Tracheobronchial malacia and stenosis in children in intensive care: bronchograms help to predict oucome

Single-center review on safety of biodegradable airway stenting in pediatric population

BACKGROUND

Tracheobronchomalacia (TBM) and airway stenosis are recognized etiologies of airway obstruction among children. Their management is often challenging, requiring multiple interventions and prolonged respiratory support with associated long-term morbidity. Metallic or silicone stents have been used with mixed success and high complication rates. More recently biodegradable Ella stents (BES) provided an attractive interventional option.

OBJECTIVES

We report our experience in the treatment of TBM and vascular airway compression using BES. We deliberately downsized them to minimize intraluminal granulation tissue formation.

MATERIALS AND METHODS

Retrospective study over an 8-year period between November 2012 and December 2020 of pediatric patients with severe airway obstruction requiring airway stenting for extubation failure, malacic death spells, recurrent chest infections, or lung collapse.

RESULTS

Thirty-three patients (5 tracheal and 28 bronchial diseases) required 55 BES during the study period. The smallest patient weighed 1.8 kg. Median age of patient at first stent implantation was 13.1 months (IQR 4.9-58.3). The majority of the bronchial stents were in the left main bronchus (93%), of which 57% for vascular compression. Repeat stents were used in 19 patients (57.7%), with a range of two to four times. We did not experience erosion, infection, or obstructive granuloma needing removal by forceps or lasering. Three stent grid occluded with secretions needing bronchoscopic lavage. Stent migration occurred in three patients.

CONCLUSIONS

BES holds promise as a treatment option with low rate of adverse effects for a specific subset of pediatric patients with airway malacia or vascular compression. Further studies are warranted.

[The role of bronchoscopy in slide tracheoplasty in children]

OBJECTIVES

To study the role of bronchoscopy in slide tracheoplasty.

METHODS

A retrospective analysis was conducted on the diagnosis and treatment of four children with tracheal stenosis admitted to Hunan Provincial People's Hospital from 2017 to 2020. The role of bronchoscopy was summarized in the preoperative evaluation, intraoperative positioning and measurement, and postoperative wound evaluation and treatment during slide tracheoplasty.

RESULTS

Bronchoscopy evaluation before slide tracheoplasty showed that 3 of the 4 children had complete trachea rings, 2 had pulmonary artery sling, and 2 had multiple stenosis. Slide tracheoplasty was performed in the hospital on 3 children, and the midpoint of the stenosis segment was judged under bronchoscopy, and the length of the stenosis segment was measured, which assisted in the resection of the stenosis segment of the trachea. The pathogens were identified by lavage after the surgery. One child who developed scar traction 9 months after slide tracheoplasty in another hospital was improved by interventional treatment under bronchoscopy. Mucosal changes were found under bronchoscopy in 2 children 4 days after surgery, and the treatment plan was adjusted. One month after surgery, 2 children had granulation hyperplasia, which was improved by cryotherapy under bronchoscopy. One child abandoned treatment due to anastomotic necrosis and died. Three survivors were followed up for over 6 months with good prognosis, but all had tracheobronchial malacia.

CONCLUSIONS

Bronchoscopy can be used for the management of slide tracheoplasty in children with tracheal stenosis, which is helpful to postoperative rehabilitation and follow-up.

Pulmonary artery sling: An overview

Pulmonary artery sling is a rare childhood vascular tracheobronchial compression syndrome that is frequently associated with tracheal stenosis. Consequently, neonates or infants may present with critical airway obstruction if there is long segment airway narrowing and complete rings. Rapid diagnosis of this cardiac vascular malformation and evaluation of the extent and severity of airway involvement is essential to plan surgery, typically a slide tracheoplasty to relieve critical airway obstruction. Long term outcome can be excellent following surgical repair of the stenosed airway and reimplantation of the left pulmonary artery. In this review we focus on the embryology, diagnostic workup, airway investigations and management for this rare but challenging congenital condition.

