Neonates With Tracheomalacia Generate Auto-Positive End-Expiratory Pressure via Glottis Closure.

BACKGROUND: In pediatrics, tracheomalacia is an airway condition that causes tracheal lumen collapse during breathing and may lead to the patient requiring respiratory support. Adult patients can narrow their glottis to self-generate positive end-expiratory pressure (PEEP) to raise the pressure in the trachea and prevent collapse. However, auto-PEEP has not been studied in newborns with tracheomalacia. The objective of this study was to measure the glottis cross-sectional area throughout the breathing cycle and to quantify total pressure difference through the glottis in patients with and without tracheomalacia. RESEARCH QUESTION: Do neonates with tracheomalacia narrow their glottises? How does the glottis narrowing affect the total pressure along the airway? STUDY DESIGN AND METHODS: Ultrashort echo time MRI was performed in 21 neonatal ICU patients (11 with tracheomalacia, 10 without tracheomalacia). MRI scans were reconstructed at four different phases of breathing. All patients were breathing room air or using noninvasive respiratory support at the time of MRI. Computational fluid dynamics simulations were performed on patient-specific virtual airway models with airway anatomic features and motion derived via MRI to quantify the total pressure difference through the glottis and trachea. RESULTS: The mean glottis cross-sectional area at peak expiration in the patients with tracheomalacia was less than half that in patients without tracheomalacia (4.0 ± 1.1 mm2 vs 10.3 ± 4.4 mm2; P = .002). The mean total pressure difference through the glottis at peak expiration was more than 10 times higher in patients with tracheomalacia compared with patients without tracheomalacia (2.88 ± 2.29 cm H2O vs 0.26 ± 0.16 cm H2O; P = .005). INTERPRETATION: Neonates with tracheomalacia narrow their glottises, which raises pressure in the trachea during expiration, thereby acting as auto-PEEP.

Care recommendations for the respiratory complications of esophageal atresia-tracheoesophageal fistula.

Tracheoesophageal fistula (TEF) with esophageal atresia (EA) is a common congenital anomaly that is associated with significant respiratory morbidity throughout life. The objective of this document is to provide a framework for the diagnosis and management of the respiratory complications that are associated with the condition. As there are no randomized controlled studies on the subject, a group of experts used a modification of the Rand Appropriateness Method to describe the various aspects of the condition in terms of their relative importance, and to rate the available diagnostic methods and therapeutic interventions on the basis of their appropriateness and necessity. Specific recommendations were formulated and reported as Level A, B, and C based on whether they were based on "strong", "moderate" or "weak" agreement. The tracheomalacia that exists in the site of the fistula was considered the main abnormality that predisposes to all other respiratory complications due to airway collapse and impaired clearance of secretions. Aspiration due to impaired airway protection reflexes is the main underlying contributing mechanism. Flexible bronchoscopy is the main diagnostic modality, aided by imaging modalities, especially CT scans of the chest. Noninvasive positive airway pressure support, surgical techniques such as tracheopexy and rarely tracheostomy are required for the management of severe tracheomalacia. Regular long-term follow-up by a multidisciplinary team was considered imperative. Specific templates outlining the elements of the clinical respiratory evaluation according to the patients' age were also developed.

Tracheoscopic Findings and Their Impact on Respiratory Symptoms in Children with Esophageal Atresia.

INTRODUCTION: Esophageal atresia (EA) is often accompanied by tracheobronchial malformations leading to stridor, recurrent bronchitis, and occasionally to life-threatening obstructive apnea after surgical repair. The aim of this study was to identify the presence of tracheomalacia in patients with EA and tracheoesophageal fistula (TEF) pre- and postoperatively and to find endoscopic correlates leading to clinical airway symptoms. METHODS: In a cohort of 362 patients with EA-TEF who underwent 595 tracheoscopies at the Children's Hospital of Cologne between January 1983 and December 2002, impaired tracheal lumen, localization of TEF, tracheal pulsations, and corresponding clinical symptoms were retrospectively analyzed. RESULTS: The incidence of tracheomalacia was higher in patients with EA and TEF (Gross B-D) compared with patients with EA alone (Gross A) and average tracheal collapse does not significantly change before and after surgical repair of the esophagus in all types. Patients with cyanosis while eating and obstructive apnea presented with an average tracheal collapse of 89%. The presence of respiratory symptoms such as cough, stridor, or bronchitis was not associated with a higher grade of tracheal collapse compared with patients without any airway symptoms (average tracheal collapse of 37% in symptomatic patients vs. 33% in nonsymptomatic patients). CONCLUSION: Tracheomalacia tends to be present independently of surgical procedure. Tracheomalacia should be measured by tracheoscopy (in % of tracheal collapse). Patients with a tracheal collapse of >80%, a ventral pulsation, and obstructive apnea or cyanosis in combination, are at risk for life-threatening situations and further surgical treatment should be considered.

