Modulated Fibrosis and Mechanosensing of Fibroblasts by SB525334 in Pediatric Subglottic Stenosis

OBJECTIVE

Subglottic stenosis (SGS) may result from prolonged intubation where fibrotic scar tissue narrows the airway. The scar forms by differentiated myofibroblasts secreting excessive extracellular matrix (ECM). TGF-β1 is widely accepted as a regulator of fibrosis; however, it is unclear how biomechanical pathways co-regulate fibrosis. Therefore, we phenotyped fibroblasts from pediatric patients with SGS to explore how key signaling pathways, TGF-β and Hippo, impact scarring and assess the impact of inhibiting these pathways with potential therapeutic small molecules SB525334 and DRD1 agonist dihydrexidine hydrochloride (DHX).

METHODS

Laryngeal fibroblasts isolated from subglottic as well as distal control biopsies of patients with evolving and maturing subglottic stenosis were assessed by α-smooth muscle actin immunostaining and gene expression for α-SMA, FN, HGF, and CTGF markers. TGF-β and Hippo signaling pathways were modulated during TGF-β1-induced fibrosis using the inhibitor SB525334 or DHX and analyzed by RT-qPCR for differential gene expression and atomic force microscopy for ECM stiffness.

RESULTS

SGS fibroblasts exhibited higher α-SMA staining and greater inflammatory cytokine and fibrotic marker expression upon TGF-β1 stimulation (p < 0.05). SB525334 restored levels to baseline by reducing SMAD2/3 nuclear translocation (p < 0.0001) and pro-fibrotic gene expression (p < 0.05). ECM stiffness of stenotic fibroblasts was greater than healthy fibroblasts and was restored to baseline by Hippo pathway modulation using SB525334 and DHX (p < 0.01).

CONCLUSION

We demonstrate that distinct fibroblast phenotypes from diseased and healthy regions of pediatric SGS patients respond differently to TGF-β1 stimulation, and SB525334 has the superior potential for subglottic stenosis treatment by simultaneously modulating TGF-β and Hippo signaling pathways.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:287-296, 2024.

Combined Endoscopic Laser and Cryotherapy Management of Pediatric Central Airway Obstruction Secondary to a Histoplasmosis-Related Broncholith

Broncholithiasis due to pulmonary histoplasmosis causing central airway obstruction and broncho-mediastinal fistula is a rare complication in the pediatric population. A 16-year-old previously healthy female was referred to a university hospital for worsening cough and shortness of breath for over a two-year period. Radiologic investigation revealed a calcified subcarinal lymph node eroding into the left mainstem bronchus causing central airway obstruction and collapse of the left lower lobe. Direct laryngoscopy and bronchoscopy showed a large obstructive lesion in the left mainstem bronchus. Debulking of the endobronchial lesion was performed with neodymium-doped yttrium aluminum garnet (Nd:YAG) laser and cryotherapy. Pathology examination was consistent with broncholith. Great clinical and radiological response to the procedure was evident with complete re-expansion of the left lung and resolution of symptoms.

Anesthetic Management for a Patient with Rosai-Dorfman Disease, Cowden Syndrome, and Lhermitte-Duclos Disease: An Extremely Rare Disease Combination

Rosai-Dorfman disease (RDD) is a rare condition that causes massive lymphadenopathy, most commonly in the cervical area. Cowden syndrome (CS) causes hamartomas in the skin and mucosa and predisposes individuals to various malignancies. Lhermitte-Duclos disease (LDD), or dysplastic cerebellar gangliocytoma, is often associated with CS. A 41-year-old female with all three conditions presented with abnormal uterine bleeding and endometrial intraepithelial neoplasia (EIN). Precautions should be considered when evaluating patients with RDD and CS preoperatively and during airway management owing to the potential for multisystem involvement, anatomical distortion, and difficult airways. The likelihood of having all three conditions is extremely rare.

Development and Disorders of the Airway in Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD), a disorder characterized by arrested lung development, is a frequent cause of morbidity and mortality in premature infants. Parenchymal lung changes in BPD are relatively well-characterized and highly studied; however, there has been less emphasis placed on the role that airways disease plays in the pathophysiology of BPD. In preterm infants born between 22 and 32 weeks gestation, the conducting airways are fully formed but still immature and therefore susceptible to injury and further disruption of development. The arrest of maturation results in more compliant airways that are more susceptible to deformation and damage. Consequently, neonates with BPD are prone to developing airway pathology, particularly for patients who require intubation and positive-pressure ventilation. Airway pathology, which can be divided into large and small airways disease, results in increased respiratory morbidity in neonates with chronic lung disease of prematurity.

