Tracheal stenosis in prolonged mechanically ventilated patients: prevalence, risk factors, and bronchoscopic management

Laser-assisted endoscopic transoral surgery in apnoeic phase-management strategy for acquired supracarinal tracheal stenosis

Acquired supracarinal tracheal stenosis can be defined as postintubation tracheal stenosis of the lower third of the trachea that cannot be bypassed by standard or adjustable flange tracheostomy tubes. Owing to difficulty of access in the deep trachea, the transoral laser-assisted endoscopic surgical management of such stenoses is a challenge both for the surgeon and the anaesthetist alike. It requires good rapport and efficient cooperation between the teams to ensure appropriate oxygenation and carbon-dioxide washout while providing intermittent apnoeic phases to the surgeon for clear visualisation of the target area and use of Diode laser which is otherwise hazardous in an oxygen/nitrous oxide rich environment.From our tertiary care referral centre with strong work load for such pathologies, we report one such case of acquired tracheal stenosis successfully managed with transoral Diode laser-assisted surgery.

Risk factors for patients with tracheal stenosis: a systematic review and meta-analysis

OBJECTIVE

To systematically evaluate potential risk factors for tracheal stenosis and to provide a reference for the prevention and management of patients with this condition.

METHODS

Databases were searched to identify studies of the risk factors for tracheal stenosis, from their inception to October 2023, then a meta-analysis was performed. The study was registered with PROSPERO under the registration number CRD42023428906.

RESULTS

Ten studies of a total of 2525 patients were included. The meta-analysis showed that tracheotomy, diabetes, the duration of intubation, the duration of mechanical ventilation, respiratory tract infection, a high incision, and a ratio of intratracheal tube cuff diameter (C)/transverse diameter at the level of the clavicle (T) >150% were risk factors for the development of tracheal stenosis.

CONCLUSION

Measures such as shortening the duration of mechanical ventilation and intubation, reducing and avoiding tracheotomy after prolonged intubation, early tracheotomy in patients with obesity who require prolonged mechanical ventilation, appropriate choices of incision location and catheter, the maintenance of appropriate C/T, the prevention of respiratory infection, and the control of diabetes mellitus should limit the risk of tracheal stenosis.

Device associated complications in the intensive care unit

Invasive devices are routinely used in the care of critically ill patients. Although they are often essential components of patient care, devices such as intravascular catheters, endotracheal tubes, and ventilators are a common source of complications in the intensive care unit. Critical care practitioners who use these devices need to use strategies for risk reduction and understand approaches to management when adverse events occur. This review discusses the identification, prevention, and management of complications of vascular, airway, and mechanical support devices commonly used in the intensive care unit.

Type and morphology affect the success rate of bronchoscopy for postintubation tracheal stenosis

Objective

With advancements in respiratory interventional techniques, bronchoscopic intervention technology has emerged as a viable approach for managing postintubation tracheal stenosis (PITS). However, there was a paucity of research investigating the potential impact of stenosis characteristics and morphology (such as stenosis degree, length, type, and morphology) on bronchoscopic intervention treatment prognosis for PITS patients. This study was to assess the impact of various preoperative stenosis characteristic factors on the bronchoscopic cure rate among patients.

Methods

This is a retrospective study analyzing the medical records of patients with PITS who received bronchoscopic intervention at the tertiary interventional pulmonology center.

Results

Among the cases, 115 individuals achieved a in a success rate of 79.86% for bronchoscopic intervention therapy and were assigned to Group S. On the other hand, 29 cases required surgical intervention, accounting for a surgical treatment rate of 20.14% and were assigned to Group F. The stenosis in the Group F predominantly exhibited irregular shapes with scar granulation accompanied by tracheal chondromalacia collapse. Patients in group S experienced fewer total procedures, rigid bronchoscopy treatment, intraoperative hypoxemia, needed emergency re-bronchoscopy in 24 h and transferred to ICU postoperatively. Patients with pure scar and granuloma, the rate of bronchoscopic success cure was higher than patients with scar granulation accompanied by tracheal chondromalacia (odds ratio: 8.208; 95% confidence interval: 2.755-24.459), and regular stenosis morphology was associated with a higher bronchoscopic success cure rate (odds ratio: 9.463; 95% confidence interval: 3.128-28.623).

