Pediatric tracheobronchomalacia and major airway collapse

Paediatric tracheobronchomalacia: Incidence, patient characteristics, and predictors of surgical intervention

OBJECTIVES

Tracheobronchomalacia (TBM), a condition where an abnormality of the tracheal walls causes collapse during the respiratory cycle, is a common cause of airway obstruction in childhood. TBM can present with a large spectrum of disease severity and underlying pathologies that may be managed medically and surgically, and it is not always clear which patients would most benefit from surgical intervention. We aim to describe the incidence, patient characteristics, and predictors of surgical intervention in a large cohort of paediatric patients.

METHODS

We performed a retrospective review of all children diagnosed with TBM to a paediatric Otolaryngology unit in the west of Scotland between 2010 and 2020. Odds ratios for clinical predictors of surgery were calculated using logistic regression with uni- and multivariate analysis.

RESULTS

249 patients were identified of which 219 proceeded to data collection. Primary malacia was noted in 161 (73.5%) and secondary in 58 (26.5%). Causes of secondary malacia included compression by the innominate artery (11%) and vascular rings (7.8%). Surgical interventions were performed in 28 patients (12.8%) including division of vascular ring, aortopexy, and surgical tracheostomy. Multivariate analysis showed secondary TBM, acute life-threatening events, and difficulty weaning from mechanical ventilation were independent risk factors for surgical intervention.

CONCLUSIONS

TBM can present with a myriad of airway symptoms and is frequently associated with other airway and mediastinal pathologies necessitating multiple interventions. Children aged <1 year present with a more severe form of the disease and the presence of particular independent risk factors may indicate a need for surgical intervention.

Cleft-lip-plate patient with tracheobronchomalacia: A case report and review of the literature in Japan

Background

Tracheobronchomalacia (TBM) is a severe life-threatening perioperative complication. It is a rare condition caused by congenital and developmental anomalies of the trachea and/or the bronchus. It is often difficult to diagnose TBM before surgery as this congenital disease presents very few symptoms preoperatively and most often appears postoperatively.

Case presentation and Review

The study describes a case of cleft-lip-plate (CL/P) in a 7-month-old Japanese female with TBM and Tetralogy of Fallot syndrome. Before undergoing cleft-lip surgery, her TBM was not fully elucidated by preoperative examinations, and the operation was completed uneventfully. After the surgery, however, she started showing severe respiratory distress and developed hypoxia and bradycardia in the operating room. CPR was performed successfully, but a bronchoscopy revealed a severely collapsed airway, and the pathological condition was diagnosed as TBM occurred postoperatively. Eight months later, she died of sudden respiratory failure similar to that of the postoperative event caused by TBM. A literature review was conducted on the complications of CL/P from 1990 to 2017 in Japan.

Conclusions

It was hypothesized that CL/P with congenital heart disease (CHD) and TBM with CHD may crossover in relatively high rates. Currently, there are very few solutions available to treat severe airway obstruction related to TBM. This highlights the need for preoperative diagnosis of TBM as an important step in overcoming severe airway complications.

An Update on Tracheal and Airway Collapse in Dogs

Tracheal and airway collapse (bronchomalacia) are common causes of chronic cough in middle-aged to older dogs in which weakening of cartilage within the respiratory system leads to narrowing of airways, irritation, inflammation, partial to complete airway obstruction, and other secondary effects. Tracheomalacia occurs in small-breed dogs, whereas bronchomalacia can occur in any size dog. Successful treatment involves correct identification of the problem, recognition of concurrent disease processes, and appropriate medical therapy. Surgical intervention and intraluminal stenting are readily available so it is important to understand indications for such procedures.

Ultrashort Echo-Time MRI for the Assessment of Tracheomalacia in Neonates

BACKGROUND

Bronchoscopy is the gold standard for evaluating tracheomalacia; however, reliance on an invasive procedure limits understanding of normal airway dynamics. Self-gated ultrashort echo-time MRI (UTE MRI) can assess tracheal dynamics but has not been rigorously evaluated.

METHODS

This study was a validation of UTE MRI diagnosis of tracheomalacia in neonates using bronchoscopy as the gold standard. Bronchoscopies were reviewed for the severity and location of tracheomalacia based on standardized criteria. The percent change in cross-sectional area (CSA) of the trachea between end-inspiration and end-expiration was determined by UTE MRI, and receiver-operating curves were used to determine the optimal cutoff values to predict tracheomalacia and determine positive and negative predictive values.

RESULTS

Airway segments with tracheomalacia based on bronchoscopy had a more than threefold change in CSA measured from UTE MRI (54.4 ± 56.1% vs 14.8 ± 19.5%; P < .0001). UTE MRI correlated moderately with bronchoscopy for tracheomalacia severity (ρ = 0.39; P = .0001). Receiver-operating curves, however, showed very good ability of UTE MRI to identify tracheomalacia (area under the curve, 0.78). A "loose" definition (> 20% change in CSA) of tracheomalacia had good sensitivity (80%) but low specificity (64%) for identifying tracheomalacia based on UTE MRI, whereas a "strict" definition (> 40% change in CSA) was poorly sensitive (48%) but highly specific (93%).

