The Prevalence of Adverse Events After Prehospital Neuromuscular Blockade-Assisted Airway Management

OBJECTIVES: Neuromuscular blockade-assisted airway management is associated with harmful physiologic adverse events, such as hypoxemia, hypotension, bradycardia, and cardiac arrest. The national scope of these events in the prehospital setting is unknown. We sought to estimate the prevalence of adverse events associated with prehospital neuromuscular blockade-assisted airway management in the United States. METHODS: We conducted an observational, cross-sectional study of the 2023 National Emergency Medical Services Information System Public-Release Research Dataset. We included all adult 9-1-1 non-cardiac arrest emergency medical services activations in which neuromuscular blockade-assisted airway management was performed. The primary outcome was the prevalence of hypoxemia, hypotension, and bradycardia within 10 minutes of neuromuscular blocking agent administration. The secondary outcomes were the timing of adverse events relative to neuromuscular blockade, the odds of adverse events occurring based on vital signs before neuromuscular blockade, and the prevalence of EMS-witnessed cardiac arrest after NMBA administration. RESULTS: Of 54,190,579 9-1-1 emergency medical services activations, there were 11,525 (0.02%) neuromuscular blockade-assisted airway cases. Endotracheal intubation was the first technique performed in 97.5% of cases. First pass success was 80.6%. Overall, 27.5% of patients experienced at least one adverse event in the first 10 minutes after neuromuscular blockade. The prevalence of hypoxemia, hypotension, bradycardia, and cardiac arrest within 10 minutes of neuromuscular blockade were 25.0%, 15.0%, 2.7%, and 1.9%, respectively. The odds of an adverse event occurring were higher when vital signs were abnormal before neuromuscular blockade. The presence of preexisting hypoxemia increased the odds of post-neuromuscular blockade hypoxemia by 9.1 (95% CI, 7.9-10.4) and the presence of preexisting hypotension increased the odds of post-neuromuscular blockade hypotension by 16.8 (95% CI, 13.1-21.8). Half of the cases of hypoxemia and hypotension occurred within 6 minutes (95% CI, 6-7) and 10 minutes (95% CI, 9-11), respectively. CONCLUSIONS: In this national series, 1 of every 4 patients undergoing neuromuscular blockade-assisted airway management experienced a physiologic adverse event. Emergency medical services agencies that adopt this procedure should implement measures to mitigate adverse events.