Tracheomalacia and Tracheobronchomalacia in Children and Adults

Quantitative Assessment of Regional Dynamic Airway Collapse in Neonates via Retrospectively Respiratory-Gated 1 H Ultrashort Echo Time MRI

BACKGROUND

Neonatal dynamic tracheal collapse (tracheomalacia, TM) is a common and serious comorbidity in infants, particularly those with chronic lung disease of prematurity (bronchopulmonary dysplasia, BPD) or congenital airway or lung-related conditions such as congenital diaphragmatic hernia (CDH), but the underlying pathology, impact on clinical outcomes, and response to therapy are not well understood. There is a pressing clinical need for an accurate, objective, and safe assessment of neonatal TM.

PURPOSE

To use retrospectively respiratory-gated ultrashort echo-time (UTE) MRI to noninvasively analyze moving tracheal anatomy for regional, quantitative evaluation of dynamic airway collapse in quiet-breathing, nonsedated neonates.

STUDY TYPE

Prospective.

POPULATION/SUBJECTS

Twenty-seven neonatal subjects with varying respiratory morbidities (control, BPD, CDH, abnormal polysomnogram).

FIELD STRENGTH/SEQUENCE

High-resolution 3D radial UTE MRI (0.7 mm isotropic) on 1.5T scanner sited in the neonatal intensive care unit.

ASSESSMENT

Images were retrospectively respiratory-gated using the motion-modulated time-course of the k-space center. Tracheal surfaces were generated from segmentations of end-expiration/inspiration images and analyzed geometrically along the tracheal length to calculate percent-change in luminal cross-sectional area (A % ) and ratio of minor-to-major diameters at end-expiration (r D,exp ). Geometric results were compared to clinically available bronchoscopic findings (n = 14).

STATISTICAL TESTS

Two-sample t-test.

RESULTS

Maximum A % significantly identified subjects with/without a bronchoscopic TM diagnosis (with: 46.9 ± 10.0%; without: 27.0 ± 5.8%; P < 0.001), as did minimum r D,exp (with: 0.346 ± 0.146; without: 0.671 ± 0.218; P = 0.008). Subjects with severe BPD exhibited a far larger range of minimum r D,exp than subjects with mild/moderate BPD or controls (0.631 ± 0.222, 0.782 ± 0.075, and 0.776 ± 0.030, respectively), while minimum r D,exp was reduced in CDH subjects (0.331 ± 0.171) compared with controls (P < 0.001).

DATA CONCLUSION

Respiratory-gated UTE MRI can quantitatively and safely evaluate neonatal dynamic tracheal collapse, as validated with the clinical standard of bronchoscopy, without requiring invasive procedures, anesthesia, or ionizing radiation.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019;49:659-667.

3D-printed, externally-implanted, bioresorbable airway splints for severe tracheobronchomalacia

OBJECTIVES/HYPOTHESIS

To report the clinical safety and efficacy of three-dimensional (3D)-printed, patient-specific, bioresorbable airway splints in a cohort of critically ill children with severe tracheobronchomalacia.

STUDY DESIGN

Case series.

METHODS

From 2012 to 2018, 15 subjects received 29 splints on their trachea, right and/or left mainstem bronchi. The median age at implantation was 8 months (range, 3-25 months). Nine children were female. Five subjects had a history of extracorporeal membrane oxygenation (ECMO), and 11 required continuous sedation, six of whom required paralytics to maintain adequate ventilation. Thirteen were chronically hospitalized, unable to be discharged, and seven were hospitalized their entire lives. At the time of splint implantation, one subject required ECMO, one required positive airway pressure, and 13 subjects were tracheostomy and ventilator dependent, requiring a median positive end-expiratory pressure (PEEP) of 14 cm H₂ O (range, 6-20 cm H₂ 0). Outcomes collected included level of respiratory support, disposition, and splint-related complications.

RESULTS

At the time of discharge from our institution, at a median of 28 days postimplantation (range, 10-56 days), the subject on ECMO was weaned from extracorporeal support, and the subjects who were ventilated via tracheostomy had a median change in PEEP (discharge-baseline) of -2.5 cm H₂ O (range, -15 to 2 cm H₂ O, P = .022). At median follow-up of 8.5 months (range, 0.3-77 months), all but one of the 12 surviving subjects lives at home. Of the 11 survivors who were tracheostomy dependent preoperatively, one is decannulated, one uses a speaking valve, six use a ventilator exclusively at night, and three remain ventilator dependent.

CONCLUSIONS

This case series demonstrates the initial clinical efficacy of the 3D-printed bioresorbable airway splint device in a cohort of critically ill children with severe tracheobronchomalacia.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:1763-1771, 2019.

CT-based anatomical features of large airway and heart volume in dogs of different body size

Differences in the prevalence and clinical signs of cardiopulmonary diseases in dogs of different body sizes have been reported. It was hypothesized that the anatomical features of the heart and large airways varies by body size in dogs and might influence clinical manifestations of cardiopulmonary disease. The purpose of this study was to compare various anatomical features of the thoracic organs (heart, trachea, etc.) in dogs according to body size using computed tomography (CT) images. Dogs without clinically significant heart and lung disease (n=226) that underwent CT were divided into three groups on the basis of bodyweight: small (<7kg), medium (7-20kg), and large (>20kg). The following parameters were calculated from CT images using OsiriX and compared among groups: relative heart volume (heart volume/thoracic volume), relative distance from mainstem bronchi to vertebra (distance from mainstem bronchi to vertebra/heart length), longitudinal/transverse diameter ratio of trachea, and angle of bronchus. Small dogs had larger hearts relative to their thorax, a shorter distance from the heart to the vertebra, and laterally-elongated oval-shaped tracheas, compared to medium and/or large dogs. These differences in anatomical features according to body size may potentially contribute to different clinical manifestations when the heart is enlarged.

