The Impact of Face Shields on the Quality of Colonoscopy During the COVID-19 Pandemic


 Background: The coronavirus disease 2019 (COVID-19) has become a global pandemic. Healthcare workers are at a higher risk for exposure to COVID-19 infection than the general population. During the COVID-19 pandemic, endoscopists are recommended to wear personal protective equipment (PPE), including face shields, to prevent COVID-19 transmission. However, to the best of our knowledge, there are no reports on the impact of face shields on the quality of colonoscopy. This study aimed to determine whether the use of PPE, including face shields, affects the quality of colonoscopy during the COVID-19 pandemic.Methods: We retrospectively reviewed the medical records of patients who underwent screening or surveillance colonoscopy performed at Dong-A University Hospital between June 2020 and March 2021 during the COVID-19 pandemic. Endoscopists wore isolation gowns, disposable gloves, and KF94 masks from June 2020 to October 2020. From November 2020, endoscopists additionally wore face shields. Therefore, we compared the colonoscopy quality indicators during the 5 months without the use of face shields and the 5 months with the use of face shields. We calculated the overall adenoma detection rates (ADRs) of the group using face shields and the group not using face shields. Further, the polyp detection rate (PDR), sessile serrated lesion detection rate (SSLDR), advanced neoplasia detection rate (ANDR), polyp per colonoscopy, and adenoma per colonoscopy were calculated for each group.Results: In total, 1,359 patients were included in the study; the face shield and non-face shield groups comprised 679 and 680 patients, respectively. We found no statistically significant differences in the PDR (49.04 vs. 52.50%, p=0.202), ADR (38.59 vs. 38.97%, p=0.884) SSPDR (1.91 vs. 1.32%, p=0.388), and ANDR (3.98 vs. 3.97%, p=0.991) between the groups. In both the experienced endoscopist group and trainee endoscopist group, there was no difference in the colonoscopy quality indicators between the groups of patients examined by endoscopists with and without face shields.Conclusions: The quality indicators of colonoscopy were not affected by face shields during the COVID-19 pandemic.

Gastroenterological Association, European Society of Gastrointestinal Endoscopy, and Asian Paci c Society for Digestive Endoscopy, have made recommendations for clinicians to follow during the COVID-19 period. The common recommendations of these were to assess the risk of COVID-19 to determine when to perform an endoscopy and that all endoscopists wear appropriate personal protective equipment (PPE) to prevent COVID-19 transmission.[6-10] PPE includes an isolation gown, disposable gloves, a mask, and face shield or goggles. A face shield is used for protection of the facial area from exposure to infectious agents. Many protective devices have previously been used during endoscopy, but face shields have not been used before the COVID-19 pandemic.
Colonoscopy is the gold standard for the screening and diagnosis of colorectal cancer (CRC). [11,12] However, poor-quality colonoscopy can lead to post-colonoscopy CRC (PCCRC). [13] An increased adenoma detection rate (ADR) has reduced the risk of PCCRC and CRC-related mortality. [14,15] ADR is affected by the resolution of the colonoscope. [16,17] High resolution provides clear images, making it easy to detect abnormalities in the colonic mucosa. The sharpness of the screen is an important factor in uencing the ADR during colonoscopy. [18] Since the face shield is a device worn in front of the eyes, it may affect the visual eld of the user observing the screen. However, there are no reports on the impact of the use of a face shield on the quality of colonoscopy including ADR. Therefore, it is necessary to determine whether the use of a face shield affects the ADR or other colonoscopy quality indicators.

