A comparison of direct laryngoscopic views depending on pillow height
This study was conducted to determine the optimal pillow height for the best laryngoscopic view.
Fifty patients were enrolled and preanesthetic airway evaluations were recorded. After induction of anesthesia, the Macintosh 3 blade was used for direct laryngoscopy without a pillow or with a pillow 3, 6, or 9 cm high in randomized order while the laryngeal view was imaged continuously on a monitor of the integrated video system. The best direct laryngoscopic view was sought for in each condition and graded by one anesthesiologist. The correlations between the preanesthetic airway assessments and the pillow height providing the best laryngoscopic view were analyzed.
The laryngoscopic view with the 9-cm pillow was significantly superior to that with other pillows and without a pillow (P < 0.001). The incidence of difficult laryngoscopy (Cormack and Lehane grade 3) was 16% without a pillow. In these cases, laryngoscopic views were improved with a 9-cm pillow. In five patients with a short neck (<15 cm), better laryngoscopic view was observed with a 3- or 6-cm pillow compared with the 9-cm pillow. Neck length had a significant correlation (ρ = 0.326, P = 0.027) with the pillow height providing the best laryngoscopic views.
We recommend the use of a 9-cm pillow during direct laryngoscopy in the sniffing position. In contrast, pillows <9 cm appear to be advantageous in short-necked patients.
KeywordsPillow height Laryngoscopic view Sniffing position
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