Error rates vary widely from one clinical trial to another, depending on study criteria, type of device, and extent of patient education, among other factors. Nonetheless, several studies (spanning 3 decades) found the error rate to be close to, or greater than, 90%.7,10,21
The most recent of these, published in 2009,21 was based on observation of the inhaler technique used by patients with asthma or COPD directly following appointments in an outpatient clinic. The authors found that, although >98% of the study participants claimed to know how to use their inhalers, 94% committed at least one error. In this study and a number of others, user error was more likely in patients using MDIs.13,18,21,22
Adding a spacer (eg, a valved holding chamber such as the AeroChamber) can be helpful, as the spacer affords the patient more time to inhale the medication. But patients who use an MDI with a spacer often make mistakes, too, and patient education is essential.23-26
Breath-activated dry powder inhalers (DPIs)—such as the Flexhaler, HandiHaler, Aerolizer, and Diskus—also reduce the likelihood of error. DPIs eliminate a step that MDI users often struggle with: the need to simultaneously press down on the canister and begin a slow, deep inhalation.
What’s more, DPIs do not have to be shaken before use. Nonetheless, using a DPI still involves a series of actions. For the HandiHaler and Aerolizer, patients must load the dose, and some patients fail to read the directions and swallow the capsule instead of loading it into the device. Patients must remember to exhale away from the device (ie, not into the dry powder) before inhaling, then hold their breath for approximately 10 seconds. There is potential for error at each step.
Stress the need to exhale before using the inhaler
Forgetting to exhale before inhaling is a common, and significant, mistake regardless of the type of device. It is paramount to stress the need to exhale gently for a few seconds before inhaling (slowly and deeply for patients using an MDI, rapidly and deeply with most DPIs). For MDI users, poor timing, described earlier, is another common and serious mistake. Patients using an MDI with a valved holding chamber sometimes inhale for too long before pressing down on the inhaler, then are unable to continue inhaling although the aerosol is still in the chamber. A common error made by patients using multidose DPIs is simply to forget to load the dose.
Physicians need to brush up on their skills, too
It’s not just patients who lack proficiency in inhaler technique. Numerous studies have demonstrated poor skill among physicians and other health care professionals.27-34 Evidence also shows that targeted education results in substantial improvement.32,35
In one study undertaken to evaluate family medicine residents’ proficiency in using asthma inhalers, participants (an intervention group at one clinic and a control group at another) all were given a pretest. The intervention group then received educational materials and a tutorial, as well as the opportunity for hands-on practice, after which both groups were given a post-test. The residents who received the training had a 170% jump, on average, in proficiency score, vs a 55% increase for the control group (P<.001).35
Inhaled Medication Instructional Videos
Courtesy of: National Jewish Health
Another study—this one involving first-year interns—looked at level of improvement based on the type of education provided. Initially, only 5% of the interns could use an MDI without error. After a lecture and demonstration, 13% had an error-free technique. But when each intern participated in an intensive one-on-one session, the error-free rate reached 73%. The researchers’ conclusion: Lectures are relatively ineffective in teaching interns inhaler technique compared with a one-on-one approach.32
The Chicago Breathe Project,36 a new program aimed at improving education in the use of asthma inhalers for physicians and minority patients, provides further evidence of the value of clinician education. After a series of workshops for residents at 5 academic institutions, the physicians’ knowledge of proper use of inhalers rose dramatically—from just 5% preprogram to 91% postprogram (P<.001). Six months after the educational activity, the residents (n=161) were more likely (44% vs 11% preprogram) to assess patients’ inhaler technique.36
Teaching patients when time is tight
National and international guidelines stress the need to teach patients correct use of asthma and COPD inhalers.1,37,38 Providing the requisite education includes observation of each patient’s inhaler technique with proper use demonstrated, as needed.