Study design and patients
We retrospectively reviewed the medical records of patients who underwent screening or surveillance colonoscopy at Dong-A University Hospital between June 2020 and March 2021 during the COVID-19 pandemic. All patients were aged between 30-79 years and underwent either the rst screening colonoscopy of their lives or surveillance colonoscopy after 3 years since the last examination.
Colonoscopies were performed by four experienced endoscopists and three gastroenterology fellows. All experienced endoscopists who participated in the study had more than 5 years of experience. All gastroenterology fellows who participated in the study were either second-or third-year fellows who could perform colonoscopies independently. The endoscopists wore isolation gowns, disposable gloves, and KF94 masks from June 2020 to October 2020; patients examined under this condition were classi ed as the non-face shield group. From November 2020 onward, the endoscopists additionally wore face shields, and the patients examined under this condition were classi ed as the face shield group (Figure 1). Therefore, we compared the colonoscopy quality indicators during 5 months without the use of face shields and 5 months with the use of face shields. Only patients with adequate bowel preparations (Boston bowel preparation scale score ≥2 in all segments, described as good or excellent) were included in the study. Patients with a history of colorectal surgery, CRC, in ammatory bowel disease, or active bleeding symptoms were excluded from the study.
Risk strati cation and endoscopic procedures with personal protective equipment Dong-A University Hospital is a tertiary hospital that treats patients with COVID-19. Since the COVID-19 pandemic, our hospital has classi ed patients' risk of COVID-19 infection into three categories. Patients showing no symptoms (e.g., cough, temperature >37.5°, breathlessness, diarrhea), with no contact with COVID-19-positive patients, and who did not stay in high-risk areas in the previous 14 days were classi ed as low-risk patients. Patients showing symptoms, with no contact with COVID-19-positive patients, and who did not stay in high-risk areas in the previous 14 days or patients without symptoms but had contact with COVID-19-positive patients or stayed in high-risk areas in the previous 14 days were classi ed as intermediate-risk patients. Patients showing symptoms and meeting one of the latter two criteria were classi ed as high-risk patients. During the chart review, we performed screening or surveillance colonoscopy for low-risk patients. Intermediate-or high-risk patients underwent polymerase chain reaction test for COVID-19 to con rm negative results, and the necessity of colonoscopy was evaluated.
Subsequently, colonoscopy was performed for patients with negative results but not for con rmed COVID-19 patients. High-de nition video processor systems (i.e., CV-290 EVIS LUCERTA ELITE [Olympus Medical, Tokyo, Japan] and EPK-i7010 [Pentax, Hoya Corporation, Tokyo, Japan]) were used to all colonoscopies. Patients were prepared with 1-2 L of a polyethylene glycol solution containing ascorbic acid with an additional 1-2 L of water. For sedation, we used midazolam 2-5 mg and/or propofol 10-60 mg.
De nitions of polyp detection rate, adenoma detection rate, sessile serrated lesion detection rate, and advanced neoplasia detection rate We de ned the polyp detection rate (PDR) as the proportion of patients with at least one polyp, including adenoma and hyperplastic polyp (HP), among all the patients examined. We de ned ADR as the proportion of patients with at least one adenoma among all the patients examined. We added features of clinically signi cant sessile serrated lesions (SSLs) to our de nition of SSL. Therefore, SSL was de ned as follows: (a) SSL with or without dysplasia, (b) HP measuring ≥5 mm in the proximal colon (proximal to the splenic exure), or (c) HP ≥10 mm in the whole colon. Advanced adenoma was de ned as follows: any adenoma ≥10 mm in size, with villous histology or with high-grade dysplasia, and any SSL ≥10 mm in size or with dysplasia. The sessile serrated lesion detection rate (SSLDR) and ANDR were calculated in the same way as PDR and ADR.

Endpoint
The primary endpoint was the comparison of the ADR between the groups. The secondary endpoint was the comparison of the PDR, SSPDR, ANDR, adenoma per colonoscopy (APC), intubation time, and withdrawal time.

Statistical and data analyses
The data were divided into two groups: data from procedures performed with the use of face shields and data from procedures performed without the use of face shields. Continuous data were analyzed by Student's t-test and are represented as mean ± standard deviation. Categorical data were analyzed using Pearson's chi-squared or Fisher's exact test. All analyses were performed using the Statistical Package for the Social Sciences software version 26.0 (IBM, Armonk, New York, USA). Statistical signi cance was set at p <0.05.

Ethics statement
Our research protocol was approved by the ethics committee in accordance with international agreements (World Medical Association Declaration of Helsinki: Ethical principles for medical research involving human subjects). Due to the retrospective characteristics of the study, informed consent was waived and the study was approved by the Institutional Review Board of Dong-A University College of Medicine (DAUHIRB-21-110).

Demographic and clinical characteristics
In total, 1,359 patients were included in this study; 680 and 679 procedures were performed without and with face shields, respectively. The demographic and clinical characteristics of the patients are summarized in Table 1. There were no signi cant differences between the two groups (face shield vs. non-face shield) regarding patient's age and sex, bowel preparation, sedation, use of antiplatelet or anticoagulation, time of examination, indication for examination, type of colonoscope, and endoscopist's experience (Table 1).