CONCLUSIONS

Self-gated UTE MRI can noninvasively assess tracheomalacia in neonates without sedation, ionizing radiation, or increased risk. This technique overcomes major limitations of other diagnostic modalities and may be suitable for longitudinal population studies of tracheal dynamics.

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.

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.

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.

Bronchoscopic assessments and clinical outcomes in pediatric patients with tracheomalacia and bronchomalacia

BACKGROUND

Tracheomalacia and bronchomalacia (TM/BM) are one of the serious causes of airway obstruction in infants and children. This study reviewed our bronchoscopic assessments and clinical outcomes in pediatric patients with TM/BM, and investigated risk factors of surgical intervention for TM/BM.

METHODS

Fifty-seven consecutive patients who were diagnosed as TM/BM by bronchoscopy between 2009 and 2013 were reviewed retrospectively. They were divided into two groups according to the presence (group E, n = 26) or absence (group N, n = 31) of acute life-threatening events and extubation failure (ALTE/EF). The severity of TM/BM was evaluated by Oblateness Index which was obtained from bronchoscopic images.

RESULTS

Oblateness Index was significantly higher in Group E than in Group N. Patients in Group E underwent surgical intervention for TM/BM more frequently, and had significantly longer intubation period and hospital stay. Clinical symptoms of ALTE/EF, Oblateness Index ≥ 0.70, and multiple malacic lesions were significant risk factors indicating surgical events in patients with TM/BM.

CONCLUSIONS

Patients with TM/BM who had ALTE/EF had more severe malacic lesions indicating surgical intervention, and worse clinical outcomes. Oblateness Index is a simple and semi-quantitative index for bronchoscopic assessment of TM/BM, and can be one of the prognostic tools to predict clinical severity of pediatric TM/BM.

Effect of Prenatal versus Postnatal Vitamin D Deficiency on Pulmonary Structure and Function in Mice

Epidemiologic studies have linked gestational vitamin D deficiency to respiratory diseases, although mechanisms have not been defined. We hypothesized that antenatal vitamin D deficiency would impair airway development and alveolarization in a mouse model. We studied the effect of antenatal vitamin D deficiency by inducing it in pregnant mice and then compared lung development and function in their offspring to littermate controls. Postnatal vitamin D deficiency and sufficiency models from each group were also studied. We developed a novel tracheal ultrasound imaging technique to measure tracheal diameter in vivo. Histological analysis estimated tracheal cartilage total area and thickness. We found that vitamin D-deficient pups had reduced tracheal diameter with decreased tracheal cartilage minimal width. Vitamin D deficiency increased airway resistance and reduced lung compliance, and led to alveolar simplification. Postnatal vitamin D supplementation improved lung function and radial alveolar count, a parameter of alveolar development, but did not correct tracheal narrowing. We conclude that antenatal vitamin D deficiency impairs airway and alveolar development and limits lung function. Reduced tracheal diameter, cartilage irregularity, and alveolar simplification in vitamin D-deficient mice may contribute to increased airways resistance and diminished lung compliance. Vitamin D supplementation after birth improved lung function and, potentially, alveolar simplification, but did not improve defective tracheal structure. This mouse model offers insight into the mechanisms of vitamin D deficiency-associated lung disease and provides an in vivo model for investigating preclinical preventive and therapeutic strategies.

Tracheobronchomalacia Is Associated with Increased Morbidity in Bronchopulmonary Dysplasia

RATIONALE

Tracheobronchomalacia is a common comorbidity in neonates with bronchopulmonary dysplasia. However, the effect of tracheobronchomalacia on the clinical course of bronchopulmonary dysplasia is not well-understood.

OBJECTIVE

We sought to assess the impact of tracheobronchomalacia on outcomes in neonates with bronchopulmonary dysplasia in a large, multi-center cohort.

METHODS

We preformed a cohort study of 974 neonates with bronchopulmonary dysplasia admitted to 27 neonatal intensive care units participating in the Children's Hospital Neonatal Database who had undergone bronchoscopy. In hospital morbidity for neonates with bronchopulmonary dysplasia and tracheobronchomalacia (N=353, 36.2%) was compared to those without tracheobronchomalacia (N=621, 63.8%) using mixed-effects multivariate regression.

RESULTS

Neonates with tracheobronchomalacia and bronchopulmonary dysplasia had more comorbidities, such as gastroesophageal reflux (OR=1.65, 95%CI 1.23- 2.29, P=0.001) and pneumonia (OR=1.68, 95%CI 1.21-2.33, P=0.002) and more commonly required surgeries such as tracheostomy (OR=1.55, 95%CI 1.15-2.11, P=0.005) and gastrostomy (OR=1.38, 95%CI 1.03-1.85, P=0.03) compared with those without tracheobronchomalacia. Neonates with tracheobronchomalacia were hospitalitized (118 ± 93 vs 105 ± 83 days, P=0.02) and ventilated (83.1 ± 91.1 vs 67.2 ± 71.9 days, P=0.003) longer than those without tracheobronchomalacia. Upon discharge, neonates with tracheobronchomalacia and BPD were more likely to be mechanically ventilated (OR=1.37, 95CI 1.01-1.87 P=0.045) and possibly less likely to receive oral nutrition (OR=0.69, 95%CI 0.47-1.01, P=0.058).

