Endoscopic airway findings in children with or without prior endotracheal intubation

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.

Anesthesia for laryngotracheal reconstruction in children: A narrative review

Laryngotracheal stenosis, congenital or acquired, is a common cause of pediatric airway obstruction. Acquired subglottic stenosis frequently results from prolonged neonatal intubation. The clinical presentation of subglottic stenosis is variable, ranging from biphasic stridor and frequent upper respiratory infections to acute airway compromise. Optimal patient care requires clinical coordination within a multidisciplinary subspecialty team. Medical management includes optimizing respiratory status, gastroesophageal reflux, speech, feeding, nutrition therapies, and providing psychosocial support. If surgical intervention is required, the otolaryngologist, anesthesiologist, and perioperative team must collaborate closely to ensure successful operative outcomes. This narrative review of laryngotracheal stenosis will discuss the pathophysiology, clinical evaluation, medical management, and surgical interventions, and focus on the perioperative anesthetic considerations for children undergoing laryngotracheal reconstruction.

Pediatric bilateral vocal cord granulomas presenting as airway foreign body following prolonged intubation due to COVID-19 related multisystem inflammatory syndrome

Background

This report is a case of bilateral vocal cord granulomas (VCG) in a 9-year-old child presenting as an airway foreign body and stridor following prolonged intubation due to COVID-19 pneumonia complicated by multisystem inflammatory syndrome in children (MIS-C).

Case presentation

This case reports a 9-year-old male who presented to the emergency department with acute stridor concerning for airway obstruction. X-ray findings suggested an airway foreign body; however, on rigid bronchoscopy, ball-valving bilateral VCG obstructing 90% of the glottic airway were identified. After excision of the VCGs, the patient's symptoms resolved with no postoperative complications.

Conclusion

With suspected foreign body aspiration in a pediatric patient with a history of prolonged intubation, it is important to consider a broad differential diagnosis. VCGs are rare complications of prolonged intubation that could be in children with prior history of intubation following COVID-19 pneumonia.

Subglottic Post-Extubation Upper Airway Obstruction Is Associated With Long-Term Airway Morbidity in Children

OBJECTIVES

Post-extubation upper airway obstruction is the most common cause of extubation failure in children, but there are few data regarding long-term morbidity. We aim to describe the frequency of long-term airway sequelae in intubated children and determine the association with post-extubation upper airway obstruction.

DESIGN

Retrospective, post hoc analysis of previously identified prospective cohort of children in the pediatric/cardiothoracic ICU at Children's Hospital Los Angeles from July 2012 to April 2015. A single provider blinded to the upper airway obstruction classification reviewed the electronic medical records of all patients in the parent study, before and after the index extubation (extubation during parent study), to identify pre-index and post-index upper airway disease. Primary outcomes were prevalence of newly diagnosed airway anomalies following index extubation.

SETTING

Single center, tertiary, 391-bed children's hospital.

PATIENTS

From the parent study, 327 children younger than 18 years (intubated for at least 12 hr) were included if they received subsequent care (regardless of specialty) after the index extubation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

New airway anomalies were identified in 40 of 327 children (12.2%). Patients labeled with subglottic upper airway obstruction at the index extubation were more likely to be diagnosed with new airway anomalies on subsequent follow-up, receive long-term Otolaryngology follow-up, or receive airway surgery (all p ≤ 0.006). In multivariable modeling, upper airway obstruction as the primary reason for initial intubation (odds ratio, 3.71; CI, 1.50-9.19), reintubation during the index ICU admission (odds ratio, 4.44; CI, 1.67-11.80), pre-index airway anomaly (odds ratio, 3.31; CI, 1.36-8.01), and post-extubation subglottic upper airway obstruction (odds ratio, 3.50; CI, 1.46-8.34) remained independently associated with the diagnosis of new airway anomalies.

CONCLUSIONS

Post-extubation subglottic upper airway obstruction is associated with a three-fold greater odds of long-term airway morbidity. These patients may represent an at-risk population that should be monitored closely after leaving the ICU.

[Ventilation in Pediatric Anesthesia]

About nine percent of all anesthesia procedures per year are performed in children. The risk for complications in pediatric anesthesia is higher in comparison with adults. There are significant differences in anatomy, physiology and pharmacology between pediatric and adult patients. Respiratory complications and circulations dysregulation occur more often in children. The most important consideration in the safe practice of pediatric anesthesia is to ensure a patent airway. Appropriate intraoperative management of newborns and infants needs a senior anesthetist with good knowledge and clinical experience including the management of possible complications.

