Incidence Rate of Post-Intubation Tracheal Stenosis in Patients Admitted to Five Intensive Care Units in Iran

Inter-rater reliability of a novel objective endpoint for benign central airway stenosis interventions: Segmentation-based volume rendering of computed tomography scans

OBJECTIVES

To evaluate the reliability of a novel segmentation-based volume rendering approach for quantification of benign central airway obstruction (BCAO).

DESIGN

A retrospective single-center cohort study.

SETTING

Data were ascertained using electronic health records at a tertiary academic medical center in the United States.

PARTICIPANTS AND INCLUSION

Patients with airway stenosis located within the trachea on two-dimensional (2D) computed tomography (CT) imaging and documentation of suspected benign etiology were included. Four readers with varying expertise in quantifying tracheal stenosis severity were selected to manually segment each CT using a volume rendering approach with the available free tools in the medical imaging viewing software OsiriX (Bernex, Switzerland). Three expert thoracic radiologists were recruited to quantify the same CTs using traditional subjective methods on a continuous and categorical scale.

OUTCOME MEASURES

The interrater reliability for continuous variables was calculated by the intraclass correlation coefficient (ICC) using a two-way mixed model with 95% confidence intervals (CI).

RESULTS

Thirty-eight patients met the inclusion criteria, and fifty CT scans were selected for measurement. The most common etiology of BCAO was iatrogenic in 22 patients (58%). There was an even distribution of chest and neck CT imaging within our cohort. The average ICC across all four readers for the volume rendering approach was 0.88 (95% CI, 0.84 to 0.93), suggesting good to excellent agreement. The average ICC for thoracic radiologists for subjective methods on the continuous scale was 0.38 (95% CI, 0.20 to 0.55), suggesting poor to fair agreement. The kappa for the categorical approach was 0.26, suggesting a slight to fair agreement amongst the raters.

CONCLUSION

In this retrospective cohort study, agreement was good to excellent for raters with varying expertise in airway cross-sectional imaging using a novel segmentation-based volume rendering approach to quantify BCAO. This proposed measurement outperformed our expert thoracic radiologists using conventional subjective grading methods.

Risk factors for developing subglottic and tracheal stenosis from the medical intensive care unit

Objective

Endotracheal intubation is a common procedure in the medical intensive care unit (MICU), but it carries risk of complications including, but not limited to, subglottic stenosis (SGS) and tracheal stenosis (TS). Current literature suggests identifiable risk factors for the development of airway complications. This study is a comprehensive evaluation of potential risk factors in patients who developed SGS and TS following endotracheal intubation in our MICU.

Methods

Patients intubated in our MICU were identified from 2013 to 2019. Diagnoses of SGS or TS within 1 year of MICU admission were identified. Data extracted included age, sex, body measurements, comorbidities, bronchoscopies, endotracheal tube size, tracheostomy, social history, and medications. Patients with prior diagnosis of airway complication, tracheostomy, or head and neck cancer were excluded. Univariate and multivariate logistic regressions were performed.

Results

A total of 136 patients with TS or SGS were identified out of a sample of 6603 patients intubated in the MICU. Cases were matched to controls who did not develop airway stenosis based on identical Charlson Comorbidity Index scores. Eighty six controls were identified with a complete record of endotracheal/tracheostomy tube size, airway procedures, sociodemographic data, and medical diagnosis. Regression analysis showed that SGS or TS were associated with tracheostomy, bronchoscopy, chronic obstructive pulmonary disease, current tobacco use, gastroesophageal reflux disease, systemic lupus erythematosus, pneumonia, bronchitis, and numerous medication classes.

Conclusion

Various conditions, procedures, and medications are associated with an increased risk of developing SGS or TS.

Level of evidence

4.

Diagnostic Dilemma: A Patient With Pulmonary Fibrosis Who Presented for Severe Tracheal Stenosis After COVID-19 Pneumonia

A 44-year-old man with pulmonary fibrosis presented to our pulmonary hypertension clinic with biphasic stridor and dyspnea. He was sent to the emergency department, where he was found to have 90% subglottic tracheal stenosis and was successfully treated with balloon dilation. Seven months prior to the presentation, he required intubation for coronavirus disease 2019 (COVID-19) pneumonia complicated by hemorrhagic stroke. He was discharged after percutaneous dilatational tracheostomy, which was decannulated after three months. Our patient possessed several risk factors for tracheal stenosis, including endotracheal intubation, tracheostomy, and airway infection. Furthermore, our case is of great importance given the developing literature on COVID-19 pneumonia and its subsequent complications. Additionally, his history of interstitial lung disease may have confounded his presentation. Therefore, it is important to understand stridor, as it is an important exam finding that clinically distinguishes upper and lower airway disease. Our patient's biphasic stridor is consistent with the diagnosis of severe tracheal stenosis.