Conclusion

Irregular airway stenosis, chondromalacia or airway collapse are key factors affecting the success rate of bronchoscopic treatment for post-intubation tracheal stenosis. Level of evidence: 4 (historically controlled studies).

Involvement of PD-1+CD4+ T cells in the development of traumatic tracheal stenosis by regulating the IL-17/STAT3 pathway

Studies have highlighted an upregulation of PD-1 expression in CD4+ T cells, which accelerates lung fibrosis by activating the IL-17/STAT3 pathway, leading to IL-17A and TGF-β1 secretion. However, the relation with traumatic tracheal stenosis (TS) remains unexplored. Our analysis found significant increases in PD-1+CD4+ T cells, IL-17A, and TGF-β1 in the TS patients (n = 10). The cellular model used CD4+ T cells co-cultured with bronchial fibroblasts while the animal model used a nylon brush to scrape the damaged tracheal mucosa. Interventions with PD-1 and STAT3 inhibitors both in vitro (n = 5) and in vivo (n = 6) showed decreased expression of TGF-β1 and IL-17A in CD4+ T cells, decreased collagen I synthesis in vitro, and reduced tractal fibrosis in vivo. Furthermore, PD-1's modulation of the STAT3 was evident. This research unveils PD-1+CD4+ T cells' role in TS, thus suggesting a novel immunotherapeutic strategy to counteract tracheal fibrosis.

Tissue-engineered tracheal implants: Advancements, challenges, and clinical considerations

Restoration of extensive tracheal damage remains a significant challenge in respiratory medicine, particularly in instances stemming from conditions like infection, congenital anomalies, or stenosis. The trachea, an essential element of the lower respiratory tract, constitutes a fibrocartilaginous tube spanning approximately 10-12 cm in length. It is characterized by 18 ± 2 tracheal cartilages distributed anterolaterally with the dynamic trachealis muscle located posteriorly. While tracheotomy is a common approach for patients with short-length defects, situations requiring replacement arise when the extent of lesion exceeds 1/2 of the length in adults (or 1/3 in children). Tissue engineering (TE) holds promise in developing biocompatible airway grafts for addressing challenges in tracheal regeneration. Despite the potential, the extensive clinical application of tissue-engineered tracheal substitutes encounters obstacles, including insufficient revascularization, inadequate re-epithelialization, suboptimal mechanical properties, and insufficient durability. These limitations have led to limited success in implementing tissue-engineered tracheal implants in clinical settings. This review provides a comprehensive exploration of historical attempts and lessons learned in the field of tracheal TE, contextualizing the clinical prerequisites and vital criteria for effective tracheal grafts. The manufacturing approaches employed in TE, along with the clinical application of both tissue-engineered and non-tissue-engineered approaches for tracheal reconstruction, are discussed in detail. By offering a holistic view on TE substitutes and their implications for the clinical management of long-segment tracheal lesions, this review aims to contribute to the understanding and advancement of strategies in this critical area of respiratory medicine.

Imaging of Large Airway Disorders

Large airway disorders encompass a large variety of diseases and pathology, with broad categories including anatomic variants, congenital abnormalities, acquired abnormalities, inflammatory/infiltrative causes, infection, and tumors. The most common diseases in each category are discussed with a focus on the salient imaging findings. Pitfalls to beware of are discussed through the article, and concludes with a general method to approaching large airways pathology that should provide the reader with a basic framework and understanding of this complex topic.

Airway collapse hinders recovery in bronchoscopy therapy for postintubation tracheal stenosis patients

BACKGROUND

Expiratory central airway collapse (ECAC) following postintubation airway stenosis (PITS) is a rare phenomenon. The impact of airway malacia and collapse on the prognosis and the success rate of bronchoscopic interventional therapy in patients with PITS had been inadequately investigated.

OBJECTIVE

The aim of this research was to assess the influence of airway malacia and collapse on the efficacy of bronchoscopic interventional therapy in patients with PITS.

DESIGN

This retrospective analysis examined the medical documentation of individuals diagnosed with PITS who underwent bronchoscopic intervention at the tertiary interventional pulmonology center of Emergency General Hospital from 2014 to 2021.

MAIN OUTCOME MEASURES

Data pertaining to preoperative, perioperative, and postoperative stages were documented and subjected to analysis.

