We thank Xue et al. for their recent letter regarding our recent article1and are happy to respond to their questions and comments.
Their first question related to the number of neonates included in the study. We had two neonates in our study; one was randomized to the GlideScope (Verathon Medical, Bothell, WA) and the other to direct laryngoscopy (Heine, Dover, NH). We routinely use a size 1 Miller blade in the normal neonatal population without difficulty in our institution and reserve the size 0 mostly for premature neonates. Xue et al. further questioned our choice of blade size for the GlideScope Cobalt. Before conducting our study, we piloted various sizes of the GlideScope blade and found that the size 2 blade provided optimal views in our patient population. All our patients fell within the manufacturer body weight guidelines for the size 2 blade; however, manufacturer guidelines are not always consistent with individual patient requirements. The GlideScope device and blade sizes have evolved and have been redesigned several times. For example, a size 3 blade was recommended for patients weighing more than 10 kg at the time of our study. It would have been physically impossible to place a size 3 blade in the pharynx of a normal 11-kg 1-yr-old patient because of the blade's size. Recently, a new size 2.5 blade has been introduced, and weight guidelines have been adjusted accordingly. Manufacturer-suggested blade sizes in children should be accepted cautiously until validated by clinical evaluation.
Xue et al. state that optimum external laryngeal manipulation should be used with poor laryngoscopic views to improve visualization. We agree with this assertion, and optimum external laryngeal manipulation was permitted in our study and used when the view was poor. However, we did not track the number of maneuvers performed to optimize laryngoscopic view. Although this information may have been useful, we chose to capture this as a component of the time to best view. This could be one of the contributing factors to the difference in time to best view between the GlideScope and traditional direct laryngoscopy (median time GlideScope = 8.1 s, direct laryngoscopy = 9.9 s, P = 0.03).