Expiratory Central Airway Collapse Research Articles

Long‐term pneumatic stenting with positive expiratory pressure therapy for severe expiratory central airway collapse

AbstractExpiratory central airway collapse (ECAC) comprising excessive central airway collapse (EDAC) and tracheobronchomalacia. Treatment is challenging for severe cases that are not candidates for surgical management. We report a case of severe ECAC successfully managed with continuous positive airway pressure (CPAP) therapy. A 75‐year‐old female patient status post right pneumonectomy, presented with chronic cough. Dynamic bronchoscopy evaluation showed severe EDAC which improved with intraprocedural noninvasive positive pressure (NIPPV) therapy. Due to patients' comorbidities, she was not a candidate to surgical tracheobronchoplasty. Therefore, we attempted pneumatic stenting with long‐term CPAP therapy resulting in improvement of symptoms and functional capacity. The long‐term efficacy of pneumatic stenting has not been clearly established yet. Literature review of management of ECAC with NIPPV consist primarily of case reports and there is only one clinical trial being conducted to assess the efficacy of CPAP therapy in ECAC. While NIPPV arises as a sufficient alternative for management of severe ECAC, larger scale studies are needed to prove the real efficacy of NIPPV in this setting.

Airway collapse hinders recovery in bronchoscopy therapy for postintubation tracheal stenosis patients.

Expiratory central airway collapse (ECAC) following postintubation airway stenosis (PITS) is a rare phenomenon. The impact of airway malacia and collapse on the prognosis and the success rate of bronchoscopic interventional therapy in patients with PITS had been inadequately investigated. The aim of this research was to assess the influence of airway malacia and collapse on the efficacy of bronchoscopic interventional therapy in patients with PITS. This retrospective analysis examined the medical documentation of individuals diagnosed with PITS who underwent bronchoscopic intervention at the tertiary interventional pulmonology center of Emergency General Hospital from 2014 to 2021. Data pertaining to preoperative, perioperative, and postoperative stages were documented and subjected to analysis. The patients in malacia and collapse group (MC group) exhibited a higher frequency of perioperative complications, including intraoperative hypoxemia, need for reoperation within 24h, and postoperative intensive care unit admission rate (P < 0.05, respectively). Meanwhile, patients in group MC demonstrated significantly worse postoperative scores (higher mMRC score and lower KPS score) compared to those in pure stenosis group (P < 0.05, respectively), along with higher degrees of stenosis after treatment and a lower success rate of bronchoscopic intervention therapy cured (P < 0.05, respectively). Pearson analysis results showed that these terms were all significantly correlated with the occurrence of airway malacia and collapse in the airway (P < 0.05, respectively). The presence of malacia or collapse in patients with PITS was associated with increased perioperative complications following bronchoscopic interventional therapy, and significantly reduced the long-term cure rate compared to patients with pure tracheal stenosis. Trial registration Chinese Clinical Trial Registry on 06/12/2021. ChiCTR2100053991.

Preoperative Workup of Patients With Excessive Central Airway Collapse: Does Stent Evaluation Serve a Role?

Tracheobronchoplasty (TBP) is a definitive anatomic intervention for patients with severe symptomatic expiratory central airway collapse. Although stent evaluations have been described for surgical workup, current literature does not address if improvement during stent evaluation is sustained after TBP. We compared health-related quality of life (HRQOL) and functional status responses after airway stenting to those post-TBP. A retrospective review was performed in patients with severe expiratory central airway collapse who underwent stent evaluation followed by TBP from January 2004 to December 2019. Baseline, poststent, 3- and 12-month postoperative HRQOL scores, and functional status were analyzed with statistical tests as appropriate. One hundred twenty patients underwent a stent evaluation and TBP. Baseline and stent evaluation measurements were compared with statistically and clinically significant differences in the Cough Quality-of-life Questionnaire (CQLQ) (55 vs. 68, P <0.01), Modified Medical Research Council (mMRC) 0 to 2 (90% vs. 47%, P <0.01), 6-minute walk test (6MWT) (1301ft vs. 1138ft, P <0.01). Improvements in the HRQOL and functional status were maintained from stent evaluation to 3 months postoperatively [CQLQ 55 vs. 54, P =0.63; mMRC 0 to 2 (87% vs. 84%), P =0.39; 6MWT 1350ft vs. 1314ft, P =0.33], and 12 months postoperatively [CQLQ 54 vs. 54, P =0.91; mMRC 0 to 2 (95% vs. 86%), P =0.74; 6MWT 1409ft vs. 1328ft, P =0.13]. The magnitude of change between the data was not significantly different between the stent evaluation, 3-, and 12 months postoperative. Predicted forced expiratory volume in 1-second measurements at baseline, after stent placement, 3 months, and 12 months post-TBP were 74%, 79%, 73%, and 73%, respectively, and not clinically significant. Improvement after stent evaluation and the magnitude of improvement may be predictive of postoperative outcomes up to 1 year after surgery.