Tracheomalacia and Tracheobronchomalacia in Pediatrics: An Overview of Evaluation, Medical Management, and Surgical Treatment

Tracheobronchomalacia (TBM) refers to airway collapse due to typically excessive posterior membrane intrusion and often associated with anterior cartilage compression. TBM occurs either in isolation or in association with other congenital or acquired conditions. Patients with TM typically present non-specific respiratory symptoms, ranging from noisy breathing with a typical barking cough to respiratory distress episodes to acute life-threatening events and recurrent and/or prolonged respiratory infections. There are no definitive standardized guidelines for the evaluation, diagnosis, and treatment of TBM; therefore, patients may be initially misdiagnosed and incorrectly treated. Although milder cases of TBM may become asymptomatic as the diameter of the airway enlarges with the child, in cases of severe TBM, more aggressive management is warranted. This article is an overview of the clinical presentation, evaluation, diagnosis, medical management, and surgical treatment options in pediatric tracheomalacia.

Helical multi-detector CT scan as a tool for diagnosing tracheomalacia in children

BACKGROUND/AIMS

Tracheomalacia (TM) is not an unusual diagnosis in pediatric respiratory clinics. The aim of this study was to assess the accuracy of paired static end-inspiratory/end-expiratory helical multi-detector CT scan (MDCT) in detecting TM.

METHODS

FB was performed in 28 children suspected of TM on the grounds of presence of recurrent episodes of vibrating cough and a need for more specific diagnostic information. Children diagnosed with flexible bronchoscopy (FB) as having TM were further investigated with MDCT. The cross-sectional area ratio of the trachea during end-expiration and end-inspiration, at the level of maximum end-expiration collapse (CSR), determined the basis for the MDCT diagnosis of TM. FB and MDCT were also performed in five children who suffered from mainly dry-but not honking, barking, or vibrating-cough for more than 3 months, and served as controls.

RESULTS

The diagnosis of TM was established bronchoscopically in 26 out of 28 children. CRS was significantly smaller in patients (0.59 ± 0.14) compared with controls (0.85 ± 0.11) (P = 0.001). The optimal CSR cut-off point for TM diagnosis, as it was estimated by the ROC curve, was ≤0.705 (95%CI: ≤0.635-≤0.850) with a sensitivity 84.6% (95%CI: 65.1-95.6), and specificity 100.0% (95%CI: 47.8-100.0).

CONCLUSIONS

MDCT can effectively diagnose TM in the majority of children and can be used as an alternative to FB. In children, the established criterion of CSR ≤0.5 should be replaced by CSR ≤0.7 that seems to be a more appropriate threshold.

Diagnostic flexible versus rigid bronchoscopy for the assessment of tracheomalacia in children

OBJECTIVE

This project compares the degree of tracheal collapse determined by rigid and flexible bronchoscopy in paediatric patients with tracheomalacia.

METHODS

A total of nine patients with tracheomalacia underwent both rigid and flexible video bronchoscopy. All patients were breathing spontaneously. Cross-sectional images of the airway were processed using the ImageJ program and analysed via colour histogram mode technique in order to delineate the luminal area. Paired t-tests (conducted using Stata software version 13.0) quantified differences between rigid and flexible bronchoscopes regarding the ratios of luminal pixels at maximum airway collapse to expansion. Correlation between both techniques in terms of airway collapse to expansion ratios was determined by calculating the Pearson correlation coefficient (R).

RESULTS

The difference in ratios of maximum collapse to expansion between rigid and flexible bronchoscopy was not statistically significant (p = 0.4656) and was positively correlated (R = 0.523).

CONCLUSION

The ratios suggest that rigid and flexible bronchoscopy are equally efficacious in assessing tracheomalacia severity, and may be used interchangeably in a clinical setting.

Tracheal collapsibility in adults is dynamic over time

BACKGROUND

Tracheal collapse is a weakness of the tracheal wall leading to expiratory central airway collapse of more than 50% compared to inspiration. It has previously been discussed whether the collapsibility of the greater airways is a stable or a dynamic condition. Indeed, other well-known lung diseases such as asthma are characterized by dynamic changes with respect to pulmonary function indices. There are several different morphologies of the trachea related to collapsibility such as the crescent type and the saber-sheath type both involving the tracheal cartilage and excess dynamic airway collapse only involving the posterior membranous part of the trachea. Is the morphology of the trachea important for the course of the disease? The effect or adverse effects of inhaled corticosteroids are thought to play a role in the increasing incidence of the excess tracheal collapse. In this pilot study, we hypothesized that the excess collapsibility of the tracheal wall is dynamic.

METHODS

We prospectively examined 20 patients with excessive tracheal collapse on previous CT scans performed primarily due to bronchiectasis. A repeat CT scan was performed in order to evaluate the collapsibility. Before the repeat scan, patients were trained in maximal inspiration, expiration and breathholding. CT was performed in full inspiration and at end-expiration. Image assessment was performed on a dedicated CT workstation using standard lung window display settings. The percentage expiratory collapse based on cross sectional areas from carina to the thoracic inlet was calculated. Pulmonary function tests were performed and analysed in accordance with the American Thoracic Society and the European Respiratory Society guidelines.

RESULTS

Repeat CT scan were performed after 24 month +/- 7.2. Six of the 20 participants (30%) were males. Mean age was 67 +/- 11.3 years. Mean FEV1 was 83% of predicted, FVC 96.6 % of predicted and FEV1/FVC-ratio 71%. In 45% of the patients tracheal expiratory collapse improved (by more than 10%) based on percentage change in cross sectional areas in expiration compared to inspiration. 35% of patients showed disease progression with increased collapse and in 20% the collapsibility remained unchanged.

CONCLUSION

We demonstrate that the collapsibility in a large fraction of the patients had actually improved at the follow up examination. We do not find any dependency of the change in collapsibility on the morphology of the trachea after end expiration, use of corticosteroid, or recurrent infections. In addition, no correlation between the changes in collapse and changes in the pulmonary function tests and the symptoms is observed.

First series of minimally invasive, robot-assisted tracheobronchoplasty with mesh for severe tracheobronchomalacia

OBJECTIVE

Tracheobronchomalacia is a progressive, debilitating disease with limited treatment options. Open tracheobronchoplasty (TBP) is an accepted surgical option for management of severe tracheobronchomalacia. This study examined the outcomes of the first reported series of robot-assisted TBP (R-TBP).

