Evaluation of neonatal subglottic stenosis: a 3-year prospective study

Subglottic Stenosis After Pediatric Tracheostomy

OBJECTIVES

To determine the incidence of subglottic stenosis (SGS) in children after tracheostomy and identify risk factors for development.

STUDY DESIGN

Retrospective cohort.

METHODS

All patients (<18 years) undergoing tracheostomy at a tertiary children's hospital between 2015 and 2020 were included. Patients with a direct laryngoscopy (DL) concurrent with tracheostomy and a subsequent DL were included. Medical records, including operative reports, were reviewed to identify subglottic stenosis and associated risk factors.

RESULTS

A total of 140 patients were included with mean age at tracheostomy of 2.4 years (standard deviation [SD]: 4.3) (median: 0.5 years, interquartile range [IQR]: 0.3-1.5 years) and gestational age of 33.8 weeks (SD: 5.9) (median: 36 weeks, IQR: 28-39 weeks). At initial DL, 24% (N = 34) had subglottic injury and 26% (N = 37) developed SGS. The incidence of SGS after tracheostomy was 11.5 cases per 100 patients per year. At tracheostomy, lower birth weight (1.8 vs. 2.3 kg, p = 0.005), shorter gestational age (31.8 vs. 34.6 weeks, p = 0.01), younger age (0.8 vs. 2.9 years, p = 0.01), lower weight (5.8 vs. 14.7 kg, p = 0.01), and subglottic injury (44% vs. 21%, p = 0.01) were associated with the development of SGS. Multivariable logistic regression analysis associated birth weight (odds ratio [OR]: 0.49, 95% confidence interval [CI]: 0.31-0.75, p = 0.001) and early subglottic injury (OR: 3.22, 95% CI: 1.31-7.88, p = 0.01) with SGS development.

CONCLUSIONS

The incidence of SGS after pediatric tracheostomy is estimated at 11.5 cases per 100 patients per year. Low birth weight and subglottic injury at the time of tracheostomy were associated with SGS in this vulnerable population of children.

LEVEL OF EVIDENCE

3 Laryngoscope, 2024.

Factors associated with laryngeal injury after intubation in children: a systematic review

PURPOSE

The purpose of this study is to evaluate all potential factors associated with laryngeal injury after endotracheal intubation in the pediatric population.

METHODS

A systematic literature search was conducted in Medline, Embase, Cochrane, web of science and Google scholar up to 20th of March 2023. We included all unique articles focusing on factors possibly associated with intubation-injury in pediatric patients. Two independent reviewers determined which articles were relevant by coming to a consensus, quality of evidence was rated using GRADE criteria. All articles were critically appraised according to the PRISMA guidelines. The articles were categorized in four outcome measures: post-extubation stridor, post-extubation upper airway obstruction (UAO) necessitating treatment, laryngeal injury found at laryngoscopy and a diagnosed laryngotracheal stenosis (LTS).

RESULTS

A total of 24 articles with a total of 15.520 patients were included. The incidence of post-extubation stridor varied between 1.0 and 30.3%, of post-extubation UAO necessitating treatment between 1.2 and 39.6%, of laryngeal injury found at laryngoscopy between 34.9 to 97.0% and of a diagnosed LTS between 0 and 11.1%. Although the literature is limited and quality of evidence very low, the level of sedation and gastro-esophageal reflux are the only confirmed associated factors with post-extubation laryngeal injury. The relation with age, weight, gender, duration of intubation, multiple intubations, traumatic intubation, tube size, absence of air leak and infection remain unresolved. The remaining factors are not associated with intubation injury.

CONCLUSION

We clarify the role of the potential factors associated with laryngeal injury after endotracheal intubation in the pediatric population.

Point-of-care ultrasound to confirm endotracheal tube cuff position in relationship to the cricoid in the pediatric population

BACKGROUND

Anatomically, the subglottic area and the cricoid ring are the narrowest portions of the larynx. To limit the potential for damage related to mucosal pressure injuries from the presence of an endotracheal tube, the cuff should be placed below the cricoid in children. Previously, no clinical or imaging method has been used in real time to determine the exact location of the endotracheal tube cuff after endotracheal intubation. Point-of-care ultrasound may provide an option as a safe and rapid means of visualizing the endotracheal tube cuff and its relationship to the cricoid ring thereby achieving ideal endotracheal tube cuff positioning-below the cricoid.

METHODS

In this prospective, nonrandomized trial, point-of-care ultrasound was used following endotracheal intubation in children to evaluate the position of the endotracheal tube cuff in relationship to the cricoid and tracheal rings. After anesthesia was induced and the trachea was intubated, the endotracheal tube cuff and its position in relation to the cricoid and tracheal rings were identified in the longitudinal plane using point-of-care ultrasound. With the patient's neck in a neutral position, the level of the proximal (cephalad) margin of the saline-filled cuff of the endotracheal tube was identified and recorded in relationship to the cricoid and tracheal rings. The ideal position is defined as the cephalad margin of the endotracheal tube cuff below the level of the cricoid.

RESULTS

The study cohort included 80 patients, ranging in age from 1 to 78 months. In all patients, the cuff of the ETT, cricoid, and tracheal rings were identified. The cephalad end of the endotracheal tube cuff was found at the level of the cricoid in 16.3% of patients, at the first tracheal ring in 27.5% of patients, at the second tracheal ring in 23.8% of patients, at the third tracheal ring in 17.5% of patients, and at below the fourth tracheal ring in 15% of patients. Initial endotracheal tube cuff position had no significant association with age, height, weight, endotracheal tube size, and endotracheal tube type.

CONCLUSION

Point-of-care ultrasound provides a rapid and effective means of identifying the position of the endotracheal tube cuff in relationship to the cricoid ring. The technique may have applications in the perioperative arena, emergency departments, and intensive care units.

