The role for endobronchial biopsy in the era of endobronchial ultrasound guided transbronchial needle aspiration for the diagnosis of sarcoidosis: a single center experience.

BACKGROUND AND AIM: Endobronchial biopsy (EBBX) has been reported to increase diagnostic yield for pulmonary sarcoidosis. The purpose of this study is to investigate the diagnostic yield for EBBX following endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA). METHODS: We identified a cohort of patients in the University of Minnesota Sarcoidosis Registry who had EBBx and EBUS-TBNA as part of workup for abnormal chest imaging. Data regarding demographics, biopsy approach and technique were recorded. RESULTS: Our cohort included 37 patients (53.24±9.5, Male, 22±0.57; 3.8% were African American). In these patients who had EBBX, EBUS-TBNA was performed in 100% of patients and TBBX was performed in 2 patients (5%). EBBX was positive in 9 patients (24%) and EBUS-TBNA was positive in 34 patients (92%). TBBX was diagnostic in one of two patients. EBBX was the only diagnostic tissue in 3 of the 37 patients (8%).  Conclusion: The diagnostic yield of EBBX is lower than previously reported, with only 8% of EBBXs demonstrating granulomatous inflammation. However, instrumentation used for obtaining EBBX as well as the presence of visible lesions does influence the diagnostic yield. Studies with adequate power are needed before implementing changes in clinical practice.  When performed alongside EBUS-TBNA, EBBX did not significantly add to the diagnostic yield in sarcoidosis unless visible lesions were observed.

Development and performance evaluation of a solenoid valve assisted low-cost ventilator on gas exchange and respiratory mechanics in a porcine model.

INTRODUCTION: During the COVID-19 pandemic, ventilator shortages necessitated the development of new, low-cost ventilator designs. The fundamental requirements of a ventilator include precise gas delivery, rapid adjustments, durability, and user-friendliness, often achieved through solenoid valves. However, few solenoid-valve assisted low-cost ventilator (LCV) designs have been published, and gas exchange evaluation during LCV testing is lacking. This study describes the development and performance evaluation of a solenoid-valve assisted low-cost ventilator (SV-LCV) in vitro and in vivo, focusing on gas exchange and respiratory mechanics. METHODS: The SV-LCV, a fully open ventilator device, was developed with comprehensive hardware and design documentation, utilizing solenoid valves for gas delivery regulation. Lung simulator testing calibrated tidal volumes at specified inspiratory and expiratory times, followed by in vivo testing in a porcine model to compare SV-LCV performance with a conventional ventilator. RESULTS: The SV-LCV closely matched the control ventilator's respiratory profile and gas exchange across all test cycles. Lung simulator testing revealed direct effects of compliance and resistance changes on peak pressures and tidal volumes, with no significant changes in respiratory rate. In vivo testing demonstrated comparable gas exchange parameters between SV-LCV and conventional ventilator across all cycles. Specifically, in cycle 1, the SV-LCV showed arterial blood gas (ABG) results of pH 7.54, PCO2 34.5 mmHg, and PO2 91.7 mmHg, compared to the control ventilator's ABG of pH 7.53, PCO2 37.1 mmHg, and PO2 134 mmHg. Cycle 2 exhibited ABG results of pH 7.53, PCO2 33.6 mmHg, and PO2 84.3 mmHg for SV-LCV, and pH 7.5, PCO2 34.2 mmHg, and PO2 93.5 mmHg for the control ventilator. Similarly, cycle 3 showed ABG results of pH 7.53, PCO2 32.1 mmHg, and PO2 127 mmHg for SV-LCV, and pH 7.5, PCO2 35.5 mmHg, and PO2 91.3 mmHg for the control ventilator. CONCLUSION: The SV-LCV provides similar gas exchange and respiratory mechanic profiles compared to a conventional ventilator. With a streamlined design and performance akin to commercially available ventilators, the SV-LCV presents a viable, readily available, and reliable short-term solution for overcoming ventilator supply shortages during crises.

Risk of Post-Intubation Laryngotracheal Stenosis With Respect to COVID-19 Status in a Large Multicenter Cohort Cross-Sectional Study.