RESULTS

The patients in malacia and collapse group (MC group) exhibited a higher frequency of perioperative complications, including intraoperative hypoxemia, need for reoperation within 24 h, and postoperative intensive care unit admission rate (P < 0.05, respectively). Meanwhile, patients in group MC demonstrated significantly worse postoperative scores (higher mMRC score and lower KPS score) compared to those in pure stenosis group (P < 0.05, respectively), along with higher degrees of stenosis after treatment and a lower success rate of bronchoscopic intervention therapy cured (P < 0.05, respectively). Pearson analysis results showed that these terms were all significantly correlated with the occurrence of airway malacia and collapse in the airway (P < 0.05, respectively).

CONCLUSION

The presence of malacia or collapse in patients with PITS was associated with increased perioperative complications following bronchoscopic interventional therapy, and significantly reduced the long-term cure rate compared to patients with pure tracheal stenosis. Trial registration Chinese Clinical Trial Registry on 06/12/2021.

REGISTRATION NUMBER

ChiCTR2100053991.

Tracheal Stenosis in Open Versus Percutaneous Tracheostomy

OBJECTIVE

This study aims to investigate if there is an increased risk of developing tracheal stenosis after tracheostomy with an open versus percutaneous tracheostomy.

METHODS

The patient cohort included patients receiving open or percutaneous tracheostomies at Catholic Health Initiatives Midwest facilities from January 2017 to June 2023. The primary aim was to compare the differences in the risk of developing tracheal stenosis between open and percutaneous tracheostomy techniques. Between-technique differences in the risk of developing tracheal stenosis were assessed via a Cox proportional hazard model. To account for death precluding patients from developing tracheal stenosis, death was considered a competing risk.

RESULTS

A total of 828 patients met inclusion criteria (61.7% open, 38.3% percutaneous); 2.5% (N = 21) developed tracheal stenosis. The median number of days to develop tracheal stenosis was 84 (interquartile range: 60 to 243, range: 6 to 739). Tracheal stenosis was more frequent in patients who received a percutaneous tracheostomy (percutaneous: 3.5% vs. open: 2.0%); however, the risk of developing tracheal stenosis was statistically similar between open and percutaneous techniques (HR: 2.05, 95% CI: 0.86-4.94, p = 0.108).

CONCLUSIONS

This study demonstrates no significant difference in the development of tracheal stenosis when performing an open versus a percutaneous tracheostomy. Tracheal stenosis is a long-term complication of tracheostomy and should not influence the decision about the surgical technique used.

Differential expression of miRNAs revealed by small RNA sequencing in traumatic tracheal stenosis

Introduction: Traumatic tracheal stenosis (TTS) is a major cause of complex difficult airways, without clinically definitive efficacious drugs available. The aim of this study was to provide a general view of interactions between micro and messenger ribonucleic acids (miRNAs and mRNAs) and many potential mechanisms in TTS via small RNA sequencing. Methods: In this study, the identification of miRNAs was completed using small RNA sequencing and samples from four TTS patients and four normal control cases. By using bioinformatics tools, such as miRanda and RNAhybrid, for identifying the candidate target genes of miRNAs with differential expression in each sample, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes were employed for enriching the predicted target genes of miRNAs with differential expression based on the correspondence between miRNAs and their target genes. We detected the expression of the candidate miRNAs using quantitative real-time polymerase chain reaction (qRT-PCR). Results: Twenty-four miRNAs with significant differential expression were identified, including 13 upregulated and 11 downregulated ones. Bioinformation technology was adopted to predict 2,496 target genes. These miRNA-target genes were shown to be primarily enriched in cells and organelles with catalytic activity and binding function, such as binding proteins, small molecules, and nucleotides. Finally, they were observed to process into TTS through the intercellular and signal regulation of related inflammatory signaling and fibrosis signaling pathways. QRT-PCR confirmed the upregulation of miR21-5p and miR214-3p and the downregulation of miR141-3p and miR29b-3p, which was expected to become a high-specific miRNA for TTS. Conclusion: Among all the miRNAs detected, 24 miRNAs demonstrated differential expression between the TTS and normal control groups. A total of 2,496 target genes were predicted by bioinformation technology and enriched in inflammatory and fibrotic signaling pathways. These results provide new ideas for further studies and the selection of targets for TTS in the future.