CONCLUSIONS

Tracheobronchomalacia is common in neonates with bronchopulmonary dysplasia who undergo bronchoscopy and is associated with longer and more complicated hospitalizations.

Tracheobronchomalacia

The term tracheobronchomalacia refers to excessively compliant and collapsible central airways leading to symptoms. Although seen as a coexisting condition with various other pulmonary condition, it may cause symptoms by itself. The condition is often misdiagnosed as asthma, bronchitis or just chronic cough due to a lack of specific pathognomonic history and clinical findings. The investigation revolves around different modes of imaging, lung function testing and usually confirmed by flexible bronchoscopy. The treatment widely varies based on the cause, with most cases treated conservatively with non-invasive ventilation. Some may require surgery or stent placement. In this article, we aim to discuss the pathophysiology behind this condition and recognize the common symptoms and causes of tracheobronchomalacia. The article will highlight the diagnostic steps as well as therapeutic interventions based on the specific cause.

Pediatric tracheomalacia

Tracheomalacia (TM) is defined as an increased collapsibility of the trachea due to structural anomalies of the tracheal cartilage and/or posterior membrane. Tracheomalacia has a wide range of etiologies but is most commonly present in children born with esophageal atresia and tracheal esophageal fistula. Clinical symptoms can range from minor expiratory stridor with typical barking cough to severe respiratory distress episodes to acute life-threatening events (ALTE). Although the majority of children have mild-to-moderate symptoms and will not need surgical intervention, some will need life-changing surgical treatment. This article examines the published pediatric literature on TM, discusses the details of clinical presentation, evaluation, diagnosis, and a variety of treatments.

Paediatric Tracheomalacia

Intrathoracic tracheomalacia is characterized by increased compliance of the central airway within the thorax. This leads to excessive dynamic collapse during exhalation or periods of increased intrathoracic pressure such as crying. Extrathoracic tracheomalacia involves dynamic collapse of the airway between the glottis and sternal notch that occurs during inhalation rather than exhalation. The tone of the posterior membrane of the trachea increases throughout development and childhood, as does the rigidity of the tracheal cartilage. Abnormalities of airway maturation result in congenital tracheomalacia. Acquired tracheomalacia occurs in the normally developed trachea due to trauma, external compression, or airway inflammation. Although tracheomalacia can be suspected by history, physical examination, and supportive radiographic findings, flexible fiberoptic bronchoscopy remains the "gold standard" for diagnosis. Current treatment strategies involve pharmacotherapy with cholinergic agents, positive pressure ventilation, and surgical repair.

Tracheal and airway collapse in dogs

Tracheal and airway collapse (bronchomalacia) are common causes of chronic cough in middle-aged to older dogs where weakening of cartilage within the respiratory system leads to narrowing of airways, coughing, wheezing, and other secondary effects. Successful treatment involves correct identification of the problem, recognition of concurrent problems, and appropriate medical therapy. Surgical and noninvasive treatment options are becoming readily available, and it is important to understand indications for such procedures.

Chronic cough in preschool children

Cough may be the first overt sign of disease of the airways or lungs when it represents more than a defense mechanism, and may by its persistence become a helpful pointer of potential disease for both patient and physician. On the other hand, impairment or absence of the coughing mechanism can be harmful and even fatal; this is why cough suppression is rarely indicated in childhood. Pediatricians are concerned more with the etiology of the cough and making the right diagnosis. Whereas chronic cough in adults has been universally defined as a cough that lasts more than 8 weeks, in childhood, different timing has been reported. Many reasons support defining a cough that lasts more than 4 weeks in preschool children as chronic, however; and this is particularly true when the cough is wet. During childhood, the respiratory tract and nervous system undergo a series of anatomical and physiological maturation processes that influence the cough reflex. In addition, immunological response undergoes developmental and memorial processes that make infection and congenital abnormalities the overwhelming causes of cough in preschool children. Cough in children should be treated on the basis of etiology, and there is no evidence in support of the use of medication for symptomatic cough relief or adopting empirical approaches. Most cases of chronic cough in preschool age are caused by protracted bacterial bronchitis, tracheobronchomalacia, foreign body aspiration, post-infectious cough or some combination of these. Other causes of chronic cough, such as bronchiectasis, asthma, gastroesophageal reflux, and upper respiratory syndrome appear to be less frequent in this age group. The prevalence of each depends on the population in consideration, the epidemiology of infectious diseases, socioeconomic aspects, and the local health system.