Endotracheal tube cuff position in relation to the cricoid in children: A retrospective computed tomography-based analysis

Background:

The use of cuffed endotracheal tubes (ETT) has become the standard of care in pediatric practice. The rationale for the use of a cuffed ETT is to minimize pressure around the cricoid while providing an effective airway seal. However, safe care requires that the cuff lie distal to the cricoid ring following endotracheal intubation. The current study demonstrates the capability of computed tomography (CT) imaging in identifying the position of the cuff of the ETT in intubated patients.

Methods:

In this retrospective study, the ETT cuff position was examined on the sagittal plane images of neck and chest CT scans of 44 children. The position of the proximal and the distal aspect of the ETT cuff inside the trachea was recorded in relation to the vertebral levels. The vertebral levels were used to estimate the location of the cricoid ring and its relationship to the cuff.

Results:

The vertebrae were used as the primary landmarks to define the position of the cricoid and its relationship to the cuff of the ETT. Correlating vertebral levels with the cricoid for different age groups, the proximal (cephalad) edge of the ETT cuff was below the cricoid in 41 of 44 patients (93%). The ETT cuff was deep in 6 patients, below the 1^st thoracic vertebra, with 2 ETTs in the right mainstem bronchus.

Conclusion:

This is the first study demonstrating that the cuff of the ETT and its position in the trachea can be identified on CT imaging in children. The ETT cuff was below the level of the cricoid in the majority of patients irrespective of the patient's age as well as the size, make, and type of ETT.

Short-term complications and long-term morbidities associated with repeated unplanned extubations

OBJECTIVE

To describe characteristics associated with repeated unplanned extubations, short-term complications and outcomes, and longer-term morbidities including acquired subglottic stenosis.

STUDY DESIGN

Cohort study including neonates admitted to a tertiary care neonatal intensive care unit who experienced an unplanned extubation in a 5-year period.

RESULTS

We reviewed 588 events involving 300 patients. Ten percent had airway trauma with reintubation, 42% required ≥2 reintubation attempts, and 39% led to increased baseline oxygen. Increased odds of repeated events were seen in patients with bronchopulmonary dysplasia and were associated with higher rates of tracheostomy and longer length of stay. The 9% of patients diagnosed with acquired subglottic stenosis had more unplanned extubations, higher rates of airway trauma and tracheitis, and were an older gestational age at birth.

CONCLUSION

Unplanned extubations lead to short- and long-term morbidities. Certain patient characteristics are associated with increased odds of repeated events and the development of acquired subglottic stenosis.

Acquired subglottic cysts in children: A rare and challenging clinical entity. A systematic review

INTRODUCTION

Subglottic cysts (SGCs) are a rare cause of laryngeal stenosis that mainly seem to affect preterm infants with an intubation history.

PURPOSE

To review the related literature and compare different management protocols for patients presenting SGCs, as well as briefly report our clinical case treated at Verona University Hospital by Pediatric Airways Team.

METHODS

The articles resulting from a PubMed and MEDLINE search were analysed and selected using previously established criteria. A systematic review of the selected papers was conducted following PRISMA guidelines.

RESULTS

The search yielded 571 related articles; cross-checking of articles led to the identification and exclusion of 239 duplicates. The remaining 332 papers were screened according to previously established eligibility criteria. The final number of selected articles was 13.

CONCLUSIONS

Well-planned teamwork, with active collaboration between the ENT specialists, pediatricians and anesthesiologists, is the key to achieve multidisciplinary management of patients diagnosed with SGCs. Long-term follow-up is crucial considering the high recurrence rate of this disease.

Predictors of the need for tracheostomy in the neonatal intensive care unit

OBJECTIVES

Many infants in the neonatal intensive care unit (NICU) require prolonged periods of respiratory support. Microlaryngoscopy and bronchoscopy (MLB) is performed to evaluate for airway pathology and facilitate decision-making regarding further airway interventions or tracheostomy. The objectives of this study are to describe the operative findings of MLB performed on infants in the NICU and determine which pre-operative characteristics or operative findings are predictive of the need for tracheostomy.

METHODS

The medical records of preterm inpatients in the NICU at a single tertiary care hospital who underwent MLB between January 1, 2013 and January 7, 2016 were reviewed. Baseline and demographic characteristics and intra-operative findings were compared between patients who underwent tracheostomy and those who were successfully weaned from respiratory support.

RESULTS

Seventy-three preterm patients underwent MLB for respiratory failure, of whom 41 (56.2%) underwent tracheostomy. Patients who underwent tracheostomy had lower mean gestational age (27.4 vs. 30.5 weeks), higher prevalence of bronchopulmonary dysplasia (73.2% vs. 37.5%), lower mean birth weight (1.1 kg vs. 1.6 kg), and a greater number of extubation events (5.2 vs. 3.0) than those who weaned from respiratory support. Abnormal MLB findings were common in both groups, though no single MLB finding differed significantly between groups.

CONCLUSIONS

Preterm infants in the NICU with gestational age ≤30 weeks, birth weight <1.5 kg, severe pulmonary disease, and who have failed more than 3 extubation attempts are more likely to require tracheostomy.

A multidisciplinary, video-based, curriculum for management of the intubated and surgical airway patient for a pediatric hospital in El Salvador

OBJECTIVE

Primary objective is to determine the rate of intubation with inappropriately sized endotracheal tubes (ETTs) in a pediatric intensive care unit (PICU) in El Salvador. Secondary objective is to determine effectiveness of a video-based curriculum to teach local providers on pediatric advanced airway management and surgical approach to patients requiring airway reconstruction.

METHODS

Data for 296 intubated pediatric patients was collected over a six month period in a 16-bed PICU in El Salvador. Results of a learning behavior assessment survey completed by local healthcare workers informed a curriculum to complement on-site education during annual surgical airway mission trips. The video-based curriculum addressed proper sizing and use of cuffed endotracheal tubes, care of the intubated child and perioperative considerations of the surgical airway patient. Providers completed pre and post-curriculum quizzes to measure knowledge acquisition.

