Posterior Glottic Injury Following Prolonged Intubation in COVID-19 Patients.

OBJECTIVE: The objective of this study was to characterize the risk factors for posterior glottic injury (PGI) in patients with coronavirus disease 2019 (COVID-19) who underwent prolonged intubation. STUDY DESIGN: This was a case-control study designed to assess the risk factors associated with development of PGI in COVID-19 patients who underwent prolonged intubation. SETTING: This single-center study was conducted at a tertiary care academic hospital in a metropolitan area. METHODS: We retrospectively reviewed patients who underwent prolonged intubation (≥7 days) for COVID-19 and compared those with PGI to those without. Patient demographics, comorbidities, and intubation characteristics were compared. Factors associated with PGI development among COVID-19 patients were assessed using multivariate regression. RESULTS: We identified 56 patients who presented with PGI following prolonged intubation for COVID-19 and 60 control patients who underwent prolonged intubation for COVID-19 but did not develop PGI. On univariate analyses, the number of reintubations due to failed extubation efforts was significantly associated with development of PGI (odds ratio [OR], 2.9; 95% CI, 1.4-6.2). On multivariate analyses, patients with cardiovascular disease (OR, 3.3; 95% CI, 1.2-9.0); non-COVID-19 respiratory illnesses, which included obstructive sleep apnea and asthma (OR, 5.9; 95% CI, 2.0-17.8); and diabetes mellitus (OR, 11.6; 95% CI, 3.7-36.6) were more likely to develop PGI. CONCLUSION: Our results represent the largest case-control study investigating risk factors for PGI in the setting of prolonged intubation specific to COVID-19. Our study suggests a significant role of comorbidities associated with poor wound healing with development of PGI.

Characterization of Fibroblasts in Iatrogenic Laryngotracheal Stenosis and Type II Diabetes Mellitus.

OBJECTIVES: Iatrogenic laryngotracheal stenosis (iLTS) is the pathological narrowing of the glottis, subglottis, and/or trachea due to scar tissue. Patients with type 2 diabetes mellitus (T2DM) are over 8 times more likely to develop iLTS and represent 26% to 53% of all iLTS patients. In this investigation, we compared iLTS scar-derived fibroblasts in patients with and without T2DM. STUDY DESIGN: Controlled ex vivo study. METHODS: iLTS scar fibroblasts were isolated and cultured from subglottic scar biopsies in iLTS patients diagnosed with or without type 2 diabetes (non-T2DM). Fibroblast proliferation, fibrosis-related gene expression, and metabolic utilization of oxidative phosphorylation (OXPHOS) and glycolysis were assessed. Contractility was measured using a collagen-based assay. Metabolically targeted drugs (metformin, phenformin, amobarbital) were tested, and changes in fibrosis-related gene expression, collagen protein, and contractility were evaluated. RESULTS: Compared to non-T2DM, T2DM iLTS scar fibroblasts had increased α-smooth muscle actin (αSMA) expression (8.2× increased, P = .020), increased contractility (mean 71.4 ± 4.3% vs. 51.7 ± 16% Δ area × 90 minute-1 , P = .016), and reduced proliferation (1.9× reduction at 5 days, P < .01). Collagen 1 (COL1) protein was significantly higher in the T2DM group (mean 2.06 ± 0.19 vs. 0.74 ±.44 COL1/total protein [pg/µg], P = .036). T2DM iLTS scar fibroblasts had increased measures of OXPHOS, including basal respiration (mean 86.7 vs. 31.5 pmol/minute/10 µg protein, P = .016) and adenosine triphosphate (ATP) generation (mean 97.5 vs. 25.7 pmol/minute/10 µg protein, P = .047) compared to non-T2DM fibroblasts. Amobarbital reduced cellular contractility; decreased collagen protein; and decreased expression of αSMA, COL1, and fibronectin. Metformin and phenformin did not significantly affect fibrosis-related gene expression. CONCLUSION: T2DM iLTS scar fibroblasts demonstrate a myofibroblast phenotype and greater contractility compared to non-T2DM. Their bioenergetic preference for OXPHOS drives their increased contractility, which is selectively targeted by amobarbital. LEVEL OF EVIDENCE: NA Laryngoscope, 131:1570-1577, 2021.