METHODS

We retrospectively reviewed the records of patients with clinical suspicion for tracheobronchomalacia who had dynamic computed tomography scan and subsequent R-TBP from May 2016 to December 2017.

RESULTS

Four hundred thirty-five patients underwent dynamic computed tomography scan for suspicion of tracheobronchomalacia. Of this group, 42 patients underwent R-TBP. In the surgery group, the median age was 66 years (interquartile range, 39-72 years) and there were 30 women (71%). Respiratory comorbidities included asthma (88%) and chronic obstructive pulmonary disease (52%). The median operative time was 249 minutes (interquartile range, 266-277 minutes). Median hospital length of stay was 3 days (interquartile range, 2-4.75 days), and there were 19 postoperative complications (11 minor and 8 major). There were no mortalities at 90 days. Comparison of preoperative and postoperative pulmonary function testing demonstrated improvement in forced expiratory volume at 1 second by 13.5% (P = .01), forced vital capacity by 14.5% (P < .0001), and peak expiratory flow rate by 21.0% (P < .0001). Quality of life questionnaires also showed improvement with 82% reporting overall satisfaction with the procedure.

CONCLUSIONS

R-TBP can be performed with low morbidity and mortality. Early follow-up reveals significant improvement in pulmonary function testing and high patient satisfaction when compared with preoperative baseline. Long-term follow-up is needed to demonstrate the durability of R-TBP and substantiate its role in the management of patients with symptomatic, severe tracheobronchomalacia.

Common causes of congenital stridor in infants

Stridor is a high-pitched respiratory sound that signals upper airway obstruction. It can be encountered by clinicians in a variety of clinical settings and requires a team-based, interdisciplinary approach. Early recognition is crucial, as the differential diagnosis can be broad, and causes range from benign to life-threatening. This article reviews the most commonly encountered causes of chronic congenital stridor in infants, focusing on the diagnostic approach, pathophysiology, clinical presentation, and management strategies.

The Prevalence of Gastroesophageal Reflux in Patients With Excessive Central Airway Collapse

BACKGROUND

Gastroesophageal reflux (GER) is increasingly recognized as an exacerbating or causal factor in several respiratory diseases. There is a high prevalence of GER in infants with airway malacia. However, such data are lacking in adults.

METHODS

This retrospective study was conducted to determine the relationship between GER and excessive central airway collapse (ECAC). The study included consecutive patients with ECAC referred to the Complex Airway Center at Beth Israel Deaconess Medical Center who underwent esophageal pH testing for GER between July 2014 and June 2018.

RESULTS

Sixty-three of 139 patients with ECAC (45.3%) had documented GER as shown by an abnormal esophageal pH test result. The mean DeMeester score was 32.2, with a symptom association probability of 39.7% of GER-positive patients. Twenty-nine of 63 patients (46%) with GER reported improvement in respiratory symptoms following maximal medical therapy or antireflux surgery without requiring further treatment for ECAC.

CONCLUSIONS

GER is prevalent among patients with ECAC, and aggressive reflux treatment should be considered in these patients prior to considering invasive airway procedures or surgery.

Comparison of the cuff pressures of a TaperGuard endotracheal tube during ipsilateral and contralateral rotation of the head: A randomized prospective study

BACKGROUND

Maintaining optimal intracuff pressure of the endotracheal tube is important during airway management. Rotation of the head can affect the cuff pressure of the endotracheal tube. We investigated the change in cuff pressure and the degree of tube displacement according to the direction of head rotation (toward the same side vs opposite side of tube fixation) using a TaperGuard endotracheal tube.

METHODS

We conducted a prospective study in 58 patients, aged 18 to 70 years, who underwent tympanomastoidectomy under general anesthesia. TaperGuard endotracheal tube was secured at the corner of the mouth, either on the same side as that of the head rotation (Group S, n = 29) or on the opposite side (Group O, n = 29). After endotracheal intubation, the endotracheal tube cuff pressure was set at 22 cmH2O in the neutral position of the head. The cuff pressure was measured again after lateral rotation of the head and readjusted to 22 cmH2O. In addition, the change in distance from the carina to the tip of the endotracheal tube was measured before and after the change in position. The incidences of cough, sore throat, and hoarseness were assessed at 30 minutes, 6 hours, and 24 hours after surgery.

RESULTS

There were no differences between groups in terms of patient characteristics and duration of anesthesia. The change in cuff pressure after head rotation in Group S (8.07 ± 1.07 cmH2O) was greater than that in Group O (2.24 ± 0.95 cmH2O) (P < .001). In addition, 21 (72.4%) patients in Group S and no patient in Group O had pressures above 30 cmH2O (P < .001). Furthermore, the tube tip moved away from the carina by 8.55 ± 7.01 mm in Group S and by 2.83 ± 4.72 mm in Group O (P < .001).

CONCLUSION

Fixation of the TaperGuard endotracheal tube on the side contralateral to head rotation was associated with a smaller intracuff pressure increase and lesser tube displacement compared to fixation of the tube on the ipsilateral side.

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

PURPOSE

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.

MATERIALS AND METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Addressing Unmet Clinical Needs with 3D Printing Technologies

Recent advances in 3D printing have enabled the creation of novel 3D constructs and devices with an unprecedented level of complexity, properties, and functionalities. In contrast to manufacturing techniques developed for mass production, 3D printing encompasses a broad class of fabrication technologies that can enable 1) the creation of highly customized and optimized 3D physical architectures from digital designs; 2) the synergistic integration of properties and functionalities of distinct classes of materials to create novel hybrid devices; and 3) a biocompatible fabrication approach that facilitates the creation and cointegration of biological constructs and systems. This progress report describes how these capabilities can potentially address a myriad of unmet clinical needs. First, the creation of 3D-printed prosthetics to regain lost functionalities by providing structural support for skeletal and tubular organs is highlighted. Second, novel drug delivery strategies aided by 3D-printed devices are described. Third, the advancement of medical research heralded by 3D-printed tissue/organ-on-chips systems is discussed. Fourth, the developments of 3D-printed tissue and organ regeneration are explored. Finally, the potential for seamless integration of engineered organs with active devices by leveraging the versatility of multimaterial 3D printing is envisioned.