Comparison of Mechanical Forces used in Open Tracheotomy versus Percutaneous Tracheotomy Techniques

OBJECTIVE

To understand the etiology of tracheotomy-induced tracheal stenosis by comparing the differences in techniques and mechanical force applied with open tracheotomy (OT) versus percutaneous tracheotomy (PCT) placement.

METHODS

This study is an unblinded, experimental, randomized controlled study in an ex-vivo animal model. Simulated tracheostomies were performed on 10 porcine tracheas, 5 via a tracheal window technique (OT) and 5 using the Ciaglia technique (PCT). The applied weight during the simulated tracheostomy and the compression of the trachea were recorded at set times during the procedure. The applied weight during tracheostomy was used to calculate the tissue force in Newtons. Tracheal compression was measured by anterior-posterior distance compression and as percent change.

RESULTS

Average forces for scalpel (OT) versus trocar (PCT) were 2.6 N and 12.5 N (p < 0.01), with the dilator (PCT) it was 22.02 N (p < 0.01). The tracheostomy placement with OT required an average force of 10.7 N versus 23.2 N (p < 0.01) with PCT. The average change in AP distance when using the scalpel versus trocar was 21%, and 44% (p < 0.01), with the dilator it was 75% (p < 0.01). The trach placement with OT versus PCT had an average AP distance change of 51% and 83% respectively (p < 0.01).

CONCLUSION

This study demonstrated that PCT required more force and caused more tracheal lumen compression when compared to the OT technique. Based on the increased force required for PCT, we suspect there could also be an increased risk for tracheal cartilage trauma.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:103-107, 2024.

Swiss Cheese Trachea: An Unwarranted, Unique Form of Post-intubation Tracheal Stenosis

How to cite this article: Bajad P, Pahuja S, Agarwal S, Khanna A. Swiss Cheese Trachea: An Unwarranted, Unique Form of Post-intubation Tracheal Stenosis. Indian J Crit Care Med 2024;28(1):84-85.

Medical comorbidities in patients with prolonged disorder of consciousness: A narrative review

BACKGROUND

A few studies specifically addressed medical comorbidities (MCs) in patients with severe acquired traumatic or non-traumatic brain injury and prolonged disorders of consciousness (pDoC; i.e., patients in vegetative state/unresponsive wakefulness syndrome, VS/UWS, or in minimally conscious state, MCS).

OBJECTIVE

To provide an overview on incidence of MCs in patients with pDoC.

METHODS

Narrative review on most impacting MCs in patients with pDoC, both those directly related to brain damage (epilepsy, neurosurgical complications, spasticity, paroxysmal sympathetic hyperactivity, PSH), and those related to severe disability and prolonged immobility (respiratory comorbidities, endocrine disorders, metabolic abnormalities, heterotopic ossifications).

RESULTS

Patients with pDoC are at high risk to develop at least one MC. Moderate or severe respiratory and musculoskeletal comorbidities are the most common MCs. Epilepsy and PSH seem to be more frequent in patients in VS/UWS compared to patients in MCS, likely because of higher severity in the brain damage in VS. Endocrine metabolic, PSH and respiratory complications are less frequent in traumatic etiology, whereas neurogenic heterotopic ossifications are more frequent in traumatic etiology. Spasticity did not significantly differ between VS/UWS and MCS and in the three etiologies. MCs are associated with higher mortality rates, worse clinical improvement and can impact accuracy in the clinical diagnosis.

CONCLUSIONS

The frequent occurrence of several MCs requires a specialized rehabilitative setting with high level of multidisciplinary medical expertise to prevent, appropriately recognize and treat them. Comprehensive rehabilitation could avoid possible progression to more serious complications that can negatively impact clinical outcomes.

Hypothermia and Prolonged Time From Procedure End to Extubation After Endovascular Thoracic Aortic Surgery

OBJECTIVE

Perioperative hypothermia (core temperature <36°C) occurs in 50%-to-80% of patients recovering from thoracic aortic surgery, though its effects have not been described fully in this context. The authors, therefore, sought to characterize the incidence of perioperative hypothermia and its association with time from procedure end to extubation in endovascular aortic surgical patients.

DESIGN

A retrospective cohort study.

SETTING

At a single academic tertiary center.

