Flow-Volume Curve Analysis for Predicting Recurrence After Endoscopic Dilation of Airway Stenosis

Modified blade: an interventional option in rigid bronchoscopy for non-resectable benign tracheal stenosis

INTRODUCTION

Benign tracheobronchial stenosis is a abnormal tracheal lumen narrowing that may incur progressive dyspnea and life-threatening hypoxemia. There is no consensus on which patients should be treated with endoscopic or surgical method. This study investigates the outcomes of bronchoscopic dilatation in the treatment of benign tracheal stenosis using a device equipped with a blade to cut the stenotic lesions with dense fibrosis.

MATERIALS AND METHODS

The procedure was carried out in an operating room under general anesthesia. All patients were intubated with a Rigid Bronchoscope (RB) placed just above the stenosis. Through Rigid Bronchoscopy combined modalities were used as needed: radial incisions of the mucosal stenosis with blade at the levels of 4, 8 and 12 o'clock, with back and forth movements, then the stenotic area was dilated more easily with a rigid bronchoscope. Dilatation was performed by passing the RB of increasing diameter through stenotic areas and then Balloon dilatation of increasing diameter. There were no complications during the procedure.

RESULT

We conducted an observational, retrospective, single-centre study in the Thoracic Surgery Unit of the University of 'Luigi Vanvitelli' of Naples from November 2011 to September 2021. We included all consecutive patients with benign tracheal stenosis inoperable. During the study period, 113 patients were referred to our department with benign tracheal stenosis inoperable. 61 patients were treated with the blade. During the follow-up, a recurrence of the stenosis was observed in 8 patients in the first month and in 4 patients in the third month. Instead in the patients treated with the use of laser (52 patients), during the follow-up a recurrence was observed in 16 patients in the first month and in 6 patients in the third month; no patient relapsed after 6 months and after 1 year. Long term successful bronchoscopic management with blade was attained by 99% in simple and 93% in mixed stenosis and in complex type stenosis.

CONCLUSION

Our study underlines the importance of the use of the blade in bronchoscopic treatment as a valid conservative approach in the management of patients with inoperable benign tracheal stenosis as an alternative to the use of the laser, reducing the abnormal inflammatory reaction in order to limit recurrences.

Advances in Endoscopic Management of Endobronchial Carcinoid

INTRODUCTION

Bronchial carcinoid (BC) tumors represent between 1% and 5% of all lung cancers and about 20-30% of carcinoid tumors; they are classified into two groups: typical and atypical bronchial carcinoids. The aim of the present study was to review the results of endoscopic treatments as an alternative to surgical treatment in selected patients.

MATERIALS AND METHODS

The present study was a retrospective and multicentric study, in which all data were reviewed for patients with BC in the central airways, referred to the Thoracic Surgery Units of Luigi Vanvitelli University of Naples and Sant'Andrea Hospital in Rome between October 2012 and December 2022 Overall, 35 patients, 13 of whom were female, were included in the study (median age, 53 years; range, 29-75 years). All patients underwent rigid bronchoscopy combined with flexible bronchoscopy. Tumor clearance was mostly performed by use of Argon Plasma Coagulation or Thulep Laser, mechanical debridement and excision with the use of forceps and aspirator through the working channel of the 8.5 mm-sized rigid bronchoscope. There were no complications during the treatment.

RESULTS

Endobronchial treatment provided complete tumor eradication in all patients; two patients had controlled bleeding complications; however, bleeding was well controlled without patient desaturation, and only one patient died of renal failure during the follow-up period. We found two recurrences in the left and right main bronchus, in patients with atypical carcinoma during fiberoptic bronchoscopy follow-up. Only one patient died of renal failure. At the first analysis, there were no significant differences between the patients receiving endobronchial treatment and patients receiving surgical treatment in the present study (p-value > 0.05-it means statistically insignificant).

CONCLUSIONS

Endobronchial treatment is a valid and effective alternative for patients with BC unsuitable for surgery.

Intraoperative ventilatory leak: Real-time guidance for management of air leak in lung cancer patients undergoing VATS lobectomy

BACKGROUND

Persistent air leak (PAL) is a common complication after video-assisted thoracoscopic surgery (VATS) lobectomy. We aimed to evaluate whether the intraoperative quantitative measurement of air leaks using a mechanical ventilation test could predict PAL and identify those patients needing additional treatment for the prevention of PAL.

METHODS

This was an observational, retrospective, single-center study that included 82 patients who underwent VATS lobectomy with a mechanical ventilation test for VL. Only 2% of patients who underwent lobectomy surgery had persistent air leaks.

RESULTS

At the end of lobectomy performed in patients with non-small cell lung cancer, the lung was reinflated at a 25-30 mmH2O pressure and ventilatory leaks (VL) were calculated and in relation to the entity of the air leaks, we evaluated the most suitable intraoperative treatment to prevent persistent air leaks.

