Single use and conventional bronchoscopes for Broncho alveolar lavage (BAL) in research: a comparative study (NCT 02515591)

Respiratory mucosal immune memory to SARS-CoV-2 after infection and vaccination

Respiratory mucosal immunity induced by vaccination is vital for protection from coronavirus infection in animal models. In humans, the capacity of peripheral vaccination to generate sustained immunity in the lung mucosa, and how this is influenced by prior SARS-CoV-2 infection, is unknown. Here we show using bronchoalveolar lavage samples that donors with history of both infection and vaccination have more airway mucosal SARS-CoV-2 antibodies and memory B cells than those only vaccinated. Infection also induces populations of airway spike-specific memory CD4+ and CD8+ T cells that are not expanded by vaccination alone. Airway mucosal T cells induced by infection have a distinct hierarchy of antigen specificity compared to the periphery. Spike-specific T cells persist in the lung mucosa for 7 months after the last immunising event. Thus, peripheral vaccination alone does not appear to induce durable lung mucosal immunity against SARS-CoV-2, supporting an argument for the need for vaccines targeting the airways.

Single-use flexible bronchoscopes vs traditional reusable flexible bronchoscopes: a prospective controlled study

BACKGROUND

Single-use flexible bronchoscopes(SFB) eliminate the risk of bronchoscopy-related infection compared with traditional reusable flexible bronchoscopes(RFB). At present, there is no comparative study between SFB and RFB in the aspects of biopsy and interventional therapy. This study aims to explore whether SFB can perform complex bronchoscopic procedures such as transbronchial biopsies just like RFB.

METHODS

We conducted a prospective controlled study. A total of 45 patients who required bronchoscopic biopsy in our hospital from June 2022 to December 2022 were enrolled. The patients were divided into the SFB group and the RFB group, and routine bronchoscopy, bronchoalveolar lavage, and biopsy were performed respectively. Data on the time of routine bronchoscopy, the recovery rate of bronchoalveolar lavage fluid(BALF), biopsy time, and bleeding volume were collected. Then we used the two-sample t-test and the χ² test to assess the performance differences between SFB and RFB. We also designed a questionnaire to compare the performance between SFB and RFB by different bronchoscope operators.

RESULTS

The routine examination time of SFB and RFB was 3.40 ± 0.50 min and 3.55 ± 0.42 min, respectively. There was no significant difference between the two groups (P = 0.308). The recovery rate of BALF was (46.56 ± 8.22) % in the SFB group and (47.00 ± 8.07) in the RFB group, without a significant difference between the two groups(P = 0.863). The biopsy time was similar(4.67 ± 0.51 min VS 4.57 ± 0.45 min) in both groups, with no significant difference(P = 0.512). The positive biopsy rate was 100% in both groups, with no significant difference. Overall, the bronchoscope operators were generally satisfied with SFB.

CONCLUSION

SFBs are non-inferior to RFBs in routine bronchoscopy, bronchoalveolar lavage, and biopsy. It is suggested that SFBs have a wider clinical application.

Airway-resident T cells from unexposed individuals cross-recognize SARS-CoV-2

T cells can contribute to clearance of respiratory viruses that cause acute-resolving infections such as SARS-CoV-2, helping to provide long-lived protection against disease. Recent studies have suggested an additional role for T cells in resisting overt infection: pre-existing cross-reactive responses were preferentially enriched in healthcare workers who had abortive infections¹, and in household contacts protected from infection². We hypothesize that such early viral control would require pre-existing cross-reactive memory T cells already resident at the site of infection; such airway-resident responses have been shown to be critical for mediating protection after intranasal vaccination in a murine model of SARS-CoV³. Bronchoalveolar lavage samples from the lower respiratory tract of healthy donors obtained before the COVID-19 pandemic revealed airway-resident, SARS-CoV-2-cross-reactive T cells, which correlated with the strength of human seasonal coronavirus immunity. We therefore demonstrate the potential to harness functional airway-resident SARS-CoV-2-reactive T cells in next-generation mucosal vaccines.

Development of endotracheal intubation devices for patients with tumors

The incidence and mortality of malignant tumors are rapidly increasing in the world. Patients with malignant tumors often need surgery for treatment. Endotracheal intubation is a necessary technique for surgical patients undergoing general anesthesia. It is also an important procedure for critically ill patients in the emergency room or ICU. Most patients with head and neck tumors and some specific patients have difficult airways, so the operator may need to use a variety of intubation devices. The commonly used devices for endotracheal intubation include endotracheal tube, direct laryngoscope, video laryngoscope, introducer, optical stylet, fiberoptic bronchoscope. With the advancement in science and technology, the endotracheal intubation devices have been improved, and new devices have been developed. These devices are safer and more feasible in clinical practice. In this review, we summarized the features and applications of some of the currently used devices. Each device has its own uniqueness and meets different needs. The devices and their respective properties are strongly suggested to be mastered by the anesthesiologists as well as related staffs, so as to select the appropriate device for intubation.

