Study finds MDI with spacer is as efficacious as nebulizer in Acute severe asthma

Asthma is a heterogeneous ,potentially serious heterogeneous disease with varied clinical presentation. Some patients may remain symptom free from weeks to months where as few may have frequent exacerbations. Cornerstone in the treatment of acute exacerbation includes inhaled short-acting β2-agonists (SABA).

Researchers from PGIMS, Rohtak, India compared the effectiveness of metered dose inhaler (MDI) with spacer and jet nebulizer for delivering SABA in children aged 5–14 years presenting to the emergency department with acute asthma.

In this prospective randomized controlled study, a total of 100 children between 5 and 14 years of age, who was already a known case of asthma, who presented to pediatric emergency department with acute exacerbation were enrolled. Subjects were randomly assigned into 2 groups- Group 1 (MDI with spacer group) received salbutamol with the help of MDI (4 puffs) and spacer (250 ml) thrice at intervals of 20 min, and subjects in Group 2 (nebulizer group) received salbutamol by jet nebulizer thrice at 20 min interval. Improvement in clinical symptoms and duration of emergency stay were primary end points while need to PICU admission was considered secondary end point.

Key findings of the study include-

-Researchers observed that the decrease in respiratory rate at 20 min interval was significantly lower in MDI with spacer group, but no significant difference was observed at 40 and 60 min interval.

-Increase in heart rate in children with MDI with spacer group was significantly lower (P < 0.001) than that of nebulizer group at 20, 40, and 60min.

-There was no significant difference between two groups in following parameters- pCO2 change on venous blood gas analysis, decrease in use of accessory muscles of respiration, wheeze and PEFR.

-No significant differences were observed for the need for PICU admission and adverse events(tremors) between both the groups.

-Eighteen out of 50 patients (36.0%) in MDI with spacer group and 26 out of 50 patients (52.0%) from nebulizer group required longer stay (>6 h) in the emergency department and the difference was not statistically significant.

Inhalation route is preferred as the drug that directly reaches the airway, resulting in faster onset of action and fewer side effects. Thus, it can be delivered with the help of an inhaler or a nebulizer. The major issues with the use of pressurized MDI alone are the deposition of aerosolized particles in the oropharyngeal region and the in-coordination between the device actuation and inhalation in children which can be addressed by using a spacer or valved holding chambers along with it. The problems with jet nebulizers are the requirement of a compressor for aerosol generation, and the fall in the temperature of the liquid in the nebulizer chamber due to liquid evaporation in the nebulized droplets.

Authors conclude-"In children aged 5–14 years presenting to the emergency department with acute exacerbation of asthma, efficacy of MDI with spacer for delivering SABA was comparable with that of nebulizer".

Source:Journal of pediatric critical care