The Impact of Tracheal Stenosis on Distal Airway Pressure with Jet Ventilation

OBJECTIVE

This study investigates the effects of tracheal stenosis on distal airway pressure during low-frequency jet ventilation (LFJV) in tracheal stenosis resection procedures, focusing on variables like stenosis size, depth, scope type, and inlet pressure.

METHODS

A 3D-printed human airway model was employed, featuring inserted tracheal stenoses of varied sizes and depths. Distal airway pressure was measured with 16 pressure transducers, and data were processed via MATLAB. The study varied stenosis size, depth, scope type, and inlet pressure during five sequential jet bursts under LFJV.

RESULTS

Using a subglottiscope resulted in significantly reduced distal airway pressure compared to a laryngoscope. Interestingly, neither stenosis size nor depth significantly influenced distal airway pressure. However, increased distance between the scope and stenosis raised normalized pressure. A linear rise in normalized distal airway pressure was noted with increased inlet pressure, regardless of stenosis dimensions.

CONCLUSION

In this model, scope type and inlet pressure were noted to be significant determinants of distal airway pressure, while stenosis size and depth were not. The distance between the scope and the stenosis did influence distal pressures. These findings may have clinical implications for managing airway pressures in patients undergoing LFJV, potentially reducing the risk of ventilator-induced lung injury.

LEVEL OF EVIDENCE

NA (Basic Research) Laryngoscope, 134:2300-2305, 2024.

Low-Dose Cisplatin-Based Radiation Therapy for Refractory Recurrent Respiratory Papillomatosis

Recurrent respiratory papilloma (RRP) often presents multiple lesions in the respiratory tract and sometimes becomes fatal because of severe airway obstruction. We report the case of a 69-year-old woman who had juvenile-onset RRP in the trachea that was refractory to surgical treatment, and complete remission was achieved by low-dose cisplatin combined with de-escalated radiotherapy without any side effects. This case report is the first to illustrate the data on low-dose cisplatin for refractory benign RRP, and our experience reinforces the opinion that low-dose cisplatin combined with de-escalated radiotherapy can be an effective and safe treatment alternative for uncontrollable and lethal RRP. Laryngoscope, 134:2335-2337, 2024.

Micro-CT Imaging of Tracheal Development in Down Syndrome and Non-Down Syndrome Fetuses

OBJECTIVES

Down syndrome (DS) is associated with airway abnormalities including a narrowed trachea. It is uncertain whether this narrowed trachea in DS is a consequence of deviant fetal development or an acquired disorder following endotracheal intubation after birth. This study aimed to compare the tracheal morphology in DS and non-DS fetuses using microfocus computed tomography (micro-CT).

METHODS

Twenty fetal samples were obtained from the Dutch Fetal Biobank and divided into groups based on gestational age. Micro-CT images were processed to analyze tracheal length, volume, and cross-sectional area (CSA).

RESULTS

Mean tracheal length and tracheal volume were similar in DS and non-DS fetuses for all gestational age groups. Mean, minimum, and maximal tracheal CSA were statistically significantly increased in the single DS fetus in the group of 21-24 weeks of gestation, but not in other gestational age groups. In 90% of all studied fetuses, the minimum tracheal CSA was located in the middle third of the trachea.

CONCLUSION

Tracheal development in DS fetuses was similar to non-DS fetuses between 13 and 21 weeks of gestation. This suggests that the narrowed tracheal diameter in DS children may occur later in fetal development or results from postnatal intubation trauma. The narrowest part of the trachea is in majority of DS and non-DS fetuses the middle third.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 2024.

Primary Vocal Cord Aspergillosis Can Involve the Trachea and Bronchus in Previously Healthy Patients: A Case Report

Primary vocal cord aspergillosis is extremely rare in immunocompetent individuals, in whom lesions are mainly confined to the larynx, with the possibility of tracheal and bronchial infection largely ignored. In this article, we present a case of primary vocal cord aspergillosis involving the trachea and bronchus in a previously healthy 55-year-old woman. Our case highlights that vocal cord aspergillosis can involve the trachea and bronchus and that laryngoscopy alone may be insufficient to secure a comprehensive diagnosis in healthy patients presenting with hoarseness, pharyngalgia, and normal chest radiography. Furthermore, influenza B virus infection may be a risk factor for this rare disease.

Host Immune Response Modulation in Avian Coronavirus Infection: Tracheal Transcriptome Profiling In Vitro and In Vivo

Infectious bronchitis virus (IBV) is a highly contagious Gammacoronavirus causing moderate to severe respiratory infection in chickens. Understanding the initial antiviral response in the respiratory mucosa is crucial for controlling viral spread. We aimed to characterize the impact of IBV Delmarva (DMV)/1639 and IBV Massachusetts (Mass) 41 at the primary site of infection, namely, in chicken tracheal epithelial cells (cTECs) in vitro and the trachea in vivo. We hypothesized that some elements of the induced antiviral responses are distinct in both infection models. We inoculated cTECs and infected young specific pathogen-free (SPF) chickens with IBV DMV/1639 or IBV Mass41, along with mock-inoculated controls, and studied the transcriptome using RNA-sequencing (RNA-seq) at 3 and 18 h post-infection (hpi) for cTECs and at 4 and 11 days post-infection (dpi) in the trachea. We showed that IBV DMV/1639 and IBV Mass41 replicate in cTECs in vitro and the trachea in vivo, inducing host mRNA expression profiles that are strain- and time-dependent. We demonstrated the different gene expression patterns between in vitro and in vivo tracheal IBV infection. Ultimately, characterizing host-pathogen interactions with various IBV strains reveals potential mechanisms for inducing and modulating the immune response during IBV infection in the chicken trachea.

Recurrent Laryngeal Nerve Intraoperative Neuromonitoring Indications in Non-Thyroid and Non-Parathyroid Surgery

Introperative nerve monitoring (IONM) of the recurrent laryngeal nerve (RLN) is a well-established technique to aid in thyroid/parathyroid surgery. However, there is little evidence to support its use in non-thyroid or non-parathyroid surgery. The aim of this paper was to review the current evidence regarding the use of IONM in non-thyroid/non-parathyroid surgery in the head and neck and thorax. A literature search was performed from their inception up to January 2024, including the term "recurrent laryngeal nerve monitoring". IONM in non-thyroid/non-parathyroid surgery has mainly been previously described in oesophageal surgery and in tracheal resections. However, there is little published evidence on the role of IONM with other resections in the vicinity of the RLN. Current evidence is low-level for the use of RLN IONM in non-thyroid/non-parathyroid surgery. However, clinicians should consider its use in surgery for pathologies where the RLN is exposed and could be injured.

Drug delivery systems for wound healing treatment of upper airway injury

INTRODUCTION

Endotracheal intubation is a common procedure to maintain an open airway with risks for traumatic injury. Pathological changes resulting from intubation can cause upper airway complications, including vocal fold scarring, laryngotracheal stenosis, and granulomas and present with symptoms such as dysphonia, dysphagia, and dyspnea. Current intubation-related laryngotracheal injury treatment approaches lack standardized guidelines, relying on individual clinician experience, and surgical and medical interventions have limitations and carry risks.

AREAS COVERED

The clinical and preclinical therapeutics for wound healing in the upper airway are described. This review discusses the current developments on local drug delivery systems in the upper airway utilizing particle-based delivery systems, including nanoparticles and microparticles, and bulk-based delivery systems, encompassing hydrogels and polymer-based approaches.

EXPERT OPINION

Complex laryngotracheal diseases pose challenges for effective treatment, struggling due to the intricate anatomy, limited access, and recurrence. Symptomatic management often requires invasive surgical procedures or medications that are unable to achieve lasting effects. Recent advances in nanotechnology and biocompatible materials provide potential solutions, enabling precise drug delivery, personalization, and extended treatment efficacy. Combining these technologies could lead to groundbreaking treatments for upper airways diseases, significantly improving patients' quality of life. Research and innovation in this field are crucial for further advancements.

