This study aimed to assess the efficacy of a novel aerosol-exposure protection (AP) mask in preventing coronavirus disease in healthcare professionals during upper gastrointestinal endoscopy and to evaluate its clinical feasibility.
In Study 1, three healthy volunteers volitionally coughed with and without the AP mask in a cleanroom. Microparticles were visualized and counted with a specific measurement system and compared with and without the AP mask. In Study 2, 30 patients underwent endoscopic resection with the AP mask covering the face, and the SpO2 was measured throughout the procedure.
In Study 1, the median number of microparticles in volunteers 1, 2, and 3 with and without the AP mask was 8.5 and 110.0, 7.0 and 51.5, and 8.0 and 95.0, respectively (
The AP mask could provide protection from aerosol exposure and can be safely used for endoscopy in clinical practice.
The new coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), rapidly spread throughout the world, with over 83 million patients becoming infected with it and over 1.8 million deaths globally by January 5, 2021 [
Healthcare professionals (HCPs) are particularly at risk of infection. It has been reported that approximately 20% of the HCPs in Italy have been infected with coronavirus during the pandemic [
Protection of HCPs is well established as mentioned above; however, protection of HCPs from the patient’s side has not yet been standardized. Consequently, we developed a novel aerosol-exposure protection (AP) mask for upper GI endoscopy, with a plastic file folder covering the patients’ faces. This study aimed to evaluate the preclinical efficacy of aerosol exposure prevention and the clinical feasibility of AP masks during therapeutic endoscopy.
The AP mask was made of an A4-sized plastic file folder as follows (
First, an exploratory study was performed to investigate the efficacy of aerosol-exposure prevention by the AP mask in a preclinical setting in a clean room where we could eliminate air dust and precisely visualize and measure the aerosol. Study 1 was not conducted in a real clinical setting because of the need for these specific requirements and limited space. Study 1 included only three volunteers. Three healthy volunteers were recruited from the National Cancer Center Hospital, Tokyo, Japan. In Study 2, the AP mask was clinically tested in patients with early esophageal and gastric endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). This study was carried out in accordance with the ethical principles defined by the Declaration of Helsinki and approved by the Institutional Review Board (2020-027) on July 13, 2020, at the National Cancer Center Hospital. Our protocol was registered on June 20, 2020, at the University Hospital Medical Information Network Clinical Trials Registry (UMIN) as UMIN000040815. Written informed consent for this study was obtained from all participants.
Three healthy volunteers (Seiichiro Abe, Mai Ego Makiguchi, Yutaka Okagawa) checked that they were afebrile and asymptomatic relating to COVID-19 before the study. A COVID-19 polymerase chain reaction (PCR) test was not performed due to limited resources during the pandemic in Japan [
Study 1 assessed the effectiveness of aerosol exposure protection with and without the AP mask using aerosol particle visualization analysis.
Study 2 aimed to evaluate the clinical feasibility of the AP mask. Patients undergoing EMR or ESD for early esophageal cancer and early gastric cancer were enrolled from May to July 2020 at the National Cancer Center Hospital.
ESD/EMR was performed following the Japan Gastroenterological Endoscopy Society (JGES) recommendations for GI endoscopy during the COVID-19 pandemic [
EMR and ESD were performed as described previously [
The ESD procedure was performed as follows: first, marking dots were drawn around the lesion; second, saline or hyaluronic acid was injected into the submucosa; and third, mucosal incision and submucosal dissection were made using a needle knife and IT knife 2 (KD-611L; Olympus Medical, Tokyo, Japan). EMR and ESD were generally performed using a therapeutic endoscope for ESD (GIF-Q260J; Olympus Medical, Tokyo, Japan) and a standard endoscope for EMR (GIF-H260; Olympus Medical, Tokyo, Japan) and the following generators: ESG-100 (Olympus Medical, Tokyo, Japan) or VIO 3 (ERBE, Tübingen, Germany).
In our hospital, we performed ESD with propofol-based deep sedation. Propofol was administered using a target-controlled infusion pump with an initial target blood concentration of 2 µg/ml; if necessary, the target blood concentration was changed by 0.1–0.2 µg/ml [
Electrocardiogram, oxygen saturation, and non-invasive blood pressure measurements were constantly monitored during sedation. Desaturation was defined as SpO2 <94%.
