Visibility of video laryngoscope in high-illuminance environment simulating outdoor conditions: effects of screen conditions and polarized sunglasses

TL;DR

This study examines how polarized sunglasses and screen cleaning affect the visibility of a video laryngoscope in bright outdoor-like conditions.

Contribution

The study identifies practical interventions to improve video laryngoscope visibility in high-illuminance environments.

Findings

Polarized sunglasses significantly improved visibility compared to no sunglasses.

Cleaning the monitor screen had a greater impact on visibility than wearing sunglasses alone.

Combining screen cleaning with sunglasses provided the best visibility improvement.

Abstract

Video laryngoscopes generally increase the success rate of tracheal intubation and clinical outcome compared to traditional direct laryngoscopes. However, there is a concern that their effectiveness can be compromised in bright outdoor environments. The impact of polarized sunglasses on the visibility of a video laryngoscope in a high-illumination environment simulating outdoor conditions was assessed. Additionally, the effect of screen smudges on screen visibility was examined.

A high-illumination environment was created using artificial light equivalent to daylight outdoors. Twenty-four anesthesiologists participated in this study. A commercially available laryngoscope was utilized to evaluate the visibility of the monitor screen and visualize the larynx. The experiment involved a fixed order sequence, including viewing with the naked eye, wearing sunglasses, cleaning the screen without wearing sunglasses, and cleaning the screen while wearing sunglasses, to evaluate visibility with each intervention. A visual analog scale (VAS) (0–100 mm) was used to evaluate the visibility of the larynx displayed on the screen.

Polarized sunglasses significantly enhanced visibility, with a median VAS score of 12 compared to 5 (P = 0.004). Moreover, cleaning the monitor screen significantly improved visibility more than wearing sunglasses alone, with a median VAS score of 38 compared to 12 (P = 0.002). Additionally, wearing sunglasses after cleaning the monitor screen provided even better visibility compared to only cleaning the screen, with a median VAS score of 57 compared to 38 (P = 0.002).

Based on these findings, it is suggested that when using a video laryngoscope outdoors in sunny conditions, the first step to address impaired visibility should be to clean the screen. Wearing sunglasses, if possible, can also be effective in improving visibility.

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