Before answering, be forewarned it is kind of a trick question.
For both adult and pediatric patients, asthma is one of the more common diagnoses we encounter in our clinics, EDs, and hospitals. And despite our best efforts to encourage use of controller meds, asthma flares do happen. Whether it be a respiratory viral infection or a sudden springtime pollen surge, those asthmatic airways can narrow and breathing can become difficult.
When acute asthma attacks happen, the main immediate therapy our patients need is an aerosolized bronchodilator. Such medication can be delivered in two principal forms – through a metered dose inhaler (MDI) or through using a solution administered via a nebulizer device. Both methods deliver the same medication, often albuterol, to the airways in an aerosolized form. But which is more effective? Which method relieves symptoms better, shortens ED stays the most, reduces the need for hospitalization most effectively?
When tackling a thorny clinical question, it can be very helpful to turn to the Cochrane Reviews. This service helps clarify the science underlying the art of medicine. The Cochrane folks recently looked at which form of treatment works best for acute asthma attacks. They found 39 trials involving over 2,600 patients, both adults and kids. The bottom-line? There was no difference in efficacy between the two methods of beta agonist delivery. I know, it seems counter-intuitive. An electrically powered machine spewing out a cloudy mist for five or ten minutes must surely work better than taking a couple of hits off a small aerosol canister, right? Well, when looking at the actual evidence, that does not appear to be the case. Two tiny disclaimers:
- The Cochrane Review only looked at studies where MDIs were used along with a spacer device, since these are well-known to improve the delivery of the beta agonist. (Spacers, by the way, are a covered benefit for PHC members.)
- The review looked at treatment of acute attacks, not chronic asthma medication. Nonetheless, if both delivery methods are equally efficacious for acute attacks, the odds are they will work similarly for chronic management as well.
So, when contemplating whether to transition your patient with difficult-to-manage asthma from an MDI to a nebulizer, make sure they are using a spacer, and make sure they know how to use the MDI and spacer. Not only do MDIs cost less than nebulizers, they are easier to carry around in one’s purse or pocket.
Richard Fleming, MD