Peixe Encravado na Árvore Respiratória de Uma Criança: Um Caso Invulgar / Ingrown Fish in a Child's Respiratory Tree: An Unusual Case

Corpos estranhos nos orifícios naturais da cabeça e pescoço são de ocorrência comum na prática clínica, sobre¬tudo nas urgências de otorrinolaringologia. Entretanto, um peixe inteiro nas vias aéreas é uma ocorrência relati¬vamente invulgar. Assim, nesta comunicação, descreve-se uma peça anatómica das vias respiratórias de uma criança que apresenta um pequeno peixe encravado e que se encontra exposta no Museu de Anatomia do De¬partamento de Ciências Morfológicas da Faculdade de Medicina da Universidade Eduardo Mondlane. Esta peça representa um importante exemplo anatómico no processo de ensino-aprendizagem das causas de asfixia sobre¬tudo em crianças que se dedicam à pesca e/ou gostam de fazer mergulhos nos rios ou nos mares.

Foreign bodies in the natural orifices of the head and neck are a common occurrence in clinical practice, especially in urgent cases of otolaryngology. However, a whole fish in the airways is a relatively unusual occurrence. Thus, in this communication, an anatomical piece of the respiratory tract of a child that presents a small ingrown fish is described in the Museum of Anatomy of the Department of Morphological Sciences of the Faculty of Medicine of the Eduardo Mondlane University. This piece represents an important anatomical specimen in the teaching-learning process of the causes of asphyxia, especially in children who dedicate themselves to fishing and / or like to do dives in rivers or seas.

Postoperative sore throat and subglottic injury after McGrath® MAC videolaryngoscopic intubation with versus without a stylet in patients with a high Mallampati score: a randomized controlled trial.

BACKGROUND: A tracheal tube stylet can be used to assist successful tracheal intubation, especially during videolaryngoscopic intubation because videolaryngoscopes with a Macintosh-type blade such as McGrath® MAC videolaryngoscope have more acute angle than conventional Macintosh laryngoscope. However, the use of a stylet during tracheal intubation can raise concerns about stylet-induced postoperative airway complications, such as sore throat, subglottic injury, and hoarseness. In this study, we compared the incidence of postoperative airway complications after McGrath® MAC videolaryngoscopic intubation with versus without a stylet in patients with a high Mallampati score. METHODS: In 104 patients with Mallampati score III or IV and who were scheduled for lumbar or thoracic spine surgery, McGrath® MAC videolaryngoscopic intubation was performed either with a stylet (group S, n = 52) or without a stylet (group N, n = 52). The primary outcome measure was the incidences of sore throat evaluated at 1 and 24 h postoperatively. Secondary outcome measures were the incidences of subglottic injury and postoperative hoarseness. RESULTS: The incidence of CL grade III in group S and N was 3.8 and 5.8%, respectively. No patient showed CL grade IV. The incidences of sore throat at 1 (26.9 vs 19.2%, P = 0.485) and 24 h (17.3 vs 13.5%, P = 0.786, respectively) postoperatively were not significantly different between the group S and N. However, the incidence of subglottic injury was significantly higher in the group S, compared with the group N (65.4 vs 42.3%, P = 0.030). The incidence of postoperative hoarseness did not differ significantly between the two groups. CONCLUSIONS: The use of a stylet during McGrath® MAC videolaryngoscopic intubation did not have a significant impact on the incidence of postoperative sore throat in patients with a high Mallampati score. Avoiding the use of a stylet during intubation with McGrath® MAC videolaryngoscope may reduce the incidence of subglottic injury in such patients. TRIAL REGISTRATION: Clinical Research Information Service (identifier: KCT0002427 , date of registration: June 12, 2017).

Glottic Stenosis: An Anatomic Analysis and New Treatment With a Self-Retaining Interarytenoid Spring.