Cuffed endotracheal tubes in neonates and infants of less than 3 kg body weight-A retrospective audit

BACKGROUND

Large prospective clinical studies have shown that modern cuffed pediatric tracheal tubes can be used safely, even in children weighing ≥3 kg. There is a growing interest in their use in children weighing <3 kg so that they, too, can benefit from the potential advantages, particularly the high probability of these tubes fitting into and sealing the pediatric airway at the first intubation attempt. This study aimed to find a cut-off body weight for procedures requiring a cuffed tracheal tube to seal the airway in children weighing <3 kg and to evaluate the frequency and predictive factors for the requirement to place a cuffed instead of an uncuffed tracheal tube.

METHODS

This study was a retrospective analysis of 269 children weighing 2000-2999 g, primarily intubated by pediatric anesthetists. Frequency of intubation with uncuffed Sheridan tubes versus cuffed Microcuff^® Pediatric Endotracheal Tube (PET) 3.0 mm ID was studied. Predictive variables were assessed by means of logistic regression analysis. The ROC curve for weight at intubation time and Youden index was calculated.

RESULTS

The 149 (55.4%) children were finally intubated with a cuffed tracheal tube. Logistic regression demonstrated that body weight at tracheal intubation and birth weight were the strongest predictors for the appropriateness of cuffed/uncuffed tracheal tubes. The threshold weight at tracheal intubation was 2700 g for a probability >50% of using a cuffed tracheal tube.

CONCLUSION

Half of the children weighing 2000-2999 g received a Microcuff^® PET 3.0 mm ID, especially those with a body weight above 2700 g. Because of the anatomical dimensions in patients with a body weight of 2000-2999 g, cuffed tracheal tubes with smaller outer diameters may be required to better fit their airways.

Anatomical In Vitro Investigations of the Pediatric Larynx: A Call for Manufacturer Redesign of Tracheal Tube Cuff Location and Perhaps a Call to Reconsider the Use of Uncuffed Tracheal Tubes

BACKGROUND

Some in vivo studies question the traditional "funnel-shaped" infant larynx; further anatomic examinations were warranted. Examination of fixative free fresh autopsy laryngeal and upper tracheal specimens and multiple measurements was needed to determine consistency between current tracheal tube designs and anatomic observations.

METHODS

Larynges from 19 males and 11 females (Caucasian term newborn to 126 months) were examined by the same forensic pathologist. Measurements included anterior/posterior (A/P) and transverse (T) diameters of the cricoid outlet (CO), interarytenoid diameter (IAD), cricothyroid membrane (CTM), distance from the vocal cords (VC) to CO (VC-CO), and calibration of the larynx lumen with uncuffed tracheal tubes as measuring rods. Assessment of "safe tracheal tube placement" was assessed using manufacturer recommended cuffed Microcuff (Kimberly-Clark, Koblenz, Germany) tubes.

RESULTS

In 77% (95% confidence interval [CI], 58-90) of specimens, the proximal end of the cuff was within the CO and in 23% even with or close to the CO. The VC-CO varied from 9.1 to 13.17 mm in infants, 11.55 to 15.17 mm in toddlers, and 13.19 to 18.34 mm in children. The AP/T ratio of the CO was nearly 0.99 in most larynges; the IAD was greater than CO in all specimens. The CTM could be minimally distended in all specimens.

CONCLUSIONS

First, despite being marketed as a safer tracheal tube design, the proximal end of the Microcuff cuff rested within or close to the cricoid cartilage theoretically increasing potential cuff-induced injury when using the VC markings for positioning. Our data suggest that the optimal cuff free distance (VC-CO) would be ~13.5 mm for a Microcuff internal diameter (ID) size 3.0, ~15 mm for size 3.5, and ~16 to 19 mm for greater sizes.Second, the CO was virtually circular in all specimens, suggesting that appropriately sized uncuffed tubes should provide an adequate seal in most neonates and toddlers, thus avoiding the potential for cuff-related necrosis injury.Third, the IAD was always greater than CO confirming that the narrowest point of the infant larynx is the nondistensible cricoid cartilage and not the easily distended glottis.Fourth, appropriately sized Microcuff tubes with the cuff deflated completely filled the lumen of the CO and proximal trachea in all specimens. Our data suggest the need for all manufacturers to further evaluate tracheal tube cuff locations and lengths in relation to the VC safe insertion markings, particularly for neonates and toddlers.Fifth, the CTM is minimally distensible, thus having important implications for emergency surgical airway access with most currently available emergency airway devices.

Cuffed pediatric endotracheal tubes-Outer cuff diameters compared to age-related airway dimensions

BACKGROUND

Reliable sealing of the pediatric airway requires appropriately sized tracheal tube cuffs. The aim of this study was to compare residual cuff diameters of pediatric tracheal tubes with pediatric airway dimensions.

