Aerosol and droplet generation in upper and lower GI endoscopy: whole procedure and event-based analysis

Aerosol protection using modified N95 respirator during upper gastrointestinal endoscopy: a randomized controlled trial

BACKGROUND/AIMS

The coronavirus disease 2019 pandemic has affected the worldwide practice of upper gastrointestinal endoscopy. Here we designed a modified N95 respirator with a channel for endoscope insertion and evaluated its efficacy in upper gastrointestinal endoscopy.

METHODS

Thirty patients scheduled for upper gastrointestinal endoscopy were randomized into the modified N95 (n=15) or control (n=15) group. The mask was placed on the patient after anesthesia administration and particles were counted every minute before (baseline) and during the procedure by a TSI AeroTrak particle counter (9306-04; TSI Inc.) and categorized by size (0.3, 0.5, 1, 3, 5, and 10 µm). Differences in particle counts between time points were recorded.

RESULTS

During the procedure, the modified N95 group displayed significantly smaller overall particle sizes than the control group (median [interquartile range], 231 [54-385] vs. 579 [213-1,379]×103/m3; p=0.056). However, the intervention group had a significant decrease in 0.3-µm particles (68 [-25-185] vs. 242 [72-588]×103/m3; p=0.045). No adverse events occurred in either group. The device did not cause any inconvenience to the endoscopists or patients.

CONCLUSIONS

This modified N95 respirator reduced the number of particles, especially 0.3-µm particles, generated during upper gastrointestinal endoscopy.

Cytosponge procedures produce fewer respiratory aerosols and droplets than esophagogastroduodenoscopies

Esophagogastroduodenoscopies (EGD) are aerosol-generating procedures that may spread respiratory pathogens. We aim to investigate the production of airborne aerosols and droplets during Cytosponge procedures, which are being evaluated in large-scale research studies and National Health Service (NHS)implementation pilots to reduce endoscopy backlogs. We measured 18 Cytosponge and 37 EGD procedures using a particle counter (diameters = 0.3-25 μm), taking measurements 10 cm from the mouth. Two particle count analyses were performed: whole procedure and event-based. Direct comparison with duration-standardized EGD procedures shows that Cytosponge procedures produce 2.16× reduction (P < 0.001) for aerosols and no significant change for droplets (P = 0.332). Event-based analysis shows that particle production is driven by throat spray (aerosols: 138.1× reference, droplets: 16.2×), which is optional, and removal of Cytosponge (aerosols: 14.6×, droplets: 62.6×). Cytosponge burping produces less aerosols than EGD (2.82×, P < 0.05). Cytosponge procedures produce significantly less aerosols and droplets than EGD procedures and thus reduce two potential transmission routes for respiratory viruses.

Bronchoscopy masks mitigate aerosols during upper gastrointestinal endoscopies

Background and study aims Upper gastrointestinal endoscopies are considered aerosol-generating procedures (AGP) that risk spread of airborne diseases such as SARS-CoV-2. We aimed to investigate where clinically approved bronchoscopy masks applied to patients during esophagogastroduodenoscopies can mitigate spread of aerosols and droplets. Patients and methods This study included patients undergoing routine upper gastrointestinal endoscopy in a standard endoscopy room and used a particle counter to measure size and number of particles 10 cm from the mouths of 49 patients undergoing upper gastrointestinal endoscopies, of whom 12 wore bronchoscopy masks and 37 did not (controls). Particle counts in the aerosol (≤ 5 µm diameter) and droplet (> 5 µm-diameter) size ranges were measured and averaged over the duration of procedures. Results The use of bronchoscopy masks offers a 47% reduction ( P = 0.01) in particle count for particles < 5 μm in diameter over the procedure duration (aerosols). Conclusions Bronchoscopy masks or similar are a simple, low-cost mitigation technique that can be used during outbreaks of respiratory diseases such as COVID-19 to improve safety and reduce fallow times.

Necessity of pharyngeal anesthesia during transoral gastrointestinal endoscopy: a randomized clinical trial

BACKGROUND/AIMS

The necessity for pharyngeal anesthesia during upper gastrointestinal endoscopy is controversial. This study aimed to compare the observation ability with and without pharyngeal anesthesia under midazolam sedation.