The endpoints of Study 2 were to evaluate the safety of AP masks used during clinical endoscopic procedures and the presence of adverse events such as oxygen desaturation and pneumonia.
In Study 1, continuous variables are shown as medians and ranges. Continuous data were compared using the Wilcoxon Mann–Whitney
The median (range) distances of microparticle scattering without the AP mask were 60 (60–60), 0, and 68 (68–68) in volunteers 1, 2, and 3, respectively. The median (range) distances of microparticle scattering with the AP mask were 0, 0, and 0 (0–48), respectively (
A total of 34 lesions in 30 patients underwent EMR/ESD during the study period. Most of the patients were classified as Eastern Cooperative Oncology Group (ECOG) PS 0 and American Society of Anesthesiologists (ASA) Physical Status Classification II (
Six esophageal EMRs, seven esophageal ESDs, and 21 gastric ESDs were performed. All lesions achieved
The mean dosage of propofol and pentazocine (±SD) was 13.1±2.3 mg/kg/hr and 16.8±0.9 mg, respectively. During sedation, mean SpO2 (±SD) was 96.3±0.7%, and desaturation occurred in three patients (
This is the first study to evaluate the effectiveness of the AP mask through direct aerosol visualization during GI endoscopy simulation. In this study, microparticles were visualized during voluntary coughing. We compared the number of microparticles generated with and without the AP mask. Microparticles were dramatically reduced when the AP mask was worn. Although we could not distinguish the aerosol and floating material in the air in detail, most of the microparticles were thought to be aerosols in this study. Thus, the AP mask could prevent exposure to aerosols in the cleanroom. Furthermore, desaturation occurred in only three patients in this study, as reported in a previous study [
According to previous reports, exposure to SARS-CoV-2 can occur from face-to-face contact within 6 feet of a patient with symptomatic COVID-19 [
Prevention of coronavirus infections in the endoscopy unit is essential for all endoscopic staff during the COVID-19 pandemic. As previously mentioned, PPE is useful for protecting HCPs from infection. However, previous reports have shown that the coronavirus remains viable in aerosols for up to 3 hours [
Compared with previous reports, our single-use and inexpensive AP mask could entirely cover the patient’s face. In addition, our study demonstrated the visualization of the aerosols and compared the number of microparticles with and without the AP mask, which were dramatically reduced in the former. In addition, no adverse events related to wearing the AP mask occurred during clinical use.
Our study had several limitations. First, this was a single-center simulation study with a small sample size. As this was an exploratory study, we did not set the sample size. In addition, protection from aerosol particles may not necessarily result in the prevention of COVID-19 infection. Second, we could not compare the control group (without the AP mask) in a real clinical setting. Therefore, further research with a larger sample size is warranted to confirm the results of this study.
In conclusion, the AP mask could assist in protecting HCPs against COVID-19 infection from aerosol-exposure during upper GI endoscopy.
This study was supported by a research grant from Olympus Medical.
Conceptualization: Mai Ego Makiguchi, Seiichiro Abe, Yutaka Okagawa
Data curation: MEM, SA
Formal analysis: MEM, SA
Project administration: MEM, SA, YO, Ryuta Okamoto
Supervision: Yutaka Saito
Writing-original draft: MEM, SA
Writing-review & editing: MEM, SA, YO,RO, Satoru Nonaka, Haruhisa Suzuki, Shigetaka Yoshinaga, Ichiro oda, YS
We would like to thank Dr. Lady Katherine Mejía Pérez (Gastroenterology, Cleveland Clinic Foundation) for her kind support of this article.
We also thank Shin Nippon Air Technologies, Co., Ltd. in Tokyo, Japan.
Video 1. Without the aerosol-exposure protection mask, the aerosol spread over 2 feet (
Video 2. With the aerosol-exposure protection mask, aerosol did not leak outside the mask (
How to make aerosol-exposure protection (AP) mask. (A) Materials of the AP mask: an A4-sized plastic folder, string, and two pieces of gauze pad. (B) An A4-sized plastic folder was cut into a 12.5×12.5 cm square, and a 3.5 cm square was cut from its corner. (C) To insert the string, a small hole was made in the plastic folder and two pieces of gauze pad. (D) The gauze was placed on the edges of the plastic file holder with a string. (E) A healthy volunteer wearing the mask.
