Shine a light on me – the effect of luminance on laryngoscopy

Hey intubators! Did you know that the recommended luminance of your direct laryngoscope light should be about as bright as the average household light bulb ( 40-60W)? In industry speak thats equivalent to about 700 lumens or lux. In practical terms, I follow what was taught to me by Dr Levitan and Dr Paul Baker ( a New Zealand Anaesthetist), a few years ago. They both have done research into this issue of luminance and its relevance to direct laryngoscopy. They advised, if you can comfortably keep staring at a laryngoscope light for more than 5 seconds, then its not bright enough!

Here are reference articles from both of them on this topic:

Light Intensity of Curved Laryngoscope Blades in Philadelphia Emergency Departments

Visual Acuity During Direct Laryngoscopy at Different Illuminance Levels

Dr Bakers latest article in Anesthesia & analgesia Feb 2013, also examined visual acuity issues. Did you know the average distance for direct laryngoscopy visualisation is only 32 cm? So this means its your near vision that is the main factor in direct laryngoscopy. In the article he writes, for older intubators, the use of higher strength reading glasses may confer an advantage for those with presbyopia.

There are several ways to increase the luminance of your laryngoscope:
– ensure its using full strength batteries
-consider lithium batteries which give a higher power output.
-switch to LED laryngoscopes.. more luminance and can use average alkaline batteries. No dimming effect as batteries drain.

So next time you intubate consider how bright your light is on that blade! You want to light up the oropharynx like New Years eve fireworks !