Pediatric tracheomalacia and the perioperative anesthetic management of thoracoscopic posterior tracheopexy

Tracheomalacia is a broad term used to describe an abnormally compliant trachea that can lead to exaggerated collapse and obstruction with expiration. We describe the perioperative management of a complex pediatric patient undergoing a posterior tracheopexy which is a relatively new surgical treatment, with a novel surgical approach-thoracoscopy. This procedure has competing surgical and anesthetic needs and presents unique challenges to the physicians involved in caring for these patients. We also review the current literature on pediatric tracheomalacia and examine the newest treatment options to highlight the potential anesthetic challenges and pitfalls associated with management.

Applications and challenges of using 3D printed implants for the treatment of birth defects

Pediatric implants are a special subclass of a vast number of clinically used medical implants, uniquely designed to address the needs of young patients who are at the onset of their developmental growth stage. Given the vulnerability of the implant receiver, it is crucial that the implants manufactured for small children with birth-associated defects be given careful considerations and great attention to design detail to avoid postoperative complications. In this review, we focus on the most common types of medical implants manufactured for the treatment of birth defects originating from both genetic and environmental causes. Particular emphasis is devoted toward identifying the implant material of choice and manufacturing approaches for the fabrication of pediatric prostheses. Along this line, the emerging role of 3D printing to enable customized implants for infants with congenital disorders is presented, as well as the possible complications associated with prosthetic-related infections that is prevalent in using artificial implants for the treatment of birth malformations.

Etiology and Clinical Characteristics of Community-Acquired Pneumonia with Airway Malacia in Children

OBJECTIVE

The objective of this article is to study the etiology of community-acquired pneumonia in children with airway malacia.

METHODS

We retrospectively reviewed the medical records of 428 pneumonia patients. All patients underwent bronchoscopy, and bronchoalveolar lavage samples were processed for microbiological assessment.

RESULTS

In a total of 428 cases reviewed, 60 were found to have airway malacia. Pathogens were identified in 44 of the 60 specimens (73.3%), with 32 being single-pathogen infections. The most common pathogen was respiratory syncytial virus (RSV; 20%). Mixed-pathogen infections were observed in 12 patients. Airway malacia patients were younger than those without malacia (10.5 vs. 50 months, respectively; p < 0.001). Compared with those without airway malacia, wheezing, cyanosis and admission to the pediatric intensive care unit were more common in children with airway malacia and their hospital stay was longer.

CONCLUSION

RSV was the most common pathogen in those with airway malacia. Airway malacia was found to aggravate infectious pneumonia.

A Case of Tracheomalacia in Chronic Obstructive Pulmonary Disease: What Went Wrong?

Tracheobronchomalacia is defined as loss of the structural integrity of airway wall cartilaginous structures with hyperdynamic airway collapse during respiration. It is a common finding in chronic obstructive pulmonary disease (COPD) but is not always symptomatic, especially if airway narrowing is mild. Symptoms and signs develop as the severity of airway narrowing progresses. When a patient is symptomatic, a prompt study with computerized tomography and flexible bronchoscopy is mandatory for future management. We present a case of tracheobronchomalacia in a patient with COPD whose diagnosis and treatment were challenging.

Synchronized mesenchymal cell polarization and differentiation shape the formation of the murine trachea and esophagus

Tube morphogenesis is essential for internal-organ development, yet the mechanisms regulating tube shape remain unknown. Here, we show that different mechanisms regulate the length and diameter of the murine trachea. First, we found that trachea development progresses via sequential elongation and expansion processes. This starts with a synchronized radial polarization of smooth muscle (SM) progenitor cells with inward Golgi-apparatus displacement regulates tube elongation, controlled by mesenchymal Wnt5a-Ror2 signaling. This radial polarization directs SM progenitor cell migration toward the epithelium, and the resulting subepithelial morphogenesis supports tube elongation to the anteroposterior axis. This radial polarization also regulates esophageal elongation. Subsequently, cartilage development helps expand the tube diameter, which drives epithelial-cell reshaping to determine the optimal lumen shape for efficient respiration. These findings suggest a strategy in which straight-organ tubulogenesis is driven by subepithelial cell polarization and ring cartilage development.

Thoracoscopic posterior tracheopexy during primary esophageal atresia repair: a new approach to prevent tracheomalacia complications

BACKGROUND

Esophageal atresia (EA) is usually accompanied by some form of tracheomalacia (TM). During the early phases in life, excessive dynamic collapse of the trachea can cause a wide spectrum of symptoms ranging from mild complaints to apparent life-threatening events (ALTE's) or brief resolved unexplained events (BRUE's). Therapeutic strategies for severe TM include aortopexy to lift the anterior weakened cartilaginous rings or posterior tracheopexy of the floppy membranous tracheal intrusion. In this study, we describe the development of a new approach in which the posterior tracheopexy is performed directly during the primary thoracoscopic correction of EA.

METHODS

In 2017, all nine consecutive EA patients with trachea-esophageal fistula underwent a rigid tracheo-bronchoscopy (RTB) evaluation during induction of anesthesia prior to the thoracoscopic EA repair. A floppy posterior membrane was diagnosed in four patients. During the subsequent thoracoscopic procedure, the posterior membranous trachea was fixed to the anterior longitudinal spinal ligament with non-absorbable sutures. Then, the anastomosis was made between the two esophageal pouches.

RESULTS

On preoperative RTB, two patients had a severe (70-90%) mid-tracheal collapse of the pars membranacea and two patients had a moderate (33-40%) mid-tracheal collapse. Thoracoscopic posterior tracheopexy with two or three sutures was possible in all four patients, prior to the formation of the esophageal anastomosis. Median time per suture was 6 min (range 4-12 min). All operative procedures were uneventful. A median follow-up of 6 months (range 4-9 months) revealed that all patients showed further recovery without any TM symptoms or ALTE/BRUE.

CONCLUSIONS

This is the first report that introduces a new approach to thoracoscopic posterior tracheopexy during primary EA repair. We believe that this technique can prevent the potentially deleterious sequelae of mild to severe TM that may complicate the lives of EA patients. Also, a second, sometimes complex surgical procedure can be prevented as the posterior tracheopexy is performed during the primary thoracoscopic EA correction.

