Ease of placement of the laryngeal mask during manual in-line neck stabilization

We studied 20 patients, in a randomized, cross-over study, to determine if manual in-line stabilization of the head and neck altered the ease of insertion of the laryngeal mask and its correct positioning. After induction of anaesthesia and neuromuscular block, the laryngeal mask was inserted and adequacy of ventilation assessed while the patient's head and neck were placed in the Magill and manual in-line positions, in turn. Ease of insertion of the mask was assessed using a 10-cm visual analogue scale (VAS) and position using a fibreoptic bronchoscope. Time for insertion of the mask was measured. The laryngeal mask was inserted and adequate ventilation obtained at the first attempt in all 20 patients in the Magill position and in 19 of 20 patients in the manual in-line position. Insertion was always more difficult (P << 0.001; 95% CI for difference in VAS 20-55 mm) and time for insertion longer (P << 0.001; 95% CI for difference 4.9-11.9 s) in the manual in-line position compared with the Magill position. The incidence of a suboptimal position was significantly higher for the manual in-line position (seven patients) than for the Magill position (15 patients) (P < 0.005). We conclude that in paralysed patients, manual in-line stabilization of the head and neck made insertion of the laryngeal mask and its correct positioning more difficult.