The safety and effectiveness of the treatment of refractory post-intubation subglottic stenosis using short bronchial Dumon stent: a pilot study.

Background: Post-intubation subglottic stenosis (PI-SGS) is a fatal disease which could result in partial or complete narrowing of the airway. Although airway stenting is commonly used as an alternative treatment for PI-SGS patients unsuitable for surgery, complications including stent migration and excessive granulation tissue formation are frequently encountered. Additionally, tracheotomy is necessary in patients undergoing T-tube placement. Therefore, it is necessary to further enhance the effectiveness of airway stenting in refractory PI-SGS. In this study, we aimed to evaluate the safety and effectiveness of utilizing short bronchial Dumon (BD) stents in managing refractory PI-SGS. Methods: PI-SGS patients who were not suitable for surgery and in whom previous interventional treatments had proven ineffective were enrolled. Short BD stents were inserted via rigid bronchoscopy under general anesthesia. Complications and outcomes were assessed by follow-ups. Results: Fourteen patients were included and successful stent insertion was achieved in all cases. The median diameter and length of stents was 12 (0.25) and 33.5 (5) mm, respectively. During the 6-month follow-up period, complications were reported in five patients. Granulation tissue formation was the most frequently observed complication (4 in 14 patients, 28.57%), followed by stent migration (2 in 14 patients, 14.29%). Out of the total participants, 11 patients (78.57%) demonstrated good tolerance to the stent, while 3 (21.43%) required stent removal. Among these three patients, two finally underwent subsequent T-tube insertion after the removal. Twelve patients (85.71%) avoided the tracheotomy and T-tube insertion. Conclusions: The utilization of short BD stents appears to be a safe and effective approach for managing refractory PI-SGS. The complications and tolerability are acceptable.

Efficacy and Safety of Platelet-Rich Plasma on Bronchopleural Fistula: A Pilot Prospective Cohort Study.

INTRODUCTION: Bronchopleural fistula (BPF) is associated with high morbidity and mortality rates in patients undergoing pulmonary resections. Surgery, bronchoscopy, and conservative management have their limitations for small fistulas. Platelet-rich plasma (PRP) has regenerative properties, which might be efficient in enhancing tissue recovery and repairing small BPF. This study aimed to investigate efficacy and safety of PRP on BPF. METHODS: This is a pilot prospective cohort study. Patients whose fistulas smaller than 4mm were enrolled in this study, treated with PRP under bronchoscopy and followed up at 2 weeks and 4-6 weeks after the last PRP treatment. The cure rate, improvement rate and ineffectiveness rate were investigated. The severity of respiratory symptoms was evaluated by modified Medical Research Council dyspnea scale (mMRC) and COPD Assessment Test (CAT). The recurrence of fistula, new infection and mortality rate were examined. Adverse events were documented to explore the safety profile of PRP therapy. RESULTS: A total of 16 patients (mean age, 50.1 years) met the eligibility criteria. The median time from the first PRP treatment to the closure of the fistula was 12.0 (IQR 6.0, 21.5) days. Our findings indicate an effectiveness rate of 87.6%, with 68.8% of cure and 18.8% of improvement, along with significant improvement of respiratory symptoms evaluated by mMRC (P<0.001) and CAT (P<0.001). No recurrent of fistulas, newly developed infection, or death was observed. Adverse events of the procedure were most mild (82.6%) and temporary. CONCLUSIONS: PRP is a potential treatment for small BPF and is well tolerated.

Optimize Initial Freezing Time of Transbronchial Cryobiopsy for the Diagnosis of Interstitial Lung Disease: A Prospective Randomized Parallel Group Study.

BACKGROUND: Transbronchial cryobiopsy (TBCB) is increasingly being identified as a potential alternative for the diagnosis of interstitial lung disease (ILD). The specimen size of TBCB is positively related to the freezing time. However, the proper initial freezing time for the clinical application of TBCB in ILD remains unknown. METHODS: A prospective randomized parallel group study was employed to investigate ILD patients with unclear diagnosis, who were admitted to the First Affiliated Hospital of Guangzhou Medical University from May 2019 to October 2020 and required TBCB. All patients were randomly divided into 4 groups according to the different freezing times of TBCB: 3 s, 4 s, 5 s, and 6 s groups. All operations were performed under intravenous anesthesia with endotracheal intubation, 60-65 bar pressure of freezing gas source, and 1.9-mm cryoprobe. Compare differences among groups in specimen size, complications, pathological diagnosis efficiency, and multidisciplinary discussion (MDD) diagnostic efficiency. RESULTS: A total of 100 patients were recruited and randomly assigned into 4 groups (n = 25 each group). The specimen sizes of TBCB in ILD were positively correlated with the freezing time (r = 0.639, p < 0.05). None of the patients experienced Grade 3 severe bleeding. Pneumothorax occurred in 1 patient in the 4 s, 5 s, and 6 s groups, respectively. The diagnostic yield of MDD in the 3 s, 4 s, 5 s, and 6 s groups were 64%, 88%, 88%, and 96%, respectively (p < 0.05), but showing no significant differences among 4 s, 5 s, and 6 s groups. CONCLUSIONS: The specimen size and diagnostic efficiency of TBCB in ILD increased with a longer freezing time. When the freezing gas pressure is 60-65 bar, we recommended 4 s as the initial freezing time of TBCB, and this time is associated with high diagnostic efficiency and low incidence of complications.

Applied pressure of cooling gas: a neglected determinant for size of specimens in transbronchial cryobiopsy.

BACKGROUND: Transbronchial cryobiopsy (TBCB) is an option to surgical biopsy for the diagnosis in interstitial lung diseases. Several impact factors have received wide attention, including the freezing time, cryoprobe size, and contact pressure. However, the effect of the applied gas pressure on the specimen size has not been well elucidated. The purpose of this study is to investigate the effect of the applied gas pressure on the TBCB specimen size. METHODS: Cryoprobes with a diameter of 1.9 mm were used to perform TBCB on 4 beagle canines under general anesthesia. TBCB was performed with a total of 16 time-pressure combinations that were randomly combined with 4 freezing times (3, 4, 5, and 6 s) and 4 gas pressures (40, 50, 55, and 60 bar). For each combination, 8 biopsies were performed. The size and quality of specimens, as well as complications, were evaluated. RESULTS: A total of 128 TBCB specimens were obtained. With the same freezing time, the specimen sizes obtained by different applied gas pressures were significantly different (P<0.05) and positively correlated with the gas pressures (r: 0.797-0.867). With the same gas pressure, the size of the TBCB specimens was positively correlated with the freezing time (r: 0.503-0.752). In the 40-bar group, no tissues were obtained when the freezing times were 3-5 s. In the 50-bar and 55-bar groups, qualified specimens were obtained when the freezing times were 5 and 6 s. In the 60-bar group, qualified specimens were obtained when the freezing times were 3-6 s. CONCLUSIONS: The TBCB specimen size was positively correlated with the applied gas pressure. The applied gas pressure contributed to the sample size and quality. To obtain qualified specimens with a 1.9-mm cryoprobe during TBCB, the lowest limit of the normal working gas pressure range should be increased to greater than 50 bar.