A COMPARISON OF BREATH-ACTUATED AND CONVENTIONAL METERED-DOSE INHALERINHALATION TECHNIQUES IN ELDERLY SUBJECTS

Background: Poor coordination of canister actuation and inspiration of ten prevents adequate metered-dose inhaler (MDI) usage by patients, pe rhaps especially so among the elderly. Breath-actuated inhalers (BAI) have been developed to prevent this problem. Methods: We compared the adequacy of inhaler technique and patient preferences between MDI and BAI in a group of elderly subjects (mean age, 70.8 +/- 5.4 years). Hal f of the subjects were regular MDI users; half had never before used o ne. Two trained observers assessed the adequacy of MDI and BAI usage s ubjectively while performance was monitored objectively using a light source and infrared system to detect canister actuation and a spiromet er to measure the inspiratory volume. If canister actuation was not fo llowed by at least a 50 percent vital capacity, inhaler use was deemed unsuccessful. A brief teaching session preceded inhaler usage. Result s: By subjective assessment, BAI was used successfully more often than MDI (79 vs 60 percent, p<0.05). By objective assessment, BAI was used successfully more often than MDI (64 vs 36 percent, p<0.0005), althou gh the percentage of inhalations scored adequate was lower than when a ssessment was subjective. Neither device was used correctly as often b y those unfamiliar with MDIs as by those who were regular users. A sig nificantly higher percentage of patients preferred BAI to MDI (71 vs 1 9 percent, p<0.005), similar preferences being reported by MDI familia r and MDI unfamiliar groups. Conclusions: We conclude that (1) elderly subjects frequently handle inhalers poorly, (2) mishandling is better detected by objective than subjective monitoring, and (3) BAI is used correctly and preferred by patients more often than conventional MDIs .