CONCLUSION

VL is an independent predictor of PAL after VATS lobectomy; it provides a real-time intraoperative guidance to identify those patients who can benefit from additional intraoperative preventive interventions to reduce PAL.

Ventilation challenge in rigid bronchoscopy: Laser tube as an alternative management in patients with lung cancer and central airway obstruction

INTRODUCTION

Central airway tumors involving the trachea and main-stem bronchi are a common cause of airway obstruction and a significant cause of mortality among the patients of thoracic diseases with respiratory failure. Debulking in rigid bronchoscopy is quick, safe, and effective. It can be complex and hard in patients with severe bronchial or tracheal obstruction and/or with intraluminal bleeding tumors because of inadequate distal airway control. We have used laser tube as a new technique of ventilation for severe central airway obstruction.

MATERIALS AND METHODS

Forty-six patients with severe airway obstruction undergoing rigid bronchoscopy from September 2020 to June 2022 at the Thoracic Surgery Department of the University L. Vanvitelli of Naples underwent placement of laser tube.

RESULTS

In all patients who underwent rigid bronchoscopy with the use of the laser tube, a reduction of obstruction of more than 50% was obtained and in all patients no hypoxia (saturation < 88%), nor hypercapnia, nor significant bleeding were reported.

DISCUSSION

The results of this study suggest that rigid bronchoscopic debulking with the use of laser tube is a safe and effective technique in the management of central airway obstruction.

CONCLUSIONS

The use of the laser tube allows the monitoring of gas exchange, which controls hypoxemia. Thanks to the double cuff put distally to the tracheal obstruction or in the contralateral bronchus to the obstructed one, the laser tube prevents the flooding of blood from debulking below the stenosis. Rigid bronchoscopy with laser tube will expand its use in the future.

Diagnosis of malignant pleural disease: Ultrasound as "a detective probe"

BACKGROUND

Malignant pleural mesothelioma (MPM) is an invasive, aggressive pleural tumor with a predominantly local spread. The objective of this study was to assess thoracic ultrasound (TUS) as an imaging modality with high sensitivity for the identification of malignant pleural involvement and in order to guide pleural biopsies.

METHODS

In this retrospective single-center study between January 2018 and June 2022, 51 consecutive patients with impassable circumferential pleural thickening underwent TUS at the Thoracic Surgery Unit of the Vanvitelli University of Naples. Pleural biopsies were performed, and then large and multiple samples were sent to the pathological anatomy for histological examination.

RESULTS

In all patients who underwent ultrasound examination, we chose the optimal point of entry to perform pleural biopsies and selected the areas of greater thickening without pleural effusion. No patient had any complications. No drainage tubes were placed after the pleural biopsies and no pneumothorax was present during the following days of hospitalization. The patients were discharged on the second postoperative day.

CONCLUSION

With TUS the precise pleural thickening localization, local infiltration, mass extent, its nature (solid, cystic or complex) and ultrasound features can be easily defined. Furthermore, ultrasound is more economical than computed tomography and avoids the risks associated with radiation. Thoracic ultrasound is an important component of the diagnostic procedure in detecting a safe entry site for biopsies of MPMs.

Noninvasive positive pressure ventilation in the assessment of extrinsic tracheal stenosis

In patients with extrinsic tracheal stenosis caused by a mediastinal mass, an airway stent is a palliative measure to relieve airway obstruction. However, the self-expanding force of the stent may be insufficient to force a rigid stenosis. Our goal was to report a simple strategy to indirectly estimate the rigidity of the stenosis and predict airway patency after inserting the stent. Before the procedure, the inspiratory and expiratory flows and their ratio were evaluated under spontaneous breathing and after positive pressure ventilation generated by a facial mask. In patients with stenosis successfully treated with a stent (n = 11), we found significant changes in expiratory (2.3 ± 0.7 vs 2.8 ± 0.7; p = 0.03) and inspiratory (1.5 ± 0.6 vs 2.5 ± 0.9; p = 0.001) flows and a reduction of their ratio (1.4 ± 0.3 vs 1.1 ± 0.2; p = 0.01) whereas no significant changes were observed in patients (n = 2) whose stent failed to force the stenosis. In these cases, a tracheostomy was performed to assure ventilation. Our simple strategy may help physicians predict airway patency after stenting or plan alternative treatments in patients with rigid stenosis difficult to force by stenting.

Deep Learning-Based Analytic Models Based on Flow-Volume Curves for Identifying Ventilatory Patterns

INTRODUCTION

Spirometry, a pulmonary function test, is being increasingly applied across healthcare tiers, particularly in primary care settings. According to the guidelines set by the American Thoracic Society (ATS) and the European Respiratory Society (ERS), identifying normal, obstructive, restrictive, and mixed ventilatory patterns requires spirometry and lung volume assessments. The aim of the present study was to explore the accuracy of deep learning-based analytic models based on flow-volume curves in identifying the ventilatory patterns. Further, the performance of the best model was compared with that of physicians working in lung function laboratories.

