Impact of continuous bronchoscopy during exercise on ventilatory and cardiopulmonary parameters.

Continuous bronchoscopy during exercise (CBE) allows assessment of large airway dynamics during ambulatory exercise; however, it is not yet clear whether the bronchoscope alters cardiopulmonary and ventilatory parameters. Accordingly, we aimed to evaluate the impact of bronchoscopy on parameters measured during cardiopulmonary exercise testing (CPET). Ten healthy participants (33% female) completed two randomized CPETs to exhaustion on a treadmill using an incremental protocol, with and without a bronchoscopy setup (5.0 mm bronchoscope inserted via a modified facemask). Breath-by-breath gas exchange and ventilatory data, including oxygen uptake (V̇o2) and carbon dioxide output (V̇co2), minute ventilation (V̇e), and respiratory exchange ratio (RER), were assessed between CPET conditions. Nine participants completed both CPET assessments to volitional exhaustion; one participant terminated the CPET-B test early due to scope-associated throat discomfort. Exercise duration was shorter (mean difference -52 s, P = 0.02) and heart rate (HR) values were lower (-7 beats/min, P = 0.001) in CPET-B compared with CPET. Peak exercise V̇e (median difference -13 L/min, P = 0.004) was lower during CPET-B, yet breathing frequency and tidal volume values did not differ between CPET conditions. No differences were found in peak exercise V̇o2, V̇co2, and RER values, nor parameters measured at an equivalent absolute duration (isotime). In healthy adults, performing CPET with bronchoscopy does not alter peak exercise oxygen uptake or carbon dioxide output but results in a lower overall minute ventilation, despite no differences in breathing frequency or tidal volume. It is likely these discrepancies arise due to slightly lower exercise duration in the CPET with bronchoscopy trials.NEW & NOTEWORTHY This study demonstrates that cardiopulmonary exercise testing with concurrent continuous bronchoscopy provides measurement of pulmonary gas exchange, ventilation, and visualization of large airway movement during vigorous exercise. Although oxygen uptake and carbon dioxide output were not altered during exercise with bronchoscopy, peak exercise ventilation and markers of effort were lower in these trials.