A STUDY OF THE BRIGHTNESS OF LARYNGOSCOPE LIGHT

We have measured the brightness (luminance) of the light spot produced by 105 Macintosh 3 laryngoscope blades (33 bulb, 72 fibrelight) using a Hagner photometer. An estimate of the minimum luminance required fo r laryngoscopy (circa. 100 cd.m(-2)), was determined using a laryngosc ope adapted to provide a variable light output. Five (15%) of bulb bla des and 24 (33%) of the fibrelight blades faded to meet this minimum l evel. A new bulb blade produced brighter lighting conditions (maximum 700 cd.m(-2)) than a new fibrelight blade (max. 500 cd.m(-2)). In tota l, 61 (84%) of the fibrelight blades and three (9%) of the bulb blades were found to provide a light spot that encompassed areas of luminanc e below 30 cd.m(-2), which is a level for comfortable reading. The lig ht spot from a mains-powered fibreoptic bronchoscope was found to be f our times brighter (2000 cd.m(-2)) than a new battery-powered fibrelig ht laryngoscope.