Perioperative factors associated with severe early postoperative pain after single-level lumbar discectomy: A retrospective cohort study

Background: Airway instrumentation during induction can elicit acute sympathetic stimulation with transient cardiovascular fluctuations, particularly elevations in arterial blood pressure. Esmolol, an ultra–short-acting β₁-selective antagonist, is often administered peri-induction to blunt these peri-intubation responses. However, its effects on neuromuscular blockade onset in routine clinical practice remain insufficiently explored. This retrospective study evaluated the association between peri-induction intravenous esmolol administration, hemodynamic responses to endotracheal intubation, and the onset time of rocuronium-induced neuromuscular blockade.Methods: We retrospectively reviewed anesthesia charts of adult patients (18–60 years) with ASA physical status I–II who underwent elective surgery. Patients were classified according to peri-induction esmolol use: an esmolol group receiving a single intravenous bolus of 0.5 mg/kg (500 µg/kg) administered over 1 minute, and a control group without beta-blocker administration (30 patients per group). Anesthesia induction was performed with thiopental, fentanyl, and rocuronium (0.6 mg/kg). Neuromuscular blockade onset time was defined as the time from rocuronium administration to Train-of-Four count 1. Hemodynamic parameters were recorded before and after endotracheal intubation, and intubation conditions were assessed using the Cooper scale.Results: Demographic characteristics were comparable between groups. The time to Train-of-Four count 1 was significantly longer in the esmolol group compared with controls (129.9 ± 22.8 s vs. 88.5 ± 12.0 s, p < 0.001). Between-group differences in systolic and diastolic arterial pressure were observed at specific early peri-intubation time points but were not sustained thereafter. Intubation conditions were significantly better in the esmolol group, with a higher proportion of patients achieving excellent Cooper scale scores (p < 0.05).Conclusions: Peri-induction intravenous esmolol was associated with modulation of early hemodynamic responses to endotracheal intubation and a delayed onset of rocuronium-induced neuromuscular blockade. These findings suggest that esmolol may influence both cardiovascular responses and neuromuscular block onset during anesthesia induction. Future prospective investigations are needed to better delineate the clinical significance and mechanistic basis of this observed association.