Evolution of acquired tracheobronchomalacia in an infant studied by multidetector computed tomography

Acquired tracheobronchomalacia (TBM) is an uncommon complication of severe lung disease in infancy. We report a case of TBM in an ex-premature infant with severe chronic lung disease (CLD). Multidetector computed tomography (MDCT) was used to dynamically assess the patency of the large airways at different time periods during the infant's hospital course. Initially at 3 months of age, the airways maintained patency during both phases of the respiratory cycle, but at 6 months of age, diffuse TBM was evident on MDCT. Appropriate management with long-term positive end expiratory pressure (PEEP) was initiated for the infant once the diagnosis of acquired TBM was confirmed. The case highlights the efficacy and relative ease of early diagnosis of acquired TBM by MDCT in infants at risk of this condition.

Slow release of basic fibroblast growth factor (b-FGF) promotes growth of tracheal cartilage

PURPOSE

Tracheomalacia is a major cause of morbidity in conditions such as oesophageal atresia. However, symptoms usually improve with age. A more rapid growth of tracheal cartilage can be induced by basic-Fibroblast Growth Factor (b-FGF). This study aimed to investigate whether slow-release b-FGF could act as a novel treatment for tracheomalacia.

METHODS

Biodegradable gelatin hydrogel sheets incorporating 0.5, 5, or 50 μg/20 μl of b-FGF solution were inserted between the cervical trachea and esophagus of rats. No intervention was performed in rats in a control group. All animals were sacrificed 4 weeks later, and the luminal area of the cervical trachea and the thickness of the cartilage were measured.

RESULTS

The mean luminal areas in the control group and in the b-FGF groups were 3.1, 3.2, 3.8, and 2.6mm(2), respectively, and showed a peak area at 5 μg of b-FGF. A significant difference was seen only between the control group and the b-FGF 5 μg group (p<0.05). The mean thickness of the tracheal cartilage was 0.12, 0.13, 0.19, and 0.32 mm in the control and the b-FGF groups, respectively, and showed a dose-dependent increase, which was statistically significant between the b-FGF 5 μg or 50 μg groups and the control group (p<0.01).

CONCLUSION

This study showed that slow-release b-FGF enlarges the tracheal lumen and thickens the cartilage in a dose-dependent fashion.

Intrathoracic airway obstruction and gastroesophageal reflux: a canine model

INTRODUCTION

Gastroesophageal reflux (GER) is common in children with airway disorders. Previous studies have shown an association between upper airway obstruction and GER in experimental animal models. However, the cause and effect relationship between intrathoracic airway obstruction (IAO) and GER is obscure. The goal of this study is to investigate the association between IAO and GER using the canine model.

METHODS

In sedated dogs, a telemetric implant was placed subcutaneously (with one pressure sensor tip each in intrapleural space and abdomen) to monitor intrapleural pressure (IPP) and intrabdominal pressure (IAP). The IPP and the IAP were monitored intraoperatively and in conscious dogs on the 7th to 10th postoperative days. GER was assessed by determining the reflux index (RI), based on the intraesophageal pH recording performed continuously for a 24 hr period using a pH probe. After 2-3 weeks following placement of the telemetric implant, IAO was surgically created in the dog. After maintaining IAO for 2 weeks, the IPP, IAP, and pH measurements were monitored again following the same protocol as before IAO.

RESULTS

After the creation of IAO, there was no significant change observed in the mean RI either in the distal (P = 0.716) or proximal (P = 0.962) esophageal lumens. The IPP became significantly more negative (P = 0.006) and the IAP turned significantly negative (P < 0.001) from being positive compared to the respective values before IAO. However, transdiaphragmatic pressure (Pdi) did not change significantly (P = 0.08).

CONCLUSION

We conclude that moderate IAO does not cause GER in our animal model. It can be explained by the absence of significant change in Pdi after creation of IAO.

Tracheobronchomalacia in children: review of diagnosis and definition

Tracheobronchomalacia is characterised by excessive airway collapsibility due to weakness of airway walls and supporting cartilage. The standard definition requires reduction in cross-sectional area of at least 50% on expiration. However, there is a paucity of information regarding the normal range of central airway collapse among children of varying ages, ethnicities and genders, with and without coexisting pulmonary disease. Consequently, the threshold for pathological collapse is considered somewhat arbitrary. Available methods for assessing the airway dynamically--bronchoscopy, radiography, cine fluoroscopy, bronchography, CT and MR--have issues with reliability, the need for intubation, radiation dose and contrast administration. In addition, there are varying means of eliciting the diagnosis. Forced expiratory manoeuvres have been employed but can exaggerate normal physiological changes. Furthermore, radiographic evidence of tracheal compression does not necessarily translate into physiological or functional significance. Given that the criteria used to make the diagnosis of tracheobronchomalacia are poorly validated, further studies with larger patient samples are required to define the threshold for pathological airway collapse.