Schematic illustration of experimental design in a cleanroom. (A) A healthy volunteer without the aerosol-exposure protection (AP) mask. (B) A healthy volunteer with the AP mask. (C) Schematic illustration of the experimental design in a cleanroom.
Visualization of aerosol particles by light-emitting diode during simulated endoscopy.
Droplets were identified inside the aerosol-exposure protection mask during endoscopic procedures.
The Number of Aerosol Particles With/Without the Aerosol-Exposure Protection Mask
With the mask | Without the mask | ||
---|---|---|---|
Volunteer 1 | 8.5 (4-79) | 110.0 (48-231) | <0.01 |
Volunteer 2 | 7.0 (4-22) | 51.5 (26-143) | <0.01 |
Volunteer 3 | 8.0 (1-20) | 95 (11-791) | <0.01 |
Data are presented by median (range).
The Number of Aerosol Particles from the Volunteer’s Mouth
AP Mask With/Without | Volunteer 1 | Volunteer 2 | Volunteer 3 |
---|---|---|---|
1 | 55/113 | 9/84 | 3/39 |
2 | 15/74 | 7/143 | 10/11 |
3 | 15/107 | 7/57 | 7/791 |
4 | 4/48 | 15/31 | 1/78 |
5 | 4/99 | 7/30 | 6/65 |
6 | 31/48 | 22/131 | 6/158 |
7 | 9/64 | 10/26 | 12/45 |
8 | 4/231 | 7/43 | 12/45 |
9 | 6/226 | 5/44 | 9/227 |
10 | 8/115 | 7/89 | 9/112 |
11 | 7/140 | 4/46 | 9/112 |
12 | 79/144 | 5/92 | 5/347 |
AP, aerosol-exposure protection.
The Distance Generated Aerosol Particles during Cough With and Without the Aerosol-Exposure Protection Mask
Without mask (cm) | |||||
---|---|---|---|---|---|
Volunteer 1 | 60 | 60 | 60 | 60 | 60 |
Volunteer 2 | 0 | 0 | 0 | 0 | 0 |
Volunteer 3 | 68 | 68 | 68 | 68 | 68 |
Volunteer 1 | 0 | 0 | 0 | 0 | 0 |
Volunteer 2 | 0 | 0 | 0 | 0 | 0 |
Volunteer 3 | 48 | 0 | 0 | 0 | 0 |
Patient’s Characteristics (
Age (years) | 73.3±1.7 |
Gender, male/female | 25/5 |
Performance status (0/1) | 25/5 |
ASA classification (I/II/III) | 5/25/0 |
Height (cm) | 164.4±1.7 |
Body weight (kg) | 62.1±2.0 |
Comorbidity |
|
Cardiovascular disease | 8 (26.6) |
Cerebrovascular disease | 1 (3.3) |
Esophageal cancer/Gastric cancer | 14/20 (46.6/66.6) |
Other malignant disease | 8 (26.6) |
Diabetes mellites | 6 (20) |
Hypertension | 14 (46.6) |
Respiratory functional disorder | 9 (30) |
Data are presented by mean±standard deviation or number (%).
With overlapping
ASA, American Society of Anesthesiologists.
Lesion Characteristics (
Esophageal cancer | 13 |
EMR/ESD | 6/7 |
Gastric cancer | 21 |
EMR/ESD | 0/21 |
Procedure time (min) | 42.4±5.1 |
Size of the tumor (mm) | 11.9±1.6 |
Data are presented by mean±standard deviation.
EMR, endoscopic mucosal resection; ESD, endoscopic submucosal dissection.
Drugs and Dosages during Sedation (
Propofol | 30 (100) |
Dosage of drugs | |
Propofol (mg/kg/hr) | 13.1±2.3 |
Pentazocine (mg) | 16.8±0.9 |
Minimum SpO2 (%) | 96.3±0.7 |
Discontinuation cases | 0 (0) |
Data are presented by mean±standard deviation or number (%).
SD, standard deviation.