Discussion
This was a single-center retrospective study that aimed to determine whether the use of a face shield affected the quality of colonoscopy during the COVID-19 pandemic. We found that performing colonoscopy while wearing a face shield did not affect the quality indicators of colonoscopy, including the ADR. In addition, the pro ciency of both experienced endoscopists and trainee endoscopists was not affected by the use of face shields.
Endoscopists are at increased risk of contracting COVID-19 infection from airborne droplets and conjunctival contact. Upper gastrointestinal endoscopy is a procedure with a high risk of infection due to a patient's cough during examination. The live virus is also found in the patient's stool, and fecal-oral transmission of COVID-19 is also possible. [5,19] Therefore, colonoscopy may be a procedure that increases the risk of COVID-19 infection. One study quanti ed the rate of unrecognized exposure to potentially infectious biologic samples during endoscopy via the endoscopist's face. According to the result, facial exposure may result in transmission of infectious diseases. [20] According to previous studies conducted in the early phase of the COVID-19 pandemic, 19% of healthcare workers who wore masks and gloves and performed hand hygiene without additional facial protection were infected with COVID-19, but those who used additional facial protection were not infected. [21,22] For these reasons, it is important that endoscopists wear a face shield along with isolation gowns, gloves, and a mask during colonoscopy procedures in this COVID-19 pandemic.
However, wearing a face shield may affect the observation capacity of the endoscopists during colonoscopy. In previous studies, the ADR was affected by the resolution and visual eld of the colonoscopy.
[16-18] When the screen is clear and the visual eld is wide, it is easy to observe the adenomas. Therefore, there may be concerns about whether the wearing of a face shield affects the clarity or visual eld during colonoscopy and thus reduces the ADR. In addition, it was worth checking whether this change made the endoscopists uncomfortable and increased the insertion time or reduced the withdrawal time. However, we con rmed that the wearing of a face shield did not affect the quality indicators of colonoscopy, including the ADR.
This study has some limitations. When a face shield is worn, lights may be re ected on the face shield and interfere with the endoscopist's visual eld. In our hospital's endoscopic room, the lights were turned off, only the screen of the video processor was turned on, and there was no direct sunlight in the endoscopic room. However, the lighting or brightness of the endoscopic room and the position of the screen may re ect the light on the face shield, but this may indicate various differences in each endoscopic room. In this study, the impact of these differences on the colonoscopy quality indicators was not analyzed. Moreover, in this study, only one type of face shield was analyzed. Because there are various face shields, the impact on the quality indicators of colonoscopy may be different. Since this was a retrospective study based on medical records, it had inherent limitations. In our hospital, colonoscopy was performed while strictly following the recommendations, but as this was a retrospective study, we could not con rm whether the recommendations were followed or not in a few patients. However, according to our investigation of our hospital staff, compliance with facial protection was greater than 95% during the period; thus, it is estimated that our uncertainty did not signi cantly affect the results. Therefore, our results obtained by analyzing several patients' medical records in a short period of time in which the current recommendations for facial protection were strictly followed are valuable. In addition, it is meaningful to study the changes that occur due to the unprecedented pandemic that is a threat to the global population. Experts and medical societies have provided guidelines for the management of COVID-19 infection, and medical workers have strict management guidelines to prevent droplet or air transmission. The same management guidelines are also applied in the endoscopic room, and the wearing of PPE, including facial protection, is crucial for endoscopists.[6-10] Further studies will be needed to determine whether wearing a face shield is necessary for the prevention of other infections without degrading the quality indicators of the colonoscopy even when COVID-19 is over.

Conclusions
In conclusion, the quality indicators of colonoscopy were not affected by face shields during the COVID-19 pandemic. Thus, the use of face shields to prevent COVID-19 transmission will not deteriorate the quality of the colonoscopy during the COVID-19 pandemic. Our research protocol was approved by the ethics committee in accordance with international agreements (World Medical Association Declaration of Helsinki: Ethical principles for medical research involving human subjects). Due to the retrospective characteristics of the study, informed consent was waived and the study was approved by the Institutional Review Board of Dong-A University College of Medicine (DAUHIRB-21-110).

Consent for publication
Informed consent for publication was obtained from the endoscopist wearing the protective equipment in gure 1.

Availability of data and materials
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Competing interests
The authors declare that they have no competing interests.

Funding
This study was funded by Dong-A University.

Authors' contributions
Study conception (LJY, LJH), Data acquistion, anaylsis (LJY, KYW), Data interpretation (LJY, KYW, LJH), Manuscript drafting (LJY), Manuscript revisions (LJH), Agree to be personally accountable for contributions and ensure that questions related to the accuracy or integrity of any part of the work are appropriately investigated, resolved, and documented (LJY, KYW, LJH). All authors read and approved the nal manuscript.