Primary Care Corner with Geoffrey Modest MD: Errors in Inhaler Usage

By Dr. Geoffrey Modest

A recent systematic review looked at articles on patient inhaler technique over the past 40 years, finding that 1/3 of users had poor technique, and that number has not changed over these 4 decades (see Sanchis J. Chest 2016; 150(2): 394).

Details:

  • 144 articles from 1975-2014 reported on 54,354 subjects performing 59,584 observed tests of technique, from 31 countries around the world
  • 54 studies reported on asthma, 14 on COPD, and 76 on both or unspecified.
  • Mean age of adults was 54, and of children was 9.

Results for most frequent errors:

  • Metered-dose inhalers (MDI): problems with full expiration in 48%, coordination 45%, speed and/or depth of inspiration 44%, and no postinhalation breath-hold in the 5-10 second range 46%
  • Breath-activated MDIs: problems with full expiration in 32%, speed and/or depth of inspiration 33%, and no postinhalation breath-hold 39%
  • MDI plus inhalation chambers: problems with preparation/shaking in 33%; exhale/seal chamber 34%; actuate/slow deep breath/breath-hold 38%
  • Dry-powder inhalers (DPI): problems with full expiration in 46%; postinhalation breath-holding 37%; preparing the inhaler 29%
  • The overall prevalence of correct technique was 31%; of acceptable, 41%; and of poor, 31%.
  • There were no significant differences between incorrect inhaler usage comparing the first and second 20-year periods of scrutiny

Commentary:

  • These results were actually better than I expected (this may be because these were from studies, where the patients may have received more rigorous training than in many offices or health centers). Even my patients who are smokers and used to inhaling and holding their breaths some (even those who smoke marijuana) mostly do terribly with inhalers.
  • MDIs had the worst outcomes, even if adding holding chambers (though there were pretty few studies on this, and there is lots of variability in sizes and functions of these chambers)
  • There were more limited studies on kids: mostly for MDI with inhalation chambers, and the children tended to do better: adults with errors in the 34-49% range, kids in the 21-31% range
  • There are a few other studies suggesting that correctly used MDIs are as beneficial as nebulizers, but i do have several patients who just can’t use their inhalers correctly despite education/review. So in some, nebulizers do work better…
  • The bottom line: inadequate technique in using inhalers is really common, apparently with all types of inhalers but worse with MDIs and without much improvement with inhalation chambers or over time. It makes sense to me that we have the patient regularly bring in their inhalers to their appointments and that we review their usage.
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