RESULTS

Over 6-months, 281 patients were intubated. Sixty-three percent had improperly sized ETTs. Thirty-one percent had a failed or accidental extubation. All-cause mortality was 24%. One hundred and fifty-nine Salvadorian providers completed a learning behavior survey informing a video-based curriculum. Sixty-four providers completed the curriculum. Post-curriculum quiz scores increased by 18.7%. Surgeons, anesthesiologist, intensivists and speech pathologists demonstrated significant improvement (p < 0.05).

CONCLUSION

Nearly two-thirds of intubated patients in a PICU in El Salvador have improperly sized ETTs and one-third require reintubation following planned or accidental extubation. The development of this first of its kind video-based curriculum for critical care and surgical training regarding how to properly care for the intubated child is coupled with the development of a longitudinal database to record pediatric airway related morbidity and mortality in the largest pediatric hospital in El Salvador. This model and system can be used to track the reduction in airway related morbidity and mortality directly related to a systems based intervention both in El Salvador and then elsewhere.

Accuracy of stridor-based diagnosis of post-intubation subglottic stenosis in pediatric patients

OBJECTIVE

To assess the accuracy of stridor in comparison to endoscopic examination for diagnosis of pediatric post-intubation subglottic stenosis.

METHOD

Children who required endotracheal intubation for >24h were included in this prospective cohort study. Children were monitored daily and underwent flexible fiberoptic laryngoscopy after extubation. Those with moderate-to-severe abnormalities underwent another examination 7-10 days later. If lesions persisted or symptoms developed, laryngoscopy under general anesthesia was performed. Patients were assessed daily for stridor after extubation.

RESULTS

A total of 187 children were included. The incidence of post-extubation stridor was 44.38%. Stridor had a sensitivity of 77.78% (95% confidence interval [95% CI]: 51.9-92.6) and specificity of 59.18% (95% CI: 51.3-66.6) in detecting subglottic stenosis. The positive predictive value was 16.87% (95% CI: 9.8-27.1), and the negative predictive value was 96.15% (95% CI: 89.9-98.8). Stridor persisting longer than 72h or starting more than 72h post-extubation had a sensitivity of 66.67% (95% CI: 41.2-85.6), specificity of 89.1% (95% CI: 83.1-93.2), positive predictive value of 40.0% (95% CI: 23.2-59.3), and negative predictive value of 96.07% (95% CI: 91.3-98.4). The area under the receiver operating characteristic (ROC) curve was 0.78 (95% CI: 0.65-0.91).

CONCLUSIONS

Absence of stridor was appropriate to rule out post-intubation subglottic stenosis. The specificity of this criterion improved when stridor persisted longer than 72h or started more than 72h post-extubation. Thus, endoscopy under general anesthesia can be used to confirm subglottic stenosis only in patients who develop or persist with stridor for more than 72h following extubation.

The Incidence of Laryngotracheal Stenosis in Neonates With a History of Ventilator-Associated Pneumonia

OBJECTIVES/HYPOTHESIS

Neonatal patients requiring prolonged intubation are susceptible to both infection and laryngotracheal stenosis (LTS). This study investigated the effect of ventilator-associated pneumonia (VAP) on the development of LTS in neonates.

STUDY DESIGN

Retrospective case-control study.

METHODS

The incidence of LTS in neonates with VAP was compared with the incidence of LTS in matched intubated controls without VAP. Patients were treated at a tertiary-care medical center from 2004 to 2014. Eligible patient records were assessed for the development of LTS. Demographics, medical comorbidities, infection characteristics, and treatment variables were compared using unpaired t test or χ² test. Statistical significance was set a priori at P < .05.

RESULTS

When comparing the VAP patients with matched non-VAP controls, we found no significant differences in the incidence of LTS (VAP vs. non-VAP, 8.3% vs. 6.7%; P = .73). In subgroup analysis of the VAP cohort, LTS and non-LTS patients demonstrated similar VAP organisms on broncho-alveolar lavage (Klebsiella pneumoniae, Pseudomonas aeroginosa, Escherichia coli, methicillin-resistant Staphylococcus aureus, Streptococcus pneumoniae, and Enterobacter). Additionally, within the VAP cohort, LTS and non-LTS patients showed similar gestational age (LTS vs. non-LTS, 31.3 days vs. 28.1 days; P = .22), birth weight (LTS vs. non-LTS, 1.6 kg vs. 1.2 kg; P = .33), and similar intubation duration (LTS vs. non-LTS, 37.8 days vs. 27.5 days; P = .52).

CONCLUSIONS

In this neonatal cohort, VAP was not associated with an increased incidence of LTS. Given severity of the burden of LTS on the healthcare system, multi-institutional longitudinal investigation into contributing risk factors for neonatal LTS is warranted.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:2252-2255, 2020.

The pediatric airway: Historical concepts, new findings, and what matters

New observations from novel imaging techniques regarding the anatomy, dimensions, and shape of the pediatric airway have emerged and provide insight for potential changes in the clinical management of the airway in infants and children. These new findings are challenging the historical concepts of a funnel-shaped upper airway with the cricoid ring as the narrowest dimension. Although these tenets have been accepted and used to guide clinical practice in airway management, there are limited clinical investigations in children to support the validity of these concepts. Imaging modalities such as magnetic resonance imaging, computed tomography (CT) scanning, multi-detector CT imaging, and videobronchoscopy suggest the need to revisit the historical view of the pediatric airway. This manuscript reviews the historical evolution of pediatric airway studies, summarizes important scientific observations from recent investigations relevant to our clinical understanding of pediatric airway anatomy, and discusses the importance of these findings for pediatric airway management.

Severe acquired subglottic stenosis in neonatal intensive care graduates: a case-control study

OBJECTIVE

To analyse current incidence and risk factors associated with severe acquired subglottic stenosis (SASGS) requiring surgical intervention in neonates.

DESIGN

Retrospective case-control study.

SETTING

Sole tertiary children's hospital.

