Randomised crossover trial of salbutamol aerosol delivered by metered dose inhaler, jet nebuliser, and ultrasonic nebuliser in chronic lung disease

Abstract

AIMS To compare the efficacy of salbutamol delivered by metered dose inhaler (MDI), jet nebuliser, and ultrasonic nebuliser in ventilated infants with chronic lung disease.

METHODS Twenty preterm ventilated infants with chronic lung disease were enrolled in two studies. In study 1 (n=10), each infant was given 200 μg of salbutamol at 4 hour intervals and in random sequence from a metered dose inhaler–spacer device, a jet nebuliser, and an ultrasonic nebuliser with a small medication cup. The infants were monitored for heart rate, transcutaneous pO₂, pCO₂, and oxygen saturation, respiratory system resistance and compliance before and after each treatment. Infants in study 2 (n=10) were similarly studied except for the use of a different jet nebuliser.

RESULTS The mean (SEM) maximum percentage decreases in respiratory system resistance, observed at 30 minutes after aerosol delivery were study 1: MDI: 44.3 (4.3)% ; jet: 32.3 (3.4)% ; ultrasonic: 56.1 (3.2)% ; study 2: MDI: 28.6 (1.0)% ; jet: 16.9 (1.4)% ; ultrasonic: 42.1 (1.6)%. During the first hour after treatment, a significantly faster heart rate and higher transcutaneous pO₂ were associated with the use of the ultrasonic nebuliser or MDI than with the jet nebulisers in both studies. The use of the ultrasonic nebuliser but not the other devices also resulted in a lower transcutaneous pCO₂ and improved respiratory system compliance in study 2.

CONCLUSIONS These findings suggest that among the devices tested, the delivery of salbutamol aerosol to the lower respiratory tract was greatest using the ultrasonic nebuliser, and least with the jet nebulisers.