Pulmonary function and long-term follow-up of children with tracheobronchomalacia

BACKGROUND

Primary tracheobronchomalacia (TBM) is a disease of the large airways. Long-term follow-up studies of TBM patients have not been reported. This study was undertaken to further elicit the natural history of this condition and the presence of concomitant reactive airways disease through clinical profiling and pulmonary function testing.

METHODS

Twenty-one children diagnosed with TBM by bronchoscopy between 1998 and 2001 in Queensland were recruited in 2008. Parents completed a questionnaire detailing their child's respiratory symptoms over the previous 12 months. Children then undertook pulmonary function and flow-volume loop classification. Mannitol bronchial provocation testing or post-bronchodilator spirometry was performed to assess for the confounding presence of reactive airways disease.

RESULTS

Data from 19 children (12 males) were able to be analyzed. The median age was 9.4 (range 7.6-14.3) years. 15 parents indicated their child's symptoms were unresolved. The mean FEV(1) was 81% predicted with 7 <80% predicted. This was significantly lower than the percent predicted population mean (P = 0.0005). Mean FEV(1) /FVC, FEF(25-75) , and PEF were also significantly reduced (P = < 0.0001). Four participants had a classical TBM flow-volume loop on analysis. One of 15 (6.7%) participants recorded a positive test for reactive airways disease.

CONCLUSIONS

Clinical symptom profiles and pulmonary function indicate persistent functional mechanical abnormalities of the large and small airways in TBM patients, and the absence of reactive airways disease.

A comparison of fluoroscopic airway screening with flexible bronchoscopy for diagnosing tracheomalacia

BACKGROUND

Flexible bronchoscopy (FB) is the gold standard method of diagnosing tracheomalacia but it is not always feasible in settings with limited resources. Fluoroscopy is sometimes performed as an alternative diagnostic tool but there are no prospective studies that have evaluated the diagnostic accuracy of airway fluoroscopy for tracheomalacia using a-priori definitions. We determined the sensitivity, specificity, and likelihood predictive ratio of airway fluoroscopy compared with FB in children suspected of having an airway abnormality.

METHODS

Airway fluoroscopic examination was undertaken within 2-weeks of a FB in children aged <18-years and reported by a pediatric radiologist blinded to FB data. Fluoroscopic and FB methods and diagnostic criteria were standardized and defined a-priori. Tracheomalacia diagnosed by FB were independently scored (mild, moderate, severe) by 2 pulmonologists in a blinded manner.

RESULTS

In 22 children (median age 33 months, range 1-187) evaluated for airway abnormality, tracheomalacia was found in 21 children at bronchoscopy. Of these, fluoroscopy detected tracheomalacia in five children. Airway fluoroscopy was poorly sensitive (23.8%) but highly specific (100%), positive likelihood ratio was 8.6. However, in moderate-severe tracheomalacia, the sensitivity improved to 57.1% but the specificity reduced (93.3%). The agreement between bronchoscopists for tracheomalacia severity was excellent, weighted kappa 0.74 (95% CI 0.77, 0.98).

CONCLUSION

Airway fluoroscopy cannot replace FB which remains the tool for definitively diagnosing airway malacia. However, in absence of other modalities for diagnosis fluoroscopy should be considered in the setting of persistent respiratory symptoms compatible with the clinical picture of tracheomalacia.

Stridor and respiratory failure due to tracheobronchomalacia: case report and review of the literature

CONTEXT

Tracheobronchomalacia (TBM) results from structural and functional abnormalities of the respiratory system. It is characterized by excessive collapse: at least 50% of the cross-sectional area of the trachea and main bronchi. In this paper, we present a rare case of a patient with TBM who first presented with stridor and respiratory failure due to exacerbation of chronic bronchitis.

CASE REPORT

An 81-year-old Caucasian man was admitted presenting coughing, purulent sputum, stridor and respiratory failure. He had a medical history of chronic obstructive pulmonary disease (COPD) and silicosis and was a former smoker. Axial computed tomography on the chest revealed marked collapse of the trachea in its middle third. Bronchoscopy showed characteristics compatible with TBM. He was treated with noninvasive ventilation, without any good response. Subsequently, a Dumon Y stent was placed by means of rigid bronchoscopy. After the procedure, he was discharged with a clinical improvement.

CONCLUSION

TBM is fatal and often underdiagnosed. In COPD patients, stridor and respiratory failure may be helpful signs that should alert physicians to consider TBM as an early diagnosis. Thus, these signs may be important for optimizing the treatment and evolution of such patients.

Aortopexy as treatment for tracheo-bronchomalacia in children: an 18-year single-center experience

OBJECTIVES

To define the factors influencing the outcome of aortopexy as management of tracheo-bronchomalacia.

DESIGN

A retrospective, single-center, observational, cohort study.

SETTINGS

Surgical services in a tertiary care hospital.