Performance of a new single-use bronchoscope versus a marketed single-use comparator: a bench study

BACKGROUND

Single-use flexible bronchoscopes eliminate cross contamination from reusable bronchoscopes and are cost-effective in a number of clinical settings. The present bench study aimed to compare the performance of a new single-use bronchoscope (Boston Scientific EXALT Model B) to a marketed single-use comparator (Ambu aScope 4), each in slim, regular and large diameters.

METHODS

Three bronchoscopy tasks were performed: water suction and visualization, "mucus" mass (synthetic mucoid mixture) suctioned in 30 s, and "mucus" plug (thicker mucoid mixture) suction. Suction ability, task completion times, and subjective ratings of visualization and overall performance on a scale of one to 10 (best) were compared. All bronchoscopy tasks were completed by 15 physicians representing diversity in specialization including pulmonary, interventional pulmonary, critical care, anesthesia, and thoracic surgery. Each physician utilized the six bronchoscope versions with block randomization by bronchoscope and task.

RESULTS

Aspirated mean mass of "mucus" using EXALT Model B Regular was comparable to that for an aScope 4 Large (41.8 ± 8.3 g vs. 41.5 ± 5.7 g respectively, p = 0.914). In comparisons of scopes with the same outer diameter, the aspirated mean mass by weight of water and "mucus" was significantly greater for EXALT Model B than for aScope 4 (p < 0.001 for all three diameters). Mean ratings for visualization attributes were significantly better for EXALT Model B compared to aScope 4 (p-value range 0.001-0.029).

CONCLUSION

A new single-use bronchoscope provided strong suction capability and visualization compared to same-diameter marketed single-use comparators in a bench model simulation.

Percutaneous dilatational tracheostomy with single use bronchoscopes versus reusable bronchoscopes – a prospective randomized trial (TraSUB)

Background

Apart from conventional reusable bronchoscopes, single-use bronchoscopes (SUB) were recently introduced. Data suggest that SUB might prevent from the risk of cross contamination (i.e. multiresistant pathogens, SARS CoV-2) and save costs. We aimed to investigate visualization, ventilation, handling characteristics, changes in patients’ gas exchange, and costs associated with both types of bronchoscopes during percutaneous dilatational tracheostomy (PDT).

Methods

In this prospective, randomized, noninferiority study, 46 patients undergoing PDT were randomized 1:1 to PDT with SUB (Ambu aScope) or reusable bronchoscopes (CONV, Olympus BF-P60). Visualization of tracheal structures rated on 4-point Likert scales was the primary end-point. Furthermore, quality of ventilation, device handling characteristics, changes in the patients’ gas exchange, pH values, and costs were assessed.

Results

Noninferiority for visualization (the primary endpoint) was demonstrated for the SUB group. Mean visualization scores (lower values better) were 4.1 (95% confidence intervals: 3.9;4.3) for SUB vs. 4.1 (4.0;4.2) for CONV. Noninferiority of ventilation (estimated by minute volume and SpO₂) during the procedure could be shown as well. Mean score was 2.6 (2.0;3.1) for SUB vs. 2.4 (2.1;2.7) for CONV (lower values better). No significant differences regarding handling (SUB: 1.2 (1.0;1.4), CONV: 1.3 (1.1;1.6)), blood gas analyses and respiratory variables were found. Cost analysis in our institution revealed 93 € per conventional bronchoscopy versus 232.50 € with SUB, not considering an estimate for possible infection due to cross-contamination with the reusable device.

Conclusion

In our study, visualization and overall performance of the SUB during PDT were noninferior to reusable bronchoscopes. Therefore, PDT with SUB is feasible and should be considered if favored by individual institution’s cost analysis.

Trial registration.

ClinicalTrials.gov, NCT03952247. Submitted for registration on 28/04/2019 and first posted on 16/05/2019.