METHODS

The gold standard for identifying ventilatory patterns was the rules of ATS/ERS guidelines. One physician chosen from each hospital evaluated the ventilatory patterns according to the international guidelines. Ten deep learning models (ResNet18, ResNet34, ResNet18_vd, ResNet34_vd, ResNet50_vd, ResNet50_vc, SE_ResNet18_vd, VGG11, VGG13, and VGG16) were developed to identify patterns from the flow-volume curves. The patterns obtained by the best-performing model were cross-checked with those obtained by the physicians.

RESULTS

A total of 18,909 subjects were used to develop the models. The ratio of the training, validation, and test sets of the models was 7:2:1. On the test set, the best-performing model VGG13 exhibited an accuracy of 95.6%. Ninety physicians independently interpreted 100 other cases. The average accuracy achieved by the physicians was 76.9 ± 18.4% (interquartile range: 70.5-88.5%) with a moderate agreement (κ = 0.46), physicians from primary care settings achieved a lower accuracy (56.2%), while the VGG13 model accurately identified the ventilatory pattern in 92.0% of the 100 cases (P < 0.0001).

CONCLUSIONS

The VGG13 model identified ventilatory patterns with a high accuracy using the flow-volume curves without requiring any other parameter. The model can assist physicians, particularly those in primary care settings, in minimizing errors and variations in ventilatory patterns.

Clinical analysis of the "small plateau" sign on the flow-volume curve followed by deep learning automated recognition

BACKGROUND

Small plateau (SP) on the flow-volume curve was found in parts of patients with suspected asthma or upper airway abnormalities, but it lacks clear scientific proof. Therefore, we aimed to characterize its clinical features.

METHODS

We involved patients by reviewing the bronchoprovocation test (BPT) and bronchodilator test (BDT) completed between October 2017 and October 2020 to assess the characteristics of the sign. Patients who underwent laryngoscopy were assigned to perform spirometry to analyze the relationship of the sign and upper airway abnormalities. SP-Network was developed to recognition of the sign using flow-volume curves.

RESULTS

Of 13,661 BPTs and 8,168 BDTs completed, we labeled 2,123 (15.5%) and 219 (2.7%) patients with the sign, respectively. Among them, there were 1,782 (83.9%) with the negative-BPT and 194 (88.6%) with the negative-BDT. Patients with SP sign had higher median FVC and FEV₁% predicted (both P < .0001). Of 48 patients (16 with and 32 without the sign) who performed laryngoscopy and spirometry, the rate of laryngoscopy-diagnosis upper airway abnormalities in patients with the sign (63%) was higher than those without the sign (31%) (P = 0.038). SP-Network achieved an accuracy of 95.2% in the task of automatic recognition of the sign.

CONCLUSIONS

SP sign is featured on the flow-volume curve and recognized by the SP-Network model. Patients with the sign are less likely to have airway hyperresponsiveness, automatic visualizing of this sign is helpful for primary care centers where BPT cannot available.

Ultrasound for assessment and follow-up of airway stenosis

BACKGROUND

Ultrasound is a reliable tool for airway assessment and management. We evaluated the accuracy of Ultrasound in the pre-procedure planning and follow-up evaluation of patients undergoing airway stenting for benign upper airway stenosis.

METHODS

This was a retrospective single center study on patients with benign upper airway stenosis treated with airway stenting. Ultrasound evaluated the characteristics of the stenosis (distance from vocal folds, diameter and length) before treatment and any complications after treatment; these results were then statistically compared with those obtained by computed tomography, taking the endoscopy as the reference method.

RESULTS

Twenty-seven patients were evaluated. Ultrasound was significantly correlated with endoscopy and computed tomography scan measurements as distance of stenosis from vocal folds (r=0.88; p<0.001 and r=0.87; p<0.001, respectively); diameter of the stenosis (r=0.97; p<0.001 and r=0.97; p<0.001, respectively); and length of the stenosis (r=0.97; p<0.001 and r=0.97; p<0.001, respectively). Four out of 27 (15%) patients presented complications after treatment as stent migration (n=2; 7%); stent obstruction (n=1; 4%), and granulation of vocal fold (n=1; 4%). All complications but granulation of vocal fold were correctly depicted by Ultrasound and Computed Tomography without significant difference in comparison to endoscopy (p=0.87) CONCLUSIONS: Ultrasound is a promising tool in assessment of airway stenosis and follow-up of patients after stenting; it may be routinely used in adjunction to computed tomography and/or endoscopy in this setting, if our results are corroborated by future larger study.