About
a third of patients with asthma or chronic obstructive disease use
their dry powder inhalers incorrectly, putting them at risk of
developing dangerous complications from their disease, according to a
study presented to chest physicians meeting this week in Chicago.
Inhalers deliver medication to the lungs, reducing airway inflammation and airway muscle constriction.
Unlike pressurized, metered-dose inhalers that use propellants to
deliver a measured amount of medication, drug powder inhalers rely on
the force of the patient's inhalation to activate, deliver and manage
the flow of medication to the lungs.
Use of dry powder inhalers has dramatically increased in recent
years because they are seen as more user-friendly and don't require
hand-breath coordination, said study author Dr. Siegfried Wieshammer,
medical director of the Department of Internal Medicine at Klinikum
Offenburg in Germany.
Wieshammer and colleagues at the University of Heidelberg asked
224 patients of various ages and severity of disease how much training
they received and to demonstrate their inhalation technique.
Researchers reported that 32 percent made at least one serious
technical error, such as blowing into the device instead of drawing in
a fast, deep breath.
The findings were presented Tuesday at Chest 2007, the
international scientific conference of the American College of Chest
Physicians being held at McCormick Place in Chicago this week.
Dry powder inhalers are used exclusively to deliver "controller
medications," which patients take to manage their conditions on a
day-to-day basis. Researchers studied four types of dry powder inhalers
and found error rates ranging from 9 percent to 53 percent, depending
on the product.
"They all work a little differently and that's part of the
problem," said Maureen Damitz, senior director of programs for the
Respiratory Health Association of Metropolitan Chicago, formerly the
American Lung Association. "You have to be trained on proper technique
for that particular device."
Patients were most likely to make a mistake if they were older,
had more severe airway obstruction or had not been instructed on how to
use their inhalers.
"It was discouraging to see that nearly one-third of the patients
were only referred to the package insert," Wieshammer said in a phone
interview.
Patients who had not been instructed had an error rate of 53
percent, while only 23 percent of trained patients made a serious
error. Patients with severe airway obstruction had an error rate of 64
percent, while only 25 percent of those with normal lung function made
a serious mistake. Patients over the age of 60 had a 43 percent error
rate, while only 20 percent of younger patients made serious mistakes.
The errors can have serious, even life-threatening, consequences.
"It is a critical issue, because if patients are not using their
inhalers properly it means they are not getting medication," Damitz
said. "They are going to end up with symptoms; their disease is going
to get out of control. They are going to end up in the ER, they are
going to be hospitalized-everything we are trying to avoid."
An estimated 22 million Americans have been diagnosed with asthma,
a chronic inflammatory disorder of the airways characterized by
wheezing, coughing, and shortness of breath. An estimated 12 million
Americans have been diagnosed with chronic obstructive pulmonary
disease, which includes chronic bronchitis and emphysema. Both diseases
obstruct airflow and interfere with normal breathing.
Wieshammer said health care professionals should check their
patients' inhalational technique at every medical appointment to make
sure they are using their inhalers correctly.
Dr. Leslie Grammer, director of the Bazley Asthma and Allergy
Center at Northwestern University's Feinberg School of Medicine, said
errors occur with the pressurized inhalers as well.
"I have had people do some really surprising things," she said, "like not taking the cap off or spraying it on their neck."