Randomised controlled study of clinical efficacy of spacer therapy in asthma with regard to electrostatic charge.

BACKGROUND Inhalation therapy using a pressured metered dose inhaler (pMDI) and a spacer is frequently used in the treatment of airway disease in children. Several laboratory studies found a clear negative influence of electrostatic charge (ESC) on plastic spacers on the delivery of aerosol. AIMS To investigate whether ESC on plastic spacers could diminish bronchodilating responses to salbutamol. METHODS Ninety asthmatic children (aged 4-8 years) were randomised into three groups: metal Nebuchamber, plastic Volumatic, and plastic Aerochamber. The bronchodilating response was measured by the change in peak expiratory flow rate (PEF) after 100 microgram and 400 microgram salbutamol. Within the Volumatic and Aerochamber groups, a crossover comparison was made between electrostatic and non-electrostatic spacers. RESULTS We found no significant effect of ESC on the bronchodilating response to salbutamol with any of the doses in the Aerochamber and Volumatic groups. For the plastic spacers, the mean difference of the change in PEF after 100 microgram salbutamol between non-electrostatic and electrostatic spacers was only +1.7% (95% CI -1.3% to 4.7%). After 400 microgram salbutamol this was +1.9% (95% CI -1.4% to 5.1%). A comparable efficacy was found for the Nebuchamber, the Aerochamber, and Volumatic with respect to the change in PEF after 100 and 400 microgram salbutamol. CONCLUSION This study showed no negative influence of ESC on plastic spacers with regard to clinical efficacy of a beta(2) agonist (salbutamol) in children with asthma. The metal Nebuchamber, plastic Aerochamber, and plastic Volumatic were equally effective.