PARTICIPANTS

Patients who underwent surgical intervention for SASGS from January 2006 to December 2014. For each neonatal intensive care unit (NICU) graduate with acquired SASGS, two controls were selected (matched for gestation and year of birth).

MAIN OUTCOMES AND MEASURES

Incidences were calculated and cases and controls compared using conditional logistic regression analysis to identify risk factors for SASGS.

RESULTS

Thirty-seven NICU graduates required surgical intervention for SASGS of whom 35 were <30-week gestation at birth. The incidence of SASGS in surviving children who had required ventilation in the neonatal period was 27/2913 (0.93%). Incidence was higher in infants <28-week gestation (24/623=3.8%) compared with infants ≥28-week gestation (3/2290=0.13%; p=0.0001). On univariate analysis, risk factors for SASGS were: higher number of intubations (4 vs 2; p<0.001); longer duration ventilation (16 vs 9.5 days; p<0.001); unplanned extubation (45.7% vs 20.0%; p=0.007); traumatic intubation (34.3% vs 7.1%; p=0.003) and oversized endotracheal tubes (ETTs) (74.3% vs 42.9%; p=0.001). On multivariate analysis, risk factors for SASGS were: Sherman ratio >0.1 (adjusted OR (aOR) 6.40; 95% CI 1.65 to 24.77); more than five previous intubations (aOR 3.74; 95% CI 1.15 to 12.19); traumatic intubation (aOR 3.37; 95% CI 1.01 to 11.26).

CONCLUSIONS

SASGS is a serious consequence of intubation for mechanical ventilation in NICU graduates, especially in preterm infants. Minimising trauma during intubations, avoiding recurrent extubation/reintubations and using appropriate sized ETTs may help prevent this serious complication.

The therapy with ethosomes containing 5-fluorouracil for laryngotracheal stenosis in rabbit models

The aim of this study is to evaluate the efficacy of ethosomes encapsulated with 5-fluorouracil (5-FU) in treatment of laryngotracheal stenosis in rabbit models. The 5-FU ethosome was prepared by the thin film hydration method, and the amorphous, size distribution and the encapsulation efficiency was investigated. The tracheal mucosa were scraped about 0.5 cm with a nylon brush to induce the scar in airway grow, then models were divided into three groups: 5-FU ethosome group, 5-FU group and saline group, drug were injected into scar of every group by paracentesis guided under endoscope, respectively. The stenosis states were observed under laryngo fiberscope immediate, 7, 14 and 21 days after administrated. Airway stenosis of 5-FU ethosome group has no significant difference when compared with 5-FU group at 7 days after administration, but 5-FU ethosome significantly reduced the airway stenosis after 21-day administration when compared with 5-FU group again and has no restenosis during the period under observation. The fact that ethosomes encapsulated with 5-FU were effective for laryngotracheal stenosis suggests that it has potential as a new method for ameliorating airway stenosis originating from granulation tissue.

Advances in the diagnosis, management, and treatment of neonates with laryngeal disorders

Neonatal airway obstruction due to laryngeal pathology may cause significant morbidity and even mortality. The most frequently occurring etiologies anatomically from superiorly to inferiorly include: laryngomalacia, saccular cyst, vocal fold paralysis, anterior glottic web, laryngeal atresia, laryngeal cleft, subglottic stenosis, and subglottic hemangioma. The pathophysiology, presentation, and treatment options for each of these entities are discussed with a focus on a multidisciplinary, evidence-based approach.

Characteristics and surgical outcome of 98 infants and children surgically treated for a laryngotracheal stenosis after endotracheal intubation: excellent outcome for higher grades of stenosis after SS-LTR

INTRODUCTION

To describe the characteristics and surgical outcome of 98 infants and children treated for an acquired laryngeal stenosis after intubation for respiratory support.

MATERIAL AND METHODS

We retrospectively reviewed our data from the last 18 years (1994-2013) concerning infants and children with an acquired laryngotracheal stenosis who were treated in our hospital with a laryngotracheal reconstruction or a cricotracheal resection. Outcome was defined by decannulation ratio.

RESULTS

Of the 98 infants and children who were studied, 54% were preterm, 18% neonates, 13% infants and 14% children. Ninety-one SS-LTR's, two DS-LTR's and five CTR's were performed as primary surgery; three revision operations were performed (DS-LTR). Seventy-seven children had a tracheostomy prior to surgery; decannulation ratio was 93% after primary surgery and 95% after inclusion of revision surgery. For SS-LTR, the decannulation ratio was 93%, including grade III stenosis with comorbidities. Male sex and glottic involvement of the stenosis are correlated to failure of decannulation. Intubation in the term neonatal period is correlated to complicated post-operative course after SS-LTR.

CONCLUSIONS

Excellent results of surgery for acquired laryngotracheal stenosis can be obtained with a high decannulation rate. Even for higher grades of stenosis with comorbidities and glottic involvement, an SS-LTR is an effective surgical treatment for acquired laryngeal stenosis.

Optimal care and design of the tracheal cuff in the critically ill patient

Despite the increasing use of non-invasive ventilation and high-flow nasal-oxygen therapy, intubation is still performed in a large proportion of critically ill patients. The aim of this narrative review is to discuss recent data on long-term intubation-related complications, such as microaspiration, and tracheal ischemic lesions. These complications are common in critically ill patients, and are associated with substantial morbidity and mortality. Recent data suggest beneficial effects of tapered cuffed tracheal tubes in reducing aspiration. However, clinical data are needed in critically ill patients to confirm this hypothesis. Polyurethane-cuffed tracheal tubes and continuous control of cuff pressure could be beneficial in preventing microaspiration and ventilator-associated pneumonia (VAP). However, large multicenter studies are needed before recommending their routine use. Cuff pressure should be maintained between 20 and 30 cmH₂O to prevent intubation-related complications. Tracheal ischemia could be prevented by manual or continuous control of cuff pressure.