Long term outcome of babies with pulmonary hypertension

Neonatal pulmonary hypertension (PH) is associated with many severe congenital abnormalities (congenital diaphragmatic hernia) or acquired cardiorespiratory diseases such as pneumonia, meconium aspiration and bronchopulmonary dysplasia (BPD). If no cause is found it may be labelled idiopathic persistent pulmonary hypertension of the newborn. Although PH may result in life threatening hypoxia and circulatory failure, in the majority of cases, it resolves in the neonatal period following treatment of the underlying cause. However, in some cases, neonatal PH progresses into infancy and childhood where symptoms include failure to thrive and eventually right heart failure or death if left untreated. This chronic condition is termed pulmonary vascular hypertensive disease (PHVD). Although classification and diagnostic criteria have only recently been proposed for pediatric PHVD, little is known about the pathophysiology of chronic neonatal PH, or why pulmonary vascular resistance may remain elevated well beyond infancy. This review explores the many factors involved in chronic PH and what implications this may have on long term outcome when the disease progresses beyond the neonatal period.

Clinical survey and predictors for the development of tracheobronchomalacia in preterm infants

BACKGROUND

Tracheobronchomalacia (TBM) contributes to the increased morbidity and mortality observed in preterm infants. Effective strategies for the prevention of TBM are necessary to achieve better outcomes. We sought to identify risk factors associated with the development of TBM in preterm infants. Optimal cut-off values for each risk factor were also determined.

METHODS

A total of 80 infants who were born at 36 week's gestation or earlier and underwent flexible bronchoscopy were included in our study sample. A comparison of demographic and clinical risk factors between those with TBM (n = 35, 44%) and those without TBM (n = 45, 56%) was conducted using multivariate logistic regression analysis. Receiver operating characteristic curve analysis was performed to determine the appropriate cut-off values for predicting the development of TBM.

RESULTS

In the multivariate analysis, only peak inspiratory pressure (PIP) and the number of intubation days remained significantly different between infants with and without TBM. Preterm infants with TBM received higher PIP (odds ratio: [OR], 1.067; 95% confidence interval [CI], 1.010-1.128; p = .020) and were intubated for longer (odds ratio [OR], 1.019; 95% CI, 1.003-1.035; p = .016) than those without TBM. Infants who received PIP > 19.5 cmH₂ O or were intubated for >79.5 days were associated with a significantly higher risk of presence of TBM.

CONCLUSION

High PIP and prolonged intubation were major risk factors for the development of TBM in premature infants. Those who require PIP > 19.5 cmH₂ O or intubation >79.5 days warrant bronchoscopy examination for early diagnosis and management of TBM.

Congenital tracheal defects: embryonic development and animal models

Tracheal anomalies are potentially catastrophic congenital defects. As a newborn begins to breathe, the trachea needs to maintain an appropriate balance of elasticity and rigidity. If the tracheal cartilages are disorganized or structurally weak, the airways can collapse, obstructing breathing. Cartilage rings that are too small or too rigid can also obstruct breathing. These anomalies are frequently associated with craniofacial syndromes, and, despite the importance, are poorly understood. In this review, we summarize the spectrum of pathological phenotypes of the trachea and correlate them with the molecular events uncovered in mouse models.

Lower airway collapse: Revisiting the definition and clinicopathologic features of canine bronchomalacia

Bronchomalacia (BM) is an inconsistently defined term in dogs, impairing understanding of clinical presentation, therapeutic response and prognosis. Herein the authors propose to clarify the definition of canine bronchomalacia (CBM) as regional to diffuse dynamic airway collapse of segmental and/or subsegmental bronchi with associated clinical signs due to airflow limitation. In contrast to tracheal collapse, mainstem bronchial collapse, and in some cases lobar collapse, CBM requires advanced imaging. Common co-morbid conditions (e.g., chronic bronchitis, mitral valve degenerative disease, etc.) should be identified during a comprehensive diagnostic evaluation. Current empiric treatments advocated in absence of clinical trials documenting efficacy in the dog warrant evaluation, as some (e.g., bronchodilators) may have detrimental effects in certain types of airway collapse in humans. There is no direct treatment for CBM, as defined above, but non-specific therapies and targeted treatment of co-morbid disease may improve clinical signs and quality of life. In this manuscript, the authors provide a review of the different types of airway collapse focusing on CBM, reviewing their definition and etiology, proposing a classification scheme, and discussing clinical signs, diagnostic testing, and treatment. Future studies should focus on both improving understanding of the etiology and natural disease progression of CBM and treatment trials.

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.