Delayed Bilateral Vocal Cord Paralysis Following Cervical Spine Trauma

Bilateral vocal cord paralysis is a potentially life-threatening condition, depending on the position in which the vocal cords are paralyzed. When the vocal cords are fixed in adduction, patients develop respiratory distress, inspiratory stridor, aspiration, and minimal phonation deficits. This condition can result from acute injuries to the right and left recurrent laryngeal nerves, or from chronic bilateral recurrent laryngeal nerve palsy. The clinical presentation is variable with such nerve injuries. Traumatic injuries to the cervical spine are an uncommon cause of this condition. In this report, we describe a patient who developed progressive respiratory distress, inspiratory stridor, and dysphagia to liquids several weeks after suffering major trauma to the head and neck. Laryngoscopy revealed immobile bilateral vocal cords fixed in the paramedian position, resulting in severe airway obstruction that warranted an emergency tracheostomy.

Tracheostomy in infants with severe bronchopulmonary dysplasia: A review

In recent years, with increased survival of infants with severe bronchopulmonary dysplasia (BPD), long term ventilation due to severe BPD has increased and become the most common indication for tracheostomy in infants less than one year of age. Evidence shows that tracheostomy in severe BPD may improve short- and long-term respiratory and neurodevelopmental outcomes. However, there is significant variation among centers in the indication, timing, intensive care management, and follow-up care after hospital discharge of infants with severe BPD who received tracheostomy for chronic ventilation. The timing of liberation from the ventilator, odds of decannulation, rate of rehospitalization, growth, and neurodevelopment are all clinically important outcomes that can guide both clinicians and parents to make a well-informed decision when choosing tracheostomy and long-term assisted ventilation for infants with severe BPD. This review summarizes the current literature regarding the indications and timing of tracheostomy placement in infants with severe BPD, highlights center variability in both intensive care and outpatient follow-up settings, and describes outcomes of infants with severe BPD who received tracheostomy.

Correlations of Radiographic and Endoscopic Observations in Subglottic Stenosis

OBJECTIVE(S)

Subglottic stenosis (SGS) represents a constellation of diverse pathologic processes that ultimately lead to narrowing of the subglottic region and can produce significant morbidity. Existing endoscopic and radiographic assessments may not be consistent in practice.

METHODS

Severity of stenosis was evaluated and reported using the Cotton-Myer classification system from 33 endoscopic procedures from 32 unique subjects. Radiographic imaging within the preceding 3 month period was subsequently reviewed and narrowing was measured by a blinded radiologist. Degree of stenosis was reported as a percentage in 30 out of 33 endoscopic evaluations and subsequently compared to radiographically determined percentage of stenosis. Statistical analyzes were conducted to evaluate concordance between endoscopic and radiographic assessments.

RESULTS

About 45.5% (15/33) of the evaluations were in agreement using Cotton-Myer scoring, while 27.3% (9/33) were discrepant by 1 grade and 27.3% (9/33) by 2 grades. Correlation of degree of stenosis as a percentage using Spearman (coefficient: 0.233, P-value: .214) and Pearson (coefficient: 0.138, P-value: .466) methods demonstrated very weak relationships. Radiographic scoring did not predict endoscopic classification to a significant degree using mixed effects regression.

CONCLUSIONS

Radiographic and endoscopic grading of subglottic stenosis may not be reliably concordant in practice.

Factors Associated With Pediatric Emergency Airway Management by the Difficult Airway Response Team

Background

The goal of this study was to determine if difficult airway risk factors were similar in children cared for by the difficult airway response team (DART) and those cared for by the rapid response team (RRT).

Methods

In this retrospective database analysis of prospectively collected data, we analyzed patient demographics, comorbidities, history of difficult intubation, and intubation event details, including time and place of the emergency and devices used to successfully secure the airway.

Results

Within the 110-patient cohort, median age (IQR) was higher among DART patients than among RRT patients [8.5 years (0.9-14.6) versus 0.3 years (0.04-3.6); P < 0.001]. The odds of DART management were higher for children ages 1-2 years (aOR, 43.3; 95% CI: 2.73-684.3) and >5 years (aOR, 13.1; 95% CI: 1.85-93.4) than for those less than one-year-old. DART patients were more likely to have craniofacial abnormalities (aOR, 51.6; 95% CI: 2.50-1065.1), airway swelling (aOR, 240.1; 95% CI: 13.6-4237.2), or trauma (all DART managed). Among patients intubated by the DART, children with a history of difficult airway were more likely to have musculoskeletal (P = 0.04) and craniofacial abnormalities (P < 0.001), whereas children without a known history of difficult airway were more likely to have airway swelling (P = 0.04).