Single-Use and Reusable Flexible Bronchoscopes in Pulmonary and Critical Care Medicine

Flexible bronchoscopy plays a critical role in both diagnostic and therapeutic management of a variety of pulmonary disorders in the bronchoscopy suite and the intensive care unit. In the set-ting of the ongoing viral pandemic, single-use flexible bronchoscopes (SUFB) have garnered attention as various professional pulmonary societies have released guidelines regarding uses for SUFB given the concern for risk of viral transmission when using reusable flexible bronchoscopes (RFB). In addition to offering sterility, SUFBs are portable, easily accessible, and may be more cost-effective than RFB when considering the potential costs of treating bronchoscopy-related infections. Furthermore, since SUFBs are one time use, they do not require reprocessing after use, and therefore may translate to reduced cleaning and storage costs. Despite these advantages, RFBs are still routinely used to perform advanced diagnostic and therapeutic bronchoscopic procedures given the need for optimal maneuverability, handling, angle of deflection, image quality, and larger channel size for passing of ancillary instruments. Here, we review the published evidence on the applications of single-use and reusable bronchoscopes in bronchoscopy suites and intensive care units. Specifically, we will discuss the advantages and disadvantages of these devices as pertinent to fundamental, advanced, and therapeutic bronchoscopic interventions.

Sans Standardization: Effective Endoscope Reprocessing

Bronchoscopy is a commonly performed procedure within thoracic and critical care medicine. Modern bronchoscopes are technologically advanced tools made of fragile electronic components. Their design is catered to allow maximum maneuverability within the semi-rigid tracheobronchial tree. Effective cleaning and reprocessing of these tools can be a challenge. Although highly functional, the design poses several challenges when it comes to reprocessing. It is a very important step, and lapses in the procedure have been tied to nosocomial infections. The process lacks universal standardization; several organizations have developed their own recommendations. Data have shown that key stakeholders are not fully versed in the essentials of endoscope reprocessing. A significant knowledge gap exists between those performing bronchoscopy and those who are stewards of effective endoscope reprocessing. To service as a resource for bronchoscopists, this study summarizes the steps of effective reprocessing, details the important elements within a health-care facility that houses this process, and reviews some of the current data regarding the use of disposable endoscopes.

Evolution of Single-Use Urologic Endoscopy: Benchtop and Initial Clinical Assessment of a New Single-Use Flexible Cystoscope

Introduction Office cystoscopy is one of the most frequently performed procedures by a urologist. However, single-use cystoscopes remain quite undeveloped. Ambu® has developed single-use broncoscopes, rhinolaryngoscopes and duodenoscopes. Recently, they released a single-use cystoscope. In this study, we performed a benchtop and initial clinical assessment of the Ambu® aScope™ (4) Cysto single-use cystoscope. Methods Ten new, never-used Ambu® aScope™ (4) Cysto single-use cystoscopes were assessed for optical performance, maximal tip flexion and irrigation flow rate with empty working channel, 365μm laser fiber, 0.035in hydrophilic-tipped wire, 1.9Fr nitinol basket and a 1.8mm flexible stent grasper. All cystoscopes were then fully flexed 25 times in each direction, and maximal flexion angles were re-measured with and without instruments. Optical resolution, distortion, and depth of field was measured and compared to our reusable digital flexible cystoscopes. Assessment of clinical use was performed for inpatient bedside procedures using a Likert feedback survey and the NASA Task-Load-Index. Results Maximal upward flexion exceeded 200^○ and 160^○ for all working instruments in upward and downward flexion. Downward flexion demonstrated different flexion between instrument groups in pre- and post-cycling (p<0.001). There was no clinical difference between the pre- or post-cycling flexion. Flow rate decreased with increasing working instrument size (p<0.001). The Olympus HD cystoscope resolution was superior at 3mm and 5mm distance, but not at other distances. The Ambu® scope was superior to the Olympus SD scope at all distances except 3mm. The aScope™ (4) Cysto had higher Likert scale survey scores for clinical use. Conclusions The new Ambu® single-use cystoscope demonstrates good flexion across instruments and comparable optics to reusable cystoscopes. Additionally, initial inpatient bedside use of the aScope™ (4) Cysto and Monitor system compares favorably to the Olympus reusable cystoscope. Further testing in clinical scenarios such as hematuria, urothelial carcinoma and operative endoscopy is warranted.

