Dynamic Expiratory Tracheal Collapse in Morbidly Obese COPD Patients

Abstract

Morbid obesity may influence several aspects of airway function. However, the effect of morbid obesity on expiratory tracheal collapse in COPD patients is unknown. We thus prospectively studied 100 COPD patients who underwent full pulmonary function tests (PFTs), 6-minute walk test (6MWT), Saint George's Respiratory Questionnaire (SGRQ), and low-dose CT at total lung capacity and during dynamic exhalation with spirometric monitoring. We examined correlations between percentage dynamic expiratory tracheal collapse and body mass index (BMI). The association between tracheal collapse and BMI was compared to a control group of 53 volunteers without COPD. Patients included 48 women and 52 men with mean age 65 ± 7 years; BMI 30 ± 6; FEV1 64 ± 22% predicted and percentage expiratory collapse 59 ± 19%. Expiratory collapse was significantly associated with BMI (69 ± 12% tracheal collapse among 20 morbidly obese patients with BMI ≥ 35 compared to 57 ± 19% in others, p = 0.002, t-test). In contrast, there was no significant difference in collapse between healthy volunteers with BMI ≥ 35 and < 35. COPD patients with BMI ≥ 35 also demonstrated shorter 6MWT distances (340 ± 139 m vs. 430 ± 139 m, p = 0.003) and higher (worse) total SGRQ scores (48 ± 19 vs. 36 ± 20, p = 0.013) compared to those with BMI < 35. In light of these results, clinicians should consider evaluating for excessive expiratory tracheal collapse when confronted with a morbidly obese COPD patient with greater quality of life impairment and worse exercise performance than expected based on functional measures.

Tracheal collapse diagnosed by multidetector computed tomography: evaluation of different image analysis methods

“…Methods 1 and 2 using only one location for evaluation of the collapsibility are rapid and easily performed. Previous studies have most often used the location 1 cm above the aortic arch for evaluation [7,9,10]. However, in our study, this was a rather rare location for the maximal collapse.…”

“…Several methods for tracheal collapse evaluation of MDCT images have previously been used [6–8]. The most commonly used method is the determination of airway collapse at the localization of maximal collapse of the trachea [3,7,9]. In other methods, predetermined locations are used for establishing the degree of collapse in the trachea [4,5].…”

Exercise-associated Excessive Dynamic Airway Collapse in Military Personnel

“…The underlying lung pathology likely contributes to the chronic atrophy and strain of longitudinal smooth muscle given the excessive airway pressure gradients typically seen in these disease processes [19]. Nonetheless, the severity of airway collapse has been demonstrated to be independent of disease severity, which may suggest other factors may play a role [20,21].…”

Reliability and interpretation of pulmonary function tests when morbid obesity combines with chronic obstructive pulmonary disease and neuromuscular weakness

“…To the Editor, Association of chronic obstructive pulmonary disease (COPD) and obesity is increasingly being observed nowadays, particularly as part of metabolic syndrome [1]. Perioperative interpretation of pulmonary mechanics may lead to confusion in such mixed pathology.…”

“…Reverse Trendelenburg position made mechanical ventilation easier. Postoperative head elevated position along with continuous positive airway pressure if required helps by unloading of respiratory muscles and prevents dynamic expiratory midtracheal collapse in supine position observed in morbidly obese COPD patients [1].…”