A humoral stress response protects Drosophila tissues from antimicrobial peptides

7An efficient immune system must provide protection against a broad range of pathogens without causing excessive collateral tissue damage. While immune effectors have been well characterized, we know less about the resilience mechanisms protecting the host from its own immune response. Antimicrobial peptides (AMPs) are small, cationic peptides that contribute to innate defenses by targeting negatively charged membranes of microbes. While protective against pathogens, AMPs can be cytotoxic to host cells. Here, we reveal that a family of stress-induced proteins, the Turandots, protect the Drosophila respiratory system from AMPs, increasing resilience to stress. Flies lacking Turandot genes are susceptible to environmental stresses due to AMP-induced tracheal apoptosis. Turandot proteins bind to host cell membranes and mask negatively charged phospholipids, protecting them from cationic pore-forming AMPs. Collectively, these data demonstrate that Turandot stress proteins mitigate AMP cytotoxicity to host tissues and therefore improve their efficacy.

De-Epithelialized Viable Tracheal Allotransplantation Without Immunosuppressants: 5-Year Follow-Up

OBJECTIVE

Tracheal transplantation could be a better option for patients with long segmental laryngotracheal stenosis or defects, but the need for immunosuppressants limits its widespread use due to the antigenicity of the tracheal epithelium. Chemically treated or cryopreserved nonviable tracheal allografts have no immunogenicity but lead to necrosis and stenosis in long-term outcomes. The present report describes the 5-year outcomes of de-epithelialized viable tracheal allotransplantation without immunosuppressants in a patient with severe laryngotracheal stenosis.

METHODS

The recipient was a 47-year-old female with relapsing polychondritis affecting the larynx and cervical trachea and producing a 5 cm long stenosis that could not be repaired using resection and anastomosis. A tracheal allograft was obtained from a 45-year-old male donor and treated with a combination of 3% sodium dodecyl sulfate (SDS) and organ preservation solution for 138 hours. The allograft was revascularized by heterotopical implantation in the infrahyoid muscles of the recipient for 3 months and then transplantation to the laryngotracheal defect with a split-thickness skin graft sutured to the lumen and a silicon T-tube. No immunosuppressants were used postoperatively.

RESULTS

The allograft was de-epithelialized, and most of the cartilage rings remained viable after the treatment. The allograft was revascularized, viable, and mechanically stable after 3 months of heterotopic implantation. No apparent signs of rejection or destruction were observed. The T-tube was removed, and the internal lining of the allograft was repopulated 4 months after orthotopic transplantation, despite the skin graft necrotizing at 2 weeks. Endoscopy and computed tomography showed a patent airway 5 years after orthotopic transplantation. The patient was able to resume her usual quality of life.

CONCLUSION

The present study demonstrates that transplantation of the de-epithelialized viable tracheal allograft without immunosuppressants is safe and promising for patients with long laryngotracheal stenosis or defects, especially for those with malignant tumor resections.

Acute myeloid leukemia: An unusual manifestation of the trachea

Objectives

Hematologic malignancy involving the trachea is rare. It is even less common for tracheal involvement to be the initial manifestation of this disease. We present a case report highlighting an unusual diagnosis of acute myeloid leukemia (AML) that first presented with prominent tracheal manifestations. There have been only three other published case reports of extramedullary AML with involvement of the trachea.

Methods

We discuss direct laryngoscopy and bronchoscopy findings, including pinkish-white irregular lesions, which were similar to findings described in the available literature for tracheal AML.

Results

Laboratory findings from our case are reported, including peripheral smear demonstrating 57% blasts and bone marrow biopsy confirming the diagnosis of AML, and the relevance of these findings is discussed.

Conclusion

In patients with unusual airway lesions, laboratory testing and a comprehensive airway evaluation including biopsy are necessary to narrow the differential diagnosis.

Level of Evidence

5.

Global Bibliometric and Visualized Analysis of Tracheal Tissue Engineering Research

The development of tracheal tissue engineering (TTE) has seen a rapid growth in recent years. The purpose of this study was to investigate the global status, trends, and hotspots of TTE research based on bibliometrics and visualization analysis. Publications related to TTE were retrieved and included in the Web of Science Core Collection. VOSviewer and CiteSpace were used to generate knowledge maps. Six hundred fifty-five publications were identified, and the quantity of the annual publications worldwide was on the increase. International collaboration is a widespread reality. The United States led the world in the field of trachea tissue engineering, whereas University College London was the institution with the greatest contribution. In addition, Biomaterials had a great influence in this field, attracting the largest number of papers. Moreover, the topics of TTE research largely concentrated on the biomechanical scaffold preparation, the vascularization and epithelialization of scaffold, the tracheal cartilage regeneration, and the tissue-engineered tracheal transplantation. And the research on the application of decellularization and 3D printing for the construction of a tissue-engineered trachea was likely to receive more widespread attention in the future. Impact statement In recent years, tracheal tissue engineering (TTE) has experienced rapid growth. In this study, we investigated the worldwide status and trends of TTE research, and revealed the countries, institutions, journals, and authors that had made significant contributions to the field of TTE. Moreover, the possible research hotspots in the future were predicted. According to our research, researchers can gain a better understanding of the trends in this field, and stay informed of the most current research by tracking key journals, institutions, and authors.

Lipoaspirate Injection in Relapsing Idiopathic Subglottic Stenosis: Preliminary Results

OBJECTIVES

The management of idiopathic subglottic stenosis (iSGS) poses a clinical challenge due to high recurrence rates following both endoscopic and open approaches, often leading to tracheostomy. The activation of abnormal T-cells and cytokine pathways has been linked to iSGS pathogenesis. Autologous adipose tissue centrifugation yields lipoaspirate, offering optimal anti-inflammatory effects and biocompatibility widely utilized in various medical settings. This report presents the first 3 cases employing endoscopic dilation (ED) in combination with local lipoaspirate injection to address recurrent iSGS.

METHODS

A prospective observational study was conducted, involving multidisciplinary evaluation by the Tracheal Team at the University of Modena. Patients meeting specific criteria were directed to undergo ED + lipoaspirate injection.

RESULTS

Three patients fulfilled the inclusion criteria. The mean number of prior endoscopic procedures performed was 8. Endoscopic examination revealed 90% stenosis in patient A, 60% stenosis in patient B, and 60% stenosis in patient C. All patients presented inflammatory tissue or incipient granulations at the stenotic site, with an average time of 6 months between previous procedures. After 15 months, none of the patients required further procedures, and endoscopic examination revealed a significant reduction or disappearance of inflammatory tissue with a stable airway lumen.

CONCLUSIONS

The observed results are encouraging in terms of reducing local inflammation and halting stenosis progression, especially in cases of short-term relapsing iSGS.

In-house ammonia induced lung impairment and oxidative stress of ducks

Ammonia (NH3) is a toxic gas that in intensive poultry houses, damages the poultry health and induces various diseases. This study investigated the effects of NH3 exposure (0, 15, 30, and 45 ppm) on growth performance, serum biochemical indexes, antioxidative indicators, tracheal and lung impairments in Pekin ducks. A total of 288 one-day-old Pekin male ducks were randomly allocated to 4 groups with 6 replicates and slaughtered after the 21-d test period. Our results showed that 45 ppm NH3 significantly reduced the average daily feed intake (ADFI) of Pekin ducks. Ammonia exposure significantly reduced liver, lung, kidney, and heart indexes, and lowered the relative weight of the ileum. With the increasing of in-house NH3, serum NH3 and uric acid (UA) concentrations of ducks were significantly increased, as well as liver malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPX-Px) contents. High NH3 also induced trachea and lung injury, thereby increasing levels of tumor necrosis factor-α (TNF-α) and interleukin-4 (IL-4) in the lung, and decreasing the mRNA expressions of zonula occludens 1 (ZO-1) and claudin 3 (CLDN3) in the lung. In conclusion, in-house NH3 decrease the growth performance in ducks, induce trachea and lung injuries and meanwhile increase the compensatory antioxidant activity for host protection.