Gender differences in association between expiratory dynamic airway collapse and severity of obstructive sleep apnea.

Repetitive unbalances and tensions generated by inspiratory efforts against an obstructive upper airway during sleep predispose the development of expiratory central airway collapse. In addition, structures of the upper airway between men and women have differences and could be the reasons for differences in obstructive sleep apnea (OSA) prevalence between genders. The present study aimed to evaluate the association between parameters of expiratory dynamic tracheal collapse measured using chest multidetector CT and objectively measured OSA severity between men and women. A total of 901 participants who underwent chest CT and overnight in-home polysomnography from the Korean Genome and Epidemiology Study were cross-sectionally analyzed (women: 46.2%). The participants were divided into three groups based on OSA severity by apnea-hypopnea index (AHI). Multivariate linear regression analysis was performed to determine the effects of central airway collapse after adjustment for cardiovascular-related covariates. In a multivariate analysis, percentages of expiratory lumen structure reductions involving area, diameter, and perimeter were associated with AHI (all p values < 0.05) and with OSA severity (moderate-to-severe OSA than no OSA: β = 3.30%, p = 0.03; β = 2.05%, p = 0.02; β = 1.97%, p = 0.02, respectively) in women, whereas men had only a greater percentage of expiratory wall thickness reduction in moderate-to-severe OSA than no OSA (β = 0.72%, p = 0.003). In addition, women with both mild OSA and moderate-to-severe OSA had higher expiratory tracheal collapse than men without OSA, and a moderate effect of sex was observed (p for interaction = 0.007). The expiratory dynamic tracheal collapse was independently associated with severity of OSA in women than in men. Differences of pharyngeal structures and inherent features of airways by genders may affect the dissimilarities in vulnerability to sleep apnea between men and women. • The expiratory dynamic tracheal collapse was independently associated with severity of OSA in women than in men. • Women with over mild OSA had higher expiratory tracheal collapse than men without OSA, and moderate effect of sex was observed. • Structural differences of airway may affect differences in susceptibility of sleep apnea between genders.

Excessive Dynamic Airway Collapse Severity Scoring System: A Call Out for an Overall Severity Determination.

Severe excessive dynamic airway collapse (EDAC) is defined as airway narrowing due to posterior wall protrusion into the airway lumen, >90%. We aimed to establish an overall severity score to assess severe EDAC and the need for subsequent intervention. A retrospective study of patients who underwent dynamic bronchoscopy for evaluation of expiratory central airway collapse between January 2019 and July 2021. A numerical value was given to each tracheobronchial segmental collapse: 0 points (<70%), 1 point (70% to 79%), 2 points (80% to 89%), and 3 points (>90%) to be added for an overall EDAC severity score per patient. We compared the score among patients who underwent stent trials (severe EDAC) and those who did not. Based on the receiver operating characteristics curve, a cutoff total score to predict severe EDAC was calculated. One hundred fifty-eight patients were included. Patients were divided into severe (n = 60) and nonsevere (n = 98) EDAC. A cutoff of 9 as the total score had a sensitivity of 94% and a specificity of 74% to predict severe EDAC, based on an area under the curve 0.888 (95% CI: 0.84, 0.93; P < 0.001). Our EDAC Severity Scoring System was able to discern between severe and nonsevere EDAC by an overall score cutoff of 9, with high sensitivity and specificity for predicting severe disease and the need for further intervention, in our institution.

