Feasibility of Constant Work Rate Testing to Detect Exercise-Induced Laryngeal Obstruction

INTRODUCTION

Exercise-induced laryngeal obstruction (EILO) is a condition in which laryngeal structures inappropriately obstruct the upper airway during exercise. The standard diagnostic test for EILO is the continuous laryngoscopy during exercise (CLE) test, usually performed with an incremental work rate protocol regardless of the nature of the triggering event. Typically, laryngeal obstruction occurs only briefly at the end of an incremental test, near peak work capacity. We aimed to investigate constant work rate (CWR) protocols for CLE testing to expand diagnostic test modalities and improve the understanding of EILO.

METHODS

In this prospective, self-controlled feasibility study, 10 patients with EILO performed both an incremental and a CWR CLE test at 70%, 80%, and 90% of maximal exercise capacity. Laryngoscopic video data were recorded and compared, and we evaluated the ability of CWR to reproduce the symptoms and laryngeal obstruction seen in incremental testing.

RESULTS

In 70%-90% of cases, CWR testing induced at least the same severity of obstruction as incremental testing and CLE scores remained comparable across test modalities. CWR at 70% allowed observation of laryngeal obstruction for a significantly longer duration than in incremental testing (158 s; 95% confidence interval, 25-291 s; P = 0.027). Dyspnea intensity appeared higher during CWR testing compared with incremental testing.

CONCLUSIONS

Submaximal CWR CLE testing is feasible and able to induce EILO equivalent to the standard incremental CLE test. This is the first step toward tailored CLE exercise protocols, and further studies are now needed to establish the utility of CWR in clinical and research settings.

Heightened ventilatory response during stair climbing in individuals with dysfunctional breathing

Dysfunctional breathing, defined as an alteration in the normal pattern of breathing [1, 2], is recognised to be an important differential diagnosis for individuals with “unexplained” dyspnoea. It is estimated that dysfunctional breathing is present in up to 10% of the general population [3] and is a prevalent comorbid finding in individuals with airways disease, acting to amplify symptom burden and to confound accurate assessment of disease control [1, 3, 4].

This prospective cohort study confirms that patients with dysfunctional breathing experience dyspnoea and an abnormal breathing pattern when faced with undertaking everyday exercise challenges, such as climbing stairshttps://bit.ly/3OEWwPM

Safety of pulmonary function testing: data from 20 years

BACKGROUND

Pulmonary function testing (PFT) is a key investigation in the evaluation of individuals with respiratory symptoms; however, the safety of routine and specialised PFT testing has not been reported in a large data set. Using patient safety incident (PSI) records, we aimed to assess risk of PFT and to characterise these events and any associated risk factors.

METHODS

In this single-centre audit, demographics and PSI data were collected and categorised for PFT performed between 1996 and 2016 and subdivided into cardiopulmonary or non-cardiopulmonary events. The severity of each PSI was rated using the NHS National Patient Safety Agency and any hospital admission reported.

RESULTS

There were 119 PSIs reported from 186 000 PFT; that is, 0.6 PSIs per 1000 tests. Cardiopulmonary PSIs were 3.3 times more likely to occur than non-cardiopulmonary (95% CI 2.17 to 5.12). Syncope was the most frequently occurring cardiopulmonary PSI. Cardiopulmonary exercise testing was associated with 2 PSIs per 1000 tests. PSIs necessitating hospital admission and/or emergency department attendance occurred approximately once every 10 000 tests and there was no PFT-associated mortality.

CONCLUSION

Routine and specialised PFT is safe for patients, in the context of established screening preparticipation guidelines. In the event of a PSI, these are likely to be low risk of harm. Our findings highlight the most common PSIs encountered during PFT to facilitate risk reduction.