LEVEL OF EVIDENCE

IV.

Experimental use of new absorbable tracheal stent

BACKGROUND/PURPOSE

Silicone and metallic stents are not effective in children with tracheobronchial stenosis or tracheomalacia. Herein, we aimed to evaluate the clinical manifestations and histological reaction of rabbit trachea to the presence of a new poly(lactic-co-glycolic acid) with polyisoprene (PLGA/PI) polymer absorbable stent.

METHODS

Fourteen adult white rabbits (weight, 3.0-3.5kg) were randomly assigned to three groups: Group I (n=6): PLGA/PI spiral stent; Group II (n=6): PLGA/PI fragment; and Group III (n=2): controls. After a longitudinal incision on three cervical tracheal rings, the stents and fragments were inserted into the trachea and fixed onto the lateral wall with nonabsorbable sutures.

RESULTS

The stented group showed significantly more stridor at rest (p=0.0041), agitation (p=0.014), and use of accessory muscles (p=0.0002) and required more emergency endoscopies than the fragment group. Further, it showed significantly more remarkable histological inflammatory damage than the fragment and control groups (p=0.002).

CONCLUSIONS

The new PLGA/PI polymeric stent implanted into the trachea of rabbits caused more clinical manifestations and histologically verified inflammatory reaction than the PLGA/PI polymeric fragment. Future studies should be aimed at reducing the stent-wall thickness.

Positive airway pressure devices for the management of breathlessness

PURPOSE OF REVIEW

Breathlessness is a common symptom in many chronic diseases and may be refractory to pharmacotherapy. In this review, we discuss the pathophysiology of breathlessness and the role of positive airway pressure (PAP) devices to ameliorate it.

RECENT FINDINGS

Breathlessness is directly related to neural respiratory drive, which can be modified by addressing the imbalance between respiratory muscle load and capacity. Noninvasive PAP devices have been applied to patients limited by exertional breathless and, as the disease progresses, breathlessness at rest. The application of PAP is focussed on addressing the imbalance in load and capacity, aiming to reduce neural respiratory drive and breathlessness. Indeed, noninvasive bi-level PAP devices have been employed to enhance exercise capacity by enhancing pulmonary mechanics and reduce neural drive in chronic obstructive pulmonary disease (COPD) patients, and reduce breathlessness for patients with progressive neuromuscular disease (NMD) by enhancing respiratory muscle capacity. Novel continuous PAP devices have been used to maintain central airways patency in patients with excessive dynamic airway collapse (EDAC) and target expiratory flow limitation in severe COPD.

SUMMARY

PAP devices can reduce exertional and resting breathlessness by reducing the load on the system and enhancing capacity to reduce neural respiratory drive.

Difficulty in tracheal extubation followed by tracheal collapse after balloon dilatation for tracheal stenosis therapy: A case report

RATIONALE

Tracheobronchomalacia (TBM) refers to the weakening trachea or the trachea loss of structural integrity of airway cartilaginous structures. It causes tracheal stenosis, resulting in significantly high rates of mortality. Bronchoplasty by high-pressure balloon dilation under general anesthesia is a simple but effective and safe method to treat tracheobronchial stenosis. However, recurrent postoperative dyspnea after extubation due to tracheal collapse is still a challenge for anesthetists.

PATIENT CONCERNS

A 52-year-old man weighing 72 kg was scheduled for balloon dilatation surgery under general anesthesia because of breathing difficulties caused by tracheal stenosis. His previous medical history included rheumatoid arthritis, obstructive sleep apnea syndrome (OSAS), chronic bronchitis and a history of tracheal intubation. Laryngeal computerized tomography confirmed the stenosis at the level of thyroid gland.

DIAGNOSIS

The tracheal collapse after balloon dilatation for tracheal stenosis therapy.

INTERVENTIONS

Postoperatively, the patient presented with more serious and repetitive symptoms of dyspnea after extubation when compared to that before treatment. So, we had to re-insert the laryngeal mask airway (LMA), and exclude some anesthesia-associated factors, such as laryngospasm, bronchospasm and so on. After a series of treatments, we ultimately found the cause in time (the airway collapsed), and succeeded in tracheal extubation after the stent was inserted.

OUTCOMES

The patient recovered well and reported high satisfaction with anesthesia management.

LESSONS

In such an emergency even, the anesthesiologist should take valuable treatments to ensure the patient's effective ventilation. If the anesthesia-related factors can be eliminated, tracheomalacia or airway collapse should be considered whenever dyspnea occurs in the patients who unexpectedly fail to be extubated.

Tracheobronchial stenting for airway malacia

Tracheobronchomalacia is a rare but clinically troublesome condition in paediatrics. The softening of the major airways - which can include some or all of the tracheobronchial tree can lead to symptoms ranging from the minor (harsh barking cough, recurrent chest infections) to severe respiratory difficulties including prolonged ventilator support and 'near death attacks'. The causes are broadly divided into intrinsic softening of the airway wall which is considered a primary defect (e.g. syndromes; post tracheo-oesophageal fistula repair; extreme prematurity) or secondary malacia due to external compression from vascular structures or cardiac components. These secondary changes can persist even when the external compression is relieved, for example, following the repair of a pulmonary artery sling or double aortic arch. For children with severe clinical symptoms attributed to malacia, consideration is given to possible surgical remedies such as an aortopexy for short limited areas of malacia, or long term positive pressure support with CPAP either by non invasive or tracheostomy interface. More recently the role of stenting in children is receiving attention, especially with the development of newer techniques such as bioabsorbable stents which buy time for a natural history of improvement in the malacia to occur. This paper reviews the stents available and discusses the pros and cons of stenting in paediatric airway malacia.