Radiographic and computed tomographic evaluation of tracheal diameter and length in kittens

OBJECTIVE

To measure the tracheal diameter and length in kittens using radiography and CT and to evaluate the concordance between measurements obtained with these 2 modalities.

ANIMALS

15 kittens with an estimated age of 12 weeks and mean body weight of 1.49 kg.

METHODS

Radiographic and CT images were retrospectively evaluated to measure tracheal lengths and diameters. Tracheal diameters were measured at 5 different sites (A [at the level of the C2-3 intervertebral disk space], B [at the level of the C4-5 intervertebral disk space], C [at the cranial end of the manubrium sterni], D [at the level of the second rib], and E [1 cm cranial to the carina]) along the trachea. The cross-sectional area and transverse and vertical diameter ratios were calculated for each measurement site.

RESULTS

The cross-sectional area was largest at site A and decreased from site C to site E. Based on the vertical diameter ratio, the tracheal shape was most circular at sites A and E, whereas from sites B to D, it was elliptical. The vertical diameters of the trachea on radiography and CT did not differ statistically significantly. However, the tracheal length measured on radiography was approximately 6 mm longer than that measured on CT (P < .05).

CLINICAL RELEVANCE

Using the first rib as an anatomical reference, the placement of a cuffed endotracheal tube is recommended in kittens. In emergency situations, regression equations based on body weight may be helpful in predicting tracheal diameters.

Primary cilia are critical for tracheoesophageal septation

INTRODUCTION

Primary cilia play pivotal roles in the patterning and morphogenesis of a wide variety of organs during mammalian development. Here we examined murine foregut septation in the cobblestone mutant, a hypomorphic allele of the gene encoding the intraflagellar transport protein IFT88, a protein essential for normal cilia function.

RESULTS

We reveal a crucial role for primary cilia in foregut division, since their dramatic decrease in cilia in both the foregut endoderm and mesenchyme of mutant embryos resulted in a proximal tracheoesophageal septation defects and in the formation of distal tracheo(broncho)esophageal fistulae similar to the most common congenital tracheoesophageal malformations in humans. Interestingly, the dorsoventral patterning determining the dorsal digestive and the ventral respiratory endoderm remained intact, whereas Hedgehog signaling was aberrantly activated.

CONCLUSIONS

Our results demonstrate the cobblestone mutant to represent one of the very few mouse models that display both correct endodermal dorsoventral specification but defective compartmentalization of the proximal foregut. It stands exemplary for a tracheoesophageal ciliopathy, offering the possibility to elucidate the molecular mechanisms how primary cilia orchestrate the septation process. The plethora of malformations observed in the cobblestone embryo allow for a deeper insight into a putative link between primary cilia and human VATER/VACTERL syndromes.

Management of Tracheobronchial Stenosis in Chondrodysplasia Punctata

Chondrodysplasia punctata (CDP) is a rare congenital syndrome characterized by aberrant, punctate deposition of calcium during endochondral bone formation, resulting in the characteristic finding of epiphyseal stippling on radiographs. While otolaryngologic manifestations such as nasomaxillary hypoplasia and mixed hearing loss are common, tracheobronchial calcification occurs rarely in neonates with CDP. The management of CDP-related airway stenosis is complex and there is limited literature pertaining to outcomes of airway interventions. Herein, we describe the clinical course and outcome of tracheal dilation for a newborn patient with CDP. Laryngoscope, 134:1464-1468, 2024.

Lentiviral expression of wild-type LAMA3A restores cell adhesion in airway basal cells from children with epidermolysis bullosa

The hallmark of epidermolysis bullosa (EB) is fragile attachment of epithelia due to genetic variants in cell adhesion genes. We describe 16 EB patients treated in the ear, nose, and throat department of a tertiary pediatric hospital linked to the United Kingdom's national EB unit between 1992 and 2023. Patients suffered a high degree of morbidity and mortality from laryngotracheal stenosis. Variants in laminin subunit alpha-3 (LAMA3) were found in 10/15 patients where genotype was available. LAMA3 encodes a subunit of the laminin-332 heterotrimeric extracellular matrix protein complex and is expressed by airway epithelial basal stem cells. We investigated the benefit of restoring wild-type LAMA3 expression in primary EB patient-derived basal cell cultures. EB basal cells demonstrated weak adhesion to cell culture substrates, but could otherwise be expanded similarly to non-EB basal cells. In vitro lentiviral overexpression of LAMA3A in EB basal cells enabled them to differentiate in air-liquid interface cultures, producing cilia with normal ciliary beat frequency. Moreover, transduction restored cell adhesion to levels comparable to a non-EB donor culture. These data provide proof of concept for a combined cell and gene therapy approach to treat airway disease in LAMA3-affected EB.

Tracheal Tissue Engineering: Principles and State of the Art

Patients affected by long-segment tracheal defects or stenoses represent an unsolved surgical issue, since they cannot be treated with the conventional surgery of tracheal resection and consequent anastomosis. Hence, different strategies for tracheal replacement have been proposed (synthetic materials, aortic allografts, transplantation, autologous tissue composites, and tissue engineering), each with advantages and drawbacks. Tracheal tissue engineering, on the other hand, aims at recreating a fully functional tracheal substitute, without the need for the patient to receive lifelong immunosuppression or endotracheal stents. Tissue engineering approaches involve the use of a scaffold, stem cells, and humoral signals. This paper reviews the main aspects of tracheal TE, starting from the choice of the scaffold to the type of stem cells that can be used to seed the scaffold, the methods for their culture and expansion, the issue of graft revascularization at the moment of in vivo implantation, and experimental models of tracheal research. Moreover, a critical insight on the state of the art of tracheal tissue engineering is also presented.

Benign cervical schwannoma with tracheal invasion

Schwannomas commonly develop in the cervical region, 25% - 45% of cases are diagnosed in this anatomical region. Tracheal neurogenic tumors are exceedingly rare and can be misdiagnosed as invasive thyroid carcinomas or other infiltrating malignancies when present at the level of the thyroid gland. Here, we present a case of synchronous benign cervical schwannoma with tracheal invasion and papillary thyroid carcinoma in a patient who was initially hospitalized for COVID-19. The patient presented with dyspnea that was later found to be caused by tracheal extension of a cervical tumor. Surgical excision was performed, and the surgical team proceeded with segmental tracheal resection, removal of the cervical mass, and total thyroidectomy. The specimen was sent for pathological analysis, which revealed synchronous findings of a benign cervical schwannoma with tracheal invasion and papillary thyroid carcinoma. The literature on this subject, together with the present case report, suggests that neurogenic tumors should be included in the differential diagnosis of obstructing tracheal cervical masses. Surgical excision is the first-line of treatment for benign cervical schwannomas.

Concordance of esophageal and tracheal temperatures in patients using breathing circuit with heated wire humidifier: A prospective observational study

RESULTS

After excluding 4 patients with an anesthesia duration of < 2 hours, data from 34 patients (1163 sets of tracheal and esophageal temperatures) were analyzed. Concordance correlation coefficient was 0.78. The overall mean bias (95% limits of agreement) between the tracheal and esophageal temperatures was -0.16°C (-0.65°C to 0.34°C). The percentage of temperature differences within ± 0.25°C was 73.5% ± 32.3, with a median of 89.4% [0,100]. The linear mixed-effects model revealed that the estimated intercept was 0.17°C with a 95% confidence interval (CI) of 0.13°C to 0.22°C. The duration of anesthesia and the number of temperature measurements were associated with higher concordance between the tracheal and esophageal temperatures in univariate analysis.

