MADRID – Consistent with previous evidence of higher relative rates of drug delivery, mesh nebulizers offer several advantages over jet nebulizers for treatment of acute asthma in children presenting to an emergency department, according to results of a randomized trial presented at the annual congress of the European Respiratory Society.
Gerald Moody
For the primary outcome of hospital admission, the advantage of the mesh over the jet nebulizer only reached significance when used with a mask, rather than a valve, but trial results overall support the conclusion that the mesh device delivers drug more efficiently, according to Gerald Moody, RRT-NPS, clinical research coordinator at Children’s Medical Center, Dallas.
In this multicenter, single-blinded trial, 217 children presenting to an ED with acute asthma of moderate or greater severity were randomized to receive bronchodilator treatment delivered with a mesh device or a jet device. For drug delivery, aerosol masks or mouthpiece valves were permitted and selected at the discretion of the clinician administrating treatment. Masks were used in 80% of cases.
Patients remained in the study until either symptom control was achieved or a decision was reached to advise hospital admission. Patients with complex comorbidities or who had received oral corticosteroids within the previous 24 hours were excluded.
For the primary outcome of hospital discharge, the 31% reduction (P = .22) in hospitalization in favor of the mesh nebulizer failed to reach statistical significance. Although the study is likely to have been underpowered, Mr. Moody also pointed out an uneven distribution in severity of disease at baseline. In addition to a significantly higher median asthma score (9.0 vs. 8.0; P = .042) in the mesh nebulizer group, there was also a significantly higher percentage with severe disease (57% vs. 42%; P = .025).
“There were no significant differences in any of the other variables we evaluated, such as age, gender, race, or body mass index,” Mr. Moody reported.
Despite the higher disease burden in the mesh nebulizer group, there was a 48% reduction (P = .03) in hospital admissions among those randomized to the mesh nebulizer when both groups received treatment through a mask.
In addition, those treated with the mask required on average only two treatments before achieving symptom control whether they met criteria for moderate or severe asthma at baseline. The median numbers of treatments in the jet nebulizer group for moderate and severe asthma were 3 and 3.5, respectively.
In previous experimental studies, which ultimately provided the rationale for this trial, the estimated amount of drug reaching the airways with a mesh nebulizer was approximately twice as great as that estimated in the model when delivery was performed with a jet device, according to Mr. Moody.
This study appeared to corroborate that advantage. Both the median doses of albuterol (10 mg vs. 15 mg) and ipratropium (1,000 mcg vs. 1,500 mcg) were significantly lower (P less than .001 for both) among the patients randomized to the mesh nebulizer.
Although the jet nebulizers are widely employed “for their ease of use and low cost,” Mr. Moody characterized mesh nebulizers as an advance in technology. In this study, which Mr. Moody said is the first to evaluate whether the experimental evidence of greater drug delivery efficiency translates into a clinical advantage, the primary endpoint was missed, but Mr. Moody indicated that the overall findings support the potential for a difference.
The ERS-invited discussant on this study, Celeste Michala Porsbjerg, MD, Bispebjerg Hospital, Copenhagen University, expressed a concern that might deserve attention in a larger trial. Based on the premise that more efficient delivery increases drug exposure, she questioned whether it might not also increase risks.
There were no significant treatment-related adverse events reported in either arm of this study, Mr. Moody responded, but he conceded that this is an appropriate focus of attention for future studies.
Mr. Moody reported a financial relationship with Aerogen, which produces the mesh device tested in this trial.