PARTICIPANTS

Patients recovering from thoracic aortic surgery with lumbar drains.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

A total of 196 patients were included in this study, 55 of whom were hypothermic with temperatures <35.0°C at the end of surgery. Though the unadjusted time to extubation was not statistically different in the hypothermic group (median 8 minutes, IQR 5-13.5 minutes) compared to the normothermic group (median 7 minutes, IQR 4-12 minutes; p = 0.062), multivariate predictors of increased time from procedure end to extubation included hypothermia (p = 0.011), age (p = 0.009), diabetes (p = 0.015), history of carotid disease (p = 0.040), and crystalloid volume (p = 0.019).

CONCLUSIONS

Hypothermia in patients recovering from endovascular aortic surgery was associated with prolonged time from procedure end to extubation. Because of the retrospective observational nature of the authors' analysis, it was not possible to determine the extent to which prolonged mechanical ventilation was influenced by low temperature.

Incidence, causes, and predictors of unsuccessful decannulation following prolonged weaning

Background

Liberation from prolonged tracheostomy ventilation involves ventilator weaning and removal of the tracheal cannula (referred to as decannulation). This study evaluated the incidence, causes, and predictors of unsuccessful decannulation following prolonged weaning.

Methods

Observational retrospective cohort study of 532 prolonged mechanically ventilated, tracheotomized patients treated at a specialized weaning center between June 2013 and January 2021. We summarized the causes for unsuccessful decannulations and used a binary logistic regression analysis to derive and validate associated predictors.

Results

Failure to decannulate occurred in 216 patients (41%). The main causes were severe intensive care unit (ICU)-acquired dysphagia (64%), long-term ventilator dependence following weaning failure (41%), excessive respiratory secretions (12%), unconsciousness (4%), and airway obstruction (3%). Predictors of unsuccessful decannulation from any cause were age [odds ratio (OR) = 1.04 year^-1; 95% confidence interval (CI), 1.02-1.06; p < 0.01], body mass index [0.96 kg/m² (0.93-1.00); p = 0.027], Acute Physiology and Chronic Health Evaluation II (APACHE-II) score [1.05 (1.00-1.10); p = 0.036], pre-existing non-invasive home ventilation [3.57 (1.51-8.45); p < 0.01], percutaneous tracheostomies [0.49 (0.30-0.80); p < 0.01], neuromuscular diseases [4.28 (1.21-15.1); p = 0.024], and total mechanical ventilation duration [1.02 day^-1 (1.01-1.02); p < 0.01]. Regression models examined in subsets of patients with severe dysphagia and long-term ventilator dependence as the main reason for failure revealed little overlapping among predictors, which even showed opposite effects on the outcome. The application of non-invasive ventilation as a weaning technique contributed to successful decannulation in 96 of 221 (43%) long-term ventilator-dependent patients following weaning failure.

Conclusion

Failure to decannulate after prolonged weaning occurred in 41%, mainly resulting from persistent ICU-acquired dysphagia and long-term ventilator dependence following weaning failure, each associated with its own set of predictors.

Glycosaminoglycan, Antimicrobial Defence Molecule and Cytokine Appearance in Tracheal Hyaline Cartilage of Healthy Humans

Hyaline cartilage is an important tracheal structure, yet little is known about its molecular composition, complicating investigation of pathologies and replacement options. Our aim was to research tracheal hyaline cartilage structure, protective tissue factors and variations in healthy humans. The tissue material was obtained from 10 cadavers obtained from the Riga Stradins University Institute of Anatomy and Anthropology archive. Tissues were stained with Bismarck brown and PAS for glycosaminoglycans, and immunohistochemistry was performed for HBD-2, HBD-3, HBD-4, IL-10 and LL-37. The slides were inspected by light microscopy and Spearman's rank correlation coefficient was calculated. The extracellular matrix was positive across hyaline cartilage for PAS, yet Bismarck brown marked positive proliferation and growth zones. Numerous positive cells for both factors were found in all zones. All of the antimicrobial defence molecules and cytokines were found in a moderate number of cells, except in the mature cell zone with few positive cells. Spearman's rank correlation coefficient revealed strong and moderate correlations between studied factors. Hyaline cartilage is a tracheal defence structure with a moderate number of antimicrobial defence protein and cytokine immunoreactive cells as well as numerous glycosaminoglycan positive cells. The extracellular matrix glycosaminoglycans provide structural scaffolding and intercellular signalling. The correlations between the studied factors confirm the synergistic activity of them.