key: cord-0969735-t71kufkl
authors: Ahn, Jin Young; An, Sanggwon; Sohn, Yujin; Cho, Yunsuk; Hyun, Jong Hoon; Baek, Yae Jee; Kim, Moo Hyun; Jeong, Su Jin; Kim, Jung Ho; Ku, Nam Su; Yeom, Joon-Sup; Smith, Davey M.; Lee, Hyukmin; Yong, Dongeun; Lee, Youn-Jung; Kim, Ji Won; Kim, Hyeong Rae; Hwang, Jung Ho; Choi, Jun Yong
title: Environmental contamination in the isolation rooms of COVID-19 patients with severe pneumonia requiring mechanical ventilation or high-flow oxygen therapy
date: 2020-08-21
journal: J Hosp Infect
DOI: 10.1016/j.jhin.2020.08.014
sha: 39939175990c5e8a0b535c6da47cc8bad5059f47
doc_id: 969735
cord_uid: t71kufkl

BACKGROUND: Identifying the extent of environmental contamination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential for infection control and prevention. The extent of environmental contamination has not been fully investigated in the context of severe coronavirus disease (COVID-19) patients. AIM: To investigate environmental SARS-CoV-2 contamination in the isolation rooms of severe COVID-19 patients requiring mechanical ventilation or high-flow oxygen therapy. METHODS: We collected environmental swab samples and air samples from the isolation rooms of three COVID-19 patients with severe pneumonia. Patient 1 and Patient 2 received mechanical ventilation with a closed suction system, while Patient 3 received high-flow oxygen therapy and noninvasive ventilation. Real-time reverse transcription polymerase chain reaction (rRT-PCR) was used to detect SARS-CoV-2; viral cultures were performed for samples not negative on rRT-PCR. FINDINGS: Of the 48 swab samples collected in the rooms of Patient 1 and Patient 2, only samples from the outside surfaces of the endotracheal tubes tested positive for SARS-CoV-2 by rRT-PCR. However, in Patient 3’s room, 13 of the 28 environmental samples (fomites, fixed structures, and ventilation exit on the ceiling) showed positive results. Air samples were negative for SARS-CoV-2. Viable viruses were identified on the surface of the endotracheal tube of Patient 1 and seven sites in Patient 3’s room. CONCLUSION: Environmental contamination of SARS-CoV-2 can be a route of viral transmission. However, it might be minimized when patients receive mechanical ventilation with a closed suction system. These findings can provide evidence for guidelines for the safe use of personal protective equipment.

To investigate environmental SARS-CoV-2 contamination in the isolation rooms of severe COVID-19 patients requiring mechanical ventilation or high-flow oxygen therapy.

We collected environmental swab samples and air samples from the isolation rooms of three COVID-19 patients with severe pneumonia. Patient 1 and Patient 2 received mechanical ventilation with a closed suction system, while Patient 3 received high-flow oxygen therapy and noninvasive ventilation.

Real-time reverse transcription polymerase chain reaction (rRT-PCR) was used to detect SARS-CoV-2; viral cultures were performed for samples not negative on rRT-PCR.

Of the 48 swab samples collected in the rooms of Patient 1 and Patient 2, only samples from the outside surfaces of the endotracheal tubes tested positive for SARS-CoV-2 by rRT-PCR. However, in

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which began in Wuhan, China, has become a global concern. The World Health Organization (WHO)

announced the risk assessment of coronavirus disease as very high at the global level, and currently, COVID-19 is labelled as a pandemic. In addition to community transmission, SARS-CoV-2 has also caused healthcare-associated outbreaks in hospitals, leading to concerns that it is not only transmitted through direct contact with droplets but also environmental contamination or airborne transmission in specific circumstances, such as during procedures generating aerosols [1] . A study on the Middle East respiratory syndrome coronavirus (MERS-CoV) reported extensive viable virus contamination of the air and environment in a MERS outbreak unit [2] . A recent study on SARS-CoV-2 also suggested the contaminated environment as a potential medium of transmission [3] .

Identifying the exact extent of environmental contamination and associated potential risk of viral transmission is essential for infection prevention and control in hospitals and for the protection of healthcare workers. While recent guidelines recommend the use of extended personal protective equipment (PPE), the strength of recommendation is weak, and its safety has not been fully studied [4] . Furthermore, since SARS-CoV-2 infection has clinical manifestations ranging from asymptomatic infection to acute respiratory distress syndrome (ARDS) requiring mechanical ventilation, the degree of air and environmental contamination may vary depending on the disease severity and subsequent treatment. There are several reports on environmental contamination in the isolation rooms of COVID-19 patients [3, [5] [6] [7] [8] [9] [10] . The patients in these studies exhibited varying disease severities, ranging from mild symptoms to severe disease requiring intensive care. Additionally, some reports showed a higher risk of environmental contamination in the intensive care unit (ICU) [7, 9] . However, a study on the extent and risk factors of environmental contamination in critically ill patients who require intensive care and various aerosol-generating procedures (AGP) is still lacking.

In this study, we investigated virus contamination by collecting environmental swab samples and air samples from negative pressure isolation rooms of patients with COVID-19 manifesting as severe pneumonia or ARDS.

Three laboratory-confirmed COVID-19 patients who required high-flow oxygen therapy or mechanical ventilation and were hospitalized in a tertiary care hospital were enrolled in this study.

