0.70 [0.39; 1.25], p=0.22). The proportion of patients with good neurological outcomes was not significantly different (36% with and 22% without NMB, p=0.16). Early-onset pneumonia was more common with NMB (HR, 2.36 [1.24; 4.50], p=0.009) but the difference was not significant after adjustment on the propensity score (HR, 1.68 [0.90; 3.16], p=0.10).

Conclusions: Continuous intravenous NMB during TH after cardiac arrest has potential owns effects on ICU survival with a trend increase in the frequency of early-onset pneumonia. Randomised controlled trials are needed to define the role for NMB among treatments for TH-induced shivering.

Keywords: Cardiac arrest; Induced hypothermia; Neuromuscular blockade; Pneumonia.