Investigation of exertional dyspnoea by cardiopulmonary exercise testing with continuous laryngoscopy.

Exertional dyspnoea may be caused by a wide range of respiratory, cardiac and systemic conditions. There is under-recognition of exercise-induced laryngeal obstruction (EILO) and dysfunctional breathing (DB). EILO is the paradoxical closure of glottic and supraglottic laryngeal structures during exercise. We describe outcomes following a unique clinical protocol comprising cardiopulmonary exercise testing (CPET), continuous laryngoscopy (CLE), dysfunctional breathing assessment and pre and post exercise spirometry.

Methods: Patients presenting with undifferentiated exertional dyspnoea and/or suspicion for EILO underwent maximal CPET on cycle ergometer. Continuous laryngoscopy was performed concurrently, with a flexible laryngoscope placed into the pharyngeal space and secured with headgear. A video recording was taken of the movements of the vocal folds and cords during exercise. There was evaluation for erratic breathing frequency and periodic breathing by video and airflow data. Pre and post exercise spirometry were performed.

Results: 18 patients were evaluated, including professional athletes and a singer. 55% of patients evaluated were female. The mean age was 42 years (range 18-74 years). 33% (n=6) were diagnosed with EILO, of whom 83% were female, with a mean age of 31years. 17% (n=3) were diagnosed with DB and 28% (n=5) were diagnosed with ventilatory or cardiac limitation to exercise on CPET. 1 patient was diagnosed with exercise induced asthma, and one patient was unable to tolerate laryngoscopy.

Conclusion: This novel test elucidated the diagnosis in >80% of patients assessed for undifferentiated exertional dyspnoea, directing more appropriate treatment.