Head-elevated laryngoscopy position: improving laryngeal exposure during laryngoscopy by increasing head elevation.

STUDY OBJECTIVE: The objective of this study was to determine the effect of increasing head elevation and neck flexion on the quality of laryngeal view during laryngoscopy.

METHODS: Laryngoscopy with a straight blade was performed on 7 fresh human cadavers. Laryngeal views were recorded with the direct laryngoscopy video system, and the laryngoscopy angle was measured throughout the procedure with an angle finder attached to the handle of the laryngoscope. Each cadaver had laryngoscopy initiated with the head lying flat on the table and with atlanto-occipital extension. The head was then progressively elevated as much as possible (the head-elevated laryngoscopy position), increasing neck flexion and the laryngoscopy angle. Three physicians blinded to the laryngoscopy angle graded the quality of laryngeal view using the percentage of glottic opening (POGO) score.

RESULTS: The laryngoscopy angle ranged from a mean of 32 degrees +/-8 degrees (1 SD) with the head flat on the table to a mean of 67 degrees +/-8 degrees with the head-elevated laryngoscopy position. The mean midposition laryngoscopy angle was 49 degrees +/-6 degrees. Comparing the 3 positions, mean POGO scores+/-1 SD significantly increased from 31%+/-10% (flat position) to 64%+/-12% (midposition) to 87%+/-13% (head-elevated laryngoscopy position). Both the midposition and the head-elevated laryngoscopy position compared with the flat position were statistically significant at a P value of less than.0001. The midposition also differed significantly from the head-elevated laryngoscopy position (P <.0007). Additionally, there was a significant linear relationship among the 3 positions (P <.0001).

CONCLUSION: Increasing head elevation and laryngoscopy angle (neck flexion) significantly improves POGO scores during laryngoscopy on fresh human cadavers.