OBJECTIVES: Occurrence of post-intubation laryngotracheal stenosis (LTS) with respect to COVID-19 status. DESIGN: Retrospective cross-sectional inpatient database. SETTING: Eleven Midwest academic and community hospitals, United States. PATIENTS: Adults, mechanically ventilated, from January 2020 to August 2022, who were subsequently readmitted within 6 months with a new diagnosis of LTS. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Six thousand eight hundred fifty-one COVID-19 negative and 1316 COVID-19 positive patients were intubated and had similar distribution by age (median 63.77 vs. 63.16 yr old), sex (male, 60.8%; n = 4173 vs. 60%; n = 789), endotracheal tube size (≥ 7.5, 75.8%; n = 5192 vs. 75.5%; n = 994), and comorbidities. The ICU length of stay (median [interquartile range (IQR)], 7.23 d [2.13-16.67 d] vs. 3.95 d [1.91-8.88 d]) and mechanical ventilation days (median [IQR], 5.57 d [1.01-14.18 d] vs. 1.37 d [0.35-4.72 d]) were longer in the COVID-19 positive group. The occurrence of LTS was double in the COVID-19 positive group (12.7%, n = 168 vs. 6.4%, n = 440; p < 0.001) and was most commonly diagnosed within 60 days of intubation. In multivariate analysis, the risk of LTS increased by 2% with each additional ICU day (hazard ratio [HR], 1.02; 95% CI, 1.02-1.03; p < 0.001), by 3% with each additional day of ventilation (HR, 1.03; 95% CI, 1.02-1.04; p < 0.001), and by 52% for each additional reintubation (HR, 1.52; 95% CI, 1.36-1.71; p < 0.001). We observed no significant association COVID-19 status and risk of LTS. CONCLUSIONS: The occurrence of post-intubation LTS was double in a COVID-19 positive cohort, with higher risk with increasing number of days intubated, days in the ICU and especially with the number of reintubations. COVID-19 status was not an independent risk factor for LTS.

To Compare the Effects of a Standard Versus Hydrophilic Polymer Coated Airway Stent in a Porcine Model: A Randomized, Single-Blinded Study.

BACKGROUND: Stent encrustation with debris and mucostasis is a significant cause of airway injury and comorbidity, leading to ~25% of stent exchanges (1-3). Previous work from our group has shown that the experimental coating can reduce mucous adhesion in bench testing and demonstrated a signal for reducing airway injury and mucostasis in a feasibility study. OBJECTIVES: The aim of this study is to continue our inquiry in a randomized, single-blinded multi-animal trial to investigate the degree of airway injury and mucostasis using silicone stents with and without this specialized coating. METHODS: We modified commercially available silicone stents with a hydrophilic polymer from Toray Industries. We conducted an in vivo survival study in 6 mainstem airways (3 coated and 3 uncoated) of 3 pigs to compare the degree of airway injury and mucostasis between coated versus noncoated stented airways. Both stents were randomized to either left or right mainstem bronchus. The pathologist was blinded to the stent type. RESULTS: We implanted a total of six 14×15 mm silicone stents (1 per mainstem bronchi) into 3 pigs. All animals survived to termination at 4 weeks. All stents were intact; however, 1 uncoated stent migrated out. On average, all the coated stents demonstrated reduced pathology and tissue injury scores (75 vs. 68.3, respectively). The average total dried mucous weight was slightly higher in the coated stents (0.07 g vs. 0.05 g; respectively). CONCLUSION: Coated stents had lower airway injury compared with uncoated stents in this study. Of all the stents, 1 uncoated stent migrated out and was not included in the dried mucous weight totals. This could explain the slightly higher mucous weight in the coated stents. Nevertheless, this current study demonstrates promising results in lowering airway injury in stents incorporated with the hydrophilic coating, and future studies, including a larger number of subjects, would be needed to corroborate our findings.

The Feasibility of Using the "Artery Sign" for Pre-Procedural Planning in Navigational Bronchoscopy for Parenchymal Pulmonary Lesion Sampling.

