Fortunately, it wasn't hard for them to learn the correct methods.
Overall, patients misused metered-dose inhalers nearly nine out of 10 times, and Diskus inhalers seven out of 10 times, the researchers reported in the Journal of General Internal Medicine.
Two types of inhalers
The two types of inhalers work by different mechanisms, and require different steps to deliver the medication to the lungs. So for people who use both - which is quite common - the ins-and-outs of correct use can be particularly tricky, said lead researcher Dr Valerie G. Press of the University of Chicago. With metered-dose inhalers, people have to inhale slowly, for example, while the Diskus device requires a sharp inhalation.
"Respiratory inhalers require multiple co-ordinated steps," Dr Press said. "They are not just point-and-shoot."
Ideally, people who use inhalers should bring them to doctor appointments and demonstrate how they use the devices at home, Press noted. But in reality, that may not happen.
The 100 patients in the study were at one of two Chicago hospitals because of serious asthma or worsening of their chronic obstructive lung disease (COPD).
Some of the patients, Dr Press said, were hospitalised due to near-fatal complications - making it especially critical that they know how to properly use their inhalers.
When the researchers asked patients to demonstrate how they used their inhalers at home, one of the biggest problems was a failure to breathe out fully before placing the inhaler in the mouth.
Vision problems were a common obstacle. Nearly all patients with poor vision used the Diskus inhaler incorrectly, compared with slightly more than half of those with adequate vision.
It might be that vision problems make it harder for people to read the inhalers' instructions, which are typically written in very small letters, Dr Press said.
On the bright side, though, the researchers also found it didn't take much to improve patients' inhaler use.
Forty-two participants were given one or two lessons on how to use the devices, which included having them "teach" the techniques back to the researchers. All were able to master the techniques for both inhalers.
For patients with asthma or COPD, she said, trouble controlling symptoms might be a sign the inhaler isn't being used correctly. (Reuters Health/ January 2011)
Family meals better for asthmatic kids