Idiopathic subglottic stenosis in Saskatchewan Hutterite population

Background

By studying the odds of developing idiopathic subglottic stenosis in the isolated and genetically unique Hutterite population, this study sought to strengthen the hypothesis that an underlying genetic predisposition may exist for its development.

Methods

A retrospective chart review examined the medical records of all adult patients treated for idiopathic subglottic stenosis in Saskatchewan between 2008 and 2018. Cases were segregated into Hutterite and non-Hutterite.

Results

Four out of 36 cases of idiopathic subglottic stenosis occurred among Hutterites. The odds of a Hutterite developing idiopathic subglottic stenosis are 21.89 times higher than for non-Hutterites. Positive family history was only observed in the Hutterite population.

Conclusion

The study strengthens the hypothesis that genetics may play a role in the aetiology of idiopathic subglottic stenosis by demonstrating that the genetically and socially unique Hutterites are more likely to develop this rare disease. This study is the first to demonstrate that a specific subpopulation is at a higher risk for developing idiopathic subglottic stenosis.

A case of severe subglottic stenosis masking as bronchial asthma

Tracheal stenosis is an uncommon and dangerous complication after intubation and tracheostomy and its clinical presentation may be misinterpreted as bronchial asthma. A careful vigilant clinical history and examination is required for the diagnosis of such tracheal stenosis. Here, we describe a case of post intubation subglottic tracheal stenosis in a young male who presented with features mimicking bronchial asthma. IMC J Med Sci 2022; 16(2): 005. DOI: https://doi.org/10.55010/imcjms.16.015 *Correspondence: Bhupendra Kumar Jain, Department of Pulmonary Medicine, Chhindwara Institute of Medical Sciences, Chhindwara, Jabalpur Medical University, Madhya Pradesh, India; ORCID : 0000-0002-6619- 8596;Email: drbhupendrakjain@gmail.com

A two-stage in vivo approach for implanting a 3D printed tissue-engineered tracheal replacement graft: A proof of concept

OBJECTIVES

To optimize a 3D printed tissue-engineered tracheal construct using a combined in vitro and a two-stage in vivo technique.

METHODS

A 3D-CAD (Computer-aided Design) template was created; rabbit chondrocytes were harvested and cultured. A Makerbot Replicator™ 2x was used to print a polycaprolactone (PCL) scaffold which was then combined with a bio-ink and the previously harvested chondrocytes. In vitro: Cell viability was performed by live/dead assay using Calcein A/Ethidium. Gene expression was performed using quantitative real-time PCR for the following genes: Collagen Type I and type II, Sox-9, and Aggrecan. In vivo: Surgical implantation occurred in two stages: 1) Index procedure: construct was implanted within a pocket in the strap muscles for 21 days and, 2) Final surgery: construct with vascularized pedicle was rotated into a segmental tracheal defect for 3 or 6 weeks. Following euthanasia, the construct and native trachea were explanted and evaluated.

RESULTS

In vitro: After 14 days in culture the constructs showed >80% viable cells. Collagen type II and sox-9 were overexpressed in the construct from day 2 and by day 14 all genes were overexpressed when compared to chondrocytes in monolayer.

IN VIVO

By day 21 (immediately before the rotation), cartilage formation could be seen surrounding all the constructs. Mature cartilage was observed in the grafts after 6 or 9 weeks in vivo.

CONCLUSION

This two-stage approach for implanting a 3D printed tissue-engineered tracheal replacement construct has been optimized to yield a high-quality, printable segment with cellular growth and viability both in vitro and in vivo.

Intra-tracheal multiplexed sensing of contact pressure and perfusion

Incorrect endotracheal tube (ETT) cuff inflation pressure causes significant problems for intubated patients. The technical development and first in vivo use of a smart ETT for measurements at the cuff-trachea interface during mechanical ventilation are described. The intra-tracheal multiplexed sensing (iTraXS) ETT contains integrated optical fibre sensors to measure contact pressure and blood perfusion. The device is tested during mechanical ventilation in a porcine model (N=6). For contact pressure, signals were obtained in all 30 measurements. For perfusion, data could be obtained in all 33 measurements. In the 3 cases where the cuff was inflated to an artificially high-level, blood occlusion is observed.