Clinical Outcomes After Tracheobronchoplasty With Ringed Polytetrafluoroethylene Vascular Graft

BackgroundThis report describes the surgical technique and outcomes of tracheobronchoplasty (TBP) with ringed polytetrafluoroethylene (PTFE) vascular graft. MethodsWe identified all patients who underwent PTFE-TBP for severe expiratory central airway collapse from January 1, 2018 to August 2021 at Mayo Clinic, Florida. Preoperative and postoperative St George’s Respiratory Questionnaire (SGRQ), Cough-Specific Quality of Life Questionnaire (CSQLQ), pulmonary function testing, 6-minute walk test, and blinded dynamic bronchoscopy videos at 3-month follow-up were used to assess outcomes. ResultsFourteen patients (median age, 62.5 years; 64.3% female) underwent PTFE-TBP. The median operative time was 355 minutes, median hospital length of stay was 5 days, and median intensive care unit stay was 1 day. One patient had a Clavien-Dindo grade ≥3 complication. Comparison of preoperative and postoperative questionnaire scores demonstrated improvement in median SGRQ score by 14.79 (P = .013) and CSQLQ score by 22 (P = .005). Preoperative and postoperative pulmonary function and 6-minute walk test results showed no significant difference. Postoperative bronchoscopy demonstrated improvement in median collapsibility of mid trachea by 39.6% (P < .001), distal trachea by 50% (P < .001), left main bronchus by 38.2% (P < .001), right main bronchus by 37.9% (P < .001), and bronchus intermedius by 30.7% (P < .001). ConclusionsPTFE-TBP provides significant improvement in patients' symptoms and expiratory central airway collapse as judged by preoperative and postoperative quality of life questionnaires and bronchoscopy.

Unexpected Bronchomalacia Combined with Excessive Dynamic Airway Collapse was Diagnosed by Intraoperative Bronchoscopy: A Case Report

Expiratory central airway collapse (ECAC) comprises tracheobronchomalacia (TBM) and excessive dynamic airway collapse (EDAC). ECAC is a progressive disease that can be congenital or acquired, and it can be confirmed by inspiratory-dynamic expiratory chest CT or dynamic bronchoscopy. We present the case of a 65-year-old man who underwent radiofrequency ablation for hepatocellular carcinoma under general anesthesia. After tracheal intubation in the operating room, the respiratory sound in the left lung disappeared, and the respiratory sound in the right lung was clear during chest auscultation. Bronchoscopy revealed complete collapse of the left main bronchus. Intraoperative bronchoscopy confirmed that the patient had ECAC (both TBM and EDAC).

Application of 320-row multidetector free-breathing cine CT in diagnosis of pediatric expiratory central airway collapse

BackgroundPediatric expiratory central airway collapse poses diagnostic challenge due to non-specific clinical presentation with further investigations needed for definite diagnosis. The purpose of this cross-sectional study was to determine the diagnostic accuracy of 320-row multidetector free-breathing cine CT in diagnosis of pediatric expiratory central airway collapse utilizing its advantageous wide z-axis coverage. End-inspiratory and end-expiratory measurement of cross-sectional area at certain points of airway was done to calculate the percentage of expiratory central airway collapse. Flexible bronchoscopy was done thereafter as a gold standard technique for comparison.ResultsAmong the thirty-eight pediatric patients (20 males and 18 females) enrolled in this study, free-breathing cine CT correctly diagnosed expiratory central airway collapse in 32 patients with a sensitivity of 84.2%. However, a statistically significant difference was found between the results of bronchoscopy and free-breathing cine CT as regard the site, morphology and severity of airway collapse.Conclusions320-row multidetector free-breathing cine CT is still considered an effective noninvasive imaging modality in diagnosis of expiratory central airway collapse in pediatric population, despite the differences in perceived morphology and severity when compared to flexible bronchoscopy.

