|Neuromuscular blockade for at least 24 hours improved in-hospital survival rate.|
|The 2010 American Heart Association guidelines recommend limiting neuromuscular blockade (NMB) in patients with return of spontaneous circulation (ROSC) because it could be harmful. However, NMB is often used to prevent shivering in post–cardiac arrest patients receiving therapeutic hypothermia. Researchers performed a post-hoc analysis of a prospective, observational study of comatose adults with nontraumatic out-of-hospital cardiac arrest who had sustained ROSC (palpable pulses for ≥20 minutes) and were transported to four centers over a 9-month period.
Of 111 patients, 18 received NMB for at least 24 hours after ROSC (sustained NMB), 59 received NMB for less than 24 hours, and 34 received no NMB. In-hospital survival was higher in patients who received NMB at any point than in those who received no NMB (52% vs. 35%). Patients who received sustained NMB were more likely to survive than the other two groups combined (78% vs. 41%). Fifty percent of those who received sustained NMB and 28% of the other two groups had favorable neurologic outcomes (not a significant difference). The sustained-NMB group had similar prognostic scores but shorter time from collapse to ROSC, higher baseline blood pH, and lower incidence of chronic obstructive pulmonary disease than the other two groups combined. Multivariable analysis showed that sustained NMB was independently associated with survival (adjusted odds ratio, 7.23) and improvement in lactic acidosis.
The authors postulate that NMB reduces metabolic demand and global oxygen consumption, improves pulmonary gas exchange, and prevents ventilator dyssynchrony, thereby protecting against episodic rises in intracranial pressure.
Although some studies have suggested that long-term neuromuscular blockade may lead to critical illness, polyneuropathy, or generalized muscle weakness, this study suggests it may have benefit in post–cardiac arrest patients. A note of caution, however: Be sure that any patient with a chance of awareness is adequately sedated before paralysis!