Purpose: Cardiopulmonary exercise testing (CPET) has become a routine outcome measure in the long-term follow-up of patients with congenital heart disease. Anaerobic threshold (AT), a submaximal measure of exercise capacity and cardiovascular function, is one of several important markers obtained during CPET. Its utility can be limited by multiple accepted methods for identification resulting in low rates of interrater reliability. We designed and implemented a quality improvement intervention to standardize AT measurement in pediatric cardiology patients undergoing CPET 

Project Design: After identifying key drivers for appropriate AT determination, Plan-Do-Study-Act (PDSA) cycles started with N=1 tests of change and ramped to laboratory-wide adoption of new methods addressing staffing models, exercise physiologist (EP) education, and multi-modal feedback mechanisms including real-time qualitative feedback from the interpreting physician to the EP. The primary outcome measure was interrater reliability between the EP and the interpreting physician. Baseline data was collected using retrospective analysis of historical testing data. Concordance was defined as less than 10% difference in the value of AT (in mL/min of oxygen consumed). Our SMART aim was to increase interrater reliability in pediatric cardiology patients from <20% to 80% within 6 months. Rates of AT concordance were tracked real time using a publicly displayed run chart.

Results: Baseline interrater reliability of AT determination was less than 20%. Key drivers of low reliability included reliance on incorrect automated AT determination by vendor platform and lack of prior utilization of AT for clinical purposes. After implementing staffing changes and education interventions, a brisk increase from baseline to sustained interrater reliability above the team’s goal of >80% was demonstrated within 6 months. This positive change has been sustained for more than 12 months post-intervention.

Conclusions: We demonstrated a significant increase in interrater reliability of AT determination on CPET for pediatric cardiology patients at the University of Michigan. Reliability was maintained through public data tracking, continuing education curriculum, and an emphasis on the importance of quality data for utilization of AT in our clinical exercise prescription program. High interrater reliability of AT will enable it’s use as a clinically important submaximal exercise and cardiovascular function marker in our pediatric exercise laboratory.