Pulmonary function laboratories offer comprehensive testing services with advanced diagnostics

July 31, 2021

Mayo Clinic offers a comprehensive array of pulmonary function testing services at its campuses in Arizona, Florida and Minnesota and provides ready access to common pulmonary function testing in a variety of Mayo Clinic Health System locations for patients in the Upper Midwest.

"Together, our pulmonary function laboratories perform the largest number of tests annually in North America. More than 42,000 patients participated in testing at Mayo Clinic's campus in Rochester, Minnesota, in 2019 alone," says Alexander S. Niven, M.D., Pulmonary and Critical Care Medicine at Mayo Clinic in Rochester, Minnesota. "This fact, combined with Mayo Clinic's proud tradition of innovation, has positioned Mayo Clinic well to continue to advance this field in the years to come."

The COVID-19 pandemic presented remarkable challenges for pulmonary function testing, due to infection control and safety concerns associated with the performance of these procedures in patients with frequent respiratory symptoms. In a multisite, multidisciplinary collaborative effort, pulmonologists from Mayo Clinic's campuses in Florida and Minnesota worked together to rapidly inform the pulmonary function laboratories' infection control practices. Team members included infectious disease specialists, exercise physiologists, researchers, bioengineers and facility management experts.

Dr. Niven explains: "Using several commercially available particle counters and eventually a particle-free clean room to conduct our experiments, we were able to measure the concentration and characteristics of droplets generated during pulmonary function and cardiopulmonary exercise testing. These test results were published in the Annals of the American Thoracic Society in 2020 and in three articles published in Chest in 2021.

"Although we were able to clearly demonstrate that common pulmonary function tests generate particles small enough to aerosolize — that is, stay airborne for a long period of time — in many tests the concentration is quite low compared with ambient particle levels in the environment, even when tested using unfiltered devices such as peak expiratory flow meters, as documented in Respiratory Care in 2021.

"Higher aerosol concentrations are seen in procedures that require nebulized medication, such as bronchoprovocation challenge testing, or higher minute ventilation levels, as seen in maximal cardiopulmonary exercise tests. We demonstrated that use of a commercial viral filter on the expiratory limb of common nebulizer circuits can significantly reduce the concentration of aerosol released, significantly reducing pulmonary function technicians' exposure to both potentially infectious particles and methacholine. These findings were published in the American Journal of Respiratory and Critical Care Medicine in 2021. Enhanced air clearance using portable high-efficiency particulate air filters also can be effective to mitigate aerosolized particle accumulation during exercise testing, as documented in Chest in 2021.

"These results, combined with preprocedural testing, enhanced personal protective measures, and enhanced air circulation and filtration measures, enabled us to safely reopen needed testing services for our patients well in advance of other major health care systems. Our findings also allowed us to safely de-escalate some personal protective measures and eliminate room turnover delays between patients for many of our common pulmonary function procedures. Those outcomes have proved invaluable to meeting clinical demand as the challenges of the pandemic begin to subside."

Expanding diagnostic impact

Responding to the rapid evolution of health care delivery during the pandemic and beyond, pulmonary function leaders across Mayo Clinic are also working to advance the diagnostic impact of the wide array of respiratory and exercise physiology tests performed in the pulmonary function laboratories.

"We collaborate with a variety of information technology and data science experts to explore novel ways to analyze these data using artificial intelligence and integrate patient data from other clinical sources. Our goal is to provide greater opportunities for early diagnosis, clinical phenotyping, and targeted treatment and research opportunities," says Dr. Niven.

Testing procedures plus advanced diagnostics

The field of pulmonary function testing is constantly changing, and Mayo Clinic's testing procedures and service lines are evolving with it. In a major effort led by the respiratory specialty council in response to new methacholine requirements issued by the Food and Drug Administration, the pulmonary function laboratories have implemented a new protocol for bronchoprovocation challenge testing using methacholine, after extensive testing.

The pulmonary function laboratories' established testing services include the following:

Exhaled nitric oxide
Exercise provocation testing using cold, dry air
Laryngeal pharyngeal reflux testing
Comprehensive cardiopulmonary exercise testing with real-time laryngoscopy to evaluate for inducible laryngeal obstruction and tracheobronchomalacia

In addition to a full spectrum of common pulmonary function testing procedures, Mayo Clinic's pulmonary function laboratories also offer advanced diagnostics, including:

High-altitude simulation testing to more accurately titrate oxygen requirements during airline travel
Resting energy expenditure to help guide a comprehensive approach to dyspnea management that includes nutrition and weight-loss consultation

"With the combination of these established testing services and the projected expansion of Sleep Medicine's home spirometry monitoring services, we look forward to offering referring providers an opportunity to definitively phenotype patients with challenging and difficult-to-control asthma and chronic cough," says Dr. Niven.