INTRODUCTION:: Endotracheal (ET) intubation is a common cause of acquired glottic stenosis. Severe cases often require an irreversible arytenoidectomy/cordectomy, which typically results in poor voice quality. Adult human cadaver larynges were studied to gain insights about ET tube-induced posterior glottic injuries, hoping to create a less invasive remedy. STUDY DESIGN:: Human cadaver investigation and case reports. METHODS:: Microlaryngeal assessments were done on 10 human cadaver larynges (5 men, 5 women) with and without ET tubes. After supracricoid soft tissue resection, measurements were obtained, including the distance between the outer diameter of the ET tube and the medial aspect of the cricoarytenoid joint facet. Additionally, measurements of the circumferential arc of differently sized ET tubes were made alongside both cricoarytenoid joint capsules. This information was used to design a silastic stent that would function as a self-retaining interarytenoid spring to treat posterior glottic stenosis in 5 patients. Four of 5 patients included in the clinical study were tracheotomy dependent, primarily because of glottic stenosis. The human surgical technique is described in detail. RESULTS:: The shortest distance between the outer diameter of the ET tube to the medial cricoid facet averaged 5.02 mm in men and 3.62 mm in women. On the basis of the diameter of the intralaryngeal component of the initially round stent, and the position of the cricoarytenoid joint facets, the interarytenoid spring would have a subtended arc between 110° and 175°. These data helped fashion parameters for modifying a conventional T-tube to form a new self-retaining silastic interarytenoid spring. The first 5 human cases have been successful, allowing effective tracheotomy tube decannulation and excellent voice quality. CONCLUSIONS:: The anatomic investigation herein provided key insights into ET tube-induced glottic stenosis and facilitated a new straightforward procedure to surgically improve the airway yet preserve excellent vocal function in patients with acquired glottic stenosis. Level of Evidence: NA.

Demographic and Symptomatic Features of Voice Disorders and Their Potential Application in Classification Using Machine Learning Algorithms.

BACKGROUND: Studies have used questionnaires of dysphonic symptoms to screen voice disorders. This study investigated whether the differential presentation of demographic and symptomatic features can be applied to computerized classification. METHODS: We recruited 100 patients with glottic neoplasm, 508 with phonotraumatic lesions, and 153 with unilateral vocal palsy. Statistical analyses revealed significantly different distributions of demographic and symptomatic variables. Machine learning algorithms, including decision tree, linear discriminant analysis, K-nearest neighbors, support vector machine, and artificial neural network, were applied to classify voice disorders. RESULTS: The results showed that demographic features were more effective for detecting neoplastic and phonotraumatic lesions, whereas symptoms were useful for detecting vocal palsy. When combining demographic and symptomatic variables, the artificial neural network achieved the highest accuracy of 83 ± 1.58%, whereas the accuracy achieved by other algorithms ranged from 74 to 82.6%. Decision tree analyses revealed that sex, age, smoking status, sudden onset of dysphonia, and 10-item voice handicap index scores were significant characteristics for classification. CONCLUSION: This study demonstrated a significant difference in demographic and symptomatic features between glottic neoplasm, phonotraumatic lesions, and vocal palsy. These features may facilitate automatic classification of voice disorders through machine learning algorithms.

Transcricothyroid Endoscopic Subglottic Surgery for Posterior Glottic Stenosis: A Case Report.

Posterior glottic stenosis (PGS) is a rare but life-threatening condition mostly caused by damage to the interarytenoid mucosa by an endotracheal tube. In surgical treatment of PGS, airway patency is prioritized, and the laryngeal functions involved in swallowing and phonation are considerably sacrificed. In the majority of cases, lateralization of a vocal fold or partial excision of a vocal fold and arytenoid cartilage results in glottal closure insufficiency and deterioration of phonatory function. We present the first report of transcricothyroid endoscopic subglottic surgery to treat a 46-year-old man with PGS who was intubated for 10 days. Postoperative hypofunction was not observed in the aerodynamic examination and acoustic analysis, and phonatory function has been maintained within normal limits.

Difficult tracheal tube passage and subglottic airway injury during intubation with the GlideScope® videolaryngoscope: a randomised, controlled comparison of three tracheal tubes.

