Expiratory Airway 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.

Predicting parameters of airway dynamics generated from inspiratory and expiratory plethysmographic airway loops, differentiating subtypes of chronic obstructive diseases

BackgroundThe plethysmographic shift volume–flow loop (sRaw-loop) measured during tidal breathing allows the determination of several lung function parameters such as the effective specific airway resistance (sReff), calculated from the ratio...

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

ObjectivesRepetitive 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.Materials and methodsA 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.ResultsIn 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).ConclusionThe expiratory dynamic tracheal collapse was independently associated with severity of OSA in women than in men.Clinical relevance statementDifferences of pharyngeal structures and inherent features of airways by genders may affect the dissimilarities in vulnerability to sleep apnea between men and women.Key Points• 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.

Beyond the Skin: Reduced Lung Function Associated With Atopic Dermatitis in Infants.

Very few studies have examined lung function parameters using tidal breath analysis (TBA) in atopic dermatitis (AD) with its high potential for progression to asthma. To measure lung functions using TBA in infants with AD and in healthy controls (HCs), and to investigate the effects of disease severity, food sensitivity, and history of recurrent wheezing on TBA parameters in infants with AD. Two hundred thirty infants were included in this prospective cross-sectional study, including an AD group (n= 150) and an HC group (n= 80). Food sensitivity was assessed by means of food-specific IgE or the skin prick test. The severity of the disease was evaluated using the SCORing Atopic Dermatitis. Lung function was assessed using TBA. The following TBA parameters were significantly lower in the AD group than in the HC group (P < .05): time to peak tidal expiratory flow, exhaled volume to peak tidal expiratory flow, ratio of time to peak tidal expiratory flow to expiratory time, ratio of exhaled volume to peak tidal expiratory flow to total expiratory volume, expiratory flow when 25% of tidal volume remains in the lungs, respiratory rate, and minute ventilation. No difference was observed in the AD group when TBA parameters were compared according to disease severity, food sensitivity, and history of recurrent wheezing (P > .05). The receiver-operating characteristic curve demonstrated by the ratio of time to peak tidal expiratory flow to expiratory time yielded an area under the curve of 0.826 (CI, 0.772-0.879), with a cutoff value of 31.65 or higher in differentiating AD, with a sensitivity of 78.7% and a specificity of 77.5%. TBA curves can be a useful tool for demonstrating expiratory airway obstruction in AD and for providing objective information for the clinician. Bronchial obstruction was detected in young children with AD irrespective of the severity of the disease, food sensitivity, and history of recurrent wheezing.

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.

Measuring Expiratory Diaphragm Activity: An Electrifying Tool to Guide Positive End-Expiratory Pressure Strategy in Critically Ill Children?

Measuring Expiratory Diaphragm Activity: An Electrifying Tool to Guide Positive End-Expiratory Pressure Strategy in Critically Ill Children?

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).

Fentanyl induced disruption of the coordinated reciprocal activity of inspiratory and expiratory respiratory muscles

Opioid induced respiratory depression (OIRD) occurs when respiratory pump and/or airway muscle activity are reduced ostensibly due to reduced output from the brainstem respiratory control system, resulting in central (CA) and/or obstructive apnea (OA) and reduced breathing frequency. Although less commonly reported in the literature, ORID may also result from an inappropriate activation of accessory muscles leading to the “Wooden Chest Syndrome” (WCS) -when airflow is limited due to simultaneous activation of inspiratory and expiratory pump and/or airway respiratory muscles to decrease chest wall compliance and inappropriately increase airway resistance. This phenomenon is difficult to directly study in humans, but here we present data from our large animal model (adult female goats). We tested the hypothesis that IV fentanyl would lead to transient dysfunction in respiratory accessory muscles indicative of WCS. We surgically instrumented goats (n=7) with electromyographic (EMG) wires in inspiratory (diaphragm; DIA) and expiratory (Transversus Abdominus; TA) pump muscles, as well as airway dilator (Thyropharyngeus; Thy) and constrictor (Genioglossus; GG) muscles. After &gt;2 weeks of surgical recovery, responses to saline or various doses of fentanyl citrate (25-125 mcg/kg; IV) were tested for 30 min before and up to 90 min after injection. As described in an adjacent poster, particularly over the first several minutes after fentanyl injection, CA and OA were observed in some goats. However, disruption of airflow was primarily associated with increased simultaneous activation of pump and airway inspiratory and expiratory muscles resembling WCS. For most muscles, the rate of rise in muscle activity (an index of firing intensity) increased within 2 minutes following fentanyl injection and remained significantly (P&lt;0.05) elevated up to 90 minutes. During WCS periods, airflow was oscillatory or interrupted suggesting transient closure of the airway. In addition, there were time- and dose-dependent effects on frequency, duration, and total activity of the pump and airway muscles. By 60 minutes post-injection, there were periods of transient return of muscle activity and airflow to at or below baseline values. There was no significant effect of saline on muscle activity. Overall, these data suggest that following fentanyl injection in awake goats, there was an increase in firing of pump and airway muscles which ultimately disrupts the coordinated reciprocal activity of inspiratory and expiratory muscles and contributes to OIRD. Supported by NIH DA050571 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Individualized flow-controlled versus conventional pressure-controlled ventilation in on-pump heart surgery (FLOWVENTIN HEARTSURG): study protocol for a randomized controlled trial