Computed tomographic and radiographic bronchial collapse may be a normal characteristic of forced expiration in dogs

Tracheobronchomalacia has been diagnosed using radiography or bronchoscopy to confirm bronchial changes in luminal diameter during the respiratory cycle. However, studies in healthy humans suggest that some degree of bronchial collapse may be observed during the normal respiratory cycle. In this analytical study, the luminal diameter of the bronchus to each of the six pulmonary lobes and the mean percentage of expiratory collapse from end inspiratory, end expiratory, and two forced expiratory phases (10 and 15 ml/kg) were determined via computed tomography (CT) and radiography in 22 healthy Beagle dogs. The bronchial collapsibility was significantly greater during the forced expiration than the end expiration (P < 0.001); the same results were observed in dorsal and sagittal CT images and radiographs (P < 0.001). Median collapsibility values associated with 15 ml/kg forced expiratory collapse determined via cross-sectional CT images were measured as 16.6-45.5% and differed according to the pulmonary lobe. Median collapsibilities on radiography with 15 ml/kg forced expiration were 57.8% and 62.1% in the right cranial lobe and right caudal lobe, respectively. In conclusion, bronchial diameter may change during the respiratory cycle, and some degree of reduction in bronchial diameter may be an incidental finding in healthy dogs. More rigorous criteria are needed with regards to bronchial collapsibility during normal respiration for the diagnosis of bronchomalacia in order to avoid false-positive diagnoses.

Airway management during general anesthesia in an intellectually disabled patient with undiagnosed tracheomalacia

In cases of intellectually disabled patients, there is sometimes difficult to obtain sufficient information due to the intellectual disorder, even though the patient has significant medical problems. Herein, we report a case of decreased oxygen saturation and inadequate air exchange during general anesthesia in an intellectually disabled patient. We also describe the subsequent management, including the diagnosis of tracheomalacia (TM) using bronchoscopy, and the management of airway compromise with manual and/or controlled respiration, which led to the prevention of complications.

Laryngomalacia, Tracheomalacia and Bronchomalacia

Airway malacia can occur in the larynx (larygomalacia), trachea (tracheomalacia), or bronchi (bronchomalacia). As a group these are the most common congenital abnormalities of the pediatric airway and are characterized by increased airway compliance, resulting in excessive dynamic collapse during the respiratory cycle. While a diagnosis can be suspected based on clinical history and physical examination, definitive evaluation is based of nasopharyngolaryngoscopy and/or bronchoscopy. Observation and conservative management are typically all that are required. However, surgical intervention can be necessary in the most severe cases, and can result in significant improvement in symptoms.

Effect of idiopathic thoracic scoliosis on the tracheobronchial tree

Introduction

High prevalence of obstructive lung disease has been reported in patients undergoing surgical correction of thoracic scoliosis. Airway narrowing due to spine morphology is analysed as a contributing factor.

Methods

Preoperative surgical planning CTs of 34 patients with right-sided thoracic scoliosis (age: 17.6±9.0) were retrospectively analysed and compared with 15 non-scoliotic controls (age: 16.3±5.1). Three-dimensional models of spine and airway lumen were reconstructed. Based on thoracic sagittal profile, patients were divided into hypokyphosis (HypoS: <10°), normal kyphosis (NormS: ≥10° and <40°) and hyperkyphosis (HyperS: ≥40°) groups. Lumen area of bronchi, bifurcation angles and minimum spine–airway distance were measured. Pulmonary function tests were correlated to scoliosis, kyphosis and lumen area.

Results

Loss of kyphosis led to proximity between bronchus intermedius (BI) and spine. HypoS (NormS) had lumen area reductions in the right main bronchus of 29% (19%), BI of 45% (23%), right middle lobar bronchus of 46% (32%) and right lower lobe bronchus (RLL7) of 66% (37%), respectively (P<0.05). The lower right superior segmental bronchus was reduced across all scoliotic groups (P<0.05). Airways were displaced caudal by 0.65±0.45 vertebra in patients with scoliosis. Loss of kyphosis correlated negatively with forced expiratory volume in 1 s/forced vital capacity (FEV₁/FVC), FVC/(FVC predicted) and FEV₁/(FEV₁ predicted) (P<0.01). Lumen area of trachea, right upper lobar bronchus, BI and RLL7 correlated negatively with FEV₁/FVC. BI and RLL7 narrowing were strong predictors of FVC and FEV₁ loss (P<0.001).

Conclusions

Right-sided main stem airways are narrowed in HypoS and NormS. Loss of kyphosis leads to narrowing of BI and its trifurcation. FEV₁/FVC correlated negatively with airway narrowing, implying an obstructive element to lung function impairment in patients with scoliosis and hypokyphosis.

A novel endobronchial approach to massive hemoptysis complicating silicone Y-stent placement for tracheobronchomalacia: A case report

RATIONALE

Airway stabilization for severe, symptomatic tracheobronchomalacia (TBM) may be accomplished by silicone Y-stent placement. Common complications of the Y-stent include mucus plugging and granulation tissue formation.

PATIENT CONCERNS

We describe a rare case of massive hemoptysis originating from a silicone Y-stent placed for TBM.

DIAGNOSES

An emergent bronchoscopy showed an actively bleeding, pulsatile vessel at the distal end of the left bronchial limb of the Y-stent. It was felt that the bleeding was caused by, or at least impacted by, the distal left bronchial limb of the Y-stent eroding into the airway wall.

INTERVENTIONS

We hypothesized that placement of oxidized regenerated cellulose (ORC) would provide initial hemostasis, and the subsequent placement of a biocompatible surgical sealant would lead to definitive resolution.

OUTCOMES

ORC provided sufficient hemostasis and the subsequent synthetic polymer reinforced the tissue for complete cessation of the bleed.

LESSONS

The combined use of ORC and a biocompatible surgical sealant provided long-term management for life-threatening hemoptysis, and potentially morbid procedures such as embolization or surgery were avoided by advanced endobronchial therapy.

Posterior Tracheopexy for Severe Tracheomalacia Associated with Esophageal Atresia (EA): Primary Treatment at the Time of Initial EA Repair versus Secondary Treatment

Purpose

We review outcomes of posterior tracheopexy for tracheomalacia in esophageal atresia (EA) patients, comparing primary treatment at the time of initial EA repair versus secondary treatment.

Methods

All EA patients who underwent posterior tracheopexy from October 2012 to September 2016 were retrospectively reviewed. Clinical symptoms, tracheomalacia scores, and persistent airway intrusion were collected. Indication for posterior tracheopexy was the presence of clinical symptoms, in combination with severe tracheomalacia as identified on bronchoscopic evaluation, typically defined as coaptation in one or more regions of the trachea. Secondary cases were usually those with chronic respiratory symptoms who underwent bronchoscopic evaluation, whereas primary cases were those found to have severe tracheomalacia on routine preoperative dynamic tracheobronchoscopy at the time of initial EA repair.

