Sub-Tenon's lidocaine injection improves emergence agitation after general anaesthesia in paediatric ocular surgery

Objective: This study aimed to evaluate the effect of a sub-Tenon's lidocaine injection on emergence agitation in children receiving sevoflurane or halothane anaesthesia for strabismus surgery. Design: A prospective, randomised study. Setting: The study setting included a hospital where a surgical team performed strabismus surgery. Subjects: Our study enrolled 520 children, aged 4-12 years, who were scheduled for strabismus surgery. Patients were randomised into four groups. Group S/S received sevoflurane and an isotonic saline injection, group S/L received sevoflurane and a lidocaine injection, group H/S received halothane anaesthesia and an isotonic saline injection, and group H/L received halothane anaesthesia and a lidocaine injection. Anaesthesia was maintained with sevoflurane (groups S/S and S/L) or halothane (groups H/S and H/L), and at the end of surgery, the surgeon injected 1 ml of isotonic saline (groups S/S and H/S) and topical proxymethocaine 0.5% or 2% lidocaine (groups S/L and H/L) and a topical placebo (balanced salt solution) into the sub-Tenon's space. Emergence behaviour was assessed in the post-anaesthesia care unit using a five-point scale (1: asleep, 2: awake and calm, 3: irritable behaviour or consolable crying, 4: inconsolable crying, and 5: severe restlessness). We defined a score of 4 or 5 as emergence agitation. The incidence of emergence agitation was analysed using the χ 2 test and Fisher's exact test. Results: The incidence of emergence agitation in groups S/L and H/L was significantly lower than that in groups S/S and H/S (p-value = 0.022, 0.038). The lidocaine-injected group showed a significantly lower occurrence of emergence agitation (10.4%) than the saline-injected group (27.2%, p-value = 0.002). Emergence agitation was significantly higher following sevoflurane (25%) than halothane anaesthesia (13.1%, p-value = 0.046). Conclusion: Emergence agitation was significantly reduced by a sub-Tenon's lidocaine injection, regardless of the modality of anaesthesia used.