Endoscopic anterior cricoid split with balloon dilation in infants with failed extubation

Subglottic injury (SGI) is a known complication of prolonged intubation in neonates and infants and can lead to failed extubation. SGI is a spectrum that includes mucosal edema, ulceration, granulation perichondritis, and mature scar formation. Although medical management aimed at treating mucosal edema and extraesophageal reflux is successful in treating a majority of patients, some require surgical intervention to successfully achieve extubation. The surgical options for these patients include tracheostomy, open anterior cricoid split (ACS), and laryngotracheal reconstruction with cartilage grafting. Open ACS is performed through an external incision requiring placement of a drain for a few days. Extubation success rates in the 70% to 80% range have been widely reported. In this article we describe an endoscopic technique for ACS, in which after an endoscopic airway assessment confirms isolated SGI, the cricoid cartilage is divided transluminally with cold steel. Balloon dilation (BD) is then performed with an appropriately sized angiography balloon. We describe preliminary results in which two of three patients were successfully extubated after endoscopic ACS with BD. We believe that this novel technique is a promising alternative to open ACS with similar indications. In addition to the avoidance of a skin incision, endoscopic ACS with BD may enable extubation with comparably shorter lengths of postprocedure intubation than open ACS. Larger series will be required to further establish outcomes of this procedure, including success and complication rates.

Prediction of extubation outcome in preterm infants by composite extubation indices

OBJECTIVE

To determine whether composite extubation indices can predict extubation outcome in preterm infants.

DESIGN

Prospective observational study.

SETTING

Level III neonatal intensive care unit.

PATIENTS

Fifty-six preterm infants cared for in the neonatal intensive care unit of a tertiary teaching hospital during 2007 and 2008.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The study consisted of two parts. In the first part, different extubation indices were evaluated in a group of 28 neonates (derivation group). These indices included the diaphragmatic pressure-time index, the respiratory muscle pressure-time index, the maximal transdiaphragmatic pressure, the maximal inspiratory pressure, the airway pressure generated 100 milliseconds after an occlusion/maximal transdiaphragmatic pressure ratio, the airway pressure generated 100 milliseconds after an occlusion/maximal inspiratory pressure ratio, the tidal volume, and the respiratory rate to tidal volume ratio. After exploratory analysis, the best performing indices and the optimal threshold values to predict extubation outcome were selected. In the second part of the study, these indices were validated at the predetermined threshold values in an additional group of 28 preterm neonates (validation group). Four infants (14.3%) in the derivation group and four in the validation group (14.3%) failed extubation. Receiver operator characteristic curve analysis revealed that a diaphragmatic pressure-time index of ≤0.12, a respiratory muscle pressure-time index ≤0.10, a airway pressure generated 100 milliseconds after an occlusion/maximal transdiaphragmatic pressure of ≤0.14, and a airway pressure generated 100 milliseconds after an occlusion/maximal inspiratory pressure of ≤0.09 were the most accurate predictors of extubation outcome in the derivation group. In the validation group, a diaphragmatic pressure-time index of ≤0.12 and a respiratory muscle pressure-time index of ≤0.10 both had zero false-positive results, predicting with accuracy successful extubation.

CONCLUSION

Composite extubation indices such as the diaphragmatic pressure-time index and the noninvasive respiratory muscle pressure-time index can accurately predict extubation outcome in preterm neonates.

Amelioration of airway stenosis in rabbit models by photodynamic therapy with talaporfin sodium (NPe6)

It is difficult to treat patients with acquired airway stenosis, and the quality of life of such patients is therefore lowered. We have suggested the application of photodynamic therapy (PDT) as a new treatment for airway stenosis and have determined the efficacy of PDT in animal disease models using a second-generation photosensitizer with reduced photosensitivity. An airway stenosis rabbit model induced by scraping of the tracheal mucosa was administered NPe6 (5 mg kg(-1)), and the stenotic lesion was irradiated with 670 nm light emitted from a cylindrical diffuser tip at 60 J cm(-2) under bronchoscopic monitoring. PDT using NPe6 improved airway stenosis (P = 0.043) and respiratory stridor. A significant prolongation of survival time was seen in the PDT-treated animals compared to that in the untreated animals (P = 0.025) and 44% of the treated animals achieved long-term survival (>60 days). In conclusion, PDT using NPe6 is effective for improvement in airway stenosis.

Photodynamic Therapy for Airway Stenosis in Rabbit Models

BACKGROUND

Acquired airway stenosis in childhood is resistant to conventional treatment. We examined whether endoscope-assisted photodynamic therapy (PDT) is effective for airway stenosis in animal models of which the pathophysiologic progressions are similar to those of clinical cases showing rapid deterioration.

METHODS

Tracheal mucosa-scraped rabbits were administered IV porfimer sodium (Photofrin; Wyeth K.K., Tokyo, Japan) [2 mg/kg], and the tracheal lesions were irradiated with 630 nm of light emitted from a cylindrical diffuser tip via a transtracheal approach.

RESULTS

Rabbits without PDT (untreated animals) showed dense granulation tissue in the scraped lesion, resulting in airway stenosis complicated with respiratory stridor. PDT ameliorated the degree of airway stenosis (p = 0.008) and reduced respiratory stridor; rabbits that received PDT showed patchy granulation tissue that was only 20 to 30% of the volume of that seen in the untreated animals. Survival time of rabbits that received PDT was significantly prolonged compared with that of untreated animals (p = 0.03).

CONCLUSIONS

PDT was effective for airway stenosis in rabbit models. This suggests that PDT has the potential as a new therapeutic method for airway stenosis originating from granulation tissue.

Piloting a novel porcine model for endolaryngeal injury following prolonged intubation

OBJECTIVES

(1) To develop a practical animal model of endolaryngeal damage secondary to prolonged endotracheal intubation. (2) To demonstrate the contribution of chronic hypoxia to laryngeal injury in the context of this model.

METHODS

Four Sus scrofa piglets were anaesthetized and intubated for 24h. Two animals were maintained in a state of constant hypoxia (pO(2)<60 mmHg) while two others were ventilated with 100% oxygen. Prior to sacrifice, fluorescein dye was infused intravenously to highlight areas of hypoperfusion. The larynx and trachea were then harvested for gross and histological examination.