Determining optimal cuff volume for cuffed endotracheal tubes commonly used in pediatric patients: A prospective observational study

OBJECTIVES

To determine an optimal cuff inflation volume to achieve safe cuff pressure (20-25 cmH2O) in cuffed endotracheal tubes (ETTs) with an inner diameter of 4.5, 5.0, and 5.5 mm, which are commonly used in pediatric anaesthesia clinical practice and to create a formula to determine the optimal cuff volume.

METHODS

This study was carried out between February and June 2021 in Ankara City Hospital, Ankara, Turkey. A total of 127 pediatric patients who were intubated with 4.5, 5.0 and 5.5 numbered cuffed ETTs were included in this study. The same brand of cuffed ETT was used for each patient. The diameter of the subglottic transverse airway was measured by ultrasound for selecting the appropriate tube. Cuff pressure was measured with a cuff manometer to ensure optimum cuff pressure (20-25 cmH2O).

RESULTS

We found out that the mean ideal cuff volume inflated for 4.5 size tube was 1.7±0.3 ml, 1.9±0.3 ml for 5.0 size tube, and 2.1±0.3 ml for 5.5 size tube. Additionally we developed the "endotracheal cuff volume (ml) = 1,027 x height (m) + 0,104 x subglottic transverse diameter (mm) - 0,0191" formula to predict the most suitable inflation volume for ETT cuffs.

CONCLUSION

In this study, we suggested the optimal cuff volume to inflate the cuffs of ETTs 4.5, 5.0, and 5.5, which are frequently used in pediatric anaesthesia practice, in the appropriate cuff pressure range.ClinicalTrials.gov ref. no.: NCT04948359.

More Than 1 Way to Put in A T-Tube: A Review of Different Techniques Used in Insertion of Montgomery T-Tubes

OBJECTIVE

The Montgomery T-tube is a commonly used device initially designed as a temporary airway stent, but also used as a long-term airway solution for stenosis. For patients undergoing either endoscopic or open airway procedures, proper techniques for inserting these tubes are well documented. This review compiles the techniques used for insertion of the Montgomery T-tube stent.

METHODS

The NCBI Pubmed database was queried using the keywords: "stent," "Montgomery," "T-tube," "stenosis," "technique." A total of 33 papers were reviewed with 12 papers selected for the study. Papers were selected based on inclusion criteria of English language and whether the paper described a technique for insertion of a Montgomery T-tube into the airway. Papers were excluded if they did not describe the technique of insertion of Montgomery T-tubes or dealt with another aspect of T-tube management.

RESULTS

The 12 selected papers each described a different technique for insertion of a Montgomery T-tube stent. Though nearly all the selected studies described using a modified Seldinger technique for insertion of the T-tube, there were discrepancies and a wide array of different instruments used. The instrument and/or technique that was selected was often determined by the individual need of the patient. Several studies addressed the challenge of interrupting ventilation while inserting or exchanging a T-tube in the operating room. These studies described attaching the T-tube to the endotracheal tube to pass the T-tube into the airway while allowing for continuous ventilation. Yet other studies used optical forceps or rigid bronchoscopes to allow placement of the T-tube with direct visualization.

CONCLUSION

There are many techniques used for the insertion of a Montgomery T-tube. Nearly all studies described using a modified Seldinger technique and all the studies agreed on the necessity of a team approach for placement of the Montgomery T-tube.

Anaesthesia Management for Neurosurgery in a Patient With Congenital Lung Agenesis

Congenital lung agenesis is a rare congenital abnormality associated with an absence or under-development of either one or both lungs, and its presentation in adulthood is even rarer. We describe a 40-year-old female patient with a history of congenital agenesis of the right lung and a high-grade glioma in the frontal region of the brain presenting for craniotomy and excision of the tumor in an MRI suite. Lung protective strategies of ventilation were utilized intraoperatively. The remote location of the MRI suite made access to extra manpower support challenging. The patient was managed uneventfully and discharged stable to the high-dependency unit. Our case describes how congenital lung agenesis poses a unique set of challenges for anaesthetic management, particularly in neurosurgical patients, and provides guidance to a multidisciplinary team approach.

Contact with adult hens affects the composition of skin and respiratory tract microbiota in newly hatched chicks

Chickens in commercial production are hatched in hatcheries without any contact with their parents and colonization of their skin and respiratory tract is therefore dependent on environmental sources only. However, since chickens evolved to be hatched in nests, in this study we evaluated the importance of contact between hens and chicks for the development of chicken skin and tracheal microbiota. Sequencing of PCR amplified V3/V4 variable regions of the 16S rRNA gene showed that contact with adult hens decreased the abundance of E. coli, Proteus mirabilis and Clostridium perfringens both in skin and the trachea, and Acinetobacter johnsonii and Cutibacterium acnes in skin microbiota only. These species were replaced by Lactobacillus gallinarum, Lactobacillus aviarius, Limosilactobacillus reuteri, and Streptococcus pasterianus in the skin and tracheal microbiota of contact chicks. Lactobacilli can be therefore investigated for their probiotic effect in respiratory tract in the future. Skin and respiratory microbiota of contact chickens was also enriched for Phascolarctobacterium, Succinatimonas, Flavonifractor, Blautia, and [Ruminococcus] torque though, since these are strict anaerobes from the intestinal tract, it is likely that only DNA from nonviable cells was detected for these taxa.

Internal mammary artery perforator flap in the management of tracheoesophageal fistulae

BACKGROUND

A pathological communication between the trachea and oesophagus - a tracheoesophageal fistula - may be congenital or acquired, benign or malignant, necessitating a multidisciplinary approach. Conservative attempts at closure of this abnormal connection are ineffective; the interposition of healthy vascular tissue offers the least chance of recurrence.

METHODS

Outcomes of an islanded fasciocutaneous internal mammary artery perforator flap applied for tracheoesophageal fistula management were assessed in four radiated patients with laryngeal carcinoma using retrospective records.

RESULTS

Four male patients, with an average age of 60.75 years, underwent tracheoesophageal fistula closure between September 2017 and February 2021. A left-sided second internal mammary artery perforator flap was used in all cases, with an average dimension of 10.5 × 4.5 cm. There were no complications of tracheoesophageal leak, flap issues or donor site morbidity on follow up.

CONCLUSION

Recent advances in angiosomal territory mapping and microvascular dissection techniques, combined with an understanding of tracheoesophageal fistula pathology, have changed management perspectives in these difficult-to-treat patients.

Evaluation of a New Method for CyberKnife Treatment for Central Lung and Mediastinal Tumors by Tracheobronchial Tracking

BACKGROUND

CyberKnife treatment for central lung tumors and mediastinal tumors can be difficult to perform with marker less.

PURPOSE

We aimed to evaluate a novel tracheobronchial-based method (ie, tracheobronchial tracking) for the purpose of minimally invasive CyberKnife treatment for central lung and mediastinal tumors.

METHODS

Five verification plans were created using an in-house phantom. Each plan included five irradiation sessions. The reference plan irradiated and tracked the simulated tumor (using the target tracking volume, TTV). Trachea plans tracked the simulated tracheo-bronchus and irradiated the simulated tumor and included two types of subplans: correlated plans in which the displacement of the simulated tracheobronchial and the simulated tumor were correlated, and non-correlated plans in which these factors were not correlated. Moreover, 15 mm and 25 mm TTVs were evaluated for each plan. The sin waveform and the patient's respiratory waveform were prepared as the respiratory model. Evaluations were performed by calculating the dose difference between the radiophotoluminescent glass dosimeter (RPLD)-generated mean dose values (generated by the treatment planning system, TPS) and the actual absorbed RPLD dose. Statistical analyses were performed to evaluate findings for each plan. Correlation and prediction errors were calculated for each axis of each plan using log files to evaluate tracking accuracy.

