The effect of heliox on nebulizer function using a beta-agonist bronchodilator

Objective: To evaluate nebulizer performance when heliox was used to power the nebuliser, Methods: Conventional and continuous nebulizer designs were evaluated. The conventional nebulizer was used with 5 mg albuterol and flows of 8 L/min ai r; 8 L/min heliox and 11 L/min heliox; it was also used with In mg albutero l and a heliox flow of 8 L/min. The continuous nebulizer was set to deliver 10 mg of albuterol over 40 min at flows of 2 L/min air, 2 L/min heliox and 3 L/min heliox; it was also used with 20 lug albuterol and a heliox flow o f 2 L/min, A cotton plug at die nebulizer mouthpiece was used to trap aeros ol during simulated spontaneous breathing. The amount of albuterol deposite d on the cotton plug was determined spectrophotometrically. Particle size w as determined using an 11-stage cascade impactor. Results: For both nebulizer was, particle size and inhaled mass of albutero l decreased significantly (p < 0.001) when the nebulizer nas powered with h eliox rather than air. When powered with heliox, the reduction in inhaled m ass of albuterol was less for the conventional nebulizer (16%) than the con tinuous nebulizer (67%). The nebulization time, however, was more than twof old greater with heliox (p < 0,001), Increasing the flow of heliox increase d the particle size (p < 0.05), inhaled mass of albuterol (p < 0.05), and i nhaled mass of particles 1 to 5 mu m (p < 0.05) to levels similar to poweri ng the nebulizer with air at the lower flow. Increasing the albuterol conce ntration in the nebulizer and using the lower heliox flow increased the inh aled mass of albuterol (p < 0.05) while maintaining the smaller particle si ze pl produced with that flow. Conclusions: The use of hellos to power a nebulizer affects both the inhale d mass of medication and the size of the aerosol particles, The flow to pow er the nebulizer should be increased when heliox is used.