Descending Aortopexy and Posterior Tracheopexy for Severe Tracheomalacia and Left Mainstem Bronchomalacia.

Posterior descending aortopexy can relieve posterior intrusion of the left mainstem bronchus that may limit the effectiveness of posterior tracheobronchopexy. We review outcomes of patients undergoing both descending aortopexy and posterior tracheopexy for severe tracheobronchomalacia with posterior intrusion and left mainstem compression to determine if there were resolution of clinical symptoms and bronchoscopic evidence of improvement in airway collapse. All patients who underwent both descending aortopexy and posterior tracheopexy from October 2012 to October 2016 were retrospectively reviewed. Clinical symptoms, tracheomalacia scores based on standardized dynamic airway evaluation by anatomical region, and persistent airway intrusion requiring reoperation were collected. Data were analyzed by Wald and Wilcoxon signed-rank tests. Thirty-two patients underwent descending aortopexy and posterior tracheopexy at median age of 18 months (interquartile range 6-40 months). Median follow-up was 3 months (interquartile range 1-7 months). There were statistically significant improvements in clinical symptoms postoperatively, including cough, noisy breathing, prolonged and recurrent respiratory infections, ventilator dependence, blue spells, and brief resolved unexplained events (all P < 0.001), as well as exercise intolerance (P = 0.033), transient respiratory distress requiring positive pressure (P = 0.003), and oxygen dependence (P = 0.007). Total tracheomalacia scores improved significantly (P < 0.001), with significant segmental improvements in the middle (P = 0.003) and lower (P < 0.001) trachea, and right (P = 0.011) and left (P < 0.001) mainstem bronchi. Two patients (6%) had persistent airway intrusion requiring reoperation with anterior aortopexy or tracheopexy. Descending aortopexy and posterior tracheopexy are effective in treating severe tracheobronchomalacia and left mainstem intrusion with significant improvements in clinical symptoms and degree of airway collapse on bronchoscopy.

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.

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.

Esophageal Atresia/Tracheoesophageal Fistula Repair Complicated by Tracheomalacia: A Case Report of Successful Management of Respiratory Distress Using Caudal Morphine.

We report a case of severe respiratory distress in a neonate who was not endotracheally intubated soon after esophageal atresia/tracheoesophageal fistula (EA/TEF) repair. In this serious situation, any form of emergency respiratory support or definitive airway management may compromise the esophageal anastomosis and fistula repair. The cause of respiratory distress in the early postoperative period after EA/TEF is multifactorial, and in this case, included symptomatic tracheomalacia, which is commonly associated with EA/TEF.

Computational modeling of airway instability and collapse in tracheomalacia.

BACKGROUND: Tracheomalacia (TM) is a condition of excessive tracheal collapse during exhalation. Both acquired and congenital forms of TM are believed to result from morphological changes in cartilaginous, fibrous and/or smooth muscle tissues reducing airway mechanical properties to a degree that precipitates collapse. However, neither the specific amount of mechanical property reduction nor the malacic segment lengths leading to life threatening airway collapse in TM are known. Furthermore, the specific mechanism of collapse is still debated. METHODS: Computational nonlinear finite element models were developed to determine the effect of malacic segment length, tracheal diameter, and reduction in tissue nonlinear elastic properties on the risk for and mechanism of airway collapse. Cartilage, fibrous tissue, and smooth muscle nonlinear elastic properties were fit to experimental data from preterm lambs from the literature. These elastic properties were systematically reduced in the model to simulate TM. RESULTS: An intriguing finding was that sudden mechanical instability leading to complete airway collapse occurred in airways when even a 1 cm segment of cartilage and fibrous tissue properties had a critical reduction in material properties. In general, increased tracheal diameter, increased malacic segment length coupled with decreased nonlinear anterior cartilage/fibrous tissue nonlinear mechanical properties increased the risk of sudden airway collapse from snap through instability. CONCLUSION: Modeling results support snap through instability as the mechanism for life threatening tracheomalacia specifically when cartilage ring nonlinear properties are reduced to a range between fibrous tissue nonlinear elastic properties (for larger diameter airways > 10 mm) to mucosa properties (for smaller diameter airways < 6 mm). Although reducing posterior tracheal smooth muscle properties to mucosa properties decreased exhalation area, no sudden instability leading to collapse was seen in these models.