Optical Devices in Tracheal Intubation-State of the Art in 2020

The review article is focused on developments in optical devices, other than laryngoscopes, in airway management and tracheal intubation. It brings information on advantages and limitations in their use, compares different devices, and summarizes benefits in various clinical settings. Supraglottic airway devices may be used as a conduit for fiberscope-guided tracheal intubation mainly as a rescue plan in the scenario of difficult or failed laryngoscopy. Some of these devices offer the possibility of direct endotracheal tube placement. Hybrid devices combine the features of two different intubating tools. Rigid and semi-rigid optical stylets represent another option in airway management. They offer benefits in restricted mouth opening and may be used also for retromolar intubation. Awake flexible fiberoptic intubation has been a gold standard in predicted difficult laryngoscopy for decades. Modern flexible bronchoscopes used in anesthesia and intensive care are disposable devices and contain optical lenses instead of fibers. Endotracheal tubes with an incorporated optics are used mainly in thoracic anesthesia for lung separation. They are available in double-lumen and single-lumen versions. They offer a benefit of direct view to the carina and do not require flexible fiberscope for their correct placement.

Bronchoscopy precautions and recommendations in the COVID-19 pandemic

As the airways of SARS-CoV-2 infected patients contain a high viral load, bronchoscopy is associated with increased risk of patient to health care worker transmission due to aerosolised viral particles and contamination of surfaces during bronchoscopy. Bronchoscopy is not appropriate for diagnosing SARS-CoV-2 infection and, as an aerosol generating procedure involving a significant risk of transmission, has a very limited role in the management of SARS-CoV-2 infected patients including children. During the SARS-CoV-2 pandemic rigid bronchoscopy should be avoided due to the increased risk of droplet spread. Flexible bronchoscopy should be performed first in SARS-CoV-2 positive individuals or in unknown cases, to determine if rigid bronchoscopy is indicated. When available single-use flexible bronchoscopes may be considered for use; devices are available with a range of diameters, and improved image quality and degrees of angulation. When rigid bronchoscopy is necessary, jet ventilation must be avoided and conventional ventilation be used to reduce the risk of aerosolisation. Adequate personal protection equipment is key, as is training of health care workers in correct donning and doffing. Modified full face masks are a practical and safe alternative to filtering facepieces for use in bronchoscopy. When anaesthetic and infection prevention control protocols are strictly adhered to, bronchoscopy can be performed in SARS-CoV-2 positive children.

Pediatric bronchoscopy: recent advances and clinical challenges

Introduction: During the last 40 years equipment has been improved with smaller instruments and sufficient size working channels. This has ensured that bronchoscopy offers therapeutic and interventional options.Areas covered: We provide a review of recent advances and clinical challenges in pediatric bronchoscopy. This includes single-use bronchoscopes, endobronchial ultrasound, and cryoprobe. Bronchoscopy in persistent preschool wheezing and asthma is included. The indications for interventional bronchoscopy have amplified and included balloon dilatation, endoscopic intubation, the use of airway stents, whole lung lavage, closing of fistulas and air leak, as well as an update on removal of foreign bodies. Others include the use of laser and microdebrider in airway surgery. Experience with bronchoscope during the COVID-19 pandemic has been included in this review. PubMed was searched for articles on pediatric bronchoscopy, including rigid bronchoscopy as well as interventional bronchoscopy with a focus on reviewing literature in the past 5 years.Expert opinion: As the proficiency of pediatric interventional pulmonologists continues to grow more interventions are being performed. There is a scarcity of published evidence in this field. Courses for pediatric interventional bronchoscopy need to be developed. The COVID-19 experience resulted in safer bronchoscopy practice for all involved.

Single-Use (Disposable) Flexible Bronchoscopes: The Future of Bronchoscopy?

The coronavirus disease (COVID-19) pandemic has highlighted the importance of reducing occupational exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The reprocessing procedure for reusable flexible bronchoscopes (RFBs) involves multiple episodes of handling of equipment that has been used during an aerosol-generating procedure and thus is a potential source of transmission. Single-use flexible bronchoscopes (SUFBs) eliminate this source. Additionally, RFBs pose a risk of nosocomial infection transmission between patients with the identification of human proteins, deoxyribonucleic acid (DNA) and pathogenic organisms on fully reprocessed bronchoscopes despite full adherence to the guidelines. Bronchoscopy units have been hugely impacted by the pandemic with restructuring of pre- and post-operative areas, altered patient protocols and the reassessment of air exchange and cleaning procedures. SUFBs can be incorporated into these protocols as a means of improving occupational safety. Most studies on the efficacy of SUFBs have occurred in an anaesthetic setting so it remains to be seen whether they will perform to an acceptable standard in complex respiratory procedures such as transbronchial biopsies and cryotherapy. Here, we outline their potential uses in a respiratory setting, both during and after the current pandemic.

Single-Use (Disposable) Flexible Bronchoscopes: The Future of Bronchoscopy?