Arterial blood gas analysis in dogs with bronchomalacia

Canine bronchomalacia (CBM) is a structural airway disease leading to chronic cough and intermittent respiratory distress, primarily affecting elderly dogs of small breeds. Results of blood gas analysis have been reported in dogs with several diseases, but not yet in those with CBM. Eleven dogs with CBM were recruited in this study. Most dogs presented with mild hypoxemia and normocapnia, and all with increased alveolar-arterial difference for O₂ (A-aDO₂). In computed tomography, abnormal lung patterns, such as atelectasis and parenchymal band, were detected in all dogs, consistent with the regions affected by CBM. We conclude that CBM causes abnormal lung patterns and results in impaired oxygenation. Blood gas analysis is a useful tool for detecting mild pulmonary lesions and concurrent CBM.

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.

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.

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.

Airway Problems in Neonates-A Review of the Current Investigation and Management Strategies

Airway problems in the neonatal population are often life threatening and raise challenging issues in diagnosis and management. The airway problems can result from congenital or acquired lesions and can be broadly classified into those causing obstruction or those due to an abnormal "communication" in the airway. Many different investigations are now available to identify the diagnosis and quantify the severity of the problem, and these tests can be simple or invasive. Bronchography and bronchoscopy are essential to determine the extent and severity of the airway problem and to plan treatment strategy. Further imaging techniques help to delineate other commonly associated abnormalities. Echocardiography is also important to confirm any associated cardiac abnormality. In this review, the merits and disadvantages of the various investigations now available to the clinician will be discussed. The current therapeutic strategies are discussed, and the review will focus on the most challenging conditions that cause the biggest management conundrums, specifically laryngotracheal cleft, congenital tracheal stenosis, and tracheobronchomalacia. Management of acquired stenosis secondary to airway injury from endotracheal intubation will also be discussed as this is a common problem. Slide tracheoplasty is the preferred surgical option for long-segment tracheal stenosis, and results have improved significantly. Stents are occasionally required for residual or recurrent stenosis following surgical repair. There is sufficient evidence that a multidisciplinary team approach for managing complex airway issues provides the best results for the patient. There is ongoing progress in the field with newer diagnostic tools as well as development of innovative management techniques, such as biodegradable stents and stem cell-based tracheal transplants, leading to a much better prognosis for these children in the future.

Tracheobronchomalacia diagnosed by tracheobronchography in ventilator-dependent infants

BACKGROUND

Tracheobronchomalacia prevalence in premature infants on prolonged mechanical ventilation is high.

OBJECTIVE

To examine the prevalence of tracheobronchomalacia diagnosed by tracheobronchography in ventilator-dependent infants, and describe the demographic, clinical and dynamic airway characteristics of those infants with tracheobronchomalacia.

MATERIALS AND METHODS

This retrospective review studies 198 tracheobronchograms performed from 1998 to 2011 in a cohort of 158 ventilator-dependent infants <2 years of age. Dynamic airway assessment during tracheobronchography determined the optimal positive end-expiratory pressure to maintain airway patency at expiration in those infants with tracheobronchomalacia.

RESULTS

Tracheobronchograms were performed at a median age of 52 weeks post menstrual age. The primary diagnoses in these infants were bronchopulmonary dysplasia (53%), other causes of chronic lung disease of infancy (28%) and upper airway anomaly (13%). Of those with bronchopulmonary dysplasia, 48% had tracheobronchomalacia. Prematurity (P=0.01) and higher baseline - pre-tracheobronchogram positive end-expiratory pressure (P=0.04) were significantly associated with tracheobronchomalacia. Dynamic airway collapse during tracheobronchography showed statistically significant airway opening at optimal positive end-expiratory pressure (P < 0.001). There were no significant complications noted during and immediately following tracheobronchography.

CONCLUSION

The overall prevalence of tracheobronchomalacia in this cohort of ventilator-dependent infants is 40% and in those with bronchopulmonary dysplasia is 48%. Infants born prematurely and requiring high pre-tracheobronchogram positive end-expiratory pressure were likely to have tracheobronchomalacia. Tracheobronchography can be used to safely assess the dynamic function of the airway and can provide the clinician the optimal positive end-expiratory pressure to maintain airway patency.