A case of massive saddle pulmonary embolism and benign tracheal stenosis in a patient with COVID-19 infection

Since December 2019, the novel coronavirus disease 2019 (COVID-19) outbreak that started in Wuhan, China, has become a global pandemic affecting millions of people around the globe. These patients are prone to a number of complications either related to their disease or to the different treatment modalities. Pulmonary embolism (PE) and benign post-intubation tracheal stenosis (BTS) are among these complications. In this study, we report the case of a patient with a recent COVID-19 infection that got complicated by a massive PE as well as a BTS.

Incidence of Laryngotracheal Lesions After Orotracheal Intubation in Coronavirus Disease Patients

OBJECTIVES/HYPOTHESIS

To evaluate the incidence of lesions and severe sequelae and the risk factors for the development of laryngotracheal lesions after orotracheal intubation (OTI) in coronavirus disease (COVID-19) patients.

STUDY DESIGN

Prospective cohort study.

METHODS

In this prospective cohort study, we evaluated patients diagnosed with COVID-19 who were consecutively admitted to a tertiary hospital and required OTI from March 1, 2020 to October 31, 2020. Patients discharged were called for outpatient follow-up and endoscopic examination.

RESULTS

A total of 1,357 patients diagnosed with COVID-19, as confirmed by nasal swab reverse transcription polymerase chain reaction, were admitted. OTI for mechanical ventilation was required in 421 patients (31%). Of the intubated patients, 172 (40.9%) were discharged and 249 (59.1%) died. Outpatient evaluation by videoendoscopy was performed in 95 patients (55.2%) approximately 100 days after extubation. Laryngotracheal lesions were observed in 38 patients (40%), with 17.9% diagnosed with laryngotracheal stenosis or unilateral immobility while 6.3% had severe stenosis (grades 3 and 4). The factors presenting statistical significance for the development of laryngotracheal lesions were the endotracheal tube (ETT) size; prone position over the OTI period; and the increased leukocyte count, d-dimer, prothrombin time (PT), and international normalized ratio (INR) on the day OTI was performed.

CONCLUSIONS

The incidence of laryngotracheal lesion in COVID-19 patients is 40%, with 6.3% of them presenting with severe stenosis. There was a greater risk for the development of laryngotracheal lesions in patients using a larger ETT, kept in a prone position, presenting a greater inflammatory reaction (increased leukocyte count), or developing coagulation disorders (increased d-dimer, PT, and INR).

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

Interventional pulmonology during COVID-19 pandemic: current evidence and future perspectives

COVID-19, caused by SARS-CoV-2 infection, has become increasingly prevalent worldwide, reaching a pandemic stage in March 2020. The organization of health care services had to change because of this new disease, with the need to reallocate staff and materials, besides changing management protocols. A very important challenge is not to expose patients and health care workers to the risk of infection and not to waste personal protective equipment (PPE). In the field of interventional pulmonology, various aspects related to COVID-19 must be taken into great consideration. Although bronchoscopy is not a first-line test for patients with suspected SARS-CoV-2 infection, it has a role in selected cases and it can be useful for differential diagnosis. However, bronchoscopy is an aerosol-generating procedure, that’s why its unjustified use could contribute to propagate the virus. For this reason, the utility of each procedure must be carefully evaluated, the patient has to be properly investigated before the procedure, which has to be performed with specific precautions, including adequate PPE. In this review, we summarize the knowledge and the principal statements about endoscopic activity in COVID-19 period, in both diagnosis of COVID-19 and management of patients. How to safely perform both bronchoscopic and pleural-related procedures (thoracoscopy, pleural biopsy and drainage of pleural effusions) is described with the aim to help the staff to decide when and how performing a procedure. We also highlight how interventional pulmonology could help in matter of complications related to COVID-19.

Ultrasound as a bedside tool for diagnosis of post-intubation tracheal stenosis

Background

Screening of post-intubation stenosis can allow early diagnosis, early management of stenosis, and possible prevention of progress. Fiberoptic bronchoscope is the gold standard for diagnosis of tracheal stenosis. Other imaging modalities as computed tomography can be considered but are not available in intensive care unit.