The coronavirus disease (COVID-19) pandemic has highlighted the importance of reducing occupational exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The reprocessing procedure for reusable flexible bronchoscopes (RFBs) involves multiple episodes of handling of equipment that has been used during an aerosol-generating procedure and thus is a potential source of transmission. Single-use flexible bronchoscopes (SUFBs) eliminate this source. Additionally, RFBs pose a risk of nosocomial infection transmission between patients with the identification of human proteins, deoxyribonucleic acid (DNA) and pathogenic organisms on fully reprocessed bronchoscopes despite full adherence to the guidelines. Bronchoscopy units have been hugely impacted by the pandemic with restructuring of pre- and post-operative areas, altered patient protocols and the reassessment of air exchange and cleaning procedures. SUFBs can be incorporated into these protocols as a means of improving occupational safety. Most studies on the efficacy of SUFBs have occurred in an anaesthetic setting so it remains to be seen whether they will perform to an acceptable standard in complex respiratory procedures such as transbronchial biopsies and cryotherapy. Here, we outline their potential uses in a respiratory setting, both during and after the current pandemic.

Expert panel consensus statement on the applications and precaution strategies of bronchoscopy in patients with COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus with higher transmissibility compared with SARS coronavirus (SARS-CoV) and Middle East respiratory distress syndrome coronavirus. Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 is an unprecedented global crisis that has not been experienced, which is still disrupting health systems, economies, and societies around the world by the rapid spread. Bronchoscopy plays an important role in diagnosis and therapy of pulmonary diseases, especially in patients with severe pulmonary infection, however, application of bronchoscopy in patients suspected or confirmed SARS-CoV-2 infection is extremely limited for the potential airborne transmission from aerosol generated during the procedure. This consensus statement was completed by expert panel of Interventional & Minimally Invasive Respiratory Committee of China Medical Education Association, and the issues were summarized as seven key topics to define the indications of bronchoscopy and matters needing attentions on the bronchoscopy procedures in patients with COVID-19, as well as the protective precaution strategies to avoid nosocomial SARS-CoV-2 infection.

Nasal Pneumococcal Density Is Associated with Microaspiration and Heightened Human Alveolar Macrophage Responsiveness to Bacterial Pathogens

Rationale: Pneumococcal pneumonia remains a global health problem. Colonization of the nasopharynx with Streptococcus pneumoniae (Spn), although a prerequisite of infection, is the main source of exposure and immunological boosting in children and adults. However, our knowledge of how nasal colonization impacts on the lung cells, especially on the predominant alveolar macrophage (AM) population, is limited.Objectives: Using a controlled human infection model to achieve nasal colonization with 6B serotype, we investigated the effect of Spn colonization on lung cells.Methods: We collected BAL from healthy pneumococcal-challenged participants aged 18-49 years. Confocal microscopy and molecular and classical microbiology were used to investigate microaspiration and pneumococcal presence in the lower airways. AM opsonophagocytic capacity was assessed by functional assays in vitro, whereas flow cytometry and transcriptomic analysis were used to assess further changes on the lung cellular populations.Measurements and Main Results: AMs from Spn-colonized individuals exhibited increased opsonophagocytosis to pneumococcus (11.4% median increase) for approximately 3 months after experimental pneumococcal colonization. AMs also had increased responses against other bacterial pathogens. Pneumococcal DNA detected in the BAL samples of Spn-colonized individuals were positively correlated with nasal pneumococcal density (r = 0.71; P = 0.029). Similarly, AM-heightened opsonophagocytic capacity was correlated with nasopharyngeal pneumococcal density (r = 0.61, P = 0.025).Conclusions: Our findings demonstrate that nasal colonization with pneumococcus and microaspiration prime AMs, leading to brisker responsiveness to both pneumococcus and unrelated bacterial pathogens. The relative abundance of AMs in the alveolar spaces, alongside their potential for nonspecific protection, render them an attractive target for novel vaccines.

Human alveolar macrophages predominately express combined classical M1 and M2 surface markers in steady state

Alveolar macrophages (AM) are critical to the homeostasis of the inflammatory environment in the lung. Differential expression of surface markers classifies macrophages to either classically (M1) or alternatively activated (M2). We investigated the phenotype of human alveolar macrophages (AM) in adults living in two different geographical locations: UK and Malawi. We show that the majority of AM express high levels of M1 and M2 markers simultaneously, with the M1/M2 phenotype being stable in individuals from different geographical locations. The combined M1/M2 features confer to AM a hybrid phenotype, which does not fit the classic macrophage classification. This hybrid phenotype may confer to alveolar macrophages an ability to quickly switch between M1 or M2 associated functions allowing for appropriate responses to stimuli and tissue environment.