RESULTS

All four specimens demonstrated areas of edema, erythema, and ulceration on gross examination. Areas of significant histological inflammation, ulceration, and necrosis involved tube-mucosa contact, in particular, the arytenoids, the interarytenoid area, and the subglottis.

CONCLUSIONS

This animal model represents a practical and novel means for the investigation and treatment of laryngeal injury secondary to prolonged endotracheal intubation. Significant injury to the endolarynx was evident after only 24h of intubation and the injury involved similar areas within the larynx as described in human studies. Although clinical experience suggests that chronic hypoxia is a risk factor for endolaryngeal injury, this model did not provide experimental evidence to support this observation, most likely due to the small study size.

Incidence of severe acquired subglottic stenosis in newborns

OBJECTIVE

To determine the change in the statewide incidence of severe acquired subglottic stenosis (SGS) in newborns over the past decade.

METHODS

Multicenter, statewide retrospective study of all patients under the age of 12 months who were diagnosed with acquired SGS that required surgical intervention by anterior cricoid split (ACS) or tracheostomy between 1993 and 2003.

RESULTS

There were 34 patients (19 male; 15 female) with a median age of 4 months at the time of surgery. The primary surgical intervention performed was ACS 20, and tracheostomy 14 (incidence rate of 41%). Subsequently, 11 patients who failed decannulation following ACS underwent tracheostomy. Five patients died due to reasons unrelated to their SGS, and among the 29 survivors, 8 remain cannulated. The overall success rate for ACS was 35%. The mean annual statewide incidence of severe acquired SGS over the 10-year period was 4.95 per 100,000 live births.

CONCLUSION

The annual incidence of acquired SGS in newborns requiring open surgical intervention is in the order of 0.005%. The incidence of acquired SGS provides us with a benchmark figure that reflects the quality and standard of obstetric, neonatal and pediatric care across the state.

Acquired paediatric subglottic cysts: a series from Manchester

Subglottic cysts (SGC) have long been regarded as a rare cause of airway obstruction but through increased awareness an increase in the number of cases of SGC has been reported.

OBJECTIVE

This paper describes the pathogenesis and management of SGC.

DESIGN

Retrospective case series. Ethical approval not sought.

SETTING

Royal Manchester Children's Hospital.

PATIENTS

Two hundred and six new referrals for direct laryngotracheobronchoscopy (DLTB) were identified from records between September 2003 and September 2005.

MAIN OUTCOMES MEASURED

Age at birth, sex, length of intubation, presenting symptoms, age at presentation, DLTB findings, interventional procedures, and follow-up DLTBs.

RESULTS

Fourteen out of 206 (6.8%) infants were diagnosed as with subglottic cysts. This represented the fourth most common cause of upper airway pathology. Thirteen out of 14 (93%) infants were preterm (26.8 weeks S.D. 25.3-28.3 weeks). All infants had been intubated ranging from 1 to 180 days (median 42 days). The onset of symptoms ranged from 1 to 13 months (median 4.25 months). Initially, 8/14 (57.2%) infants had SGC cysts marsupialised with microforceps. A further six cysts (50%) were decapped between 2 and 4 months and one between 6 and 12 months.

CONCLUSION

The number of cases of SGC has been increasing over the last three decades and represents the fourth most common causes of airway obstruction in our series. There is a delay in onset of symptoms and high rate of recurrence in the first 4 months. It is therefore prudent to reschedule further endoscopic evaluation between 2 and 4 months and after 6 months should the clinical need arise.

Tracheostomy in infants and children after cardiothoracic surgery: indications, associated risk factors, and timing

BACKGROUND

Respiratory insufficiency in children after cardiothoracic surgery delays weaning from the ventilator and prolongs intensive care unit stay. There is little consensus as to the indications for tracheostomy and its safety in this population.

METHODS

We reviewed our institutional experience in 37 consecutive infants and children (median age, 8.6 months; weight, 7.2 kg) requiring a tracheostomy after cardiothoracic surgery between January 1998 and December 2001, with follow-up to June 2003.

RESULTS

Twenty-four children underwent tracheostomy after corrective (n = 15) or palliative (n = 9) surgery for congenital heart disease, 8 had undergone thoracic transplantation, and 5 had undergone thoracic surgery. Median duration of pretracheostomy ventilation was 30 days, and median total duration of ventilation was 73 days. Tracheostomy was performed earlier in patients undergoing transplantation (median of 20 days postoperatively), with a duration of ventilation of 34 days. No patient experienced mediastinitis, and a wound infection in 1 child was the only identified complication. Twenty-two children survived to hospital discharge, of whom 15 have since been decannulated; 6 still have a tracheostomy in situ and 1 has been lost to follow-up. A number of preoperative and postoperative factors were identified in this cohort. These were preoperative respiratory insufficiency, a history of neonatal ventilation, the need for cardiac reoperations, diaphragmatic paralysis, tracheobronchomalacia, neurological comorbidity, and associated chromosomal abnormalities.

CONCLUSION

Tracheostomy can be performed safely and without increased risk of complications in infants and children early after cardiothoracic surgery. The presence of identifiable factors in patients in whom weaning has been unsuccessful should alert clinicians to early consideration of tracheostomy.

Possible risk factors associated with moderate or severe airway injuries in children who underwent endotracheal intubation

OBJECTIVE

To analyze the role of risk factors associated with moderate or severe airway injuries in children who underwent endotracheal intubation.

DESIGN

Prospective cohort study.

SETTING

Pediatric intensive care unit.

PATIENTS

All patients who required endotracheal intubation during a 25-mo period (October 1999 through October 2001). Exclusion criteria were death before extubation and weight of <1250 g.

INTERVENTIONS

Airway endoscopy at extubation and reevaluation for those reintubated.

