Can flow-volume loops be used to diagnose exercise induced laryngeal obstructions? A comparison study examining the accuracy and inter-rater agreement of flow volume loops as a diagnostic tool.

BACKGROUND

Pre- and post-exercise flow-volume loops are often recommended as an easy non-invasive method for diagnosing or excluding exercise-induced laryngeal obstructions in patients with exercise-related respiratory symptoms. However, at present there is no evidence for this recommendation.

AIMS

To compare physician evaluated pre- and post-exercise flow-volume loops and flow data with laryngoscopic findings during exercise.

METHODS

Data from 100 consecutive exercise tests with continuous laryngoscopy during the test were analysed. Laryngoscopic images were compared with the corresponding pre- and post-exercise flow-volume loops assessed by four separate physicians and with data from the loops (forced inspiratory flow (FIF) at 25% vs. FIF at 75% of forced inspiratory vital capacity (FIVC), forced expiratory flow at 50% of forced expiratory volume vs. FIF at 50% of FIVC, and FIVC vs. FIF at 50% of FIVC).

RESULTS

There was no significant association between the laryngoscopic findings and the flow-volume data. There was no agreement between the four physicians in their assessment of the flow-volume loops (kappa <0.00), and none of the individual physician's assessments were significantly associated with the laryngoscopic findings.

CONCLUSIONS

Exercise-induced laryngeal obstructions cannot be diagnosed or excluded by physician evaluated pre- and post-exercise flow-volume loops or flow data alone.