Analysis of Pressure Distribution During Direct Microlaryngoscopy.

OBJECTIVE: This study aimed to investigate the pressure distribution during direct microlaryngoscopy and its relation with the positioning of the patient.

STUDY DESIGN: This is a prospective study in cadavers.

MATERIALS AND METHODS: The pressure distribution during direct microlaryngoscopy was investigated in five adult fresh cadavers by using matrix-based piezoresistive thin-film sensors. The pressure among three head and neck positions (extension-extension, neutral, and flexion-extension) was studied.

RESULTS: The real-time pressure and its distribution were recorded as 3-D contours. The map commonly showed two peak pressure points, with one focused on the middle of the laryngoscope (peak pressure 1) and the other one focused on the distal part of the laryngoscope (peak pressure 2). The mean average pressure in this study was 38 ± 13 kPa, and the flexion-extension position had the lowest average pressure and peak pressure. However, the average pressure and peak pressure 1 showed no significant difference among the three positions (P > 0.05); peak pressure 2 in the flexion-extension position was significantly lower than that in the extension-extension position (P = 0.024) and the neutral position (P = 0.020).

CONCLUSIONS: The results of this study indicate that the flexion-extension position induced lower pressure exerted on the laryngoscope and is an optimal position for direct microlaryngoscopy. Hyoid bone may play an important role in the pressure exerted.