Dynamic laryngeal narrowing during exercise: a mechanism for generating intrinsic PEEP in COPD?

Abstract

IntroductionPatients with COPD commonly exhibit pursed-lip breathing during exercise, a strategy that, by increasing intrinsic positive end-expiratory pressure, may optimise lung mechanics and exercise tolerance. A similar role for laryngeal narrowing in modulating exercise airways resistance and the respiratory cycle volume–time course is postulated, yet remains unstudied in COPD. The aim of this study was to assess the characteristics of laryngeal narrowing and its role in exercise intolerance and dynamic hyperinflation in COPD.MethodsWe studied 19 patients (n=8 mild–moderate; n=11 severe COPD) and healthy age and sex matched controls (n=11). Baseline physiological characteristics and clinical status were assessed prior to an incremental maximal cardiopulmonary exercise test with continuous laryngoscopy. Laryngeal narrowing measures were calculated at the glottic and supra-glottic aperture at rest and peak exercise.ResultsAt rest, expiratory laryngeal narrowing was pronounced at the glottic level in patients and related to FEV1 in the whole cohort (r=−0.71, p<0.001) and patients alone (r=−0.53, p=0.018). During exercise, glottic narrowing was inversely related to peak ventilation in all subjects (r=−0.55, p=0.0015) and patients (r=−0.71, p<0.001) and peak exercise tidal volume (r=−0.58, p=0.0062 and r=−0.55, p=0.0076, respectively). Exercise glottic narrowing was also inversely related to peak oxygen uptake (% predicted) in all subjects (r=−0.65, p<0.001) and patients considered alone (r=−0.58, p=0.014). Exercise inspiratory duty cycle was related to exercise glottic narrowing for all subjects (r=−0.69, p<0.001) and patients (r=−0.62, p<0.001).ConclusionsDynamic laryngeal narrowing during expiration is prevalent in patients with COPD and is related to disease severity, respiratory duty cycle and exercise capacity.

Singing for Lung Health: service evaluation of the British Lung Foundation programme

“…Gick and Nicol (8) also propose that singing mimics breathing control and retraining exercise for people with respiratory disease. Furthermore, singing could augment adaptive vocal fold narrowing in COPD patients which may further beneficially reduce PEEPi (9). An improved mucociliary clearance mechanism has also been proposed by Goldenberg (10) whereby singing may increase airway shear stress and alter the viscosity of mucous making it easier to clear.…”

Dynamic laryngeal narrowing in COPD may have effects on the trachea

“…We thank Leong and colleagues for their comments regarding our manuscript1 and for highlighting the role of the central airways in modulating pressure and airflow in patients with a label of ‘obstructive airways disease’ 2. We agree that a functional role of the glottis may indeed be to regulate and interact with excessive dynamic airway narrowing.…”

Quantification and Analysis of Laryngeal Closure From Endoscopic Videos

“…8), an attenuated fluctuation was seen in both GAA and SGI as the vocal folds adduct on expiration, likely to generate intrinsic positive end-expiratory pressure (PEEP), a phenomenon which has been described in subjects with obstructive airways disease (Fig. 9, left) [35].…”