RESULTS

Dose differences were statistically significant only in comparisons with the non-correlated plan. When evaluated using the sin waveform, the mean values for correlation and prediction errors in each axis and for all plans were less than 0.6 mm and 0.1 mm, respectively. In the same manner, they were less than 1.1 mm and 0.2 mm when evaluated using the patient's respiratory waveform.

CONCLUSION

Our newly-developed tracheobronchial tracking method would be useful in facilitating minimally invasive CyberKnife treatment in certain cases of central lung and mediastinal tumors.

Biomechanical Evaluation of Tracheal Needle Puncture Forces: Comparative Analysis of Annular Ligaments and Tracheal Cartilage

Percutaneous tracheotomies (PCT) are commonly performed minimally invasive procedures involving the creation of an airway opening through an incision or puncture of the tracheal wall. While the medical intervention is crucial for critical care and the management of acute respiratory failure, tracheostomy complications can lead to severe clinical symptoms due to the alterations of the airways biomechanical properties/structures. The causes and mechanisms underlaying the development of these post-tracheotomy complications remain largely unknown. In this study, we aimed to investigate the needle puncture process and its biomechanical characteristics by using a well establish porcine ex vivo trachea to simulate the forces involved in accessing airways during PCT at varying angular approaches. Given that many procedures involve inserting a needle into the trachea without direct visualization of the tracheal wall, concerns have been raised over the needle punctures through the cartilaginous rings as compared to the space between them may result in fractured cartilage and post-tracheostomy airway complications. We report a difference in puncture force between piercing the cartilage and the annular ligaments and observe that the angle of puncture does not significantly alter the puncture forces. The data collected in this study can guide the design of relevant biomechanical feedback system during airway access procedures and ultimately help refine and optimize PCT.

Site of Tracheostomy and Its Influence on The Surgical Outcome and Quality of Life After Tracheal Resection and Anastomosis in Patients with Tracheal Stenosis

Introduction  With the advances in critical care, the incidence of post intubation tracheal stenosis is increasing. Tracheal resection and anastomosis have been the gold standard for the management of grades III and IV stenosis. Scientific evidence from the literature on the determining factors and outcomes of surgery is not well described. Objective  This study was aimed at determining the influence of tracheostoma site on the surgical outcomes and postoperative quality of life of patients undergoing tracheal resection anastomosis. Methods  Thirteen patients who underwent tracheal resection and anastomosis during a period of 3 years were followed up prospectively for 3 months to determine the degree of improvement in their quality of life postsurgery by comparing the pre and postoperative validated Tamil/vernacular version of RAND SF-36 scores and Medical Research Council (MRC) dyspnea score. Results  As per preoperative computed tomography (CT), the mean length of stenosis was found to be 1.5 cm while the mean length of trachea resected was 4.75 cm. We achieved a decannulation rate of 61.53%. There was an estimated loss of 3.20 +/- 1.90 cm of normal trachea from the lower border of the stenosis until the lower border of the stoma that was lost during resection. Analysis of SF-36 and MRC dyspnea scores revealed significant improvement in the domains of physical function postoperatively in comparison with the preoperative scores ( p  < 0.05). Conclusion  Diligent placement of tracheostomy in an emergency setting with respect to the stenotic segment plays a pivotal role in minimizing the length of the resected segment of normal trachea.

Wnt signaling regulates ion channel expression to promote smooth muscle and cartilage formation in developing mouse trachea

Ion channels play critical roles in the physiology and function of the nervous system and contractile tissue; however, their role in noncontractile tissue and embryonic development has yet to be understood. Tracheobronchomalacia (TBM) and complete tracheal rings (CTR) are disorders affecting the muscle and cartilage of the trachea and bronchi, whose etiology remains poorly understood. We demonstrated that trachealis muscle organization and polarity are disrupted after epithelial ablation of Wntless (Wls), a cargo receptor critical for the Wnt signaling pathway, in developing trachea. The phenotype resembles the anomalous trachealis muscle observed after deletion of ion channel encoding genes in developing mouse trachea. We sought to investigate whether and how the deletion of Wls affects ion channels during tracheal development. We hypothesize that Wnt signaling influences the expression of ion channels to promote trachealis muscle cell assembly and patterning. Deleting Wls in developing trachea causes differential regulation of genes mediating actin binding, cytoskeleton organization, and potassium ion channel activity. Wnt signaling regulates the expression of Kcnj13, Kcnd3, Kcnj8, and Abcc9 as demonstrated by in vitro studies and in vivo analysis in Wnt5a and β-catenin-deficient tracheas. Pharmacological inhibition of potassium ion channels and Wnt signaling impaired contractility of developing trachealis smooth muscle and formation of cartilaginous mesenchymal condensation. Thus, in mice, epithelial-induced Wnt/β-catenin signaling mediates trachealis muscle and cartilage development via modulation of ion channel expression, promoting trachealis muscle architecture, contractility, and cartilaginous extracellular matrix. In turn, ion channel activity may influence tracheal morphogenesis underlying TBM and CTR.NEW & NOTEWORTHY Ion channels play critical roles in the physiology and function of the nervous system and contractile tissue; however, their role in noncontractile tissue and embryonic development has yet to be understood. In this study, we focused on the role of ion channels in the differentiation and patterning of the large airways of the developing respiratory tract. We identify a mechanism by which Wnt-beta-catenin signaling controls levels of ion channel-encoding genes to promote tracheal differentiation.

Role of ultrasonography in upper airway assessment: A comparison with computerized tomography measurements

INTRODUCTION

This study aimed to compare ultrasonography (US) measurements of the upper airway to computerized tomography (CT) measurements. Our study's primary outcome is to research the accuracy of US measurements in the evaluation of upper airway diameters when CT is taken as the gold standard; the secondary outcome is to determine the time required to obtain US measurements.

METHODS

This prospective study included patients ≥18 years old that had undergone thoracic or neck CT due to current clinical necessity. The US measurement for each patient was performed by two researchers with different levels of experience, both of whom were blinded to each other and the CT measurements. Measurements were obtained from the vocal cords and subglottic region. The duration of the US performance was also recorded.

RESULTS

The US and CT measurements were obtained from 94 patients. Concordance between US and CT measurements was found in the Bland-Altman analysis, with a mean -0.05 mm difference for vocal cord diameter and -1.2 mm for subglottic diameter. The intra-class correlation coefficients (ICC) between the CT and US measurements were 0.993, and 0.609 for vocal cord and subglottic diameter measurements, respectively. The ICC between US performers was 0.992 for vocal cord diameter and 0.959 for subglottic diameter. The US's mean time for vocal cord diameter measurement was 38 ± 23 s, and the mean time for subglottic diameter measurement was 49 ± 30 s.

CONCLUSION

The concordance between US and CT measurements is high and the measurements of different practitioners with different experience levels are compatible with each other.

Primary benign intratracheal schwannoma: A case report and review of the literature

Shwannomas are rare benign tumours especially in tracheal. A 16-year-old male presented with a chronic cough, and a thoracic CT scan revealed a pedunculated tumour measuring approximately 11 × 13 mm in size, located 22 mm away from the main carina. Tissue sample was obtained via rigid bronchoscopy and cryobiopsy, and the pathological analysis confirmed the diagnosis of a benign nerve sheath tumour consistent with schwannoma. The patient subsequently underwent resection of the tumour and tracheal anastomosis. Schwannomas are uncommon pulmonary tumours that typically occur in adults, with a higher incidence among females. The presenting symptoms vary depending on the size and location of the tumour. Treatment options include therapeutic bronchoscopy or surgical resection, with the choice of approach based on tumour characteristics (pedunculated or sessile), preoperative surgical risk, and risk of recurrence. The prognosis is generally favourable, with a low risk of recurrence and excellent outcomes.