IMPACT OF SMOKING HISTORY ON OUTCOMES IN EXPIRATORY CENTRAL AIRWAY COLLAPSE PATIENTS UNDERGOING TRACHEOBRONCHOPLASTY

IMPACT OF SMOKING HISTORY ON OUTCOMES IN EXPIRATORY CENTRAL AIRWAY COLLAPSE PATIENTS UNDERGOING TRACHEOBRONCHOPLASTY

Tracheobronchomalacia and Excessive Dynamic Airway Collapse: Current Concepts and Future Directions.

Tracheobronchomalacia (TBM) and excessive dynamic airway collapse (EDAC) are airway abnormalities that share a common feature of expiratory narrowing but are distinct pathophysiologic entities. Both entities are collectively referred to as expiratory central airway collapse (ECAC). The malacia or weakness of cartilage that supports the tracheobronchial tree may occur only in the trachea (ie, tracheomalacia), in both the trachea and bronchi (TBM), or only in the bronchi (bronchomalacia). On the other hand, EDAC refers to excessive anterior bowing of the posterior membrane into the airway lumen with intact cartilage. Clinical diagnosis is often confounded by comorbidities including asthma, chronic obstructive pulmonary disease, obesity, hypoventilation syndrome, and gastroesophageal reflux disease. Additional challenges include the underrecognition of ECAC at imaging; the interchangeable use of the terms TBM and EDAC in the literature, which leads to confusion; and the lack of clear guidelines for diagnosis and treatment. The use of CT is growing for evaluation of the morphology of the airway, tracheobronchial collapsibility, and extrinsic disease processes that can narrow the trachea. MRI is an alternative tool, although it is not as widely available and is not used as frequently for this indication as is CT. Together, these tools not only enable diagnosis, but also provide a road map to clinicians and surgeons for planning treatment. In addition, CT datasets can be used for 3D printing of personalized medical devices such as stents and splints. An invited commentary by Brixey is available online. Online supplemental material is available for this article. ©RSNA, 2022.

Stent Evaluation for Expiratory Central Airway Collapse: Does the Type of Stent Really Matter?

Careful selection of patients with expiratory central airway collapse (ECAC) that may benefit from tracheobronchoplasty (TBP) can be aided by a short-term airway stent evaluation. This can be performed with either silicone Y-stents (SYSs) or uncovered self-expanding metallic airway-stents (USEMAS). No direct comparison has been made between these 2 stent types. This was a small retrospective review of consecutive patients that underwent a stent evaluation. A propensity score was used to match patients in the USEMAS and SYS groups. Outcomes included complications, changes in the health-related quality-of-life (HR-QoL), and changes in exercise capacity. Baseline measurements were compared with those obtained during stent evaluation and after TBP. Forty-two patients with severe ECAC underwent USEMAS placement, while 18 patients had an SYS placed. Propensity score matching resulted in 13 matched SYS and USEMAS pairs. The SYS group had an increased rate of mucus plugging (38.5% vs. 0%, P <0.047). Although not statically significant, a clinical improvement was observed in HR-QoL and exercise capacity in the USEMAS group during stent placement. In patients who underwent TBP, both USEMAS and SYS groups had a statistically significant change in the Modified Medical Research Council Dyspnea Scale during stent evaluation and after TBP. In patients with severe ECAC, short-term evaluation with airway stents appears to be safe and improves respiratory symptoms, HR-QoL, and exercise capacity. The use of USEMAS led to a lower complication rate, a greater improvement in HR-QoL and exercise capacity, and appeared to better predict how the patients would respond to TBP.

