Illumination of bulb-on-blade laryngoscopes in the out-of-hospital setting.

OBJECTIVES To determine what percentage of out-of-hospital laryngoscopes meet a predetermined minimal illumination criterion and what factors may be altered to improve illumination. METHODS This was an observational study of the illumination of laryngoscopes currently in use by the Emergency Health Services of Nova Scotia. Each laryngoscope was measured at baseline. This illumination was compared with the illumination after replacement with new batteries, replacement with a new bulb, replacement with new batteries and a new bulb together, and attachment of a disposable blade. The percentage of laryngoscopes that met a previously defined minimal brightness criterion was determined. RESULTS Fifty-one laryngoscopes were measured. These laryngoscopes had a mean (+/-SD) illumination of 624 (+/-297) lux at baseline. Laryngoscope illumination increased after replacement with new batteries by 168 lux (95% confidence interval [CI] = 121 to 216), replacement with a new bulb by 679 lux (95% CI = 524 to 834), replacement with new batteries and a new bulb by 937 lux (95% CI = 770 to 1,104), and attachment of a disposable blade by 2,401 lux (95% CI = 2,075 to 2,740). Fourteen percent of laryngoscopes (7/51) at baseline met the minimal illumination criterion. CONCLUSIONS Only a small percentage of out-of-hospital laryngoscopes met the minimal illumination criterion. There was a statistically significant increase in illumination after replacement with new batteries, replacement with a new bulb, replacement with new batteries and a new bulb, or attachment of a disposable blade. Optimal changing of lightbulbs and batteries in the out-of-hospital setting will have to be more clearly defined.