Tracheobronchomalacia in pediatric patients with esophageal atresia: comparison of diagnostic laryngoscopy/bronchoscopy and dynamic airway multidetector computed tomography

PURPOSE

Diagnostic laryngoscopy and bronchoscopy (DLB) has been the traditional preoperative diagnostic modality for evaluating presence and severity of tracheobronchomalacia (TBM), and requires anesthesia. Alternatively, multidetector computed tomography (MDCT) is potentially a noninvasive modality that provides high-resolution, 3-dimensional (3D) imaging of the thorax providing preoperative guidance for pediatric surgeons. This study compares MDCT with intraoperative DLB in the assessment of TBM in symptomatic pediatric patients with esophageal atresia (EA).

METHODS

Following IRB approval all pediatric patients (≤18 years) who had EA and who underwent an MDCT study as a preoperative evaluation of TBM prior to aortopexy were retrospectively reviewed. Patients with incomplete reports on intraoperative DLB or MDCT studies were excluded. Two pediatric radiologists independently evaluated all MDCT studies in a blinded fashion. On both DLB and MDCT studies, TBM was scored as present or absent in five anatomic segments: upper, middle, and lower trachea, as well as right and left main stem bronchi. Operative reports including DLB findings were reviewed and compared to findings from MDCT study using the chance corrected kappa (κ) coefficient. Diagnostic accuracy of dynamic MDCT for detecting TBM was determined by sensitivity and specificity, and interobserver agreement between two radiology reviewers was measured by the kappa statistic.

RESULTS

The final study population included 18 patients (8 males and 10 females) with ages ranging from 1month to 11years (median: 7 months). Their presenting clinical symptoms included apneic spells (n=15, 83%) and failure to extubate (n=3, 17%). The overall diagnostic accuracy of dynamic airway MDCT compared to DLB was 91% (82/90 possible segments for TBM) with excellent overall agreement across all 5 anatomic segments (κ=0.82, p<0.001). The agreements for upper, mid, lower trachea, and right and left trachea were 89% (κ=0.73, p<0.001), 94% (κ=0.85, p<0.001), 89% (κ=0.76, p<0.001), 94% (κ=0.82, p<0.001), and 89% (κ=0.61, p=0.005); respectively. Interobserver agreement between two radiologists was excellent (κ=0.98, 95% confidence interval: 0.94-1.00, p<0.001) with only 1 disagreement between two radiologists that was found for the left main bronchus. Fifteen (83.3%) of the patients clinically improved after the aortopexy.

CONCLUSION

MDCT with 3D imaging is a highly accurate and reliable preoperative noninvasive imaging modality for evaluating TBM in pediatric patients with EA providing anatomic information consistent with and complimentary to bronchoscopy.

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.

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.

Anesthesia for subglottic stenosis in pediatrics

Any site in the upper airway can get obstructed and cause noisy breathing as well as dyspnea. These include nasal causes such as choanal atresia or nasal stenosis; pharyngeal causes including lingual thyroid; laryngeal causes such as laryngomalacia; tracheobronchial causes such as tracheal stenosis; and subglottic stenosis. Lesions in the oropharynx may cause stertor, while lesions in the laryngotracheal tree will cause stridor. Subglottic stenosis is the third leading cause of congenital stridors in the neonate. Subglottic Stenosis presents challenges to the anesthesiologist. Therefore, It is imperative to perform a detailed history, physical examination, and characterization of the extent and severity of stenosis. Rigid endoscopy is essential for the preoperative planning of any of the surgical procedures that can be used for correction. Choice of operation is dependent on the surgeon's comfort, postoperative capabilities, and severity of disease. For high-grade stenosis, single-stage laryngotracheal resection or cricotracheal resection are the best options. It has to be borne in mind that the goal of surgery is to allow for an adequate airway for normal activity without the need for tracheostomy. Anesthesia for airway surgery could be conducted safely with either sevofluraneor propofol-based total intravenous anesthesia.

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.

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.

Computed tomography versus bronchography in the diagnosis and management of tracheobronchomalacia in ventilator dependent infants

AIM

To assess the relative accuracy of dynamic spiral computed tomography (CT) compared with tracheobronchography, in a population of ventilator dependent infants with suspected tracheobroncho-malacia (TBM).

SETTING

Paediatric intensive care unit in a tertiary teaching hospital.

PATIENTS AND METHODS

Infants referred for investigation and management of ventilator dependence and suspected of having TBM were recruited into the study. Tracheobronchography and CT were performed during the same admission by different investigators who were blinded to the results of the other investigation. The study was approved by the hospital research ethics committee, and signed parental consent was obtained.

