Providers urged to mind their accuracy in pulmonary function testing

Key takeaways:

• Pulmonary function testing results can indicate obstructive patterns.
• Providers must properly coach patients before they breathe into spirometers.
• Guidelines recommend the use of Z scores in assessing patients.

SAN ANTONIO — Pulmonary function testing may be routine, but it still comes with challenges, Nicole Soucy, PA-C, said at the Association of PAs in Allergy, Asthma & Immunology 16th annual conference.

“We look at patients’ lung function to determine what kind of disease state they have,” Soucy, who is president of the APA-AAI, told Healio. During the conference, Soucy led a workshop on pulmonary function testing.

“It’s really a crash course or refresher for most of the people who work in allergy because we use this test quite often,” she continued, adding that it also can serve as an introduction to practitioners who may be new to asthma, allergy and immunology.

Nicole Soucy

The course focused on technique and interpretation, which Soucy called “the biggest hurdle to mount when you’re first starting off in this specialty.”

Pulmonary function testing provides information that may indicate obstructive patterns, Soucy said, which she called the biggest thing to look for in asthma.

“With asthma, you get inflammation in the airway that actually makes it difficult when you exhale,” she said. “With that information, you can get a sense of how much air trapping there is.”

Those numbers can help practitioners understand how much control patients have over their asthma, she continued.

“We can diagnose asthma based on that, and it can help guide our treatment,” Soucy said.

FEV₁, which is impaired in people with asthma, and forced vital capacity (FVC) are particularly valuable, she noted.

“The ratio between the two is how we understand whether someone has an obstructive defect, a restrictive defect or even a mixed defect where they have elements of both,” she said.

Accuracy is essential in these readings, but it is not always easy to achieve, with “issues on both sides of the coin,” Soucy said.

“You can have issues with the provider themselves and how they coach the patient through that procedure and getting accurate values,” she said. “Even inputting the incorrect information into the machine can give you false results.”

Soucy said that double-checking the patient’s weight, height and other information input into spirometers is the most important part of the procedure. Soucy also encouraged practitioners to review recommendations from the American Thoracic Society to use Z scores in interpreting lung function.

“It will help take off some of the bias that you can get in terms of height, gender and weight,” Soucy said. “In the future, I think we’re going to be moving away from using that FEV₁ reading and using more Z scores.”

Also, patients need a lot of coaching because the kind of breathing that pulmonary function testing requires is not natural, Soucy said, as they try to maximize how much air they inhale and then exhale as quickly and as forcefully as they can.

“You’re blowing out as much air as possible at one time,” she said. “If they don’t give their maximal effort, you’re going to get incorrect results.”

Some practices use nose clips to ensure their patients get the best reading they can. Pediatric patients provide challenges as well.

“It’s hard and really variable between kids. I’ve had adults who can’t do pulmonary function tests,” Soucy said.

Generally, she said, she and her colleagues do not attempt this testing among children aged younger than 5 years, which can make things difficult when they are trying to first diagnose asthma.

Equipment can be challenging too, Soucy continued.

“Spirometers are really expensive. A lot of times, they’re older systems,” she said.

Soucy noted that mouthpieces sometimes can be big and bulky, which presents problems for children and even some adults, leading to improper use.

“It would be nice to have mouthpieces for smaller kids,” she said.

Even when numbers are accurate, Soucy said, they need to be interpreted.

“The American Thoracic Society has an outline of interpretation, and I think that would probably be the first source I would go to,” she said.

UpToDate also provides algorithms and an outline for interpreting pulmonary function test results, she added.

“For a beginner or someone who doesn’t do this very often, those are the two places I would start,” Soucy said.

Despite the challenges and changes, Soucy said, accurate pulmonary function testing remains essential to successful outcomes.

“As providers who treat these patients, knowing how to do these procedures is very important,” she said. “It’s been something I had to learn, but it’s been very important to my patient care.”

For more information:

Nicole Soucy, PA-C, can be reached at nsoucy24@gmail.com.