Hemicricoidectomy with modified rotational thyro-crico-tracheal anastomosis: a newborn in the family of crico-tracheal resection and anastomosis techniques

Objective

The aim of the present study is to describe our novel surgical technique of hemicricoidectomy and reconstruction with modified rotational thyro-crico-tracheal anastomosis for the treatment of non-squamous cell subglottic tumours. The procedure has been defined as Type E crico-tracheal resection and anastomosis (CTRA) following the University of Brescia (C)TRA classification introduced elsewhere.

Methods

A detailed anatomical step-by-step dissection was reproduced and illustrated on a cadaveric laryngo-tracheal specimen. Moreover, oncological and functional outcomes of the first 5 patients who underwent Type E CTRA at our Institution between October 2016 and September 2022 are described.

Results

Three patients underwent Type E CTRA for cricoid chondrosarcoma (CS) and 2 patients for subglottic adenoid cystic carcinoma (ACC). No post-operative complication was reported. All patients maintained intact oral intake and an intelligible voice at discharge. All but one patient with obstructive sleep apnoea hypopnea syndrome and lung comorbidity were successfully decannulated before discharge. At the last follow-up (April 2023), one patient experienced local recurrence of CS that was still amenable to conservative treatment by transoral debulking, while the remaining patients were free of disease.

Conclusions

With the proper indications, Type E CTRA is a feasible and effective conservative surgical technique for selected non-squamous cell subglottic tumours.

Treatment and outcomes of minor salivary gland cancers of the larynx and trachea: a systematic review

Objectives

Malignant minor salivary glands carcinomas (MiSGC) of the larynx and trachea are rare tumours and published evidence is sparse. We conducted a systematic review to describe shareable treatment strategies and oncological outcomes of these neoplastic entities.

Methods

Full text English manuscripts published from January 1st 2000 to December 14th 2022 were included. Data on demographics, treatments and outcomes were collected. A pooled analysis of 5-year overall survival (OS) was performed.

Results

Seventeen articles and 365 patients met the inclusion criteria. The most common subsites involved were subglottic and distal trachea. Adenoid cystic carcinoma was, by far, the most frequent histotype. The first-choice treatment strategy was surgery (86.8%), while adjuvant treatments were delivered in 57.4% of patients. Only 12.9% were treated with definitive radiotherapy with/without chemotherapy. The mean follow-up was 68.3 months. One hundred nine (34.9%) deaths were recorded and 62.4% were cancer-related. Five-year OS ranged from 20% to 100% and, at pooled analysis, it was 83% (range, 78-87%).

Conclusions

In case of MiSGC of the larynx and trachea, surgery remains the mainstay of treatment. Adjuvant treatments are frequently delivered. Survival estimates are good overall, but highly heterogeneous.

Post-Implantation Inflammatory Responses to Xenogeneic Tissue-Engineered Cartilage Implanted in Rabbit Trachea: The Role of Cultured Chondrocytes in the Modification of Inflammation

Immune responses to tissue-engineered grafts made of xenogeneic materials remain poorly studied. The scope of current investigations is limited by the lack of information on orthotopically implanted grafts. A deeper understanding of these processes is of great importance since innovative surgical approaches include the implantation of xenogeneic decellularized scaffolds seeded by cells. The purpose of our work is to study the immunological features of tracheal repair during the implantation of tissue-engineered constructs based on human xenogeneic scaffolds modified via laser radiation in rabbits. The samples were stained with hematoxylin and Safranin O, and they were immunostained with antibodies against tryptase, collagen II, vimentin, and CD34. Immunological and inflammatory responses were studied by counting immune cells and evaluating blood vessels and collagen. Leukocyte-based inflammation prevailed during the implantation of decellularized unseeded scaffolds; meanwhile, plasma cells were significantly more abundant in tissue-engineered constructs. Mast cells were insignificantly more abundant in tissue-engineered construct samples. Conclusions: The seeding of decellularized xenogeneic cartilage with chondrocytes resulted in a change in immunological reactions upon implantation, and it was associated with plasma cell infiltration. Tissue-engineered grafts widely differed in design, including the type of used cells. The question of immunological response depending on the tissue-engineered graft composition requires further investigation.

Case Report: Human Tracheal Transplantation Undergoes Progressive Reepithelialization Over Time

OBJECTIVES

Tracheal transplantation is an ideal option for the reconstruction of long-segment circumferential tracheal defects. Our group performed the first successful vascularized single-staged tracheal transplantation in January 2021. Although a rigid biocompatible structure is necessary for a functioning tracheal replacement, the importance of ciliated epithelium, which allows for critical mucociliary clearance, is now being appreciated. Here, we examined the histological changes of the first single-staged human tracheal transplant from serial endoscopic biopsies.

METHODS

Biopsies of the tracheal mucosa were serially obtained since the time of the tracheal transplantation. Samples were examined via hematoxylin and eosin, electron microscopy, and immunohistochemistry.

RESULTS

One week after transplantation, there is loss of ciliated epithelium and seromucinous cells, with only a basal layer of epithelium remaining. By 2 weeks, however, the epithelium begins to recover, albeit differently depending on the location of the biopsy. Near the site of tracheal anastomosis, there is epithelial proliferation, with the appearance of early ciliated cells. However, in the midgraft, there appears to be evidence of squamous metaplasia. Over time, however, normal ciliated epithelium and mucous cells appear without signs of chronic inflammation.

CONCLUSIONS

Critically, the tracheal allograft regained normal appearing respiratory epithelium after initial ischemic injury. The histologic differences at the midgraft versus anastomosis may suggest unique mechanisms of reepithelialization. At the recipient-donor interface, there may be a faster direct migration of recipient-derived epithelial cells, in line with preclinical studies. The midgraft, in contrast, responds with epithelial proliferation from the donor basal cells or dedifferentiated mucous cells.

LEVEL OF EVIDENCE

N/A Laryngoscope, 2023.

The Evolution and Outcomes of the "Maddern Procedure" for the Treatment of Subglottic Stenosis

INTRODUCTION

A novel technique to treat subglottic stenosis, the "Maddern Procedure", has been gaining acceptance in academic centers. This study describes the technique in detail, as well as its evolution over the first 28 patients performed at an academic center.

METHODS

A prospective case-series, with descriptive technique modifications cataloged throughout the 6 years needed to accumulate the patient cohort with a minimum of 2 years of follow-up (11/2015-11/2021). Main outcomes examined included changes to surgical indications, complications, and post-operative outcomes as measured by validated measures of voice and breathing.

RESULTS

Complete resection of subglottic scaring was performed, at first transcervically (2 pts), then transorally (26 pts). Successful performance of the procedure occurred in all patients without complications, with either successful decannulation of previously existing tracheotomies, or removal of perioperative tracheotomies. Buccal grafts (8/26) replaced skin graft as the graft of choice. Although high subglottic disease was first thought to be a contraindication, superior results became evident in cases of high stenosis rather than disease that included the upper trachea, with 4/26 patients requiring subsequent tracheal resection or tracheal dilation. Of the 22 remaining patients, 19/22 had successful arresting of restenosis, with 2/22 undergoing subsequent cricotracheal resection, and 1/22 pts requiring subglottic dilation. Overall, 19/26 Maddern pts (73%) had objectively favorable outcomes, with 24/26 (92%) reporting that they would have undergone the procedure again.

CONCLUSION

Full-thickness mucosal resection and relining of the subglottis is a developing technique that is a safe, yet technically challenging procedure which addresses the recurrent nature of the disease.

LEVEL OF EVIDENCE

Level 4 (Case-series) Laryngoscope, 133:3100-3108, 2023.