Expiratory central airway collapse during positive pressure ventilation: a case report

BackgroundPhysiologic narrowing of the central airway occurs during expiration. Conditions in which this narrowing becomes excessive are referred to as expiratory central airway collapse. Expiratory central airway collapse is usually managed by applying positive pressure to the airways, which acts as a pneumatic stent. The particularity of the case reported here included the patient’s left main bronchus being permeable during spontaneous breathing but collapsing during general anaesthesia, despite positive pressure ventilation and positive end-expiratory pressure.Case presentationWe present the case of a 55-year-old man admitted for the placement of a ureteral JJ stent. Rapid desaturation occurred a few minutes after the onset of anaesthesia. After excluding the most common causes of desaturation, fibreoptic bronchoscopy was performed through the tracheal tube and revealed complete collapse of the left main bronchus. The collapse persisted despite the application of positive end-expiratory pressure and several recruitment manoeuvres. After recovery of spontaneous ventilation, the collapse was lifted, and saturation increased back to normal levels. No evidence of extrinsic compression was found on chest X-rays or computed tomography scans.ConclusionCases of unknown expiratory central airway collapse reported in the literature were usually managed with positive pressure ventilation. This approach has been unsuccessful in the case described herein. Our hypothesis is that mechanical bending of the left main bronchus occurred due to loss of the patient’s natural position and thoracic muscle tone under general anaesthesia with neuromuscular blockade. When possible, spontaneous ventilation should be maintained in patients with known or suspected ECAC.

Semiquantitative Chest Computed Tomography Assessment Identifies Expiratory Central Airway Collapse in Symptomatic Military Personnel Deployed to Iraq and Afghanistan.

Purpose:We noted incidental findings on chest computed tomography (CT) imaging of expiratory central airway collapse (ECAC) in dyspneic patients after military deployment to southwest Asia (mainly Iraq and Afghanistan). We developed a standardized chest CT protocol with dynamic expiration to enhance diagnostic reliability and investigated demographic, clinical, and deployment characteristics possibly associated with ECAC.Materials and Methods:We calculated ECAC in 62 consecutive post-9/11 deployers with dyspnea who underwent multi-detector chest CT acquisition. ECAC was defined as ≥70% reduction in the cross-sectional tracheal area at dynamic expiration. We compared demographics (age, smoking, body mass index), comorbid conditions (gastroesophageal reflux, obstructive sleep apnea [OSA]), and clinical findings (air trapping, forced expiratory volume in 1 second percent predicted) in deployers with and without ECAC. We examined associations between ECAC and forced expiratory volume in 1 second percent predicted, air trapping, OSA, deployment duration, and blast exposure.Results:Among 62 consecutive deployers with persistent dyspnea, 37% had ECAC. Three had severe (>85%) collapse. Those with ECAC were older (mean age 46 vs. 40 y, P=0.02), but no other demographic or clinical characteristics were statistically different among the groups. Although not statistically significant, ECAC odds were 1.5 times higher (95% confidence interval: 0.9, 2.5) for each additional year of southwest Asia deployment. Deployers with ECAC had 1.6 times greater odds (95% confidence interval: 0.5, 4.8) of OSA.Conclusions:Findings suggest that ECAC is common in symptomatic southwest Asia deployers. Chest high-resolution CT with dynamic expiration may provide an insight into the causes of dyspnea in this population, although risk factors for ECAC remain to be determined. A standardized semiquantitative approach to CT-based assessment of ECAC should improve reliable diagnosis in dyspneic patients.

Expiratory central airway collapse and symptoms in smokers.

