Investigation of exertional dyspnoea by cardiopulmonary exercise testing with continuous laryngoscopy

Abnormal breathlessness at maximal exercise may be caused by a range of conditions, including exercise-induced bronchospasm, breathing pattern disorder, or exercise-induced laryngeal obstruction. These three disorders may not be detected on standard cardiopulmonary exercise testing. The aim of this study was to describe diagnostic outcomes of an expanded protocol during cardiopulmonary exercise testing.

Retrospective cohort study.

Patients presenting with abnormal breathlessness on maximal exercise underwent continuous laryngoscopy with cardiopulmonary exercise testing on a stationary cycle ergometer. Breathing pattern disorder was evaluated by video and ventilatory data. Pre- and post-exercise spirometry was performed.

24 adult patients were evaluated; 10 were professional athletes. Mean age was 40 years (range 18-73). Nine of 24 (38 %) were diagnosed with exercise-induced laryngeal obstruction and referred for speech pathology. Six of these had supraglottic exercise-induced laryngeal obstruction; all were aged <30 years; 5/6 were professional athletes. One patient had breathing pattern disorder and was referred for physiotherapy; one had exercise-induced bronchospasm, requiring escalation of asthma medication; one had muscle tension dysphonia resulting in referral to an otolaryngologist who administered a laryngeal injection of botulinum toxin. A further four patients had unexplained lower maximal oxygen consumption with cardiac limitation and were referred for further cardiac investigation.

In patients reporting abnormal breathlessness at maximal exercise, this expanded exercise protocol provided diagnostic information in 66.7 % cases which contributed to further personalised management.