Comparative analysis of LMA Blockbuster® clinical performance: Blind versus Miller laryngoscope-guided insertion in paediatric general anaesthesia - A double-blinded, randomised controlled trial.

Background and aims: The second-generation supraglottic airway device is conventionally inserted blindly, which might result in suboptimal placement. Limited literature exists on under-vision insertion techniques, particularly in paediatric patients. The primary objective of this study was to compare the oropharyngeal leak pressure (OPLP) between the blind insertion of the LMA Blockbuster^® and the Miller laryngoscope-guided insertion in children. Secondary outcomes included the number of insertion attempts, haemodynamic disturbances, insertion time and airway complications.

Methods: This randomised controlled trial study enroled 100 patients aged 1-4 years undergoing elective surgery. Patients were randomised into blind insertion (Group A) or Miller laryngoscope-guided insertion (Group B) of the LMA Blockbuster^®. The primary outcome measure was OPLP. Insertion time, haemodynamic changes and postoperative complications were also assessed. The Chi-square, Fisher's exact and t-test were applied appropriately, with the significance level set at P < 0.05.

Results: Significantly higher mean OPLP was observed in Group B compared to Group A - 27.9 [standard deviation (SD): 1.58] cmH₂O versus 25.94 (SD: 0.63) cmH₂O [mean difference (MD): 1.96 (95% confidence interval {CI}: 1.48, 2.44; P < 0.001)]. Mean insertion time was longer in Group B, that is, 11.9 (SD: 1.91) s versus 8.7 (SD: 0.6) s [MD: 3.2 s; (95% CI: 2.63, 3.76; P < 0.001)]; however, the difference was not clinically relevant. First-attempt insertion, haemodynamic stability and postoperative complications were comparable (P > 0.05).

Conclusion: Miller laryngoscope-guided under-vision insertion of LMA Blockbuster^® improves alignment with epiglottic structures compared to blind insertion.