Traqueobroncomalacia / Tracheobronchomalacia

A 10-years-old girl with recurrent wheezing was diagnosed as asthmatic. Her spirometry showed variable central airway intrathoracic obstruction. The bronchoscopy confirmed the presence of bronchomalacia.

Se presenta el caso de una paciente de edad escolar, quien por sibilancias recurrentes se trataba como asmática. Al realizar espirometría forzada se detectó un compromiso variable de vía central intratorácica. La fibrobroncoscopía confirmó la presencia de broncomalacia.

Slow release of basic fibroblast growth factor (b-FGF) enhances mechanical properties of rat trachea.

AIM: Severe tracheomalacia is a life-threatening disease, but symptoms usually improve with growth. The aims of this study were to investigate how slow release basic-Fibroblast Growth Factor (b-FGF) acts on tracheal cartilage, and whether growth-promoted trachea is more resistant against an increase in externally-applied pressure. METHODS: Biodegradable gelatin hydrogel sheets soaked in 10 µl of distilled water (sham) or 0.5 or 5 µg/10 µl of b-FGF solution were inserted behind the cervical trachea of three-week-old male Wistar rats. The cervical trachea was harvested 4 weeks later. Extratracheal pressure was increased from 0 to 40 cmH2O in a chamber, while video-recording the internal lumen. The luminal area at each pressure was expressed as a proportion to that at 0 cmH2O. The amounts of collagen type II and glycosaminoglycan were measured by ELISA. RESULTS: The luminal areas at 40 cmH2O in the control (no intervention), sham, and each of the b-FGF groups were 0.65, 0.62, 0.72, and 0.73, respectively. The amounts of collagen type II and glycosaminoglycan in each group were 127, 136, 193, 249 µg/mg, respectively, and 15, 16, 19, 33 µg/mg, respectively. There were significant differences between the control group and the FGF 5 group (P=0.02, 0.01, 0.01, for luminal area, collagen, and glycosaminoglycan, respectively). CONCLUSION: 5 µg of slow-release b-FGF promotes matrix production (collagen type II and glycosaminoglycan). The growth-enhanced trachea was more resistant to collapse, suggesting that slowly released b-FGF might be useful in patients with severe tracheomalacia.

Tracheal ring fracture secondary to percutaneous tracheostomy: is tracheal flaccidity a risk factor?

OBJECTIVE: To evaluate the risk factors of tracheal ring fracture and whether previous tracheal ring flaccidity predisposes to it in consecutive, mechanically ventilated, intensive care unit patients undergoing different percutaneous dilatational tracheostomy procedures (Ciaglia Blue Rhino, PercuTwist, and Ciaglia BlueDolphin). DESIGN: Single-center retrospective study performed between November 2006 and July 2013. SETTING: Single-center university hospital. PARTICIPANTS: Two hundred nineteen consecutive intensive care unit patients. INTERVENTIONS: Video bronchoscopic percutaneous dilatational tracheostomies using different techniques, including Ciaglia Blue Rhino, PercuTwist, and Ciaglia BlueDolphin, were performed consecutively. During the procedure, the tracheal wall response to the routine external palpation was evaluated endoscopically to find the interanular space. An abnormal change in the tracheal ring shape (fingerprint) with anterior airway wall collapse was diagnosed as tracheal flaccidity. MEASUREMENTS AND MAIN RESULTS: Tracheal ring fracture occurred in 21 patients (9.6%). The proportion of tracheal ruptures was 16 (76.2%) after PercuTwist, 3 (14.3%) after Ciaglia Blue Dolphin, and 2 (9.5%) after the Blue Rhino technique. Significant risk factors for tracheal rupture were PercuTwist procedure (p = 0.02), tracheal flaccidity (p = 0.0001), and a period of intubation before a percutaneous dilatational tracheostomy procedure>14 days (p = 0.01). CONCLUSIONS: In addition to the PercuTwist technique and intubation>14 days before tracheostomy, tracheal flaccidity was a significant risk factor for tracheal ring fracture. In the presence of this finding, a less traumatic tracheostomy procedure should be applied.

Tracheomalacia in children and adults--not so rare as expected.

Tracheomalacia remains a special entity present also in children and adults. Tracheomalacia refers to a weakness of the trachea. Bronchoscopy is the "golden standard" for diagnosis. Differential diagnosis includes foreign body aspiration, difficult controlled asthma and other diseases. This disease may be congenital or it may be acquired. Acquired tracheomalacia can be treated. The main symptoms in tracheomalacia are: dyspnea, sputum production, hemoptysis and cough in adults and expiratory stridor and cough in children. Tracheomalacia could be progressive in some patients. We want to bring to your attention the tools for diagnosis and different methods of treatment. Tracheomalacia is not a rare disease and therefore we need to consider it.