The prevalence and clinical impacts of expiratory central airway collapse (ECAC) in smokers remain controversial. Although studies have shown associations of ECAC with airflow limitation and symptoms, others have shown that higher tracheal collapsibility is associated with lower expiratory-to-inspiratory ratio of lung volume (E/I-LV), but not airflow limitation. This study tested whether ECAC of the trachea and main bronchi could occur exclusively in smokers with lower E/I-LV and affect their symptoms independent of emphysema and intrapulmonary airway disease. ECAC was defined as the expiratory-to-inspiratory ratio of cross-sectional lumen area <0.5 for at least one of the three locations, including the trachea, right and left main bronchi on static full-inspiratory, and end-tidal expiratory CT. Symptoms were assessed using the chronic obstructive pulmonary disease (COPD) assessment test (CAT) and modified MRC scale (mMRC). Out of 241 smokers with and without COPD (n=189 and 52, respectively), ECAC was found in 21 (9%) smokers. No ECAC was found in smokers with E/I-LV ≥0.75. CAT and mMRC in smokers with ECAC were higher than in non-ECAC smokers with E/I-LV <0.75, but comparable to those in non-ECAC smokers with E/I-LV ≥0.75. In the multivariable analysis of smokers with E/I-LV <0.75, ECAC was associated with increased mMRC and CAT independent of CT-emphysema severity, wall area percent of segmental airways, and forced expiratory volume in 1s CONCLUSIONS: ECAC is associated with worsening of symptoms independent of emphysema and segmental airway disease in smokers with a lower expiratory-to-inspiratory lung volume ratio.

Excessive Dynamic Airway Collapse Masquerading as Asthma

Expiratory central airway collapse (ECAC) includes 2 different pathophysiologic entities, excessive dynamic airway collapse (EDAC) and tracheobronchomalacia (TBM). We present a chronic cough case with history of asthma that was diagnosed as EDAC by dynamic bronchoscopy and its improvement with stent trial. A 71-year-old never-smoker man with past medical history mainly relevant for chronic rhinitis, gastroesophageal reflux, and chronic opioid therapy secondary to chronic back pain presented to clinic for frequent “acute bronchitis” and pneumonia episodes requiring prolonged intravenous antibiotics and systemic corticosteroids. His respiratory symptoms included persistent and productive cough with occasional wheezing. Pulmonary function test results were normal with no obstructive or restrictive pattern, and a normal diffusion capacity. FEV1 was 2.36 L (83% of predicted), forced vital capacity was 3.21 L (86% of predicted), FEV1/forced vital capacity was 73.4 (96% of predicted), maximum vital capacity was 3.73 L (100% of predicted), and forced expiratory flow at 25% to 75% of forced vital capacity was 1.71 (78% of predicted). Flow-volume loop was normal (Figure 1). No bronchodilator or methacholine challenges were performed. Laboratory workup was relevant for an absolute eosinophil count of 250 cells/μL and total IgE level of 575 kU/L. The patient had no significant improvement with high-dose inhaled corticosteroids/long-acting inhaled beta-agonists, long-acting inhaled anticholinergics, and omalizumab. Additional evaluation was performed in consideration of an alternative diagnosis. Chest computed tomography demonstrated some areas of mucous plugging over lower lobes with minimal bronchiectasis. Dynamic bronchoscopy revealed severe EDAC (>90% collapse) at the mid and distal trachea (Figure 2, A and B), left (Figure 2, D) and right main stem (Figure 2, C) bronchus, and bronchus intermedius. He underwent stent trial with uncovered self-expanding metallic stents (Figure 2, E and F) with subsequent improvement (Figure 2, E and F) of his Modified Medical Research Council dyspnea scale score by 1 point, his St George's Respiratory Questionnaire score by 4 points, and Cough Specific Quality of Life Questionnaire score by more than 10 points. There are plans for tracheobronchoplasty; however, the patient was lost to follow-up.Figure 2(A) Distal trachea (DT), left main bronchus (LMB), right main bronchus (RMB) on inspiration. (B) DT, LMB, and RMB, on forced expiration demonstrating severe EDAC. (C) RMB on forced expiration with severe EDAC. (D) LMB on forced expiration with severe EDAC. (E) DT, LMB, and RMB after stent placement on inspiration. (F) DT, LMB, and RMB after stent placement on expiration. Note the significant improvement and minimal posterior wall collapsed pointed by the arrow after the stent placement.View Large Image Figure ViewerDownload Hi-res image Download (PPT) This case emphasizes that EDAC should be considered in the differential diagnosis in chronic cough evaluations, especially in patients with physician-diagnosed asthma who are not responding to standard medical therapy. Around 1 in every 3 patients with physician-diagnosed asthma does not have asthma after objective airway limitation testing.1Aaron S.D. Vandemheen K.L. FitzGerald J.M. Ainslie M. Gupta S. Lemiere C. et al.Reevaluation of diagnosis in adults with physician-diagnosed asthma.JAMA. 2017; 317: 269-279Crossref PubMed Scopus (275) Google Scholar Airway clearance physiotherapy is always implemented in patients with significant ECAC. All patients with severe ECAC should be considered for a stent trial. It is important to highlight that stent trial is not an effective long-term solution for ECAC. Airway stents are removed after 7 to 10 days while new testing is performed to assess objective improvement in testing and symptoms that will justify surgical correction with a tracheobronchoplasty. The differentiation between EDAC and TBM may alter the surgical approach. EDAC refers to an excessive forward displacement of the posterior tracheal wall (membranous portion) due to weakness and atrophy of the longitudinal elastic fibers. The use of this term should only be meant to describe an abnormality in the posterior or membranous portion of the tracheobronchial tree. TBM is a term that should be used to describe an abnormality in the anterior/lateral (cartilaginous) portion of the tracheal wall. Both terms are independent to the longitudinal extension of the disease and root more in their different pathophysiology.2Kheir F. Fernandez-Bussy S. Gangadharan S.P. Majid A. Excessive dynamic airway collapse or tracheobronchomalacia: does it matter?.Arch Bronconeumol. 2019; 55: 69-70Crossref PubMed Scopus (6) Google Scholar The clinical presentation has a wide spectrum ranging from asymptomatic to severe life-limiting airway symptoms such as dyspnea, cough, and sputum retention. The actual prevalence in the general population is unknown.