BackgroundIn on-pump cardiac surgery, lungs are at high risk of periprocedural organ impairment because of atelectasis formation, ventilator-induced lung injury, and hyperinflammation due to the cardiopulmonary bypass which results in postoperative pulmonary complications in half of this patient population. The new ventilation mode flow-controlled ventilation (FCV) uniquely allows full control of ins- and expiratory airway flows. This approach reduces the mechanical power of invasive ventilation as a possible cause of ventilator-induced lung injury. The scope of FLOWVENTIN HEARTSURG is to compare perioperative individualized FCV with best clinical practice pressure-controlled ventilation (PVC) modes in patients with elective on-pump cardiac surgery procedures. We hypothesize that the postoperative inflammatory response can be reduced by the perioperative application of FCV compared to PCV.MethodsFLOWVENTIN HEARTSURG is a single-center, randomized, parallel-group trial with two intervention arms: perioperative PCV modes (n = 70, PCV group) with an individualized positive end-expiratory pressure (PEEP) and a tidal volume of 6–8 ml/kg predicted bodyweight compared to perioperative FCV (n = 70, FCV group) with an individualized PEEP and driving pressure, resulting in a liberal tidal volume. As the primary study endpoint interleukin 8 plasma level is assessed 6 h after cardiopulmonary bypass as a surrogate biomarker of systemic and pulmonary inflammation. As secondary aims clinically relevant patient outcomes are analyzed, e.g., perioperative lung function regarding oxygenation indices, postoperative pulmonary and extra-pulmonary complications, SIRS-free days as well as ICU and total inpatient stays. As additional sub-studies with an exploratory approach perioperative right ventricular function parameters are assessed by echocardiography and perioperative lung aeration by electrical impedance tomography.DiscussionCurrent paradigms regarding protective low tidal volume ventilation are consciously left in the FCV intervention group in order to reduce mechanical power as a determinant of ventilator-induced lung injury in this high-risk patient population and procedures. This approach will be compared in a randomized controlled trial with current best clinical practice PCV in FLOWVENTIN HEARTSURG.Trial registrationGerman Clinical Trials Register DRKS00018956. Registered on 12 June 2020 (Version 1), last update on 22 August 2022 (Version 4).

MR imaging of the airways.

The need for airway imaging is defined by the limited sensitivity of common clinical tests like spirometry, lung diffusion (DLCO) and blood gas analysis to early changes of peripheral airways and to inhomogeneous regional distribution of lung function deficits. Therefore, X-ray and computed tomography (CT) are frequently used to complement the standard tests.As an alternative, magnetic resonance imaging (MRI) offers radiation-free lung imaging, but at lower spatial resolution. Non-contrast enhanced MRI shows healthy airways down to the first subsegmental level/4th order (CT: eighth). Bronchiectasis can be identified by wall thickening and fluid accumulation. Smaller airways become visible, when altered by peribronchiolar inflammation or mucus retention (tree-in-bud sign).The strength of MRI is functional imaging. Dynamic, time-resolved MRI directly visualizes expiratory airway collapse down to the lobar level (CT: segmental level). Obstruction of even smaller airways becomes visible as air trapping on the expiratory scans. MRI with hyperpolarized noble gases (3He, 129Xe) directly shows the large airways and peripheral lung ventilation. Dynamic contrast-enhanced MRI (DCE MRI) indirectly shows airway dysfunction as perfusion deficits resulting from hypoxic vasoconstriction of the dependent lung volumes. Further promising scientific approaches such as non-contrast enhanced, ventilation-/perfusion-weighted MRI from periodic signal changes of respiration and blood flow are in development.In summary, MRI of the lungs and airways excels with its unique combination of morphologic and functional imaging capacities for research (e.g., in chronic obstructive lung disease or asthma) as well as for clinical imaging (e.g., in cystic fibrosis).

Pulmonological issues

Pediatric leukodystrophies are rare neurodegenerative diseases involving multiple systems. Each form has unique neurologic features but are characterized by encephalopathy with accompanying impairments evidenced in reflexes, muscle tone and movement control. Weakness of expiratory, inspiratory, and upper airway muscles may lead to impaired airway secretion clearance resulting in recurrent respiratory infections, dysphagia, sleep-disordered breathing, restrictive lung disease, and ultimately chronic respiratory insufficiency.

Lactoferrin Ameliorates Ovalbumin-Induced Asthma in Mice through Reducing Dendritic-Cell-Derived Th2 Cell Responses.

