Flexibility and light emission of disposable paediatric Miller 1 laryngoscope blades*

Abstract

SummaryWith the emergence of Creutzfeldt‐Jakob disease and the discovery of prions in tonsillar material, there has been an increase in the number of available disposable laryngoscope blades. This has led to non‐conformity over many aspects of blade design. Miller 1 disposable blades have been produced in both metal and plastic and appear to have different properties of rigidity. We examined the rigidity of 11 disposable Miller 1 blades in three different axes of force. There was a significant difference in flexibility between metal and plastic blades in both primary and torsional axis (p = 0.006). We also studied the blades' light intensity and angle of light emission, finding up to an eightfold difference in the level of illumination provided at a distance of 10 mm from the tips of the blades. The area of maximal illumination varied, with some blades providing narrow beams of light, and others provided a more dispersed field of illumination. In addition, the angle of maximal illumination varied between the blade types from a central position to one directed to the right‐hand side.

Minimum and optimum light requirements for laryngoscopy in paediatric anaesthesia: a manikin study*

“…In our study the maximum illumination provided by vacuum bulbs was less than that provided by both halogen and xenon bulbs. This is in contrast with other studies where bulb-in-blade laryngoscopes provided brighter light than fibreoptic laryngoscopes [3,5,6] or where no difference was found [7]. Due to thermal radiation, halogen and xenon bulbs become very hot and are therefore not suitable for use with bulb-in-blade laryngoscopes.…”

“…The median (IQR) age of the participants was 35 (31-41) years. The median (IQR) anaesthetic experience in years was 7 [5][6][7][8][9][10][11][12]. Twenty-four (48%) of the participants wore glasses whilst performing laryngoscopy.…”

“…A study by Goodwin et al [7] showed non-uniformity of illumination and distribution of light provided by a variety of Miller 1 laryngoscope blades. Our study also showed a variation in the illumination provided by different paediatric laryngoscope blades.…”

“…There are only a few published studies that have investigated the illumination properties of the laryngoscope [3][4][5][6][7]. One of these studies included an investigation of the illumination properties of paediatric laryngoscopes [7].…”

Intensity and adequacy of laryngoscope light in seven intensive care units

“…In the CCU environment successful tracheal intubation may be time sensitive, and failure of adequate illumination of the larynx impedes visualization. Adequacy of lighting is subjective; however, the Health and Safety Executive suggests 500 Lux as a minimum for work requiring the perception of fine detail [1]. …”