Improving Quality of Dynamic Airway Computed Tomography Using an Expiratory Airflow Indicator Device.

Dynamic computed tomography (CT) of the airways is increasingly used to evaluate patients with suspected expiratory central airway collapse, but current protocols are susceptible to inadequate exhalation caused by variable patient compliance with breathing instructions during the expiratory phase. We developed and tested a low-cost single-use expiratory airflow indicator device that was designed to improve study quality by providing a visual indicator to both patient and operator when adequate expiratory flow was attained. A total of 56 patients undergoing dynamic airway CT were evaluated, 35 of whom were scanned before introduction of the indicator device (control group), with the rest comprising the intervention group. Lung volumes and tracheal cross-sectional areas on inspiratory/expiratory phases were computed using automated lung segmentation and quantitative software analysis. Inadequate exhalation was defined as absolute volume change of <500 mL during the expiratory phase. Fewer patients in the intervention group demonstrated inadequate exhalation. The average change in volume was higher in the intervention group (P=0.004), whereas the average minimum tracheal cross-sectional area was lower (P=0.01). The described expiratory airflow indicator device can be used to ensure adequate exhalation during the expiratory phase of dynamic airway CT. A higher frequency of adequate exhalation may improve reliability and sensitivity of dynamic airway CT for diagnosis of expiratory central airway collapse.

Paratracheal Paraseptal Emphysema and Expiratory Central Airway Collapse in Smokers.