Difficulty during placement of the tracheal tube is a known problem when intubating with the GlideScope® , which may lead to subglottic airway injury. This randomised, controlled clinical trial was designed to compare the resistance to passage of PVC (polyvinyl chloride), reinforced or BlockBuster tracheal tubes during intubation with the GlideScope. Secondary outcomes included the time taken to intubate and assessment of subglottic airway injury. One-hundred and seventy-seven patients were included in the data analysis. There was difficult tracheal tube passage (moderate or severe resistance) in 15 (21.4%) patients using the PVC tube compared with 4 (7.4%) and 1 (1.9%) using the reinforced and BlockBuster tubes, respectively (p = 0.003 for PVC vs. BlockBuster). The median (IQR [range]) time taken to intubate was 35 (27-45 [15-115]) s, 25 (20-27 [15-110]) s and 25 (22-30 [16-90]) s, respectively, (p < 0.001 for PVC vs. reinforced as well as PVC vs. BlockBuster). Subglottic airway injury, assessed using a fibreoptic bronchoscope after extubation, was higher with the PVC tube (p < 0.001) and the reinforced tube (p = 0.012) compared with the BlockBuster tube. We conclude that the BlockBuster tracheal tube is a better choice for orotracheal intubation with the GlideScope than PVC or reinforced tubes.

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Estenosis subglótica postintubación en niños. Diagnóstico, tratamiento y prevención de las estenosis moderadas y severas / Post-intubation subglottic stenosis in children. Diagnosis, treatment and prevention of moderate and severe stenosis

Introducción y objetivos: La estenosis subglótica es una de las causas más frecuentes de obstrucción laríngea. El 90% resultan de la intubación endotraqueal. La conducta terapéutica dependerá entre otros factores del grado de estenosis que se presente. Variará desde la conducta expectante en los grados leves hasta la cirugía compleja en los graves. Presentamos nuestra experiencia en el manejo quirúrgico de la estenosis subglótica postintubación en niños, y enfatizamos la necesidad de reconocimiento y prevención de los factores predisponentes de la estenosis por intubación. Método: Se evaluaron en forma retrospectiva 71 pacientes con estenosis subglótica moderada a severa postintubación, operados en el Servicio de Endoscopia Respiratoria durante un periodo de 8 años. Las variables analizadas fueron la edad al momento quirúrgico, el grado de la estenosis, la técnica quirúrgica utilizada, las complicaciones y los resultados. Resultados: El 84,5% de los pacientes requirió un solo tratamiento quirúrgico para lograr la decanulación. Se implementaron 3 técnicas quirúrgicas: reconstrucción laringotraqueal, resección cricotraqueal parcial y división anterior del cricoides. Se logró la decanulación en 70 casos, presentando buena ventilación, deglución y voz el 71,8%, disfonía el 23,9% y dificultad respiratoria leve el 2,8%. Un paciente falleció. Conclusión: Frente a un paciente con estenosis subglótica, seleccionar el tratamiento apropiado es la llave del éxito, disminuye el número de cirugías y previene las complicaciones (AU)

Introduction and objectives: Subglottic stenosis is one of the most common causes of upper airway obstruction. Almost 90% of them result from endotracheal intubation. Therapy depends on the degree of stenosis, among other factors. Therapeutic approaches range from watchful waiting, in mild stenosis, to complex surgery for severe cases. We report our experience on the surgical management of post-intubation subglottic stenosis in children, emphasising the need for recognition and prevention of predisposing factors of post-intubation stenosis. Methods: We retrospectively evaluated 71 patients with moderate to severe post-intubation subglottic stenosis, operated in the Respiratory Endoscopy Service in a period of eight years. The clinical variables analysed were age at surgery, degree of stenosis, surgical technique, complications and outcome. Results: In 84.5% of patients, only 1 surgical approach was required to achieve decannulation. Three surgical techniques were implemented as therapy: laryngotracheal reconstruction, partial cricotracheal resection and anterior cricoid split. Decannulation was achieved in 70 cases. In 71.8%, ventilation, swallowing and voice qualities were good; 23.9% presented dysphonia; and 2.8% presented a mild respiratory distress. One patient died. Conclusion: In patients with subglottic stenosis, selection of the most accurate treatment is the key to success, reducing the number of surgeries and preventing complications (AU)

Conservative management of laryngeal dog bite.