Results

A total of 118 patients underwent posterior tracheopexy: 18 (15%) primary versus 100 (85%) secondary cases. Median (interquartile range) age was 2 months (1–4 months) for primary (22% type C) and 18 months (8–40 months) for secondary (87% type C) cases (p < 0.001). There were statistically significant improvements in most clinical symptoms postoperatively for primary and secondary cases, with no significant differences in any postoperative symptoms between the two groups (p > 0.1). Total tracheomalacia scores improved significantly in primary (p = 0.013) and secondary (p < 0.001) cases. Multivariable Cox regression analysis indicated no differences in persistent airway intrusion requiring reoperation between primary and secondary tracheopexy adjusting for imbalances in age and EA type (p = 0.67).

Conclusion

Posterior tracheopexy is effective in treating severe tracheomalacia with significant improvements in clinical symptoms and degree of airway collapse on bronchoscopy. With no significant differences in outcomes between primary and secondary treatment, posterior tracheopexy should be selectively considered at the time of initial EA repair.

Dynamic expiratory CT: An effective non-invasive diagnostic exam for fragile children with suspected tracheo-bronchomalacia

BACKGROUND

Tracheobronchomalacia, defined as variable collapse of the airways, has been recognized as an important cause of respiratory morbidity but still widely underdiagnosed. Bronchoscopy is still considered as the gold standard, but numerous limitations are known, especially for fragile sick children. Moreover, information on parenchymal lung disease cannot be described. There is a real need for a reliable, non-invasive test to help detection of airway and parenchymal malformations in children, specifically when bronchoscopy cannot be performed.

METHODS AND RESULTS

34 paediatric patients underwent cine multidector CT for ongoing respiratory symptoms and were included. All CT images were of good quality and sedation was never needed. Airway disease such as trachea-broncomalacia with/without stenosis was described in 53% with the first being more frequent. Bronchomalacia alone was described in 10 patients and in 4 patients was associated with tracheomalacia. Moreover, CT allowed identification of parenchymal disease in 10 patients. Airways stenosis alone was detected in seven patients. The majority of patients (85%) underwent also bronchoscopy for clinical decision. The agreement between CT and bronchoscopy was explored. The two examinations did not agree only in two cases. CT dynamic showed an excellent sensitivity of 100% (81.47-100 %), a great specificity of 82% (48.22-97.72 %), NPV 100%, and PPV 90% (72-96.9 %).

CONCLUSION

Dynamic CT results an effective and highly sensitive diagnostic exam for children with tracheo-bronchomalacia. CT is especially indicated for those small and fragile patients that cannot undergo an invasive investigation. Moreover, CT allows a detailed evaluation both of the airways and the lungs which is useful for the clinical management.

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

Background: The gold standard for diagnosing excessive tracheal collapse is still evaluation during bronchoscopy. Today, multidetector computed tomography (MDCT) is used to confirm a suspicion of abnormal tracheal collapse. There is no gold standard for computed tomography (CT) image analysis of tracheal collapse.

Purpose: To evaluate four different methods for the diagnosis of tracheal collapse using the images obtained through MDCT to help clinicians evaluate the images in daily practice.

Objectives: 374 consecutive high-resolution CT scans with full inspiratory and end-expiratory CT scans were retrospectively analyzed.

Methods: The images were analyzed in four different ways. The degree of collapse was based on cross-sectional areas of individual locations or volumes of entire regions: (1) 1 cm above the carina, (2) the level of maximal collapse of the trachea, (3) the entire region from the carina to the thoracic inlet, and (4) the trachea and bronchial region as defined by the software.

Results: We compared three existing and one new method for image analysis of tracheal collapse by MDCT. The prevalence of tracheal collapse varied from 10.7% to 19.5% in this cohort of patients suffering from mixed lung diseases when using an expiratory collapse of ≥50% as a threshold. The four methods were comparable with highly significant Pearsons correlation coefficients (0.764–0.856). However, the four methods identified different patients with collapse of ≥50%. There was no correlation between symptoms and the degree of collapse.

Conclusion: The different methods identify tracheal collapse in different patients. Hence, the diagnosis of excessive tracheal collapse can not rely solely on MDCT images. Generally, there is a poor correlation between symptoms and the degree of collapse in the different methods. However, when using the maximal collapse, there is some correlation with symptoms. When in doubt regarding the diagnosis, further investigations, such as bronchoscopy, should be carried out.

[Characteristics of tidal breathing pulmonary function in children with tracheobronchomalacia]

OBJECTIVE

To investigate the characteristics of tidal breathing pulmonary function in children with tracheobronchomalacia (TBM).

METHODS

In this study, 30 children who were diagnosed with TBM using electronic bronchoscopy were enrolled in the observation group; 30 healthy children were recruited in the normal control group. For individuals in each group, the assessment of tidal breath pulmonary function was performed at diagnosis and 3, 6, 9, and 12 months after diagnosis.

RESULTS

There were no significant differences in tidal volume, inspiratory time, expiratory time, and inspiratory to expiratory ratio between the two groups (P>0.05). Compared with the control group, the observation group had a significantly higher respiratory rate and significantly lower ratio of time to peak tidal expiratory flow to total expiratory time (TPTEF/TE) and ratio of volume to peak tidal expiratory flow to total expiratory volume (VPTEF/VE). There was a time-dependent increase in TPTEF/TE and VPTEF/VE for TBM children from the time of initial diagnosis to 12 months after diagnosis.

CONCLUSIONS

Tidal breathing pulmonary function has characteristic changes in children with TBM. Tidal breathing pulmonary function tends to be recovered with increased age in children with TBM.