Expiratory central airway collapse is associated with respiratory morbidity independent of underlying lung disease. However, not all smokers develop expiratory central airway collapse, and the etiology of expiratory central airway collapse in adult smokers is unclear. Paraseptal emphysema in the paratracheal location, by untethering airway walls, may predispose smokers to developing expiratory central airway collapse. To evaluate whether paratracheal paraseptal emphysema is associated with expiratory central airway collapse. We analyzed paired inspiratory and expiratory computed tomography scans from participants enrolled in a multicenter study (Genetic Epidemiology of Chronic Obstructive Pulmonary Disease) of smokers aged 45 to 80 years. Expiratory central airway collapse was defined as greater than or equal to 50% reduction in cross-sectional area of the trachea during expiration. In a nested case-control design, participants with and without expiratory central airway collapse were included in a 1:2 fashion, and inspiratory scans were further analyzed using the Fleischner Society criteria for presence of centrilobular emphysema, paraseptal emphysema, airway wall thickening, and paratracheal paraseptal emphysema (maximal diameter ≥ 0.5 cm). A total of 1,320 patients were included, 440 with and 880 without expiratory central airway collapse. Those with expiratory central airway collapse were older, had higher body mass index, and were less likely to be men or current smokers. Paratracheal paraseptal emphysema was more frequent in those with expiratory central airway collapse than control subjects (16.6 vs. 11.8%; P = 0.016), and after adjustment for age, race, sex, body mass index, smoking pack-years, and forced expiratory volume in 1 second, paratracheal paraseptal emphysema was independently associated with expiratory central airway collapse (adjusted odds ratio, 1.53; 95% confidence interval, 1.18-1.98; P = 0.001). Furthermore, increasing size of paratracheal paraseptal emphysema (maximal diameter of at least 1 cm and 1.5 cm) was associated with greater odds of expiratory central airway collapse (adjusted odds ratio, 1.63; 95% confidence interval, 1.18-2.25; P = 0.003 and 1.77; 95% confidence interval, 1.19-2.64; P = 0.005, respectively). Paraseptal emphysema adjacent to the trachea is associated with expiratory central airway collapse. The identification of this risk factor on inspiratory scans should prompt further evaluation for expiratory central airway collapse. Clinical trial registered with ClinicalTrials.gov (NCT 00608764).

Airway stenting in excessive central airway collapse.

In tracheobronchomalacia (TBM) and other disorders, weakened airway walls lead to expiratory central airway collapse (ECAC) and can cause symptoms of cough, dyspnea, retained secretions, and recurrent pulmonary infections. Diagnosis of severe ECAC is based on the presence of >90% expiratory airway collapse on dynamic computed tomography (CT) and/or bronchoscopy. We offer patients with severe ECAC a trial of airway stenting to determine whether splinting of the central airways leads to improvements in symptoms, quality of life, exercise capacity, or respiratory function. Patients who respond positively to airway stenting are considered for tracheobronchoplasty.

Stent Trial for Expiratory Central Airway Collapse: Does the Type of Stent Really Matter?

Stent Trial for Expiratory Central Airway Collapse: Does the Type of Stent Really Matter?

Manometry Optimized Positive Expiratory Pressure (MOPEP) in Excessive Dynamic Airway Collapse (EDAC).

Positive expiratory pressure(PEP) breathing modalities are commonly prescribed in obstructive lung diseases, however practical methods of airway pressures(AP) quantification for therapeutic efficacy are lacking. Excessive dynamic airway collapse(EDAC) is characterized by expiratory central airway collapse leading to dyspnea and poor quality of life(QoL), with limited therapeutic options. To measure AP and exertional dyspnea in EDAC patients during normal breathing and with use of pursed-lip breathing(PLB), nasal PEP device(nPEP), and oral-PEP valve(oPEP) during rest and exercise using an Esophageal Manometer. EDAC patients exercised on a bicycle ergometer sequentially using normal breathing, PLB, nPEP, and oPEP for five-minute intervals. AP's were measured by continuous topographic upper airway manometry. Pre- and post-exercise BORG dyspnea scores were recorded and QoL measured with the St. George's respiratory questionnaire(SGRQ-C). The most effective and patient-preferred PEP modality was prescribed for daily activities and SGRQ-C repeated after one week. Three women with symptomatic EDAC participated. Expiratory laryngopharyngeal AP's during exercise with normal breathing, PLB, nPEP and oPEP in patient-1 were 1.7, 14, 4.5, and 7.3 mmHg, in patient-2; 2.3, 8, 8.3, and 12 mmHg, and in patient-3; 1, 15, unobtainable, and 9 mmHg, respectively. Maximal reduction in BORG scores occurred with PLB in patient 1 and with oPEP in patients 2 and 3. After 1 week mean SGRQ-C scores declined by 17-points. Upper airway manometry directly measures laryngopharyngeal pressures during rest and exercise and can be used to select and optimize PEP breathing techniques to improve respiratory symptoms in EDAC patients.