PATIENTS

One hundred five children who underwent an aortopexy for tracheo-bronchomalacia between 1990 and 2008.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Comorbidity (categorized into three groups), surgical approach, and location of malacia were reviewed and analyzed in relation to mortality, need for a second intervention, complications, time to extubation after surgery, intensive care unit stay, and clinical improvement. Median age at surgery was 24 wks (1 wk-541 wks). Two surgical approaches were used: median sternotomy (n = 46) and left anterior parasternal (n = 59). Long-term (>2 yrs) follow-up was available for 73 patients (median = 7.0 yrs [2-18 yrs]); 73% were asymptomatic, 18% had minor symptoms, and 9% needed either ventilation or tracheostomy. The overall mortality rate was 9%, of which one-third was airway-related. Multivariable analysis revealed that major comorbidities were a significant risk factor both for mortality and the need for further procedures (re-do surgery, tracheostomy, internal stents) in contrast to surgical approach and involvement of the bronchus. Intensive care unit stay and days of ventilation after surgery were also significantly higher in patients with major comorbidities.

CONCLUSIONS

Aortopexy proved to be an effective treatment for most cases of tracheo-bronchomalacia, but major comorbidity was associated with an adverse outcome. Our data suggest that aortopexy should be considered in most cases of severe tracheo-bronchomalacia.

Tracheobronchomalacia in adults

Severe, diffuse tracheobronchomalacia (TBM) is an underrecognized cause of dyspnea, recurrent respiratory infections, cough, secretion retention, and even respiratory insufficiency. Patients often have comorbidities, such as asthma or chronic obstructive pulmonary disease, and inappropriate treatment for these conditions may precede eventual recognition of TBM by months or years. Most of these patients have an acquired form of TBM in which the etiology in unknown. Diagnosis of TBM is made by airway computed tomography scan and flexible bronchoscopy with forced expiration. The prevailing definition of TBM as a 50% reduction in cross-sectional area is nonspecific, with a high proportion of healthy volunteers meeting this threshold. The clinically significant threshold is complete or near-complete collapse of the airway. Airway stenting may treat TBM, although complications resulting from indwelling prostheses often limit the durability of stents. Surgical stabilization of the airway by posterior splinting (tracheobronchoplasty) effectively and permanently corrects malacic airways. Proper surgical selection is facilitated by a short-term stent trial.

Tracheobronchomalacia in infants and children: multidetector CT evaluation

Tracheobronchomalacia (TBM) is the most common congenital central airway anomaly, but it frequently goes unrecognized or is misdiagnosed as other respiratory conditions such as asthma. Recent advances in multidetector computed tomography (CT) have enhanced the ability to noninvasively diagnose TBM with the potential to reduce the morbidity and mortality associated with this condition. Precise indications are evolving but may include symptomatic pediatric patients with known risk factors for TBM and patients with otherwise unexplained impaired exercise tolerance; recurrent lower airways infection; and therapy-resistant, irreversible, and/or atypical asthma. With multidetector CT, radiologists can now perform objective and quantitative assessment of TBM with accuracy similar to that of bronchoscopy, the reference standard for diagnosing this condition. Multidetector CT enables a comprehensive evaluation of pediatric patients suspected of having TBM by facilitating accurate diagnosis, determining the extent and degree of disease, identifying predisposing conditions, and providing objective pre- and postoperative assessments. In this article, the authors present a step-by-step primer of multidetector CT imaging for evaluating infants and children with suspected TBM, including clinical indications, patient preparation, multidetector CT techniques and protocols, two- and three-dimensional processing of multidetector CT data, and image interpretation. The major aim of this article is to facilitate the reader's ability to successfully employ multidetector CT imaging protocols for evaluation of TBM in infants and children in daily clinical practice.

A neurologic etiology for tracheomalacia?

To date, major works on tracheomalacia have assumed a structural etiology and have proposed therapies as such. We describe a possible neurologic etiology for tracheomalacia in a child with clinically significant tracheomalacia that resolved in synchrony with each treatment of his recurring hydrocephalus. Endoscopy confirms remarkable expansion of tracheal diameter 7 days after decreasing intracranial pressure. The possibility of a neurologic etiology for tracheomalacia casts this condition in a new light with potential therapeutic implications.

Congenital airway lesions and lung disease

Structural upper and lower airway disorders and parenchymal disorders are uncommon in pediatric practice, but many pediatricians will encounter them and be responsible for the ongoing care of these patients. Pediatricians need to be cognizant of these diagnoses because, even though management of these disorders generally lacks an evidence base, existing principles of good care surrounding accurate diagnosis, classifications of severity, judicious use of investigations, medication, and surgical approaches are essential to good outcomes.

Diagnosis of airway malacia by virtual bronchoscopy

The study was aimed to identify the role of virtual bronchoscopy in detection of airway malacia in children. In a pre-experimental study over 3 years (from Nov. 2003 to Oct. 2006), 35 consecutive patients were presented to Tabriz Children's Hospital with clinical manifestations of airway malacia, examined by the technique of virtual bronchoscopy. Thirty five patients including 23 males and 12 females with the mean age of 3.7 +/- 1.6 months were studied. The presence of airway malacia and its location and severity were determined by virtual bronchoscopy in all studied cases; that revealed: laryngomalacia, bronchomalacia, tracheomalacia, laryngotracheomalacia and laryngobronchomalacia in 42.8, 25.7, 20, 8.6 and 2.9% of patients, respectively. Virtual bronchoscopy is a non-invasive, accurate and rapid imaging technique with an excellent validity for diagnosis of airway malacia and stenosis, therefore it can replace conventional bronchoscopy.