Polyploidy-associated autophagy promotes larval tracheal histolysis at Drosophila metamorphosis

Polyploidy is an extended phenomenon in biology. However, its physiological significance and whether it defines specific cell behaviors is not well understood. Here we study its connection to macroautophagy/autophagy, using the larval respiratory system of Drosophila as a model. This system comprises cells with the same function yet with notably different ploidy status, namely diploid progenitors and their polyploid larval counterparts, the latter destined to die during metamorphosis. We identified an association between polyploidy and autophagy and found that higher endoreplication status correlates with elevated autophagy. Finally, we report that tissue histolysis in the trachea during Drosophila metamorphosis is mediated by autophagy, which triggers the apoptosis of polyploid cells.Abbreviations: APF: after pupa formation; Atg: autophagy related; btl: breathless; CycE: Cyclin E; DT: dorsal trunk; fzr: fizzy-related; L3: larval stage 3; PBS: phosphate-buffered saline; RI: RNAi; Tr: tracheal metamere; yki: yorkie.

Is Continued Perioperative Antithrombotic Therapy Safe When Performing Open Tracheostomy?

OBJECTIVES

To date, there are no specific guidelines on antithrombotic therapy (ATT) management, which includes both anticoagulation and antiplatelet medications, for open tracheostomy. The objective of this study was to evaluate whether the use of perioperative antithrombotic medication during open tracheostomy influences the incidence of perioperative or postoperative complications.

METHODS

A retrospective review was conducted of all patients who underwent open tracheostomies at a tertiary care medical center from January 2015 to December 2019. Charts were reviewed for demographics, comorbidities, indication for tracheostomy, ATT use, operative details, and complications.

RESULTS

A total of 217 tracheostomies were evaluated for this study, of which 148 (68.2%) were not on ATT and 69 (31.8%) were on ATT during surgery. No significant difference was observed based on ATT status in perioperative bleeding (P = .983), postoperative bleeding (P = .24), or median days to decannulation (P = .5986). ATT patients were 2.67 times more likely to experience 30-day mortality than those non-ATT patients (P = .035). There was only one death due to hemorrhage in the ATT group. This was unrelated to the tracheostomy. This compares to 2 hemorrhage-related deaths in those not on ATT.

CONCLUSION

There was no significant difference in perioperative or postoperative bleeding based on ATT use. Patients on ATT were significantly more likely to experience 30-day mortality, however only one death was due to hemorrhage in the ATT group and was unrelated to tracheostomy. Therefore, continued perioperative ATT use appears to be safe when performing open tracheostomy.

LEVEL OF EVIDENCE

4.

Retrospective computed tomography analysis of endotracheal tube constriction and mispositioning in cats and dogs

OBJECTIVE

To discover the prevalence of endotracheal tube (ETT) constriction and rostral and caudal mispositioning in anaesthetized cats and dogs, and to identify associated risk factors.

STUDY DESIGN

Retrospective analysis.

ANIMALS

A total of 146 cats and 670 dogs.

METHODS

Computed tomography images of the head/neck/thorax from orotracheally intubated cats and dogs were visually assessed for constriction or mispositioning of the ETT. If constriction was present, measurements of the cross-sectional area (CSA) of the ETT lumen at constricted and un-constricted locations were compared. Location and cause of constriction were noted and the expected increase in resistance to gas flow was calculated. Animal information was collected from clinical records. Normality of continuous variables was assessed via the Shapiro-Wilk test. Chi-square tests examined associations between variables. Kendall's tau-b test was performed between measured ETT size and degree of constriction.

RESULTS

The ETT extended rostrally beyond incisors in 52% of cases; the connector was within the oral cavity in 19% of cases. The ETT extended beyond the first rib in 25.5% of cases. The prevalence of ETT constriction was 22.7%. Median reduction in CSA was 7.68% (0.14-64.19%). Median increase in resistance assuming laminar and turbulent flow was 16.5% (0.3-680%) and 21% (0.3-1200%), respectively. The most common cause of constriction was the presence of a radiotherapy mouth gag. Significant associations existed between presence of constriction and rostral mispositioning, and caudal mispositioning and extreme brachycephaly. Increased severity of constriction was more likely in smaller ETT.

CONCLUSIONS AND CLINICAL RELEVANCE

Constriction and mispositioning of ETT occurred very commonly in this population. Checking the ETT within the oral cavity for constriction and mispositioning is recommended. Radiotherapy mouth gags increase the risk of ETT compression. Smaller ETT are at greater risk of severe constriction. Brachycephalic dogs are at particular risk of caudal mispositioning.

Tracheobronchial Amyloidosis Accompanied with Asthma: A Case Report and a Mini-Review

Tracheobronchial amyloidosis is a rare disease characterized by amyloid deposits on the tracheal and bronchial tissue. Patients with tracheobronchial amyloidosis are asymptomatic or exhibit symptoms, such as chronic wheezing, dyspnea, and cough, that are common manifestations of other disorders, including asthma. A bronchoscopic tissue biopsy using Congo red staining is the key standard for diagnosing tracheobronchial amyloidosis. Treatment strategies vary depending on the degree of airway obstruction. If the obstruction is significant and the patient is symptomatic, repeated bronchoscopic treatment, including local resection, laser therapy, stent placement, and radiation therapy, is considered a safer and better option. It is often misdiagnosed as asthma, but cases of tracheobronchial amyloidosis accompanied with asthma have not been reported. We report a case of intermittent wheezing, cough for 33 years, and shortness of breath on exertion for 7 years, which had aggravated in the previous 22 days. A pulmonary examination revealed diffuse wheezing. Pulmonary function testing revealed an obstructive ventilation dysfunction. Computerized tomography (CT) imaging revealed circumferential and irregular thickening of the tracheobronchial wall tissue with calcification and atelectasis of the right middle and lower lobe of the lung. Bronchoscopy revealed diffuse thickening of the mucosa of the trachea and bilateral main bronchi, with multiple nodular protuberances and relatively narrow lumens. The bronchial biopsies revealed massive amyloid deposits under the bronchial mucosa. The deposits exhibited a green birefringence under crossed polarized light after Congo red positive staining. The patient received standard treatment for asthma, and remains in good general condition without wheezing. It is not difficult to distinguish tracheobronchial amyloidosis through chest CT examination for patients with wheezing as long as this disease was considered. It was interesting that we present a rarer case of patient with tracheobronchial amyloidosis accompanied with asthma which both can cause symptoms such as wheezing.

The proteolysis of ZP proteins is essential to control cell membrane structure and integrity of developing tracheal tubes in Drosophila

Membrane expansion integrates multiple forces to mediate precise tube growth and network formation. Defects lead to deformations, as found in diseases such as polycystic kidney diseases, aortic aneurysms, stenosis, and tortuosity. We identified a mechanism of sensing and responding to the membrane-driven expansion of tracheal tubes. The apical membrane is anchored to the apical extracellular matrix (aECM) and causes expansion forces that elongate the tracheal tubes. The aECM provides a mechanical tension that balances the resulting expansion forces, with Dumpy being an elastic molecule that modulates the mechanical stress on the matrix during tracheal tube expansion. We show in Drosophila that the zona pellucida (ZP) domain protein Piopio interacts and cooperates with the ZP protein Dumpy at tracheal cells. To resist shear stresses which arise during tube expansion, Piopio undergoes ectodomain shedding by the Matriptase homolog Notopleural, which releases Piopio-Dumpy-mediated linkages between membranes and extracellular matrix. Failure of this process leads to deformations of the apical membrane, tears the apical matrix, and impairs tubular network function. We also show conserved ectodomain shedding of the human TGFβ type III receptor by Notopleural and the human Matriptase, providing novel findings for in-depth analysis of diseases caused by cell and tube shape changes.

Assessment of professional singers using laryngeal, respiratory, and airflow measurements

PURPOSE

In the pedagogy of classical vocal singing, it can be difficult to determine the human voice fach, especially for the voice of aspiring vocalists. Hence, an objective metric-based system for the determination of the human voice is needed. In the present study, we investigated the anthropological and aerodynamic parameters for 60 professional singers with a professionally confirmed singing range.

