Most patients commit errors when using metred dose inhalers
Most adults with obstructive lung diseases incorrectly use metred dose inhalers (MDIs), according to a recent US study.
“To the best of our knowledge, this is the first [systematic literature review] and [meta-analysis] to quantify the prevalence of MDI inhalation technique errors and identify the most problematic device use steps for US adults with obstructive lung diseases,” said researchers, pointing out that 80 percent of patients commit at least one technique mistake.
Ten studies met the eligibility criteria, yielding a pooled sample of 1,360 patients whose average ages ranged from 38–82 years. More than half (54 percent) were female and majority (74 percent) had been diagnosed with chronic obstructive pulmonary disease (COPD). [Chronic Obstr Pulm Dis 2019;6:267-280]
Because of further losses due to the use of multiple devices and attrition, MDI errors were assessed in only 1,275 participants, of whom 352 (27.6 percent) also used a spacer.
Pooled analysis of six studies showed that performance errors were very common, with 86.7 percent of the patients committing at least one inhalation technique mistake. This figure was slightly higher in those who used a spacer (four studies; 82.7 percent) vs those who did not (six studies; 78.2 percent).
In the remaining four studies, majority (76.8 percent) likewise incorrectly performed at least 20 percent of the device use steps.
“The predominance of errors documented across the many studies included … underscores the importance of patient training and education on the proper use of MDIs,” said researchers, pointing out that guidelines of COPD and asthma treatment include not only patient training but also technique reassessments.
Eight studies included a breakdown of the device use steps, revealing that the failure to attach the inhaler to the spacer when required was the most commonly committed mistake (78.1 percent). More than half of the patients also failed to exhale completely, away from the inhaler, before device use (65.5 percent).
Not holding the breath for 5–10 seconds (41.9 percent), inhaling too fast and not deeply enough (39.4 percent), not exhaling after inhalation (35.9 percent), and failing to shake the device before use (34.2 percent) were other common mistakes.
Notably, almost half (43.2 percent) did not repeat the entire process for a second puff.
“We found that 2 of 3 patients had difficulty exhaling fully and away from their MDIs before inhalation. Errors that result in not emptying the lungs completely could have negative consequences on appropriately inhaling prescribed medications,” researchers explained.
On the other hand, the failure to hold the breath for an appropriate amount of time can negatively affect the deposition of the drugs in the lungs and impair medication efficacy, they added.
“Our findings suggest the need for ongoing patient education and consideration of alternative devices, such as nebulizers, that may mitigate technique errors by eliminating some of the inhalation steps that patients have difficulty completing,” researchers said.