BACKGROUND: Electromagnetic navigation bronchoscopy (ENB) and robotic-assisted bronchoscopy (RAB) systems are used for pulmonary lesion sampling, and utilize a pre-procedural CT scan where an airway, or "bronchus sign", is used to map a pathway to the target lesion. However, up to 40% of pre-procedural CT's lack a "bronchus sign" partially due to surrounding emphysema or limitation in CT resolution. Recognizing that the branches of the pulmonary artery, lymphatics, and airways are often present together as the bronchovascular bundle, we postulate that a branch of the pulmonary artery ("artery sign") could be used for pathway mapping during navigation bronchoscopy when a "bronchus sign" is absent. Herein we describe the navigation success and safety of using the "artery sign" to create a pathway for pulmonary lesion sampling. METHODS: We reviewed data on consecutive cases in which the "artery sign" was used for pre-procedural planning for conventional ENB (superDimension™, Medtronic) and RAB (Monarch™, Johnson & Johnson). Patients who underwent these procedures from July 2020 until July 2021 at the University of Minnesota Medical Center and from June 2018 until December 2019 at the University of Chicago Medical Center were included in this analysis (IRB #19-0011 for the University of Chicago and IRB #00013135 for the University of Minnesota). The primary outcome was navigation success, defined as successfully maneuvering the bronchoscope to the target lesion based on feedback from the navigation system. Secondary outcomes included navigation success based on radial EBUS imaging, pneumothorax, and bleeding rates. RESULTS: A total of 30 patients were enrolled in this analysis. The median diameter of the lesions was 17 mm. The median distance of the lesion from the pleura was 5 mm. Eleven lesions were solid, 15 were pure ground glass, and 4 were mixed. All cases were planned successfully using the "artery sign" on either the superDimension™ ENB (n = 15) or the Monarch™ RAB (n = 15). Navigation to the target was successful for 29 lesions (96.7%) based on feedback from the navigation system (virtual target). Radial EBUS image was acquired in 27 cases (90%) [eccentric view in 13 (43.33%) and concentric view in 14 patients (46.66%)], while in 3 cases (10%) no r-EBUS view was obtained. Pneumothorax occurred in one case (3%). Significant airway bleeding was reported in one case (3%). CONCLUSIONS: We describe the concept of using the "artery sign" as an alternative for planning EMN and RAB procedures when "bronchus sign" is absent. The navigation success based on virtual target or r-EBUS imaging is high and safety of sampling of such lesions compares favorably with prior reports. Prospective studies are needed to assess the impact of the "artery sign" on diagnostic yield.

Utility of Functional Pneumonectomy by Using Intrabronchial Valves: First Case Series and Single Center Experience.

BACKGROUND: Intrabronchial valves are approved for bronchoscopic lung volume reduction in chronic obstructive pulmonary disease patients and used for prolonged air leak. There is no data on bronchoscopic functional pneumonectomy (BFP) when treating patients with persistent air leak (PAL) or for lung volume reduction purposes. METHODS: In this observational study, 10 consecutive patients who failed to improve with traditional therapies were assessed after they underwent BFP for PAL or lung volume reduction. RESULTS: Ten patients underwent 17 valve placement procedures; 82 valves were placed (median: 8; range: 5 to 12). BFP was performed in 1 single lung transplant patient with hyperinflation of native lung compromising lung function. The rest of the patients had prolonged air leak because of various reasons; spontaneous (n=7) and postoperative (n=2). Pneumonia was the only procedure-related complication seen in 1 patient. Of patients with prolonged air leak with chest tubes (n=9), all had successful chest tube removal (median of 7 days; range: 3 to 21 d). The valves were removed within 6 weeks of chest tube removal in 6 patients. Prebronchoscopic and post-BFP actual forced expiratory volume in first second values in 2 transplant patients. CONCLUSION: PAL usually occurs in patients with severe underlying lung condition or after surgery. Management of PAL can be challenging despite pleurodesis (medical or surgical). BFP offers a minimally invasive management option.

To Investigate the Effect of Targeted Overdilation in Balloon-Expandable Stents.

PURPOSE: Balloon-expandable stents are commonly used for the treatment of tracheobronchial strictures. We routinely perform targeted overdilation of these stents 1-2mm on initial deployment to prevent stent migration or allow foreshortening to target airway caliber; however, specific data on the effect of targeted overdilation is unknown. PATIENTS AND METHODS: We used three iCAST stents (6×22mm, 7×22mm, and 10×38mm) to perform the study. We had two sets of each size to average our results. Targeted overdilation was accomplished with Merit Elation balloons. RESULTS: The 6 × 22 and 7 × 22 stent OD increased from 6 to 11.4mm and 7 to 11.6mm. The 10 × 38 stent demonstrated minimal OD change with overdilation (OD change of 10.4 to 12.2mm). All stents demonstrated significant foreshortening with overdilation (20.2 to 5.65mm, 19.4 to 6mm, and 30.9 to 10.2mm for 6 × 22, 7 × 22, and 10 × 38, respectively). The breakpoint was seen at near twice the stated stent OD (13.5mm, 15mm, and 15mm with 6 × 22, 7 × 22 and 10 × 38, respectively). CONCLUSION: We have demonstrated that iCAST stents can increase their OD with subsequent foreshortening during targeted overdilation. This data can help facilitate decisions when selecting a particular iCAST stent for a specific airway application. Additionally, we have highlighted that balloon inflation diameter does not correspond to the actual stent OD during deployment. We believe that this data offers practical information for end-users of this stent type and additional data will be needed to corroborate our findings.