BACKGROUND AND AIMS: Dog bites represent an important public health issue, causing injuries from trivial to fatal. The true incidence is unknown due to the lack of national and local reporting system. School children, mostly male, are more commonly affected with the majority of injuries occurring in the head and neck area, followed by the limbs and trunk. METHODS: The conservative management of a 6-year-old girl who sustained a fracture of her laryngeal structure from an attack by her neighbours' dog is described. Only a 1 cm visible puncture wound in the midline of her neck with air escaping through the wound was seen at presentation. RESULTS: Ten days were spent in hospital including the first four in intubated Paediatric Intensive Care Unit. Initial microlaryngoscopy and bronchoscopy (MLB) showed a swelling in the right anterior subglottis not reducible by manipulation. She was re-intubated with progressively larger naso-tracheal tube until the fracture was fully reduced on her 3rd MLB. Three months post-injury, there is no evidence of airway narrowing. CONCLUSION: The literature advocates early surgical management of laryngeal trauma including dog bites. Conservative management of laryngeal fracture from a dog bite is feasible and associated with a good outcome and no long-term sequela.

A simple mechanical device reduces subglottic injury in ventilated animals.

OBJECTIVES/HYPOTHESIS: To test whether a simple inexpensive device that dynamically minimizes endotracheal cuff pressure throughout the respiratory cycle reduces endotracheal cuff pressure-related subglottic injury. STUDY DESIGN: Hypoxic animal model with one control and one experimental group. METHODS: Twelve S. scrofa domesticus piglets (14-16 kg) were intubated with standard endotracheal tubes and maintained in a hypoxic state to accelerate airway injury. Animals in the control group (n = 6) were ventilated with a constant pressure of 20 cm H2O in the endotracheal tube cuff. Animals in the experimental group (n = 6) were ventilated using a custom-designed circuit that altered the pressure in the endotracheal tube cuff in synchrony with the ventilatory cycle. Larynges were harvested at the end of the experiment and examined histologically to determine the degree of airway injury induced by the endotracheal cuff. RESULTS: Animals in the experimental group suffered significantly less airway damage than those in the control group. The differences were seen primarily in the subglottis (aggregate damage score 6.5 vs. 12, P <0.05), where the experimental endotracheal tube cuff exerted the least pressure. There was no difference in damage to the glottic or supraglottic structures. CONCLUSIONS: A simple, reliable, and inexpensive means of modulating endotracheal tube cuff pressure with the ventilatory cycle led to a substantial decrease in airway injury in our animal model. Such reduction in cuff pressure may prove important for humans, particularly those in intensive care units who tend to have underlying conditions predisposing them to tracheal damage from the endotracheal tube cuff.

Subglottic injury: a clinically relevant animal model.

OBJECTIVES/HYPOTHESIS: To develop a clinically aligned, reproducible model for subglottic injury. STUDY DESIGN: Prospective randomized control pilot study. METHODS: Juvenile (3-month-old) New Zealand White rabbits underwent intubation with a 3-cm length of an endotracheal tube that was chosen so that there would be no air leak below 20 cm of water. This tube was one or two sizes above the appropriate tube for the animal. It was held in situ with a suture placed at the trachea and secured over a button in the neck for a period of 1 week. Animals were sacrificed 1 week postextubation, and larynges were harvested. A range of histological techniques and gross morphology were utilized to examine the injury caused at the level of the subglottis. Unintubated animals constituted controlled specimens. RESULTS: Intubated animals demonstrated considerable histopathology including evidence of ulceration, inflammation, granulation tissue, perichondritis, and chondritis when compared with control animals. Morphometric analysis demonstrated a significant increase in lamina propria thickness (P = .0013), mucosal thickness (P ≤ .0001), and in goblet cell areal density (P = .014). Analysis of mucin types found a significant decrease in acidic (P = .0001) mucin coinciding with a significant increase in mixed mucin types (P = .0013). CONCLUSIONS: Our model provides a reliable and reproducible technique for acute/subacute injury to the subglottis secondary to intubation, which is consistent with previous histological findings of early changes associated with acquired subglottic stenosis (SGS). Future uses of this model could include the examination of current adjunctive therapies and their effects on limiting progression to SGS.