MEASUREMENTS

Relative risks and 95% confidence intervals were calculated in the univariate risk factor analysis (age, sex, organ failure, difficult intubation, tube size, reintubation, tube changes, and duration of intubation). p Values were calculated from the chi-square test with Yates' correction or for trend, and a value of <.05 was considered significant. To define which of the main variables were independently associated with the outcomes of interest, we used logistic stepwise forward modeling. The Mantel-Haenszel method was used for the stratified analysis between the two independently associated variables.

RESULTS

The study population consisted of 215 patients (61 newborns and 154 children). Moderate lesions occurred in 24.2% of patients, and severe lesions in 10.7% of patients. Risk factors associated with moderate or severe injury in a univariate analysis were age, sex, organ failure, reintubation, tube changes, and longer duration of intubation. According to Mantel-Haenszel stratified analysis results, reintubation and tube changes were the only variables independently associated with the outcomes.

CONCLUSIONS

We concluded that to prevent morbidity secondary to airway injury, efforts should be directed to avoid reintubation and tube changes in the concerned scenario.

Laryngeal mask versus endotracheal tube in a ferret model

Acquired subglottic stenosis in infants is a difficult iatrogenic problem with notable morbidity, primarily caused by prolonged endotracheal intubation. The laryngeal mask airway (LMA) is a recently developed, alternative airway device that does not contact the subglottis. To explore the possibility of preventing subglottic stenosis, we compared the endotracheal tube (ETT) and the LMA in terms of the incidence and severity of glottic and subglottic injury resulting from prolonged intubation in the adult ferret model of the infant airway. Ten adult ferrets were randomly intubated under inhalational anesthesia with either a 4.0 cuffless ETT or a size 1 LMA for a 24- to 48-hour period. Rigid laryngeal endoscopy was used to detect pharyngeal or glottic injury during the period of intubation and on a routine basis for 3 months after extubation. All 5 ferrets in the ETT group developed endoscopically evident glottic and subglottic injury; 2 of the 5 developed a symptomatic, mature subglottic stenosis. The 5 ferrets in the LMA group had endoscopically normal larynges. However, all ferrets in the LMA group developed significant tongue edema and cyanosis during the first 24 hours of intubation, and 3 of the 5 died of respiratory failure due to airway obstruction. In the 2 LMA survivors, evidence of oropharyngeal injury persisted until 6 weeks after extubation. We conclude that the LMA does not cause subglottic injury in this model. However, its prolonged use results in significant pharyngeal morbidity that raises serious doubt as to its potential routine use in infants requiring prolonged ventilatory support.

Neonatal subglottic stenosis--incidence and trends

OBJECTIVE/HYPOTHESIS

Neonatal subglottic stenosis is a known entity arising from endotracheal tube intubation. In the 1970s and 1980s, estimates of the incidence of subglottic stenosis were in the range of 0.9% to 8.3% of intubated neonates. Because of improved techniques of handling neonates who require ventilatory support, we thought the actual incidence of neonatal subglottic stenosis in the late 1990s was much lower.

STUDY DESIGN

We retrospectively reviewed all neonatal intensive-care unit (NICU) admissions from 1997 at our institution, which serves as a level 3 NICU. We also performed a MEDLINE search of the reported incidence of neonatal subglottic stenosis between 1960 and 1999.

METHODS

Analysis was performed to identify all children who developed subglottic stenosis at our institution. Data were also collected and analyzed with regard to average gestational age, average birth weight, average duration of intubation, and the number of children requiring tracheostomy. The reports identified in the literature were reviewed as to the incidence of subglottic stenosis.

RESULTS

A total of 544 neonates were admitted to the unit. Of these, 281 were intubated for an average of 11 days. No patients developed subglottic stenosis. Three patients required tracheostomies for other reasons. All studies published after 1983 reported an incidence of neonatal subglottic stenosis as less than 4.0%, and all studies published after 1990 reported an incidence of neonatal subglottic stenosis as less than 0.63%.

CONCLUSIONS

Although our report applies to only a single institution in a single year, after reviewing the literature we think a downward trend exists in the incidence of neonatal subglottic stenosis in the late 1990s. The current incidence of neonatal subglottic stenosis is likely between 0.0% and 2.0%.

Role of infection in the development of acquired subglottic stenosis in neonates with prolonged intubation

OBJECTIVE

To examine whether clinically diagnosed infection correlates with subsequent development of subglottic stenosis in intubated neonates.

METHODS

Sixty-two neonatal infants intubated for more than 14 days were examined. Several risk factors for subglottic stenosis, including infection, duration of intubation, frequency of intubation, the size of the endotracheal tube etc., were evaluated by multiple logistic regression analysis.

RESULTS

Infection that occurred within 14 days of intubation showed a positive correlation with subsequent subglottic stenosis. The duration of intubation, frequency of intubation and the size of the endotracheal tube did not affect the development of subglottic stenosis. The majority of infections were considered to be respiratory tract infections, including pneumonia.

CONCLUSIONS

Infection occurring within 14 days of intubation is considered to be a risk factor for acquired subglottic stenosis in neonates intubated for more than 14 days. Prevention of infection within 14 days of intubation may reduce the incidence of subglottic stenosis in neonates.

Effect of stenting after laryngotracheal reconstruction in a subglottic stenosis model

OBJECTIVES

This study addresses the impact of stenting on early wound healing after laryngotracheal reconstruction (LTR) in a rabbit model with established subglottic stenosis.

METHODS

Subglottic stenosis was created in 42 New Zealand white rabbits through a transoral, endoscopic technique. Three weeks later, endoscopy and axial CT were performed to document and grade the degree of stenosis. Subsequently, LTR was performed in all animals, with half of the animals receiving an intraluminal stent. Four rabbits from each group were euthanized on postoperative days 6, 9, 14, 21, and 28. Measurements of graft vascularization were obtained with a computerized image measurement program, and a comparison was made regarding the rate of vascularization.