Feasibility of Using the O-Arm Imaging System During ENB-rEBUS-guided Peripheral Lung Biopsy: A Dual-center Experience.

BACKGROUND: There is a paucity of real-time imaging modalities available for the bronchoscopic biopsy of peripheral lung nodules. We aim to demonstrate the feasibility of the O-arm imaging system to guide real-time biopsies of peripheral lung nodules during electromagnetic navigation bronchoscopy. METHODS: A retrospective review was performed at 2 academic medical centers utilizing O-arm guidance. RESULTS: The average nodule size was 2.1×2.0 cm and were mostly solid (66%) with a positive bronchus sign (83%). O-arm imaging confirmed tool-in-lesion in all cases. The diagnostic yield was 33%. Four cases were nondiagnostic of the 6 cases performed. In these cases, necrotic tissue was the most common (75%) and showed resolution following subsequent imaging. The average 3-dimensional (3D) spin time was 23.5 seconds. The average number of 3D spins performed per case was 4.33. The average effective dose per 3D spin was 3.73 mSv. CONCLUSION: We have demonstrated the O-arm's feasibility with electromagnetic navigation bronchoscopy for peripheral lung nodules. The O-arm was able to confirm tool-in-lesion in all cases which added confidence to the biopsy. Four high-resolution 3D spins per case may limit the total computed tomography effective dose. We also noted that both metal and radiation scatter were minimal when appropriate radiation safety standards were met. Although additional experience and data will be required to verify the O-arm approach for routine use, our initial experience is promising.

Ultrasound Assessment of Diaphragmatic Motion in Subjects With ARDS During Transpulmonary Pressure-Guided PEEP Titration.

BACKGROUND: We aimed to investigate the effects of incremental PEEP titration in patients with ARDS on regional diaphragmatic motion with bedside ultrasound. METHODS: Dorsal diaphragmatic excursion (DDE) and ventral diaphragmatic excursion (VDE) were measured using anatomic M-mode ultrasonography of the right hemidiaphragm as PEEP was randomized to -6, -3, +3, and +6 cm H2O from baseline to achieve a positive transpulmonary pressure. Inter-operator variability of DDE was assessed in 10 separate subjects. RESULTS: A total of 14 subjects ventilated for ARDS were enrolled. Subjects had a mean age of 54 ± 12 y, mean PaO2 /FIO2 = 137 ± 54 mm Hg, and mean sequential organ failure assessment (SOFA) score = 14 ± 1). Transpulmonary pressure, DDE, and DDE/VDE ratio increased with incremental PEEP titration (-1.15 cm H2O vs 3.63 cm H2O, P < .001; 4.9 mm vs 8.2 mm, P < .001; and 62% vs 93%, P < .001, respectively). When transpulmonary pressure became positive, a visual increase in DDE and DDE/VDE ratio 0.60 to 0.93 was observed (from 0.48 cm to 0.82 cm, R2 = 0.87, P = .02; and R2 = 0.93, P = .006, respectively). There was high agreement in DDE measurements between 2 ultrasonographers (intra-class correlation 0.987, P < .001). CONCLUSIONS: DDE was affected by incremental PEEP titration toward a positive transpulmonary pressure. The ultrasound assessment using anatomic M-mode allowed for specific measurement of regional diaphragmatic excursion. This pattern of motion in the dependent regions of the diaphragm during PEEP titration in subjects with ARDS achieving a positive transpulmonary pressure may reflect a potential target for future studies in the bedside assessment for lung recruitment. (Clinical Trials.gov registration NCT02463773.).

Propionibacterium acnes Causing Mediastinal Infection following Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration.

