Effect of pretreatment opioids on hemodynamics during emergency intubations: a systematic review

BACKGROUND AND IMPORTANCE: Rapid sequence intubation in emergency settings may involve opioid pretreatment to blunt hemodynamic responses during laryngoscopy and intubation; however, opioids may lead to postintubation hypotension, increasing morbidity and mortality. Global clinical practice varies significantly, reflecting uncertainty about opioids' benefits and risks. OBJECTIVE: Our goal was to evaluate the association between opioid pretreatment and hemodynamic instability, focusing on postintubation hypotension in adult patients undergoing emergency intubation. DESIGN, SETTINGS, AND PARTICIPANTS: We performed a systematic review of randomized controlled trials and observational studies comparing opioid administration vs. no opioids before adult emergency intubations. Searches included Cochrane, Embase, Medline, Scopus, and Web of Science databases until November 2024. Elective intubations were excluded. Eight (6708 patients) studies met criteria. OUTCOMES MEASURE AND ANALYSIS: The primary outcome was postintubation hypotension, variably defined across studies. Secondary outcomes included hypoxemia, first-attempt success, cardiac arrest, and vasopressor use. Independent reviewers conducted data extraction, risk-of-bias assessments, and certainty evaluation. Results were qualitatively synthesized. MAIN RESULTS: Among 6708 (2757 opioids and 3951 controls) patients, postintubation hypotension incidence varied widely (risk differences: -12.5% favoring opioids to +13.2% favoring controls). The single low-risk randomized study reported opioids increased hypotension (risk difference: 13%, odds ratio: 2.15, 95% confidence interval: 1.22-3.78). Observational studies yielded inconsistent results. Secondary outcomes showed no consistent differences. Evidence certainty was very low because of risk of bias, inconsistency, and imprecision. CONCLUSIONS: Current evidence regarding opioid pretreatment effect on postintubation hypotension risk during emergency intubation is limited and conflicting.