Static end-expiratory and dynamic forced expiratory tracheal collapse in COPD.

AIM: To determine the range of tracheal collapse at end-expiration among chronic obstructive pulmonary disease (COPD) patients and to compare the extent of tracheal collapse between static end-expiratory and dynamic forced-expiratory multidetector-row computed tomography (MDCT). MATERIALS AND METHODS: After institutional review board approval and obtaining informed consent, 67 patients meeting the National Heart, Lung, and Blood Institute (NHLBI)/World Health Organization (WHO) Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for COPD were sequentially imaged using a 64-detector-row CT machine at end-inspiration, during forced expiration, and at end-expiration. Standardized respiratory coaching and spirometric monitoring were employed. Mean percentage tracheal collapse at end-expiration and forced expiration were compared using correlation analysis, and the power of end-expiratory cross-sectional area to predict excessive forced-expiratory tracheal collapse was computed following construction of receiver operating characteristic (ROC) curves. RESULTS: Mean percentage expiratory collapse among COPD patients was 17 ± 18% at end-expiration compared to 62 ± 16% during forced expiration. Over the observed range of end-expiratory tracheal collapse (approximately 10-50%), the positive predictive value of end-expiratory collapse to predict excessive (≥80%) forced expiratory tracheal collapse was <0.3. CONCLUSION: COPD patients demonstrate a wide range of end-expiratory tracheal collapse. The magnitude of static end-expiratory tracheal collapse does not predict excessive dynamic expiratory tracheal collapse.

What's in a name? Expiratory tracheal narrowing in adults explained.

Tracheomalacia, tracheobronchomalacia, and excessive dynamic airway collapse are all terms used to describe tracheal narrowing in expiration. The first two describe luminal reduction from cartilage softening and the latter refers to luminal reduction from exaggerated posterior membrane movement. Expiratory tracheal narrowing is a frequent occurrence that can cause symptoms of airway obstruction, such as dyspnoea, wheeze, and exercise intolerance. The accurate diagnosis and quantification of expiratory tracheal narrowing has important aetiological, therapeutic, and prognostic implications. The reference standard for diagnosis has traditionally been bronchoscopy; however, this method has significant limitations. Expiratory tracheal disorders are readily detected by four-dimensional dynamic volume multidetector computed tomography (4D-CT), an emerging, non-invasive method that will potentially enable detection and quantification of these conditions. This review discusses the morphological forms of expiratory tracheal narrowing and demonstrates the utility of 4D-CT in the diagnosis, quantification, and treatment of these important conditions.

Dynamic expiratory tracheal collapse in morbidly obese COPD patients.

Morbid obesity may influence several aspects of airway function. However, the effect of morbid obesity on expiratory tracheal collapse in COPD patients is unknown. We thus prospectively studied 100 COPD patients who underwent full pulmonary function tests (PFTs), 6-minute walk test (6MWT), Saint George's Respiratory Questionnaire (SGRQ), and low-dose CT at total lung capacity and during dynamic exhalation with spirometric monitoring. We examined correlations between percentage dynamic expiratory tracheal collapse and body mass index (BMI). The association between tracheal collapse and BMI was compared to a control group of 53 volunteers without COPD. Patients included 48 women and 52 men with mean age 65 ± 7 years; BMI 30 ± 6; FEV1 64 ± 22% predicted and percentage expiratory collapse 59 ± 19%. Expiratory collapse was significantly associated with BMI (69 ± 12% tracheal collapse among 20 morbidly obese patients with BMI ≥ 35 compared to 57 ± 19% in others, p = 0.002, t-test). In contrast, there was no significant difference in collapse between healthy volunteers with BMI ≥ 35 and < 35. COPD patients with BMI ≥ 35 also demonstrated shorter 6MWT distances (340 ± 139 m vs. 430 ± 139 m, p = 0.003) and higher (worse) total SGRQ scores (48 ± 19 vs. 36 ± 20, p = 0.013) compared to those with BMI < 35. In light of these results, clinicians should consider evaluating for excessive expiratory tracheal collapse when confronted with a morbidly obese COPD patient with greater quality of life impairment and worse exercise performance than expected based on functional measures.

Severe tracheomalacia in the ICU: identification of diagnostic criteria and risk factor analysis from a case control study.