Environmental samples were collected from the negative pressure isolation rooms of these patients between 6 th March 2020 and 31 st March 2020. The isolation rooms had 12 air-changes per hour, and the average pressure gradient between the patient room and the anteroom was 2.5 hPa. All patients received intensive care in these isolation rooms without being moved to a separate ICU. Each negative pressure room had an anteroom and a restroom, but the restrooms were not being used at the time of the investigation since the enrolled patients were critically ill and could not move. Nurses performed daily routine cleaning, but disinfection was performed only after the patients were discharged. All patients were symptomatic, and their respiratory specimens persistently tested positive 

SKC BioSampler (225-9595, SKC, Inc., USA) and Swab sampler were used for sampling the air in each patient's negative pressure isolation room. The SKC BioSampler captures bioaerosols in 20 mL of phosphate-buffered saline (PBS) by an inertia impaction mechanism [11] [12] [13] . The collection efficiency of the SKC BioSampler for 100 nm sized particles, which is the known size of SARS-CoV-2, has been reported as 30-40% [14] . The Swab sampler, a useful air sampler for capturing airborne viruses, utilizes a cotton swab that acts as a filter for capturing airborne particles with 99% efficacy for airborne viruses, as per a previous report [15] . Air sampling was carried out at 1. Environmental surface samples from the patients' isolation rooms were obtained using sterile swabs, which were premoistened with a viral transport medium. All the rooms had the same size, structure, and facilities. Bedside tables, blood pressure cuffs, pillows, bedsheets, nasal prongs, outside surface of the ventilator circuit, tubing, masks, telephones, thermometers, keyboards, and fixed structures in the room (such as the doorknob, bed rails, floor, walls, window, and faucet handles), and grills of the ventilation exits in the ceiling were swabbed. All the environmental swabs were obtained on the same day as the air sampling procedure in each patient's room. 

This study was conducted in compliance with the Institutional Review Board of Severance Hospital 

Sample time points in relation to the patients' clinical courses and Ct values of rRT-PCR are summarized in Table I Prone positioning in accordance with the ARDS management guidelines was followed from HD 2 to HD 4, and regular and frequent endotracheal suction was performed through a closed suction system. Figure 1 .

The main finding of this study was the increased extent of environmental contamination of SARS- contamination of healthcare workers were significantly reduced [25] . Symptoms can be minimized by sedation, and respiration can be limited within the ventilator circuit. The closed system is maintained even during suction, which can generate aerosols, and is also recommended in the airway management guidelines for COVID-19 patients [26] . Current guidelines for critically ill patients with COVID-19 propose surgical or medical masks for respiratory protection during the management of J o u r n a l P r e -p r o o f patients on mechanical ventilation using a closed suction system if there are no additional aerosolgenerating events [4] . The results of our study support this recommendation.

There are several limitations of this study. Firstly, since a small number of patients were included in this study, the results should be cautiously interpreted. Secondly HFNC; high-flow oxygen therapy via nasal cannula † +; Either a mentioned symptom existed or the mentioned treatment was performed ‡ -; Either a mentioned symptom did not exist or the mentioned treatment was not performed J o u r n a l P r e -p r o o f 

Modes of transmission of virus causing COVID-19: implications for IPC precaution recommendations 29

Extensive Viable Middle East Respiratory Syndrome (MERS) Coronavirus Contamination in Air and Surrounding Environment in MERS Isolation Wards

Surface Environmental, and Personal Protective Equipment Contamination by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) From a Symptomatic Patient

Surviving Sepsis Campaign: guidelines on the management of critically ill adults with Coronavirus Disease 2019 (COVID-19)

Detection of air and surface contamination by SARS-CoV-2 in hospital rooms of infected patients

Environmental contamination of SARS-CoV-2 in healthcare premises

Aerosol and Surface Distribution of Severe Acute Respiratory Syndrome Coronavirus 2 in Hospital Wards

Severe acute respiratory syndrome coronavirus 2 RNA contamination of inanimate surfaces and virus viability in a health care emergency unit

Environmental contamination by SARS-CoV-2 in a designated hospital for coronavirus disease 2019

SARS-CoV-2 RNA detection of hospital isolation wards hygiene monitoring during the Coronavirus Disease 2019 outbreak in a Chinese hospital

Bioaerosol Sampling in Clinical Settings: A Promising, Noninvasive Approach for Detecting Respiratory Viruses

Collection of Viable Aerosolized Influenza Virus and Other Respiratory Viruses in a Student Health Care Center through Water-Based Condensation Growth

Characterization of Aerosols Generated During Patient Care Activities

Comparing the performance of 3 bioaerosol samplers for influenza virus

In situ lysis droplet supply to efficiently extract ATP from dust particles for near-real-time bioaerosol monitoring

Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR

Transmission of SARS and MERS coronaviruses and influenza virus in healthcare settings: the possible role of dry surface contamination

Airborne transmission of severe acute respiratory syndrome coronavirus-2 to healthcare workers: a narrative review

Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: a systematic review

Personal protective equipment and possible routes of airborne spread during the COVID-19 pandemic

Influence of tracheal suctioning systems on health care workers' gloves and equipment contamination: a comparison of closed and open systems

Consensus guidelines for managing the airway in patients with COVID-19: Guidelines from the Difficult Airway Society, the Association of Anaesthetists the Intensive Care Society, the Faculty of Intensive Care Medicine and the Royal College of Anaesthetists

The authors thank Medical Illustration & Design, part of the Medical Research Support Services of Yonsei University College of Medicine, for all artistic support related to this work.All authors: No reported conflicts.