METHODS

This prospective, single-blinded, randomized study included 500 patients who underwent transoral upper gastrointestinal endoscopy under intravenous midazolam sedation. Patients were randomly allocated to pharyngeal anesthesia: PA+ or PA- groups (250 patients/group). The endoscopists obtained 10 images of the oropharynx and hypopharynx. The primary outcome was the non-inferiority of the PA- group in terms of the pharyngeal observation success rate.

RESULTS

The pharyngeal observation success rates in the pharyngeal anesthesia with and without (PA+ and PA-) groups were 84.0% and 72.0%, respectively. The PA- group was inferior (p=0.707, non-inferiority) to the PA+ group in terms of observable parts (8.33 vs. 8.86, p=0.006), time (67.2 vs. 58.2 seconds, p=0.001), and pain (1.21±2.37 vs. 0.68±1.78, p=0.004, 0-10 point visual analog scale). Suitable quality images of the posterior wall of the oropharynx, vocal fold, and pyriform sinus were inferior in the PA- group. Subgroup analysis showed a higher sedation level (Ramsay score ≥5) with almost no differences in the pharyngeal observation success rate between the groups.

CONCLUSION

Non-pharyngeal anesthesia showed no non-inferiority in pharyngeal observation ability. Pharyngeal anesthesia may improve pharyngeal observation ability in the hypopharynx and reduce pain. However, deeper anesthesia may reduce this difference.

Air filtration mitigates aerosol levels both during and after endoscopy procedures

Objectives

Upper gastrointestinal endoscopies are aerosol-generating procedures, increasing the risk of spreading airborne pathogens. We aim to quantify the mitigation of airborne particles via improved ventilation, specifically laminar flow theatres and portable high-efficiency particulate air (HEPA) filters, during and after upper gastrointestinal endoscopies.

Methods

This observational study included patients undergoing routine upper gastrointestinal endoscopy in a standard endoscopy room with 15-17 air changes per hour, a standard endoscopy room with a portable HEPA filtration unit, and a laminar flow theatre with 300 air changes per hour. A particle counter (diameter range 0.3 μm-25 μm) took measurements 10 cm from the mouth. Three analyses were performed: whole procedure particle counts, event-based counts, and air clearance estimation using post-procedure counts.

Results

Compared to a standard endoscopy room, for whole procedures we observe a 28.5x reduction in particle counts in laminar flow (p < 0.001) but no significant effect of HEPA filtration (p = 0.50). For event analysis, we observe for lateral flow theatres reduction in particles >5 μm for oral extubation (12.2x, p < 0.01), reduction in particles <5 μm for coughing/gagging (6.9x, p < 0.05), and reduction for all sizes in anesthetic throat spray (8.4x, p < 0.01) but no significant effect of HEPA filtration. However, we find that in the fallow period between procedures HEPA filtration reduces particle clearance times by 40%.

Conclusions

Laminar flow theatres are highly effective at dispersing aerosols immediately after production and should be considered for high-risk cases where patients are actively infectious or the supply of personal protective equipment is limited. Portable HEPA filers can safely reduce the fallow time between procedures by 40%.

Does an Extraoral Suction Device Reduce Aerosol Generation and Prevent Droplet Exposure to the Examiner during Esophagogastroduodenoscopy?

Esophagogastroduodenoscopy (EGD) is an aerosol-generating procedure. A major challenge in the COVID-19 era is how to prevent the spread of aerosols and droplets in endoscopic units. We evaluated the effectiveness of an extraoral suction device in preventing indoor aerosol diffusion and droplet exposure for examiners. The study involved 61 patients who underwent EGD at our institution from 1 February to 31 March 2022. To determine whether aerosol spread increases before or after EGD examination with an extraoral suction device located in front of the patient’s mouth, aerosols of 0.3, 0.5, 1, 3, 5, and 10 μm were measured with a handheld particle counter. The degree of contamination of the plastic gowns on the examiners was assessed using the rapid adenosine triphosphate test. The extraoral suction device significantly reduced the diffusion of large particles (3, 5, and 10 μm) after finishing the EGD examination. However, the diffusion of small particles (0.3 and 0.5 μm) was significantly increased. This extraoral suction device was effective in reducing large particle diffusion during EGD examination but was limited for minimizing small particle diffusion or droplet exposure to the examiner.