RESULTS

Sixteen infants were recruited into the study. Fifteen had been born prematurely, and five had cardiovascular malformations. In 10 patients there was good or partial correlation between the two investigations, but in six patients there was poor or no correlation. Bronchography consistently showed more dynamic abnormalities, although CT picked up an unsuspected double aortic arch. Radiation doses were 0.27-2.47 mSv with bronchography and 0.86-10.67 mSv with CT.

CONCLUSIONS

Bronchography was a better investigation for diagnosing TBM and in determining opening pressures. Spiral CT is unreliable in the assessment of TBM in ventilator dependent infants. In addition, radiation doses were considerably higher with CT.

Imaging evolution of airway disorders in children

This article discusses and illustrates the insights gained from CT imaging of the lungs in infants and young children who do not have respiratory motion and at end-inspiratory and resting end-expiratory lung volumes using noninvasive controlled ventilation CT technique. The potential role of noninvasive controlled ventilation CT in developing quantitative measures of airway disease is highlighted and clinical examples demonstrating the use of the technique are shown.

Tracheobronchial intervention in children

Disorders of the major airways in children are often difficult to treat. Recent advances in interventional radiology are proving useful, for both assessment of the severity of the problem and treatment. Flexible bronchoscopy and bronchography are essential tools for diagnosis, intervention and follow-up. Echocardiography, computed tomography and magnetic resonance imaging may also be important for the evaluation of cardiovascular anomalies, which are often associated with airway obstruction. Surgery remains the first line of treatment for most congenital abnormalities of the airway and for cardiac anomalies that cause airway compression. Balloon dilatation and stenting are helpful in certain other conditions, as well as in children whose airway problem is not fully corrected by surgery. A multidisciplinary approach is required, with input from pediatric cardiothoracic surgeons, radiologists, radiographers, otolaryngologists, pulmonologists, anesthesiologists, intensivists, physiotherapists and liaison nurses.

Tracheobronchomalacia and tracheal hemorrhage in patients with Duchenne muscular dystrophy receiving long-term ventilation with uncuffed tracheostomies

STUDY OBJECTIVES

Autopsy evaluation of tracheobronchomalacia (TBM) in patients with Duchenne muscular dystrophy (DMD) who were receiving long-term ventilation through uncuffed tracheostomies.

DESIGN

Necropsies were performed in seven patients with DMD who had received positive-pressure ventilation through uncuffed tracheostomies for a duration of 5 to 30 years.

SETTING

Rehabilitation facility affiliated with a university medical center.

RESULTS

The range of peak airway pressures sustained during ventilation by all the patients was 23 mm Hg to 36 mm Hg. Bronchoscopy (which was performed in four of the five patients) detected tracheomalacia in only one of the patients. Five of the seven patients demonstrated variable degrees of airway malacia. Two patients also had tracheal perforations, one of which resulted in a fatal hemorrhage from a tracheovascular fistula.

CONCLUSIONS

Given enough time, patients receiving positive-pressure ventilation can develop airway thinning and dilation even without the use of an inflated tracheostomy cuff. There is also a potential for tracheal erosion into an adjacent artery that can lead to fatal hemorrhage. Such findings also have implications for individuals receiving noninvasive positive-pressure ventilation, who could develop TBM as a result of the continuous cycling pressures on the airway wall.

Anaesthesia and tracheobronchial stenting for central airway obstruction in adults

In the last decade, stents suitable for the management of tracheobronchial stenoses and obstruction have evolved from bulky prostheses requiring tracheal resection to small devices that are self-expanding and can be inserted using fibreoptic techniques. The experience base for this review is more than 100 patients between 1989 and 2001 who have been anaesthetized for stent insertion. Early cases required rigid bronchoscopy for the routine of insertion. Anaesthetic techniques have evolved from those that were designed and developed for laser surgery in the central airways. The advent of modern devices now extends the variety of anaesthetic management techniques that can be used. But the original one, based on the requirement for use of a rigid bronchoscope, is best for dealing with complications and extracting problem stents. The most frequent complication of the processes of stent insertion has been respiratory failure because of carbon dioxide retention, consequent on obstruction with secretions in the area of the carina. The nature of central airway problems suggests that anaesthesia induction, management and teaching should not be founded on the conventional model-base of upper airway obstruction.