Cricoid split for acute subglottic injury in the older child.

OBJECTIVES: To describe our experience of cricoid split in the older child for acquired subglottic stenosis secondary to chemical or thermal burns. METHODS: A retrospective case series. RESULTS: We describe two patients, both two years old, who benefitted from the procedure and had a return to a normal-sized airway. Neither child required a tracheostomy or further airway intervention after the cricoid split. CONCLUSIONS: Laryngotracheal reconstruction (LTR) is the standard treatment for subglottic injuries with associated subglottic stenosis in children, infants and (where possible) neonates. We have found the cricoid split a useful technique in carefully selected older children with acute subglottic injury and associated early subglottic stenosis, where LTR or ballooning is not feasible, where there is limited experience of ballooning, and/or ballooning has failed in the early stages of treatment. Cricoid split is a technique that is part of the airway surgeon's open operative repertoire and therefore should be remembered as a management option.

Management and prevention of endotracheal intubation injury in neonates.

PURPOSE OF REVIEW: To summarize the diagnosis, pathology, and management of glottic, subglottic, and tracheal injuries secondary to endotracheal intubation in neonates. RECENT FINDINGS: Published reports of intubation-related injuries include laryngeal stenosis, subglottic stenosis (SGS), tracheal rupture, subglottic cysts, and pharyngoesophageal perforation. Such injuries are multifactorial, with risk factors including patient size and weight, use of cuffed versus uncuffed endotracheal tubes, and fragility of the mucosa. In addition, the skill and awareness of the person performing the intubation may also influence risk of intubation-related injuries. Studies on fetal cricoid anatomy demonstrate differences in the configuration of cricoids lumen between premature infants and the adult larynx. Most recently reported airway injuries due to intubation have history of prematurity as a common risk factor, with increasing incidence associated with decreasing gestational age and weight. Prematurity and prolonged intubations remain the top risk factors for development of subglottic cysts. Management of above-mentioned complications includes endoscopy versus open laryngotracheoplasty for SGS, using balloon or traditional dilatation or augmentation with cartilage grafts, respectively; bridging injured area with endotracheal tube versus open resection and primary closure for tracheal rupture; and use of laser or cold techniques for removal of cysts. SUMMARY: Although intubation-related injuries may occur in anyone, neonates are at increased risk due to their small airway lumen and cricoids cartilage morphology. Endoscopic and open reconstructive techniques increase treatment options to treat glottic and SGS.

Posterior glottic diastasis: mechanically deceptive and often overlooked.

Dysphonia secondary to posterior glottic aerodynamic incompetence can often be recognizable acoustically, but difficult to document visually. This mechanical impairment in posterior glottic closure is the result of injury caused by airway instrumentation. The difficulty of recognition of this entity is due to posterior supraglottic soft tissue that obscures the complete view during posterior glottic adduction, the lack of a structural organization of the cricoarytenoid region injury that leads to this disorder, and the lack of nomenclature. A retrospective assessment was done on 3 patients who underwent surgical reconstruction to correct posterior phonatory incompetence subsequent to laryngotracheal intubation. All 3 had sustained an injury to the cricoarytenoid joints, and 2 of the 3 had undergone paraglottic space medialization laryngoplasty that failed to solve the posterior glottic insufficiency. New procedures were designed and performed in these patients to correct the posterior glottic incompetence and are described: laryngofissure and partial posterior cricoid resection, endoscopic pharyngoepiglottic-aryepiglottic fold advancement-rotation flap with interarytenoid interposition, and interarytenoid submucosal implant augmentation. Although the academic literature is replete with reports describing stenosis resulting from impaired cricoarytenoid joint abduction, the term glottic diastasis provides nomenclature for the inability to normally adduct the arytenoid cartilages. The initial experience with surgical reconstruction is preliminary, but encouraging.