COVID-19 und gastrointestinale Endoskopie –angepasste Strategien im pandemischen Wandel

Im Dezember 2019 begann mit dem Ausbruch der Coronavirus Disease 2019 (COVID-19) eine neue Herausforderung in vielen Bereichen der Medizin und des persönlichen Lebens. Der individuelle Schutz der professionellen Leistungsbringer vor der Infektion wurde zur Sicherung der Leistungsfähigkeit des Gesundheitssystems essenziell. Neue Arbeiten definierten die obere gastrointestinale Endoskopie als aerosolgenerierende Prozedur (AGP), die insbesondere aufgrund des engen Kontakts für das Personal ein erhöhtes Infektionsrisiko darstellt. Da das „severe acute respiratory syndrome coronavirus type 2“ (SARS-CoV-2) in erster Linie durch Aerosole und/oder Tröpfchen übertragen wird, besteht die Notwendigkeit der Verwendung von persönlicher Schutzausrüstung („personal protective equipment“, PPE). Empfehlungen der Leitlinien haben entsprechend früh PPE als infektionspräventive Maßnahmen empfohlen. Die strikte Verwendung von PPE hat sich mit der Erfahrung aus nunmehr 3 Jahren als effektive Präventionsstrategie bewiesen. Mit der Einführung der Vakzinierung gegen SARS-CoV‑2, einer zunehmenden Immunisierung der Bevölkerung und einem sich ändernden pandemischen Infektionsgeschehen haben sich die Anforderungen für endoskopische Abteilungen in den Krankenhäusern und in der ambulanten Versorgung stetig geändert. In der postpandemischen Situation bestehen nur noch geringe Einschränkungen, die die neue „postpandemische Realität“ beeinflussen und die Durchführung endoskopischer Leistungen ohne größere Restriktionen ermöglichen. Die Anpassungen der infektionspräventiven Strategien im Verlauf der Pandemie und die erhobenen wissenschaftlichen Daten mit folgender Anpassung der aktuellen Empfehlungen bis zum heutigen Tag werden in dieser Arbeit zusammengefasst und diskutiert.

Gastrointestinal Endoscopy in Patients with Coronavirus Disease 2019: Indications, Findings, and Safety

The coronavirus disease 2019 (COVID-19) pandemic has changed the practice of gastroenterology and how we perform endoscopy. As with any new or emerging pathogen, early in the pandemic, there was limited evidence and understanding of disease transmission, limited testing capability, and resource constraints, especially availability of personal protective equipment (PPE). As the COVID-19 pandemic progressed, enhanced protocols with particular emphasis on assessing the risk status of patients and proper use of PPE have been incorporated into routine patient care. The COVID-19 pandemic has taught us important lessons for the future of gastroenterology and endoscopy.

Protocol of a randomised controlled trial to assess medical staff's inhalation exposure to infectious particles exhaled by patients during oesophagogastroduodenoscopy and the efficacy of surgical masks in this context

BACKGROUND

Aerosol-generating procedures such as oesophagogastroduodenoscopy (OGD) result in infectious particles being exhaled by patients. This substantially increases the medical staff's risk of occupational exposure to pathogenic particles via airway inhalation and facial mucosal deposition. Infectious particles are regarded as a key route of transmission of SARS-CoV-2 and, thus, represents a major risk factor for medical staff during the ongoing COVID-19 pandemic. There is a need for quantitative evidence on medical staff's risk of multiroute exposure to infectious particles exhaled by patients during OGD to enable the development of practical, feasible and economical methods of risk-reduction for use in OGD and related procedures. This randomised controlled trial (RCT)-Personal protective EquiPment intervention TrIal for oesophagogastroDuodEnoscopy (PEPTIDE)-aims to establish a state-of-the-art protocol for quantifying the multiroute exposure of medical staff to infectious particles exhaled by patients during real OGD procedures.

METHOD AND ANALYSIS

PEPTIDE will be a prospective, two-arm, RCT using quantitative methods and will be conducted at a tertiary hospital in China. It will enrol 130 participants (65 per group) aged over 18. The intervention will be an anthropomorphic model with realistic respiratory-related morphology and respiratory function that simulates a medical staff member. This model will be used either without or with a surgical mask, depending on the group allocation of a participant, and will be placed beside the participants as they undergo an OGD procedure. The primary outcome will be the anthropomorphic model's airway dosage of the participants' exhaled infectious particles with or without a surgical mask, and the secondary outcome will be the anthropomorphic model's non-surgical mask-covered facial mucosa dosage of the participants' exhaled infectious particles. Analyses will be performed in accordance with the type of data collected (categorical or quantitative data) using SPSS (V.26.0) and RStudio (V.1.3.959).

