REDUCTION IN PATIENT TIMING ERRORS USING A BREATH-ACTIVATED METERED-DOSE INHALER

Delivery of aerosol medication to the lower respiratory tract by meter ed dose inhaler (MDI) is often limited by the patient's inability to p roperly coordinate activation of the device with inspiration. This stu dy evaluated a new breath-activated MDI device, designed to minimize p atient timing errors by sensing inspiratory flow and automatically act ivating to deliver aerosol medication. Twenty novice adult volunteers, previously naive to the technique of MDI use, and 20 patients current ly using MDIs were tested in their ability to coordinate MDI usage. Si multaneous recording of respiratory events and device activation allow ed analysis of timing errors. With a conventional MDI, a 31.0 percent incidence of errors was seen in the novice group and a 21.5 percent in cidence of errors was seen in the experienced group. These compared wi th error rates using the breath-activated MDI of 6.5 percent and 5.0 p ercent in the two groups respectively (p=0.009, p=0.04). The breath-ac tivated inhaler was preferred by 35 of 40 subjects. In conclusion, MDI technique timing errors were significantly less with this breath-acti vated MDI device in both novice and experienced subjects, and it was a lso preferred by both groups.