Airway stents in children

Airway obstruction in children is a rare, but difficult clinical problem, with no clear agreement on optimal therapeutic approach. Stenting of the airway has been used successfully in adults, and is an attractive alternative in children. Fundamental differences of pediatric compared to adult use include the benign nature of most stenoses, the narrow and soft airways of children, the required long-term tolerance and adaptation to growth. These differences may significantly alter the therapeutic balance, calling into question the precise role stents play in the treatment of airway obstruction in children. Stent placement can be technically demanding but is not exceedingly difficult. Experience is necessary to select the proper size and type of stent. Metal stents usually achieve airway patency and clinical improvement in the majority of cases, while this is less frequently the case with silicone stents. Some complications such as granulation and secretion retention seem to occur in most children after stent implantation. Unfortunately, severe complications including death have been reported in a significant proportion of children. Stent related mortality can be estimated at 12.9% from published data, but these include complication centered reports. The initial euphoria for airway stents in children has largely abated and most authors agree that they should only be employed in circumstances with no good alternatives. It is crucial that all surgical and medical alternatives are considered and the decision to place a stent is not made because other options are overlooked or not available locally. Stent use in a palliative setting has also been reported and is probably reasonable. Stents will only allow limited adaptation for the growth of pediatric airways by balloon dilatation. All metal stents should be considered as potentially permanent, and removal sometimes may only be possible through a surgical and sometimes risky approach.

Longitudinal quantification of growth and changes in primary tracheobronchomalacia sites in children

RATIONALE

Longitudinal follow-up of children with tracheobronchomalacia is essential to improving our understanding of these disorders, yet currently, there is no such data.

OBJECTIVES

To longitudinally define malacia sites and quantify the cross-sectional area (CSA) of the lumen using a bronchoscopic technique and to relate these measurements to illness profiles.

METHODS

The validated color histogram mode technique was utilized to quantify primary malacia lesions and airway sites' CSA. Illness frequency, validated scales of illness and cough diary scores were prospectively used to assess clinical profiles.

RESULTS

Thirty-five malacia sites were defined from the 2 studies of 21 children. CSA of 21 (60%) of the malacia lesions increased, 5 (14%) new lesions appeared, 5 (14%) decreased in size, 3 (8%) remained unchanged, and 1(3%) was indeterminate. Overall there was no statistically significant change in paired-data assessments of malacia sites' area while there was a significant increase in area of non-malacia sites. The median yearly growth rate for the malacia sites and non-malacia was 3.65 mm2/year sites and 5.38 mm2/year, respectively (P = 0.31). The type and severity of lesion was not associated with any difference in growth rates, illness frequency or clinical scores.

CONCLUSIONS

Malacia lesions increase in size at the same rate as non-malacia sites. However malacia may worsen and new primary lesions may develop. Neither malacia type nor severity influences their growth pattern or illness profile.

Description of a multidimensional classification system for patients with expiratory central airway collapse

BACKGROUND AND OBJECTIVE

Patients with expiratory central airway collapse present with various symptoms, aetiologies, morphologies, extent and severity of airway collapse. The aim of this study was to delineate a multidimensional classification system and common language for evaluating patients with expiratory central airway collapse.

METHODS

The classification system was based on the morphology and origin of the airway abnormality as well as stratification parameters such as functional status, extent and severity of airway collapse. Patients with expiratory central airway collapse who underwent clinical and bronchoscopic examination before and after treatment were identified from a bronchoscopy database. The classification was applied to the study patients before and after treatment to assess the utility of this stratification approach.

RESULTS

Eighteen patients were studied. Four had excessive dynamic airway collapse and 14 had tracheobronchomalacia. Post-treatment, functional status improved by one class in 12 patients, by two classes in four patients and remained unchanged in two. Severity of airway collapse improved in 15 and remained unchanged in three patients. The extent of abnormality diminished in 14 patients and did not change in four.

CONCLUSIONS

Using this classification, the morphologies and aetiologies of expiratory central airway collapse are identified, and an objective stratification of patients according to degree of functional impairment, extent of disease and severity of airway collapse is possible.

Tracheobronchomalacia and excessive dynamic airway collapse

Tracheobronchomalacia and excessive dynamic airway collapse are two separate forms of dynamic central airway obstruction that may or may not coexist. These entities are increasingly recognized as asthma and COPD imitators. The understanding of these disease processes, however, has been compromised over the years because of uncertainties regarding their definitions, pathogenesis and aetiology. To date, there is no standardized classification, diagnosis or management algorithm. In this article we comprehensively review the aetiology, morphopathology, physiology, diagnosis and treatment of these entities.

