A randomized trial of the glottic views with the classic Miller, Wis-Hipple and C-MAC (videolaryngoscope and direct views) straight size 1 blades in young children

Study objective: The Miller and Wis-Hipple size 1 blades are widely used for laryngoscopy in children and the C-MAC straight blade is used increasingly in young children, although the glottic views with these blades have not been compared. To determine whether the glottic views with these blades are equivalent.

Design: Equivalent study.

Setting: Operating room.

Patients: 96 children <2 years, ASA 1 or 2, elective surgery requiring orotracheal intubation.

Interventions: Direct laryngoscopy with the Miller and Wis-Hipple or C-MAC (videolaryngoscope and direct view) straight blades size 1; photographs of the glottic opening.

Measurements: Percent of glottic opening (POGO) was measured using a standardized scale by a blinded investigator. Heart rate, systolic blood pressure and hemoglobin oxygen saturation were measured before and after laryngoscopy.

Results: The POGO scores with the four blades/views were equivalent (fewer than 20% of the views yielded POGO scores <80). However, a post hoc comparison of the POGO scores yielded significant differences (P = 0.0001); the C-MAC videolaryngoscope view yielded significantly better scores than the Miller, Wis-Hipple and direct C-MAC views (P = 0.0009, 0.0002 and 0.0001 respectively). The POGO score with the Miller blade was superior to that with the direct C-MAC view (P = 0.024). No adverse events or complications occurred.

Conclusion: The four blades/glottic views were equivalent, although a post hoc analysis demonstrated that the glottic view with the C-MAC videolaryngoscope was superior overall and the view with the Miller size 1 was superior to that with the direct C-MAC view.