METHODS

Cuff diameters of five different brands of locally marketed pediatric cuffed tracheal tubes with internal diameters of 3.0-7.0 mm were measured at a cuff pressure of 20 cm H₂ O and compared with cuff diameters indicated by their manufacturers. The latter values were compared to tracheal dimensions using the Motoyama and Khine formulas for cuffed tracheal tube size selection.

RESULTS

There is considerable heterogeneity in cuff diameters among pediatric tracheal tube brands, except for two brands from different manufacturers (Halyard and Parker Medical) which were identically designed. Cuffs made from polyurethane revealed fewer differences (91%-118%) between measured and manufacturer-indicated values for outer cuff diameters than did those made from polyvinylchloride (91%-146%). Particularly in smaller sized tracheal tubes, cuffs did not reach 100% of the tracheal lateral diameter, while others were oversized in larger tracheal tubes, independent of the two formulas used for cuffed tracheal tube size selection. Cuff diameters indicated by the manufacturer corresponded to 86%-188% of the median and 68%-157% of the maximum mid-tracheal lateral diameter of the corresponding upper age range.

CONCLUSION

Our findings show that many of the cuff diameters of currently marketed tracheal tube brands lack an age-related anatomical rationale. A proposal for age-related anatomically based cuff diameters is provided for both recommendations for cuffed tracheal tube size selection in children.

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.

Risk factors for laryngeal trauma and granuloma formation in pediatric intubations

OBJECTIVE

Intubation has been associated with laryngeal injury that often resolves spontaneously without complication. We present a case of a child intubated for less than 48 hours, who presented with dysphonia and intermittent dyspnea two months after intubation due to epiglottic and vocal process granulomas. This is unusual in that multiple granulomas were found in the posterior glottis and supraglottis after short-term intubation. Our objective was to determine if there are risk factors for developing persistent post-intubation sequelae, including the delayed presentation and unusual location of post-intubation granulomas in our case.

STUDY DESIGN

Case report and systematic literature review.

METHODS

Pubmed database, which is inclusive of MEDLINE, was used to perform a literature review with the search terms ((pediatric OR children OR neonatal OR infant) AND (laryngeal OR supraglottic) AND intubation AND (granuloma OR injury OR complication)). Only English language results were reviewed. Titles and abstracts from 379 results were reviewed. Full text was reviewed from all original studies which included human pediatric subjects and endoscopic examinations after endotracheal intubation.

RESULTS

In our case, laryngeal granuloma size reduced significantly after starting anti-reflux medications. The remainder was removed with laryngeal microdebrider with no recurrence at 3 weeks and 2.5 years post-operatively. Overall, 28 of the 379 studies reviewed identified evidence of laryngeal trauma due to intubation, however only 6 studies documented any type of supraglottic injury. Risk factors identified for developing post-intubation sequelae included intubation duration greater than 24 h; trauma to the larynx via various mechanisms including traumatic intubation, need for reintubation and tube changes, and increased movement while intubated; and presence of respiratory tract infection during intubation.

CONCLUSION

Trauma to the larynx during intubation should be avoided to minimize post-intubation injury in pediatric patients, by using appropriate intubation protocols, endotracheal tube size, and adequate sedation.

Prevalence and characteristics of tracheal cobblestoning in children

BACKGROUND

Tracheal follicular pattern or so-called tracheal cobblestoning is a poorly described entity in the literature and is depicted as a nodular or lumpy appearance of the tracheal wall mucosa suggesting tracheal irritation from factors like gastro-esophageal reflux (GERD) or pulmonary infection. The aim of the present study was to investigate the prevalence and characteristics of tracheal cobblestones in a large pediatric population.

METHODS

A large database of rigid tracheoscopies recorded in children (0-6 years of age) undergoing general anesthesia with planned tracheal intubation for elective surgical procedures was retrospectively analyzed. Tracheoscopy records were reviewed by five pediatric airway experts (authors 3-7). Data were compared using the Mann-Whitney test, chi-square or Fisher exact test as appropriate (P < 0.05).

RESULTS

A total of 971 rigid tracheoscopy records were analyzed. The median age of the patients was 3.3 years (range 0.4-6.0 yrs). Cobblestones were present in 377 out of 971 patients (38.8%) with a male to female prevalence of 254 (40.6%)/123 (35.5%). None of the children under four months of age showed the presence of cobblestones. The prevalence of cobblestones was significantly less in patients under 3 years of age compared to over 3 years (P < 0.01). There was no association between prevalence of cobblestones and GERD, current or recent respiratory infection or concomitant enlarged tonsils.

CONCLUSION

The prevalence of tracheal cobblestones in otherwise healthy children is high and is not associated with GERD or respiratory infection. The gender and age related differences are novel interesting findings that require further investigations.