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is now a standard of care to sample mediastinal lymph nodes and masses with high diagnostic accuracy and low complication rates. However, the procedure has potential complications that might be life-threatening. Here, we present the first case of Propionobacterium acnes (P. acnes) causing mediastinitis following EBUS-TBNA of a subcarinal lymph node.

Transbronchial Lung Cryobiopsy in the Diagnosis of Interstitial Lung Disease: A Retrospective Single-center Experience.

BACKGROUND: Surgical lung biopsy (SLB) is the gold standard to aid diagnosis of interstitial lung disease (ILD). Complication rates are restrictive as routine approach for all patients with ILD. Transbronchial lung cryobiopsy (TBLC) is presumed to be a safe, less invasive alternative to assist multidisciplinary discussions regarding the diagnosis of ILD. Varying practice patterns and lack of consistent guidelines prohibit wide support of this technique. The purpose of this study was to evaluate safety and diagnostic yield of TBLC, with highlight of distinct technical features, in ILD. METHODS: Retrospective study of patients with ILD on the basis of high-resolution chest computed tomography who underwent TBLC. RESULTS: Of 121 TBLC, 40 patients (mean age, 57.2±13 y; 28 men) with ILD were referred for biopsy. Procedures were performed in endoscopy suite (60%) or operating room by using 1.9-mm cryoprobe. Biopsies were performed in 2 lobes with at least 3 to 5 specimens >5 mm in diameter. The average diameter and area of specimens were 5.7±2 mm and 40±2 mm, respectively. The most common diagnosis was nonspecific interstitial pneumonitis; usual interstitial pneumonia was diagnosed in 1 patient. Of 6 nondiagnostic specimens, 2 underwent SLB with subsequent diagnoses. Final histopathologic diagnostic rate was 85%. Bleeding was the most frequent complication. CONCLUSION: We provided a detailed description of our TLBC technique and highlighted areas of similarity and differences among comparative studies and attest that TBLC is a safe alternative to SLB in the diagnosis of ILD. Our data also indicated the tendency for moderate-to-severe bleeding occurred more in the endoscopy suite.

Transbronchial lung cryobiopsy in the diagnosis of interstitial lung disease.

Transbronchial cryoprobe lung biopsy (TBCLB) have recently been introduced as a safe diagnostic tool in the diagnosis of interstitial lung diseases. While we do not enough evidence its role and place as a diagnostic procedure, the technique has been adopted by many centers. In spite of expanding body of literature, there are variations in patient selection and procedural aspect of the procedure. It has been established as a safe procedure if safety measures are practiced. Diagnosis of interstitial lung diseases continuous to be challenging. Surgical lung biopsy considered as gold standard but its morbidity and mortality limit its utilization in every case. Multidisciplinary medical decision is a validated team work effort when approaching patients with interstitial lung disease.

Vitamin D deficiency and degree of coronary artery luminal stenosis in women undergoing coronary angiography: a prospective observational study.

BACKGROUND AND AIMS: Low serum 25-OH D levels are associated with increased cardiovascular morbidity and mortality. Recent studies have linked 25-OH D deficiency with the presence of CAD. Women, especially post-menopausal, tend to suffer from accelerated atherosclerosis, along with vitamin D deficiency. In the present study we sought to investigate whether there is a direct association of coronary artery luminal stenosis with 25-OH D deficiency in women. PATIENTS AND METHODS: We enrolled women aged >40 who were scheduled to undergo elective coronary angiography between 3/2011 and 10/2016 in a prospective observational study. RESULTS: We included a total of 105 women. Patients had hypertension (73%), hyperlipidemia (54%), diabetes (29%), smoking (31%), family history of CAD (62%), and known CAD (21%). Median 25-OH D levels were 15.8 ng/mL (range, 3.9-79). Patients had left-anterior descending (31%), left circumflex (22%), and right coronary artery disease (26%); 27% had 2-vessel and 11% had 3-vessel disease. There was a significant inverse correlation between 25-OH D levels and the degree of maximum luminal stenosis. The burden of CAD increased across categories of worsening 25-OH D deficiency. CONCLUSIONS: Vitamin D deficiency is associated with the degree of luminal stenosis and burden of CAD in women undergoing coronary angiography. Future studies should investigate if the repletion of 25-OH D impacts the progression of CAD and cardiovascular mortality.