Purpose of the study

To evaluate the validity of ultrasound (US) as a bedside test for early diagnosis of post-intubation stenosis compared to multidetector computed tomography (MDCT) and fiberoptic bronchoscope (FOB).

Results

Out of the 50 included patients, 12 patients were found to have definite stenosis by FOB. Compared to CT, significant positive correlation was found between all ultrasound parameters (laryngeal width, tracheal diameter) and corresponding CT parameters (r = 0.798, p < 0.001; r = 0.714, p < 0.001 respectively). Compared to FOB results, the yield of MDCT chest for diagnosis of stenosis had 91.6% sensitivity and 100% specificity, while the yield of US detected by mucosal irregularity as a diagnostic tool for tracheal stenosis had comparable sensitivity (91.6%) but lower specificity (88.9%).

Conclusion

Due to its high sensitivity, US could help in detection of possible post-intubation laryngotracheal stenosis in critically ill MV patients.

Preemptive veno-venous ECMO support in a patient with anticipated difficult airway: A case report

This report presents a case of endotracheal metastasis in which elective veno-venous extracorporeal membrane oxygenation (VV ECMO) was used to undergo tracheal laser-surgery prior to establishment of a definitive airway. Specifically, we describe the respiratory and airway management in an adult patient from the preclinical phase throughout elective preoperative ECMO implantation to postoperative ECMO weaning and decannulation in the Intensive Care Unit. This case report lends further supports to the idea that the extracorporeal membrane oxygenation could be electively used to provide safe environment for surgery in situations where the standard maneuvers of sustaining adequate gas exchange are anticipated to fail.

Concentric photothermal coagulation with basket-integrated optical device for treatment of tracheal stenosis

A basket-integrated optical device is developed to consistently treat tubular tissue by centering an optical diffuser in the lumen. Four nitinol arms in conjunction with the optical diffusing applicator are deployed to induce homogeneous circumferential light emission and concentric photothermal coagulation on tracheal tissue. A 1470-nm laser light is employed for the tissue testing at various irradiation conditions and evaluated in terms of thermal gradient and temperature evolution. Preliminary experiments on liver tissue demonstrate the concentric development of the radial thermal coagulation in the tissue (eccentric ratio = ~5.5%). The interstitial tissue temperature increases with the total amount of energy delivery (around 65°C). Ex vivo trachea testing yields up to 16.5% tissue shrinkage due to dehydration as well as uniform ablation of the cilia and goblet cells in a mucosa layer under 7-W irradiation for 10 s. The proposed optical device may be a feasible therapeutic method to entail the circumferential coagulation in the tubular tissues in a reliable manner.

Investigation of the Mechanical Properties of the Human Tracheal Cartilage

BACKGROUND

The tracheal cartilage plays an important role in maintaining the mechanical stability of the trachea, as it keeps the trachea open and prevents its collapse under the negative pressures of the respiratory cycle. This study aimed to evaluate and compare the mechanical properties of cartilage specimens from the cranial and caudal regions of the human trachea and compare the results with respect to age and sex of the subjects.

MATERIALS AND METHODS

After obtaining human trachea samples from brain-dead, organ-donating patients and storing them in appropriate conditions, the prepared cartilage samples from the cranial and caudal regions of the trachea were subjected to uniaxial tension and stress relaxation experiments to obtain the corresponding Young's modulus and relaxation percentage values, respectively. The results were compared in terms of the position (cranial or caudal) in the trachea, and age and sex of the patients.

RESULTS

Based on the results, no statistically significant effect of the position in the trachea on the Young's modulus of the human tracheal cartilage samples was observed, despite the generally stiffer behavior of cartilage samples from the cranial region compared to those from the caudal region of the trachea. For both the cranial and caudal regions, no significant effect of sex on the stiffness of the tracheal cartilage was observed; further, the cartilage samples of the human trachea (from both cranial and caudal regions) of the old subjects were significantly stiffer than those of the young subjects. Based on the stress relaxation data, no significant effect of age, sex, or position on the relaxation percentage was observed.

CONCLUSION

The tracheal cartilage samples of the old patients are significantly stiffer than those of the young patients. Sex and position in the trachea (cranial vs caudal) do not significantly influence the mechanical properties of the human tracheal cartilage samples. The results of this study can be useful in designing tracheal tissue-engineered scaffolds, which should be mechanically compatible with the native trachea.