Tracheomalacia and bronchomalacia in children: pathophysiology, assessment, treatment and anaesthesia management

Tracheomalacia and bronchomalacia are becoming increasingly well recognized. Although pathologically benign conditions, they are responsible for considerable morbidity, occasional mortality and significant difficulties in the operating theatre and intensive care unit. We performed an extensive literature search to identify causal associations, methods of clinical and investigative assessment, treatment modalities and anaesthetic experience with these conditions.

Airway obstruction in children with congenital heart disease: assessment by flexible bronchoscopy

We assessed the spectrum of airway disorders in children with congenital cardiac anomalies, and reviewed our experience in using flexible bronchoscopy for assessment of airway problems in this patient group. The clinical records, flexible bronchoscopic findings, and cardiac imaging results of pediatric cardiac patients who presented with either clinical or radiological signs of airway obstruction between 1992-1999 were reviewed. Flexible bronchoscopic assessment was performed with the patients under sedation and topical anesthesia, using one of two bronchoscopes, i.e., an Olympus BFN20 or Olympus BF3C20. Of a total of 52 patients, 33 had acyanotic cardiovascular lesions, the commonest being left-to-right shunts (61%), while 19 had cyanotic heart lesions, with right ventricular outflow obstruction being the commonest (63%). Twenty-seven patients had undergone either surgical or transcatheter interventions. The median age at bronchoscopic assessment was 6 months (range, 4 days to 6 years). None of the patients developed significant procedural complications. A definitive diagnosis was made in 48 (92%) patients, 8 of whom had abnormalities involving only the upper airways, 35 only the lower airways, and 5 both. Abnormalities of the upper airway included laryngomalacia (n = 6), subglottic stenosis (n = 3), pharyngeal collapse (n = 2), and 1 each of choanal stenosis and supraglottitis. Extrinsic compression was the commonest lower airway abnormality that was found in 27/40 patients (67%), with a predilection for the left main bronchus (18/27, 67%). The structures that caused extrinsic compression included dilated pulmonary arteries with or without left atrial dilation (n = 20), an anomalous aortic or pulmonary arterial course (n = 3), a dilated aorta (n = 1), and a shunt (n = 1), but were not obvious in 2 patients. Intrinsic lower airway abnormalities included bronchomalacia (n = 4), tracheal stenosis (n = 4), and one each of variant bronchial bifurcation and a pouch arising from the tracheal wall. Intraluminal mucus plugging of the lower airways occurred in the remaining 3 patients. Children with congenital heart disease are at risk of airway obstruction both before and after surgery. Flexible bronchoscopy, being safe and effective in diagnosing airway disorders in this patient group, should be considered as the first line of investigation.

Series of laryngomalacia, tracheomalacia, and bronchomalacia disorders and their associations with other conditions in children

Laryngomalacia, bronchomalacia, and tracheomalacia are commonly seen in pediatric respiratory medicine, yet their patterns and associations with other conditions are not well-understood. We prospectively video-recorded bronchoscopic data and clinical information from referred patients over a 10-year period and defined aspects of interrelationships and associations. Two hundred and ninety-nine cases of malacia disorders (34%) were observed in 885 bronchoscopic procedures. Cough, wheeze, stridor, and radiological changes were the most common symptoms and signs. The lesions were most often found in males (2:1) and on the left side (1.6:1). Concomitant malacia lesions ranged from 24% for laryngotracheobronchomalacia to 47% for tracheobronchomalacia. The lesions were found in association with other disorders such as congenital heart disorders (13.7%), tracheo-esophageal fistula (9.6%), and various syndromes (8%). Even though the understanding of these disorders is in its infancy, pediatricians should maintain a level of awareness for malacia lesions and consider the possibility of multiple lesions being present, even when one symptom predominates or occurs alone.

Left-lung-collapse bronchial deformation in giant omphalocele

Five infants with giant omphalocele had persistent collapse of the left lung and required prolonged respiratory support. Narrowing of the left main bronchus, reversible with positive end-expiratory pressure, was identified radiographically in 3 infants, and we postulate that this relates to distortion of the bronchus within the constraints of the elongated, narrow thoracic cavity characteristic of these patients. The lung collapse may be precipitated by manipulation (reduction or attempted reduction) of the omphalocele. J Pediatr Surg 36:846-850.