Pediatric Laryngotracheal Obstruction: Current Perspectives on Stridor

OBJECTIVES/HYPOTHESIS

To assess how medical advances have impacted the diagnosis, management, and outcomes of pediatric laryngotracheal obstruction, and to describe the advantages of audio-video documentation of stridorous children.

STUDY DESIGN AND METHODS

Retrospective.

METHODS AND MATERIALS

268 patients were referred for suspected laryngotracheal obstruction during the 30 months between September 1, 1995 and March 1, 1998: 173 had 206 flexible fiberoptic laryngoscopies, and 160 had 273 direct laryngoscopies. One hundred and forty-one children were identified with laryngotracheal obstruction, yielding 40 different diagnoses that could be classified into 9 major categories. Thirty-six children (25.5%) had multiple sites of upper airway obstruction.

RESULTS

138 children had follow-up >1 month. Twelve children died (8.7%), leaving 126 survivors (mean follow-up=21.1 months). Outcomes were classified as resolved (44.2%), improved (37.0%), stable (9.4%), failed (0.7%), or death (8.7%). Better outcomes were seen in more readily treated diagnostic categories, such as tracheobronchial foreign body, chronic laryngitis, and suprastomal granulation tissue; laryngeal stenosis, tracheomalacia, and recurrent respiratory papillomatosis, had less favorable outcomes (P<.001). The former group also showed superior outcome compared to laryngomalacia (P<.001) and vocal cord mobility disorders (P=.004). Ninety-four patients (68.1%) had comorbidities complicating their management. Comorbid conditions were universal among deceased patients and least common in the resolved outcomes category (56.7%), supporting the premise that patients with poor outcomes are more likely to have comorbidities than patients with resolution of laryngotracheal symptoms (P=.034).

CONCLUSIONS

Audio-video recording of pediatric laryngotracheal obstruction offers numerous advantages. Children classified into an array of diagnostic categories usually have favorable outcomes, but opportunities for continued advances exist, particularly regarding management of comorbidity and chronic obstruction.

Tracheomalacia and bronchomalacia in children: incidence and patient characteristics

OBJECTIVE

Congenital airway malacia is one of the few causes of irreversible airways obstruction in children, but the incidence in the general population is unknown. Severe airway malacia or malacia associated with specific syndromes is usually recognized and diagnosed early in infancy, but information about clinical features of children with primary malacia, often diagnosed only later in childhood, is scarce.

METHODS

We analyzed all flexible bronchoscopies performed between 1997 and 2004 in the Sophia Children's Hospital, summarized clinical features of children with primary airway malacia, estimated the incidence of primary airway malacia, and calculated the predictive value of a clinical diagnosis of airway malacia by pediatric pulmonologists.

RESULTS

In a total of 512 bronchoscopies, airway malacia was diagnosed in 160 children (94 males) at a median age of 4.0 years (range, 0 to 17 years). Airway malacia was classified as primary in 136 children and secondary in 24 children. The incidence of primary airway malacia was estimated to be at least 1 in 2,100. When pediatric pulmonologists expected to find airway malacia (based on symptoms, history, and lung function) prior to bronchoscopy, this was correct in 74% of the cases. In 52% of the airway malacia diagnoses, the diagnosis was not suspected prior to bronchoscopy. Presenting clinical features of children with airway malacia were variable and atypical, showing considerable overlap with features of allergic asthma. Peak expiratory flow was more reduced than FEV(1).

CONCLUSION

Primary airway malacia is not rare in the general population, with an estimated incidence of at least 1 in 2,100 children. Airway malacia is difficult to recognize based on clinical features that show overlap with those of more common pulmonary diseases. We recommend bronchoscopy in patients with impaired exercise tolerance, recurrent lower airways infection, and therapy-resistant, irreversible, and/or atypical asthma to rule out airway malacia.

Predictive value of infant lung function testing for airway malacia

Airway malacia is present in a small proportion of wheezing infants. The usefulness of infant lung-function testing (ILFT) in ruling out malacia in wheezy infants is unknown. We assessed the predictive value of ILFT parameters for airway malacia diagnosed by flexible bronchoscopy. Thirty-two term infants (mean (SD) age, 11.0 (4.6) months) with chronic wheeze unresponsive to asthma treatment underwent ILFT prior to bronchoscopy. Functional residual capacity measured by plethysmograph (FRCp), maximal flow at FRC (V'max(FRC)), and tidal breathing parameters were obtained. Expiratory flow-volume curves were visually examined for tidal flow limitation. Malacia was observed during bronchoscopy in 20 infants. V'max(FRC) (Z-score) was significantly lower in the group with malacia as compared with the group without malacia. Lung-function measurements had a low negative predictive value and sensitivity. While flow limitation during tidal breathing was highly predictive and 100% specific for airway malacia, only half of the infants with malacia had tidal flow limitation. In this selected group of infants, routine lung function testing could not discriminate between infants with and without airway malacia. However, the presence of tidal flow limitation was 100% predictive and specific for airway malacia.