BACKGROUND: Severe tracheomalacia (STM) is being increasingly recognized as a cause for respiratory failure in the ICU. The diagnosis is often overlooked, as chest radiography appears normal, and the role of invasive diagnostic testing for this diagnosis is not well described in the ICU setting. The prevalence and risk factors for STM are not known, and computed tomography (CT) based diagnostic criteria for ventilated patients are not well studied. METHODS: Patients admitted between January 2008 and December 2010, with respiratory failure and who failed ventilator discontinuation or required reintubation, were screened for the presence of any tracheal collapse, utilizing prior CT of the chest. Bronchoscopically confirmed cases were compared with age and sex matched controls to identify risk factors. RESULTS: Twenty-five subjects were identified as having STM, which represented 0.7% of ICU admissions and 1.6% of subjects with respiratory failure. The mean ICU stay was significantly longer in STM (30 d, 95% CI 19.7-40 d), compared to controls (4.4 d, 95% CI 3.6-5.2 d). Obesity (odds ratio 1.26, 95% CI 1.04-1.54) and gastro-esophageal reflux (odds ratio 31, 1.7- 586) were associated with increased risk for STM. The pre-intubation PaCO2 (68 mm Hg, 95% CI 57-79 mm Hg) was significantly higher in STM, compared to controls (38 mm Hg, 95% CI 35-41). The distal tracheal antero-posterior diameter (2.80 mm, 95% CI 2.15-3.46) was significantly lower in STM. A receiver operating characteristic analysis showed a distal tracheal antero-posterior diameter < 7 mm to be the optimal cutoff measurement to diagnose STM. CONCLUSION: STM was associated with prolonged ICU stay. A distal tracheal antero-posterior diameter < 7 mm on a non-intubated CT chest was suggestive of STM that required a confirmatory bronchoscopy. Gastroesophageal reflux disease and obesity were potential risk factors.

Evaluation of the trachea and intrathoracic airways by the acoustic reflection method in children with cystic fibrosis.

Tracheomalacia has been observed in older patients with cystic fibrosis (CF). The acoustic reflection method (ARM) allows a noninvasive calculation of the longitudinal cross-sectional area of the trachea (MTAv) and the airway resistance (Raw). ARM measurements were performed in 20 CF children and 20 controls during spontaneous breathing (SB), forced inspiration (FI), and forced expiration (FE). The mean MTAv value was comparable in the CF patients and the control subjects during SB, FI, and FE. The Raw was also comparable during SB and FI. However, the Raw during FE was higher in the CF patients than in the control subjects (7.9±2.3 vs. 5.0±1.5 cm H2O l(-1) s(-1), respectively, p<0.001). In the patients with CF, only the Raw during FE correlated with the predicted forced expiratory volume in 1s (R2=0.37, p=0.04). The tracheal cross-sectional area measured by the ARM is normal in children with CF but the increase in Raw during FE suggests an increase in intrathoracic airway distensibility.

Age and sex dependence of forced expiratory central airway collapse in healthy volunteers.

BACKGROUND: A recent estimate for the normal range of forced expiratory tracheal collapse differs substantially from that in an earlier study performed with comparable measurement methods. Given differences in subject characteristics between the two samples, we hypothesized that these discrepant findings may reflect a heretofore unrecognized association between forced expiratory tracheal collapse and age or sex. METHODS: We enrolled 40 female and 41 male healthy volunteers between 25 and 75 years of age who were without respiratory symptoms or known risk factors for tracheomalacia. Subjects underwent low-dose CT scanning at total lung capacity (TLC) and during forced exhalation (Expdyn) with spirometric monitoring and coaching. Percentage forced expiratory collapse was regressed on age for the total sample and separately within sex. RESULTS: Mean tracheal cross-sectional area (CSA) was 2.54 cm(2) ± 0.57 cm(2) at TLC and 1.15 cm(2) ± 0.53 cm(2) at Expdyn. Mean percentage forced expiratory collapse (%collapse) was 54% ± 20%. Men aged 24 to 31 years (n = 12) had mean %collapse of 36% ± 19%, comparable to results previously reported for similarly aged men (35% ± 18%). Men, but not women, showed a significant positive correlation (R(2) = 0.40, P < .001) between %collapse and age. Older men had both greater CSA at TLC (P = .02) and smaller CSA at Expdyn (P = .001) than younger men. CONCLUSIONS: Men exhibit positive age dependence of forced expiratory tracheal collapse. The influence of age and sex on forced expiratory tracheal collapse should be considered in the diagnostic evaluation of expiratory dynamic airway collapse and/or tracheomalacia.