An assessment of the luminance and light field characteristics of used direct laryngoscopes

Abstract

Purpose: To determine luminance and light field characteristics and the effect of residual battery potential and luminance on light colour temperature in our used Macintosh #3 and #4 fibre-light (FLB) and bulb-light (BLB) laryngoscopes. Methods: We used a power supply to provide laryngoscopes with potentials equivalent to those most commonly measured in the handles in use in our OR. Measurements were made under controlled, constant, conditions using a Pentax digital spotmeter (luminance) or a Minolta Color III colour temperature meter (light colour). Colour measurements were made while increasing the power source potential from 2-3 volts (v) in increments of 0. I v. Light field measurements were made with amm increment ruler mounted on the base of the test fixture. Results: At 2.5 and 2.8 v respectively, the #3 FLB produced luminance values of 23.9 ___ 11.4 and 41.7 _+ 17.2 cd-m -2 (mean ___ SD), and the #4 FL8 produced 58.6 _+ 21.4 and 90.9 __+ 32.2 cd'm -2. Increasing potential increased luminance values (P < 0.001) and the #4FLB produced higher luminance values (P < 0.001). BLB produced higher luminance values than did FLB across all comparisons (P < 0.001). As potentials and luminance values decreased, light temperature was reduced (P < 0.001). There were no differences in light field dimensions noted in any comparison. Conclusion: Fifteen percent of the BLB did not meet the minimum luminance for laryngoscopy of I00 cd.m -2, 92% of the FLB did not meet that same standard. ObjrD&erminer les caract&istiques de la luminance et du champ lumineux, ainsi que l'effet de la luminance et de l'~nergie de la pile r&iduels sur la thermocolorim&rie des laryngoscopes Macintosh n ~ 3 et 4 avec fibre optique (LFO) et ampoule (LA). M~thode : Nous avons utilisE une alimentation Electrique pour foumir aux laryngoscopes l'Energie ~quivalente celle qui est la plus communEment utilisEe dans les appareils en usage dans nos salles d'opEration. Les mesures ont EtE faites dans des conditions contr61&s et constantes ~ l'aide d'un photom&re digital Pentax (luminance) ou d'un thermocolorimEtre Minolta Color III (couleur de la lumiEre), l'enregistrement des couleurs a &E rEalis~ tout en augmentant le potentiel de la source EnergEtique de 2-3 volts (v) par increments de 0, I v. Les mesures du champ lumineux ont EtE obtenues avec une r~gle millim&rique montEe sur la base de l'appareil test& R~,sultats : ik 2,5 et 2,8 v respectivement, le LFO n ~ 3 a produit une luminance de 23,9 __. 11,4 et 41,7 ___ 17,2 cd-m -2 (moyenne __+ Ecart type), et le LFO n ~ 4 a produit une luminance de 58,6 --+ 21,4 et 90,9 --+ 32,2 cd'm -2. l'augmentation de potentiel EnergEtique a entra~nE une hausse de la luminance (P < 0,00 I) et le LFO n ~ 4 a produit une luminance plus importante (P < 0,00 I). Le LA a produit des valeurs de luminance plus Elev&s que le LFO pour toutes les comparaisons rEalisEes (P < 0,00 I). La temperature lumineuse a baissE en accord avec les diminutions d'Energie et de luminance (P < 0,001). Aucune difference de dimensions des champs lum...

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