Conclusion

Specific clinical risk factors predict the need for emergency airway management by the DART in the pediatric hospital setting. The coordinated use of a DART to respond to difficult airway emergencies may limit attempts at endotracheal tube placement and mitigate morbidity. 

Foreign Body Aspiration Presenting as Pneumothorax in a Child

A typical presentation of a foreign body aspiration (FBA) in a child includes witnessed choking, respiratory distress, cyanosis, coughing, wheezing, diminished breath sounds, and/or altered mental status. Following an extensive literature review, we found pneumothorax occurring secondary to FBA is a rare occurrence and should elicit prompt treatment. This 17-month-old female was admitted for respiratory syncytial virus (RSV) bronchiolitis and developed a subsequent pneumothorax during her hospital stay, consequent to aspiration of a cashew fragment two weeks before presentation. In light of the National Institute of Allergy and Infectious Diseases (NIAID)-sponsored expert panel’s addended guidelines, published and endorsed by the American Academy of Pediatrics (AAP) in 2017, we highlight a potential complication of increasing encouragement of peanut consumption in children as young as four months.

Risk Factors and Outcomes in Dogs With Respiratory Disease Undergoing Diagnostic Airway Lavage

Advanced diagnostic testing is becoming increasingly important to accurately assess pulmonary parenchymal, airway, and pulmonary vascular diseases in dogs. Due to respiratory system compromise, diagnostic procedures performed under general anesthesia, including thoracic computed tomography (CT) and bronchoalveolar lavage (BAL), are thought to carry significant risk to dogs with respiratory disease. In lieu of performing these diagnostics, empirical medical therapy is often administered, potentially delaying appropriate therapy or providing unnecessary treatment. This study prospectively evaluated risk factors and outcomes for dogs with respiratory disease undergoing general anesthesia for thoracic CT and BAL. Arterial blood gas samples were taken pre- and post-BAL to evaluate pulmonary gas exchange. Pre-BAL arterial partial pressure of oxygen-to-fractional inspired oxygen ratio was used to stratify dogs into groups of mild or moderate to severe disease severity. A novel thoracic CT disease severity scoring system was used to independently stratify dogs into mild or moderate to severe groups. Statistical comparisons between groups were made for signalment, body weight, temperature, pulse, respiratory rate, WBC count, ventilator-acquired pulmonary mechanics (specific compliance and resistance), change in arterial partial pressure of oxygen post-BAL, and outcomes. Seventeen dogs were prospectively enrolled. A comparatively lower heart rate at presentation was the only potential marker of increased disease severity identified when stratified by CT severity score. Arterial partial pressure of oxygen did not significantly decrease post-BAL regardless of disease severity or stratification method. The CT scoring system significantly correlated with the pre-BAL arterial partial pressure of oxygen-to-fractional inspired oxygen ratio. Incidence of post-procedural complications was 18%, with all complications being transient. Mortality as a direct complication of diagnostics was 0%. When considering euthanasia secondary to severity of the underlying disease and poor prognosis or death due to unrelated disease, mortality was 18%. In dogs with respiratory disease undergoing advanced diagnostic procedures, the overall incidence of post-procedural morbidity was low with no mortality directly attributed to the procedures. A novel CT disease severity scoring system was utilized and shows promise as a tool for evaluation of disease severity in this patient population when compared to arterial blood gas analysis.

The Study of Laryngoscopic and Autonomic Patterns in Exercise-Induced Laryngeal Obstruction

OBJECTIVES

(1) Identify laryngeal patterns axiomatic to exercise-induced laryngeal obstruction (EILO) and (2) investigate the role of autonomic function in EILO.

METHODS

Twenty-seven athletic adolescents (13 EILO, 14 control) underwent laryngoscopy at rest and exercise. Glottal configurations, supraglottic dynamics, systolic blood pressure responses, and heart rate recovery were compared between conditions and groups.

RESULTS

Inspiratory glottal angles were smaller in the EILO group than the control group with exercise. However, group differences were not statistically significant ( P > .05), likely due to high variability of laryngeal responses in the EILO group. Expiratory glottal patterns showed statistically greater abductory responses to exercise in the control group ( P = .001) but not the EILO group ( P > .05). Arytenoid prolapse occurred variably in both groups. Systolic blood pressure responses to exercise were higher in the control group, and heart rate recovery was faster in the EILO group. However, no significant differences were seen between the 2 groups on either autonomic parameter ( P > .05).