Asthma is a chronic respiratory disease with symptoms such as expiratory airflow narrowing and airway hyperresponsiveness (AHR). Millions of people suffer from asthma and are at risk of life-threatening conditions. Lactoferrin (LF) is a glycoprotein with multiple physiological functions, including antioxidant, anti-inflammatory, antimicrobial, and antitumoral activities. LF has been shown to function in immunoregulatory activities in ovalbumin (OVA)-induced delayed type hypersensitivity (DTH) in mice. Hence, the purpose of this study was to investigate the roles of LF in AHR and the functions of dendritic cells (DCs) and Th2-related responses in asthma. Twenty 8-week-old male BALB/c mice were divided into normal control (NC), ovalbumin (OVA)-sensitized, and OVA-sensitized with low dose of LF (100 mg/kg) or high dose of LF (300 mg/kg) treatment groups. The mice were challenged by intranasal instillation with 5% OVA on the 21st to 27th day after the start of the sensitization period. The AHR, cytokines in bronchoalveolar lavage fluid, and pulmonary histology of each mouse were measured. Serum OVA-specific IgE and IgG1 and OVA-specific splenocyte responses were further detected. The results showed that LF exhibited protective effects in ameliorating AHR, as well as lung inflammation and damage, in reducing the expression of Th2 cytokines and the secretion of allergen-specific antibodies, in influencing the functions of DCs, and in decreasing the level of Th2 immune responses in a BALB/c mouse model of OVA-induced allergic asthma. Importantly, we demonstrated that LF has practical application in reducing DC-induced Th2 cell responses in asthma. In conclusion, LF exhibits anti-inflammation and immunoregulation activities in OVA-induced allergic asthma. These results suggest that LF may act as a supplement to prevent asthma-induced lung injury and provide an additional agent for reducing asthma severity.

A new approach for the detection of obesity-related airway obstruction in lung-healthy individuals

BackgroundSubjects with obesity show an increased prevalence of airway obstruction but it is not clear in each case whether this reflects genuine lung disease. Via intentional increase in end-expiratory lung volume we studied the detection of obesity-induced airway obstruction in lung-healthy obese subjects. MethodsThe primary study population comprised 66 lung-healthy obese subjects and 23 normal weight subjects. Measurements were performed in a body plethysmograph allowing for recording and quantification of breathing loops in terms of specific airway resistance at both normal and intentionally elevated end-expiratory lung volume. The change in volume was documented by a shutter maneuver. ResultsThe voluntary increase of lung volume led to a significant reduction of expiratory airway resistance in 11 of the 66 obese subjects. This reduction could be quantified by a change of total expiratory resistance (sRtEX) of >1 kPa*s but was also clearly visible in the breathing loops. sRtEX showed the largest change among all resistance parameters. The loops of normal weight subjects remained virtually unaffected by the change in lung volume. Moreover, those of 5 obese patients with COPD who were measured for comparison partially showed a reduction of resistance but airway obstruction remained. ConclusionThe proposed breathing maneuver was simple to perform and allowed for a quantitative and qualitative detection of obesity-induced airway obstruction. This might help in reducing the likelihood of misdiagnosis and overtreatment of obese patients.

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

Tracheobronchoplasty yields long-term anatomy, function, and quality of life improvement for patients with severe excessive central airway collapse

ObjectivesThis study examines the long-term anatomic and clinical effects of tracheobronchoplasty in severe excessive central airway collapse. MethodsIncluded patients underwent tracheobronchoplasty for excessive central airway collapse (2002-2016). The cross-sectional area of main airways on dynamic airway computed tomography was measured before and after tracheobronchoplasty. Expiratory collapse was calculated as the difference between inspiratory and expiratory cross-sectional area divided by inspiratory cross-sectional area ×100. The primary outcome was improvement in the percentage of expiratory collapse in years 1, 2, and 5 post-tracheobronchoplasty. Secondary outcomes included mean response profile for the 6-minute walk test, Cough-Specific Quality of Life Questionnaire, Karnofsky Performance Status score, and St George Respiratory Questionnaire. Repeated-measures analysis of variance was used for statistical analyses. ResultsThe cohort included 61 patients with complete radiological follow-up at years 1, 2, and 5 post-tracheobronchoplasty. A significant linear decrease in the percentage of expiratory collapsibility of the central airways after tracheobronchoplasty was present. Anatomic repair durability was preserved 5 years after tracheobronchoplasty, with decrease in percentage of expiratory airway collapse up to 40% and 30% at years 1 and 2, respectively. The St George Respiratory Questionnaire (74.7 vs 41.8%, P < .001) and Cough-Specific Quality of Life Questionnaire (78 vs 47, P < .001) demonstrated significant improvement at year 5 compared with baseline. Similar results were observed in the 6-minute walk test (1079 vs 1268 ft, P < .001) and Karnofsky score (57 vs 82, P < .001). ConclusionsTracheobronchoplasty has durable effects on airway anatomy, functional status, and quality of life in carefully selected patients with severe excessive central airway collapse.

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.