Thoracic Surgery Considerations in the Child and Young Adult

Vascular rings and slings may represent life-threatening compression of the esophagus and trachea. Such anatomic variants, although rare, are encountered by all thoracic surgeons in the scope of their practice at some time. The thoracic surgeon, whether treating such patients in the practice of congenital heart surgery, or in the practice of adult cardiac or thoracic surgery must have a requisite understanding of such anatomic variants, their diagnostic workup and radiologic interpretation, as well as their surgical management. Primary tracheobronchial disorders are also frequently encountered in the scope of a thoracic surgical practice and also are discussed.

Management of the Critically Ill Adult With Congenital Heart Disease

Survival of adults with congenital heart disease (CHD) has improved significantly over the last 2 decades, leading to an increase in hospital and intensive care unit (ICU) admissions of these patients. Whereas most of the ICU admissions in the past were related to perioperative management, the incidence of medical emergencies from long-term sequelae of palliative or corrective surgical treatment of these patients is rising. Intensivists now are confronted with patients who not only have complex anatomy after congenital cardiac surgery, but also complex pathophysiology due to decades of living with abnormal cardiac anatomy and diseases of advanced age. Comorbidities affect all organ systems, including cognitive function, pulmonary and cardiovascular systems, liver, and kidneys. Critical care management requires an in-depth understanding of underlying anatomy and pathophysiology in order to apply contemporary concepts of adult ICU care to this population and optimize patient outcomes. In this review, the main CHD lesions and their common surgical management approaches are described, and the sequelae of CHD physiology are discussed. In addition, the effects of chronic comorbidities on the management of critically ill adults are explored, and the adjustments of current ICU management modalities and pharmacology to optimize care are discussed.

Respiratory Morbidity in Children with Repaired Congenital Esophageal Atresia with or without Tracheoesophageal Fistula

Congenital esophageal atresia with or without tracheoesophageal fistula (CEA ± TEF) is a relatively common malformation that occurs in 1 of 2500–4500 live births. Despite the refinement of surgical techniques, a considerable proportion of children experience short- and long-term respiratory complications, which can significantly affect their health through adulthood. This review focuses on the underlying mechanisms and clinical presentation of respiratory morbidity in children with repaired CEA ± TEF. The reasons for the short-term pulmonary impairments are multifactorial and related to the surgical complications, such as anastomotic leaks, stenosis, and recurrence of fistula. Long-term respiratory morbidity is grouped into four categories according to the body section or function mainly involved: upper respiratory tract, lower respiratory tract, gastrointestinal tract, and aspiration and dysphagia. The reasons for the persistence of respiratory morbidity to adulthood are not univocal. The malformation itself, the acquired damage after the surgical repair, various co-morbidities, and the recurrence of lower respiratory tract infections at an early age can contribute to pulmonary impairment. Nevertheless, other conditions, including smoking habits and, in particular, atopy can play a role in the recurrence of infections. In conclusion, our manuscript shows that most children born with CEA ± TEF survive into adulthood, but many comorbidities, mainly esophageal and respiratory issues, may persist. The pulmonary impairment involves many underlying mechanisms, which begin in the first years of life. Therefore, early detection and management of pulmonary morbidity may be important to prevent impairment in pulmonary function and serious long-term complications. To obtain a successful outcome, it is fundamental to ensure a standardized follow-up that must continue until adulthood.

Wheezing in Infancy: An Overview of Recent Literature

PURPOSE OF REVIEW

Wheezing in infancy is a common presentation with many potential causes. In writing this review, we sought to summarize the newest recommendations and testing available for the more common etiologies of wheezing.

RECENT FINDINGS

Regarding the diagnosis of asthma, the modified asthma predictive index has recently been established as a useful predictive tool. Non-breath held multidetector CT with 3D volume rendering airway images is also a newer helpful diagnostic tool for tracheomalacia due to ease of use and its 100% positive predictive value. We found vaccines have greatly reduced the prevalence of epiglottitis, while advances in surgery are improving outcomes in infants with vascular rings. Wheezing in infants is a common problem with an extensive differential diagnosis from relatively benign to life threatening. To prevent over-looking a diagnosis that potentially requires surgical correction or emergent care, we recommend a structured approach to the history and physical exam with targeted testing directed towards the most likely diagnoses as outlined in this review.

Long-term outcomes of complete vascular ring division in children: a 36-year experience from a single institution

Objectives

Complete vascular rings are rare and cause tracheoesophageal compression. Following surgical division, some patients have persisting tracheomalacia. We aim to assess the long-term outcomes of complete vascular ring division.

Methods

All patients (n = 132) who underwent surgical division of a complete vascular ring between 1978 and 2014 were identified from the hospital database and retrospectively reviewed.

Results

Complete vascular rings consisted of a double aortic arch (n = 80), right aortic arch with an aberrant subclavian artery and left ligamentum arteriosum (n = 50), right aortic arch with mirror image branching and left ligamentum arteriosum (n = 1), and a left aortic arch with right descending aorta and right ligamentum arteriosum (n = 1). Kommerell's diverticulum was identified in 10 patients. Preoperative tracheomalacia was identified via bronchoscopy in 25 patients. Concomitant tracheal reconstruction was not performed in any patient. Kommerell's diverticulum was resected in 1 patient. The hospital mortality rate was 1.5% (2/132). There were no late deaths. The overall survival rate was 98.3 ± 1.2% (95% CI: 93.4, 99.6) at 20 years. Postoperatively, persistent tracheal compression was reported in 3 patients, and tracheomalacia in 16 patients. The rate of freedom from reoperation was 88.6 ± 4.0% (95% CI: 77.9, 94.3) at 20 years. No patient required tracheal surgery during the follow-up period. Follow-up was 92% (121/132) complete, with a median follow-up of 11.4 years (range 44 days to 36 years). At the last follow-up, 7 patients had mild tracheomalacia.

Conclusions

Outcomes of division of a complete vascular ring are excellent. Tracheomalacia often improves following division of the vascular ring. Respiratory symptoms following complete vascular ring division are uncommon.

Tracheobronchopathy From Inhaled Corticosteroids

Inhaled corticosteroids (ICSs) have become the mainstay of asthma control. They are also recommended as an add-on therapy to long-acting beta agonists and anticholinergics in moderate to severe COPD with recurrent exacerbations. Ultimately this clinical practice has led to the widespread use of ICSs, which are supported by a more favorable side effect profile than that of systemic steroids.