CONCLUSIONS

"Paradoxical" inspiratory and blunted expiratory vocal fold pattern responses to exercise best characterize EILO. Group differences were only seen with exercise challenge, thus highlighting the utility of provocation and control groups to identify EILO.

Jet ventilation in obese patients undergoing airway surgery for subglottic and tracheal stenosis

OBJECTIVES/HYPOTHESIS

To assess the feasibility of jet ventilation in obese patients and to compare complications of jet ventilation in obese and nonobese patients.

STUDY DESIGN

Retrospective review of medical records.

METHODS

We reviewed 46 patient charts (70 procedures) with the diagnosis of tracheal or subglottic stenosis who underwent endoscopic surgery with jet ventilation between March 2014 and January 2017. Adequacy of jet ventilation was assessed by chest rise, avoidance of endotracheal intubation, and length of case and ventilation. Records were reviewed for demographic details, anesthesia records, and complications.

RESULTS

In 29/70 (41.4%) of cases, patients were obese; in 9/29 (31.0%) of these cases, patients were morbidly obese. Jet ventilation was successful in 28/29 (97%) of obese cases. In 1/29 (3.4%) of cases, the patient required alternative airway management. There were no significant differences between obese and nonobese patients in chest rise, need for endotracheal intubation, and length of surgery or ventilation (P > .05). There were 2/29 (6.9%) cases of intra- and postoperative complications including laryngospasm (1/29, 3.4%) and tachycardia (1/29, 3.4%). Rate of complications did not differ between obese and nonobese patients (P = .178).

CONCLUSIONS

Jet ventilation in obese patients can be done successfully, and complications are similar between obese patients and nonobese patients.

LEVEL OF EVIDENCE

4. Laryngoscope, 1887-1892, 2018.

Transoral Sclerotherapy for Deep Space Cervical Lymphatic Malformations in Children With Acute Airway Compromise

INTRODUCTION

Cervical lymphatic malformations in children rarely present with acute airway compromise. During an acute exacerbation or hemorrhage, lymphatic malformations involving the deep neck spaces may precipitate critical airway obstruction. These are rare clinical entities and tracheotomy is the standard procedure to bypass impending airway obstruction.

METHODS

We present our recent experience with 2 children presenting with acute airway compromise resulting from deep space cervical lymphatic malformations and describe our technique and success with transoral sclerotherapy.

RESULTS

Direct laryngoscopy-assisted transoral sclerotherapy with doxycycline may be considered an alternative to tracheotomy to address retropharyngeal and parapharyngeal space lymphatic malformations.

CONCLUSIONS

Direct laryngoscopy-assisted transoral sclerotherapy is an excellent treatment option for children with deep space cervical lymphatic malformations with airway compromise. It is effective, provides direct access, and can be an alternative to a tracheotomy.

Voice quality in laryngotracheal stenosis: impact of dilation and level of stenosis

OBJECTIVE

To assess the impact of suspension microlaryngoscopy with balloon dilation on voice-related quality of life (V-RQOL) in laryngotracheal stenosis (LTS).

METHODS

Retrospective chart review of LTS patients dilated at a tertiary-care academic hospital from 2010 to 2013. Data were obtained and then analyzed. LTS was stratified by (1) subglottic or tracheal stenosis and (2) multilevel stenosis (MLS; glottic and subglottic/tracheal). Pre- and postoperative V-RQOL and grade, roughness, breathiness, asthenia, strain (GRBAS) scores were compared. The number and frequency of balloon dilation procedures over the lifetime were secondary outcome variables.

RESULTS

Thirty-eight patients were identified: 26 subglottic/tracheal and 12 multilevel. Of these, 71.4% required multiple dilations, with greatest dilations/patient for multilevel stenosis (4.8). V-RQOL improved in the 27 patients with completed pre- and postoperative scores from a mean of 70.4 to 80 (P=.025). Pre/postoperative V-RQOLs for tracheal/subglottic (mean, 82.8/93.8) were significantly higher (P=.0001/.0001) than multilevel stenosis (48/55.3). Voice quality-of-life improvement was significant for the subglottic/tracheal cohort (P=.036) but not for the MLS group. GRBAS was performed pre- and postoperatively in 10 patients with improvement in all domains except breathiness.

CONCLUSION

Laryngotracheal stenosis is associated with dysphonia. Patients with glottic involvement have significantly worse voice quality of life than those with tracheal/subglottic stenosis. Endoscopic balloon dilation improves V-RQOL in patients with subglottic/tracheal stenosis.