Low- vs. standard-dose rocuronium for tracheal intubation with remifentanil: a systematic review and meta-analysis

Optimal intubating conditions are achieved using standard doses of neuromuscular blocking agents, but these may prolong neuromuscular blockade, which is undesirable in selected clinical scenarios. Remifentanil has been proposed as an adjunct to reduce neuromuscular blocker requirements, but evidence regarding its combination with low-dose rocuronium remains inconsistent. This systematic review and meta-analysis compared low-dose rocuronium (≤ 0.45 mg·kg⁻¹) combined with remifentanil versus standard-dose rocuronium (defined for this review as ≥ 0.6 mg·kg⁻¹), succinylcholine, or no neuromuscular blockade (NMB) in adult and pediatric patients undergoing tracheal intubation. We searched MEDLINE, Embase, Scopus, CINAHL, the Cochrane Library, and Google Scholar from inception to April 23, 2026, for randomized controlled trials. Eligible studies enrolled patients of any age with ASA physical status I–II who underwent general anesthesia with tracheal intubation for surgery. Interventions included remifentanil combined with low-dose rocuronium and either inhalational or intravenous anesthetics. The primary outcome was acceptable intubating conditions. Risk of bias was assessed using ROBUST-RCT. Random-effects meta-analyses were performed, and certainty of evidence was evaluated using GRADE. Ten studies involving 842 participants were included, of which nine contributed to the meta-analyses. In adults, the evidence was very uncertain about the effect of low-dose compared with standard-dose rocuronium on intubating conditions (RR = 0.74, 95% CI [0.40–1.37]; very low-certainty evidence). In pediatric patients, the evidence was very uncertain about the effect of low-dose rocuronium on intubating conditions compared with no neuromuscular blockade (RR = 1.21, 95% CI [0.81–1.80]; very low-certainty evidence). In adults, low-dose rocuronium combined with remifentanil likely improved intubating conditions compared with no neuromuscular blockade (RR = 1.39, 95% CI [1.22–1.58]; moderate-certainty evidence). Sensitivity analyses supported the main findings. Evidence remains very uncertain regarding the effect of low-dose rocuronium compared with standard-dose rocuronium in adults and the effect of low-dose rocuronium compared with no neuromuscular blockade in pediatric patients. However, moderate-certainty evidence indicates that low-dose rocuronium combined with remifentanil likely improves acceptable intubating conditions compared with no neuromuscular blockade in adults. Larger randomized trials are needed to determine whether reduced doses can maintain acceptable intubating conditions while minimizing the duration of neuromuscular blockade.