Lee, A.S.

Abstract Introduction: The variety of pulmonary function tests (PFTs) offered in the pulmonary function lab (PFL) can confuse providers unfamiliar with the clinical role of the individual components of the PFT, potentially leading to repeat tests, diagnostic delays, patient burden, and reduced lab efficiency. We hypothesized that a symptom- and diagnosis-based ordering set will reduce the need for repeat testing visits. Methods: Baseline data (June 2022-June 2023) were first collected to establish PFL performance benchmarks and identify common reasons for incomplete or repeat PFL visits. We then implemented an electronic order set reflecting the clinical need of the PFT, based on symptoms, diagnoses, suspected diagnoses, or other common clinical indication in addition to a physician-supervised, results-driven protocol to allow de-escalation of testing when appropriate The pre-implementation data was compared to the post-implementation data (July 2023-June 2024), evaluating for its impact on PFL access, utilization of the specific PFT components (e.g. methacholine challenge test, MCT), and on diagnoses. Results: During the study period 52,292 PFTs were performed during the pre-implementation phase compared to 58,310 tests in the post-implementation phase. Following intervention, the need for a second PFL visit for the same clinical indication decreased from 26% to 13% (p<0.0001). The same day PFL capacity increased by 3-4 patients per day. 80% of primary care providers reported the new order design was more intuitive and easier to use. Among the specific components of the PFT, there was a significant increase in the number MCTs being performed, from 2.5% to 4%, (p<0.0001), with a change rate ranging between 26 – 81% / month. In a subset analysis of 57 consecutive patients having MCTs, the primary indications were evaluation for cough or wheezing (57.9%), initial asthma evaluation (22.8%), and specifically requested by the ordering provider (19.3%). MCT was not performed in 23% due to a low baseline lung function, difficulty with repeatable efforts, recent bronchodilator administration, or due to complicating comorbidities. Of the 39 tests completed, 89% were deemed appropriate, with 32% having positive results and 42% ultimately diagnosed with asthma. Conclusions: A symptom and/or diagnosis guided ordering set for pulmonary function testing appears to improve the efficiency of the PFL, while improving provider experience, PFL access, as well as on patient burden and diagnoses. Further research is needed to determine potential benefits for provider decision-making and patient outcomes.

Abstract Rationale Pulmonary function tests (PFT) are interpreted in the context of reference values that were based on sex, age, height and previously race/ethnicity. The Global Lung Function Initiative (GLI) published spirometry references equations in 2012 and static lung volume reference equations in 2021. In 2023, the American Thoracic Society recommended removal of race from predictive equations for spirometry using the new race-neutral GLI-Global reference equations. Since the change of spirometry reference equations, we have noticed an increase in number of patients with normal spirometry but a low total lung capacity (TLC), where historically the incidence was less than 5 percent and normal spirometry was used to exclude restriction. The goal of this study was to further investigate this observation and characterize the population of patients with normal spirometry and reduced TLC, which we termed occult restriction. Methods We analyzed our existing PFT database which included 28,415 spirometry tests performed at Mayo Clinic Rochester and Mayo Clinic Florida between 2013 to 2016. 26,856 tests included lung volume measurements. The spirometry was interpreted using both GLI-2012 and GLI-Global reference equations and TLC was interpreted using GLI lung volume reference equations. Patients’ demographics including self-identified race were obtained. Patients with occult restriction were further characterized using descriptive statistics. All data analysis was done using BlueSky Statistics Version 10.3.1. Results Our study showed that 920 (3.4%) patients with normal spirometry using GLI-2012 reference equations had low TLC, while 1526 (5.7%) patients with normal spirometry using GLI-Global reference equations had low TLC. Among these patients, 697 patients had a change from abnormal to normal spirometry interpretation and 91 patients had a change from normal to abnormal spirometry interpretation when using GLI-Global reference equations. Comparing patients of different races and ethnicities, there is increased incidence of occult restriction in Caucasian patients with transition to GLI-Global, while the incidence of occult restriction decreased in African American patients. Patients who identify as African American or Southeast Asian are more likely to have occult restriction than others (Table 1). Conclusions With the change from GLI-2012 to GLI-Global spirometry reference equations, the frequency of occult restriction has increased from 3.4% to 5.7% with predominant effect on Caucasian patients. The clinical implication of this finding requires further study but clinicians need to be vigilant that a normal spirometry may not exclude restrictive lung disease using our current reference equations.