RESULTS

There was a statistically significant increase in the rate of vascularization in the stented group (mean 75% +/- 5% vs 56% +/- 3% at day 14; P < 0. 05). However, clinical and radiographic comparisons of the stented and nonstented specimens revealed a trend toward increased mucosal edema and granulation tissue in the stented group at later time intervals (days 21 and 28).

CONCLUSION

This analysis suggests that stenting does not inhibit graft vascularization in the early postoperative period after LTR; however, complications were seen in the stented group at longer time intervals.

Update on the use of auricular cartilage in laryngotracheal reconstruction

The pediatric otolaryngologist is often called upon to aid in the diagnosis and management of subglottic stenosis. This report contains an update of our experience using auricular cartilage in laryngotracheal reconstruction. A retrospective review of the medical records at St Louis Children's Hospital identified 43 children with subglottic stenosis. Thirty-one children were treated by use of auricular cartilage with a success rate of 84%, and an overall 94% success rate after revision surgery. Eight children in whom an anterior cricoid split initially failed were secondarily treated with auricular cartilage with a success rate of 75%. Two children initially treated with costochondral cartilage underwent multiple reconstructive procedures with either auricular cartilage or costochondral cartilage with an overall success rate of 50%. The remaining 2 children had long-segment tracheal stenosis and underwent repair with auricular cartilage with a 50% success rate. We find that auricular cartilage grafts are highly effective when used in a primary single-stage procedure in children with grade I or II stenosis. We have had limited success with auricular cartilage in patients with grade III stenosis and are reluctant to use it in grade IV stenosis, long-segment tracheal stenosis, staged reconstruction, or revision of an auricular or costal cartilage graft laryngotracheal reconstruction.

Changing trends in neonatal subglottic stenosis

OBJECTIVES

To determine whether there are any changes in the incidence and management of neonatal subglottic stenosis (SGS).

METHODS

A retrospective chart review of 416 infants who were admitted to the neonatal intensive care unit of the Children's National Medical Center between July 1, 1995, and June 30, 1996, was carried out. The incidence of airway obstruction requiring anterior cricoid split or placement of tracheotomy tube was determined and compared with the incidence studied 10 years ago at the same institution.

RESULTS

One of 416 neonates required surgical intervention for airway obstruction caused by SGS, for an overall neonatal SGS incidence of 0.24%. When only the neonates who were intubated for 48 hours or longer were considered, the incidence of SGS was 0.49% (1/204). In neonates who were intubated for 48 hours or longer and survived, the incidence of SGS was 0.63% (1/160). This is in comparison with the incidences of 0.65% (3/462), 1.5% (3/195), and 1.9% (3/159), respectively, seen in a study done at the Children's National Medical Center 10 years ago. Five infants in this current study required placement of a tracheotomy tube for reasons other than SGS. Two infants needed tracheotomy tube placement for micrognathia, and 3 others for central hypotonia, an omphalocele that required multiple surgical procedures, and choanal atresia with a serious heart anomaly, which was a manifestation of CHARGE association. None of these 5 infants had evidence of SGS at rigid endoscopy preceding the tracheotomy tube placement.

CONCLUSION

The incidence and management of neonatal SGS remain unchanged during this study period when compared with those of 10 years ago.

Laryngotracheal Reconstruction without Stenting

Many surgical procedures, including laryngotracheal expansion with or without grafting, have been suggested for repairing laryngotracheal stenosis in children, and although a variety of stents have been described, the practice of prolonged stenting continues to diminish. We describe 21 pediatric patients with moderate-to-severe subglottic or tracheal stenosis who had laryngotracheal reconstructions with anterior rib cartilage grafts without stenting or intubation. The patients were between 6 months and 7 years of age at the time of surgery. All patients were extubated in the operating room after the procedure was terminated. One patient required reintubation in the intensive care unit for 48 hours after surgery, and another patient required a tracheotomy. Wound infection occurred in one patient. Most patients were discharged to their homes 3 to 5 days after surgery. We report the indications, technique, results, and complications of laryngotracheal reconstruction using a rib graft without stenting.

Failed extubation in the neonatal intensive care unit

One of the roles of the pediatric otolaryngologist in the neonatal intensive care unit (NICU) is the assessment and management of the neonate who fails a trial of extubation. This paper reviews the recent 5-year institutional experience at The Hospital for Sick Children, Toronto, with neonates who failed extubation and who subsequently underwent diagnostic endoscopy. One hundred twenty-eight neonates from the NICU underwent diagnostic endoscopy. Of these, 58 neonates underwent diagnostic endoscopy for failure to extubate. Nine neonates were extubated after diagnostic endoscopy and retrial (16% of the series). Eleven neonates were extubated after additional endoscopic procedures (19% of the series). Twenty-four neonates underwent anterior cricoid split, of whom 20 or 83% (34% of the series) were eventually successfully extubated with no further airway intervention required during the study period (minimum 6 months' follow-up). Eleven neonates underwent tracheotomy (19% of the series). Four neonates underwent another external procedure to allow extubation (7% of the series). Three neonates died while still intubated (5% of the series). Our management of the neonate who fails a trial of extubation is discussed.

Subglottic ulceration and healing following endotracheal intubation in the neonate: a morphometric study

In neonates, acquired subglottic stenosis is the most serious long-term complication of endotracheal intubation and is due primarily to posttraumatic fibrosis of the infant larynx. We have examined 78 larynges, 75 of which were intubated, from infants ranging in gestation from 22 to 40 weeks, and who survived from a few hours to up to 300 days. Each larynx was morphometrically assessed for the extent of acute injury, indicated by the percentage of epithelial loss, and healing, indicated by the percentage of a subglottic ulcer covered by metaplastic squamous epithelium. Results show that acute injury is almost invariable, and up to 100% of the subglottic epithelium may be lost within a few hours of intubation, but that progression of injury is relatively short-lived. Ulcer healing starts after a few days, rapidly progresses from day 10, and in the majority of cases is complete after 30 days. This study suggests that long-standing acute injury in the subglottis is the exception rather than the rule, even with the endotracheal tube remaining in place.