ETHICS AND DISSEMINATION

Ethical approval for this RCT was obtained from the Ethics Committee of Peking Union Medical College Hospital (ZS-3377). All of the potential participants who agree to participate will provide their written informed consent before they are enrolled. The results will be disseminated through presentations at national and international conferences and publications in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05321056.

Shielding device for endoscopic procedures during lower gastrointestinal endoscopy

Objectives

The coronavirus pandemic significantly impacted endoscopic practice. During lower gastrointestinal endoscopy, infectious substances disseminate; therefore, we developed an infection control device (STEP‐L) for lower gastrointestinal endoscopy and examined its usefulness.

Methods

STEP‐L wraps around the patient's buttocks and covers the endoscope. Using lower endoscopy training models, three endoscopists performed 18 colonoscopies with STEP‐L (group S) and without (group C). Endoscopic insertion time and pigmented areas of ​​gloves and diapers after the examination were compared between both groups.

Results

Insertion of the endoscope up to the cecum was possible in all 18 examinations. The insertion time to the cecum was 52.4 ± 19.0 s in group S and 53.9 ± 13.3 s in group C. The pigmented areas of the ​​gloves measured 39,108.0 ± 16,155.3 pixels in group C, but were significantly reduced to 2610.5 ± 4333.8 pixels in group S (p < 0.05). The pigmented areas of the diapers measured 2280.9 ± 3285.2 pixels in group C, but were significantly reduced to 138.0 ± 82.9 pixels in group S (p < 0.05).

Conclusions

Using STEP‐L does not change the insertion time, and is technically feasible. STEP‐L significantly reduces the adhesion of virtual pollutants to the surroundings, suggesting that this device is useful for infection control during lower gastrointestinal endoscopy.

Management of aerosol generation during upper gastrointestinal endoscopy

In the highly contagious coronavirus disease 2019 pandemic, aerosol-generating procedures (AGPs) are associated with high-risk of transmission. Upper gastrointestinal endoscopy is a procedure with the potential to cause dissemination of bodily fluids. At present, there is no consensus that endoscopy is defined as an AGP. This review discusses the current evidence on this topic with additional management. Prevailing publications on coronavirus related to upper gastrointestinal endoscopy and aerosolization from the PubMed and Scopus databases were searched and reviewed. Comparative quantitative analyses showed a significant elevation of particle numbers, implying that aerosols were generated by upper gastrointestinal endoscopy. The associated source events have also been reported. To reduce the dispersion, certain protective measures have been developed. Endoscopic unit protocols are recommended for the concerned personnel. Therefore, upper gastrointestinal endoscopy should be classified as an AGP. Proper practices should be adopted by healthcare workers and patients.

Unsedated Transnasal Endoscopy: A Safe, Well-Tolerated and Accurate Alternative to Standard Diagnostic Peroral Endoscopy

Diagnostic unsedated transnasal endoscopy (uTNE) has been proven to be a safe and well-tolerated procedure. Although its utilization in the United Kingdom (UK) is increasing, it is currently available in only a few centers. Through consideration of recent studies, we aimed to perform an updated review of the technological advances in uTNE, consider their impact on diagnostic accuracy, and to determine the role of uTNE in the COVID-19 era. Current literature has shown that the diagnostic accuracy of uTNE for identification of esophageal pathology is equivalent to conventional esophagogastroduodenoscopy (cEGD). Concerns regarding suction and biopsy size have been addressed by the introduction of TNE scopes with working channels of 2.4 mm. Advances in imaging have improved detection of early gastric cancers. The procedure is associated with less cardiac stress and reduced aerosol production; when combined with no need for sedation and improved rates of patient turnover, uTNE is an efficient and safe alternative to cEGD in the COVID-19 era. We conclude that advances in technology have improved the diagnostic accuracy of uTNE to the point where it could be considered the first line diagnostic endoscopic investigation in the majority of patients. It could also play a central role in the recovery of diagnostic endoscopic services during the COVID-19 pandemic.