METHODS

Amongst the 60 included professional singers, there were ten participants each for sopranos, mezzo-sopranos, altos (female vocal fach), and tenors, baritones, basses (male vocal fach). Airflow measurements were recorded using spirometry whilst anthropological measurements were taken using CT scans. Appropriate statistical analyses were done using the Mann-Whitney U test and Kruskal Wallis H test with post-hoc tests and Bonferroni correction. p < 0.05 was considered statistically significant.

RESULTS

Soprano singers, who have the highest pitch, were found to be the shortest and least heavy, whilst basses, who have the lowest pitch, were found to be tallest and heaviest amongst the study participants. Furthermore, sopranos had the smallest lung volumes while the basses had the largest lung volumes (raw spirometry measures). However, when normalized ratios were considered, no differences were observed. Finally, laryngeal size showed sexual dimorphism due to developmental changes.

CONCLUSIONS

A mix of anthropological and aerodynamic measurements may be useful to assist singers and vocal pedagogues to assess and determine voice types before the beginning of their vocal studies.

Efficacy of levocetirizine in isolated rat tracheal smooth muscle

Histamine receptor-1 (H1) antagonists like levocetirizine are frequently used nowadays to treat rhinitis patients who experience rhinorrhea and sneezing. The trachea may be affected by the H1 antagonist when it is used to treat nasal symptoms, either orally or through inhalation. The purpose of this study was to ascertain in vitro effects of levocetirizine on isolated tracheal smooth muscle. As a parasympathetic mimetic, methacholine (10-6 M) causes contractions in tracheal smooth muscle, which is how we tested effectiveness of levocetirizine on isolated rat tracheal smooth muscle. We also tested the drug's impact on electrically induced tracheal smooth muscle contractions. The impact of menthol (either before or after) on the contraction brought on by 10-6 M methacholine was also investigated. According to the results, the addition of levocetirizine at concentrations of 10-5 M or more caused a slight relaxation in response to methacholine's 10-6 M contraction. Levocetirizine could prevent spike contraction brought on by electrical field stimulation (EFS). As the concentration rose, it alone had a neglect effect on the trachea's basal tension. Before menthol was applied, levocetirizine might have also inhibited the function of the cold receptor. According to this study, levocetirizine might potentially impede the parasympathetic function of the trachea. If levocetirizine was used prior to menthol addition, it also reduced the function of cold receptors.

A mariner's tale: Invasive endotracheal Mycobacterium marinum infection

Mycobacterium marinum is a ubiquitous water-borne non-tuberculous mycobacterial (NTM) pathogen. In humans, M. marinum infections are acquired through direct inoculation of skin wounds and are almost exclusively localized to skin and soft tissues. Pulmonary infection with M. marinum is extremely rare, and to our knowledge, invasive endobronchial disease has not been reported. Here, we present a case of a 71-year-old immunocompetent male surfer with invasive endotracheal M. marinum granulomatous disease. The patient was successfully cured with a regimen of azithromycin 250 mg daily, ethambutol 900 mg (15 mg/kg) daily and rifampicin 600 mg daily for 12 months following culture conversion. This case highlights several important concepts: Firstly, M. marinum infection, including invasive endobronchial infection, should be considered a rare cause of NTM pulmonary disease. Secondly, endotracheal infection can be successfully eradicated with this selected therapeutic regimen. Finally, the absence of M. marinum skin or soft-tissue infection in this patient, raises the possibility that human disease might also be acquired via inhalation of M. marinum contaminated water in rare circumstances.

Proton Beam Therapy as a Curative Treatment for a Young Case of Unresectable Tracheal Adenoid Cystic Carcinoma

Primary tracheal adenoid cystic carcinoma (TACC) is a rare malignancy without an established treatment. Central airway obstruction due to TACC often decreases the quality of life and has life-threatening consequences. A 19-year-old man with unresectable TACC and central airway obstruction suffered from progressive cough and dyspnea after exercise. Proton beam therapy (PBT) was selected as the preferred treatment over systemic anti-cancer chemotherapy for TACC. PBT led to complete remission of TACC and the almost complete disappearance of the respiratory symptoms without adverse events. PBT is a useful and safe treatment for unresectable primary TACC.

Operative technique: Tracheal resection and anastomosis in a revision surgery

Tracheal stenosis is an uncommon pathological condition in which the lumen of the trachea is reduced. Within its management an adequate preoperative workup is crucial to determine the most appropriate procedure for each patient. In this scenario tracheal resection and anastomosis is a viable approach, as a procedure in which part of the trachea is removed and then restored with a tension-free anastomosis. It is usually indicated for extensive and high-grade lesions or when previous endoscopic procedures had failed. The patient here presented had already undergone a balloon dilatation twice and a tracheal resection and referred to our clinic with a residual tracheal stenosis graded Myer-Cotton 3 involving three tracheal rings. We here illustrate step-by-step the surgical procedure and highlight a peculiar way to perform the anastomosis, especially in a revision surgery.

[A case of pediatric tracheal inflammatory myofibroblastic tumor]

Inflammatory myofibroblastic tumor is a rare tumor of mesenchymal origin. A case of intratracheal inflammatory myofibroblastic tumor in a male child was reported. The clinical characteristics, diagnosis, treatment and prognosis of the disease were reviewed based on the literature, and a differential diagnosis between inflammatory myofibroblastic tumor and hamartoma was performed to ultimately confirm the nature of the tumor in the child.

Tracheal Mirror Image Artifact in Patients With Normal and Pathologic Tracheas

Ultrasonography is gaining popularity as a diagnostic imaging modality for airway pathology. Tracheal ultrasound (US) has several nuances that are important for clinicians, including imaging artifacts, which can be mistaken for pathology. Tracheal mirror image artifacts (TMIAs) occur when the US beam is reflected back to the transducer in a nonliner direction or with multiple timesteps. It has previously been believed that the convexity of the tracheal cartilage prevents mirror image artifacts, but in reality, the air column acts as an acoustic mirror and causes TMIA. We describe a cohort of patients with both normal and pathologic tracheas, all of whom have TMIA on the tracheal US. These artifacts are important to recognize, especially as the airway US becomes more commonplace.

Successful Treatment with Definitive Concurrent Chemoradiotherapy Followed by Durvalumab Maintenance Therapy in a Patient with Tracheal Adenoid Cystic Carcinoma

Adenoid cystic carcinoma (ACC) is a rare type of malignant tracheal tumor originating from the secretory glands. Complete surgical resection is the current standard of care for tracheal ACC. However, there have been few case reports of chemoradiotherapy for unresectable tracheal ACC. We herein report a 28-year-old man with unresectable tracheal ACC who received concurrent chemoradiotherapy (CCRT) followed by maintenance therapy with durvalumab. CCRT was completed with a good response and safety, and the patient is currently receiving durvalumab as maintenance therapy. Durvalumab after CCRT can be a treatment option for patients with unresectable tracheal ACC.

Case Report: Tracheal infiltration with wheezing revealing Hodgkin's disease

Hodgkin's disease with an initial tracheobronchial involvement is not common. The symptoms might be misleading, resulting in a diagnosis delay. We report the case of a 38-year-old woman with a one-month history of wheezing associated with a dry cough. The physical examination revealed a good general state of health, bilateral wheezing and supra-clavicular lymphadenopathy. The adenopathy biopsy's histopathology revealed Hodgkin lymphoma. The whole body FDG-PET scan was an important tool to assess the diagnosis as well as for the staging. The patient was treated with chemotherapy. Another unusual aspect is the tracheobronchial metastasis confirmed by a bronchial biopsy. Thus, our patient was put on a second-line chemotherapy. She died one year after the initial diagnosis. To conclude, it is an atypical clinical presentation of an Hodgkin lymphoma with a tracheobronchial relapse. It should be considered in the differential diagnosis of asthma or a tracheal tumor.