Fiber-optic assessment of LMA position in children: a randomized crossover comparison of two techniques

This crossover study compared fiber-optic assessment of laryngeal mask airway (LMA) position in children using two LMA insertion techniques, i.e., standard and rotational.

Seventy-eight ASA I children, aged 2.5 months to 10 years, undergoing elective cataract surgery were included in this study. LMA was inserted in random order using either standard or rotational technique, removed, and thereafter crossed over to alternate technique. Positioning of LMA was assessed using fiber-optic bronchoscope with each technique. Change in the incidence of fiber-optic assessment grades 1 and 2 between two insertion techniques was measured as the primary outcome. Secondary outcome measures studied were first-attempt success rate, overall success rate, time for successful insertion, visual analogue scale for placement, complications, and maneuvers used to relieve airway obstruction.

Incidence of fiber-optic grades 1 and 2 was 61.5% with standard technique and increased to 92.3% with rotational technique (P < 0.001, McNemar's test) (RR 3.0, 95% CI 2.2-4.2). Median (IQR) fiber-optic grading was significantly better with rotational technique [2 (1-2)] as compared to standard technique [2 (2-3)], (P < 0.001, Wilcoxon signed rank test). First-attempt success rate was significantly higher (96.2%) with rotational technique compared with standard technique (80.7%) (P = 0.04, McNemar's test). Overall success rate (i.e., successful insertion with two attempts) was 100% with rotational technique compared with 89.7% with standard technique (P = 0.003, Fischer's exact test). Time for successful insertion and incidence of complications were significantly lesser with rotational technique.

Rotational technique of LMA insertion in children is associated with better seating of LMA (as observed on fiber-optic assessment) compared with the standard technique. Also, it is associated with higher success rate and lower incidence of complications.