The recent coronavirus outbreak is a serious threat to global healthcare systems as they are put on high alert to protect their patient populations. Coronaviruses (CoV) can cause a range of illnesses such as the common cold, or more severe disease such as Middle-East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV).
Accurate Illustration of the spreading novel wuhan coronavirus “2019-nCoV”.
This recent outbreak is the third highly pathogenic human CoV to emerge in the last decade and has been named COVID-19 by the World Health Organization who declared it a “public health emergency of international concern”. The current understanding about how the virus spreads is largely based on past experiences.
The spread of SARS-CoV-2 (virus that causes COVID-19 is thought to be transmitted person-to-person via respiratory droplets caused by coughs or sneezes and contracted by close-proximity (6 feet), or by touching infected surfaces. These surfaces can remain contaminated for up to 9 days, so environmental cleaning and disinfection procedures must be followed consistently and correctly.
The prevention of infectious disease transmission is a critical component of how healthcare settings deliver safe care. But what if these settings were contributing to the issues? Most of the transmission has occurred between family members or between patients and hospital workers. COVID-19 is more contagious when people are at their sickest, and as Dr. Stephanie noted back in 2014, the number of hospital-associated infections is quite staggering.
So, what can healthcare facilities do?
The Centers for Disease Control and Prevention (CDC) provide guidance to minimize the chance of exposure. This requires healthcare workers follow their infection control measures and rapidly triage and isolate patients with symptoms of COVID-19 or other respiratory infections. Patients should be provided with surgical masks until they are placed in an Airborne Infection Isolation Room (AIIR) of single occupancy. AIIR’s are designed and operated to ensure room pressure is kept at a negative pressure. The purpose of these rooms is to protect clinical staff, other patients and visitors from exposure to airborne infectious agents such as COVID-19.
To ensure safe operations, facilities should follow these six steps:
1. Maintain the correct air change rate
Although the virus is largely considered to be transmitted via droplet it is still unclear on how long COVID-19 remains airborne. According to Cole and Cook’s (1998) research, ejected droplets can have diameters of 20-40µm which means they are heavy and will fall to the surface. The air flow and exchange rate alone will not significantly impact the transmission unless the environment causes evaporation, making the droplets aerosol. According to ASHRE, precautions should therefore be taken to ensure high volumes of air change rates are still maintained as defined in ASHRAE 170 in the table below. As droplets evaporate and dry out, they have the potential to remain suspended in the air and will be transported with the air current. The increase of ventilation rates will help to reduce the cross infection of these particles and droplet nuclei by removing or diluting them. It is essential that the movement is controlled, and air is expelled from the room.
Note: the air change rate for general ward areas should also be considered during these situations to make sure enough clean air is provided to general areas.
2. Keep the pressure in a negative scale
This is important to ensure the air flow is going in the correct vector. The AIIR should be maintained at a negative pressure to its surrounding areas and this needs to be monitored and recorded. When compromised, both clinical and facility staff must be informed via local displays and/or notifications. Several cases of infection have occurred when the pressure has been reversed due to door openings. The American Institute of Architects’ guidelines recommend a minimum of 2.5 Pa of negative pressure. In the UK, the outside corridor pressure will be at a positive pressure of 10 Pa.
3. Control the access into the AIIR
This also needs to be managed and controlled to a) keep a record of who has had access into the room (it is normally for dedicated health care professionals (HCP) to be assigned to the patient to restrict the number of staff coming into contact with the patient); and b) to provide an air lock to maintain pressure.
The control of patients entering the room is achieved by enabling a higher level of access control into the room. Using access control systems to provide access strictly to authorized people will help limit the amount of HCP exposed. Together with a real time location system (RTLS), this can also be taken a level deeper to understand the exact trail of the HCP who entered the room and where they subsequently traveled. The air lock is also important to provide an ante room, where HCP apply their personal protective equipment (PPE). By making sure both doors are not open at the same time, the pressure regime isn’t impacted.
4. Control the temperature and humidity
The function of the HVAC is to provide comfortable conditions for patients, but these parameters also have an impact on both bacteria and virus growth and survival. A recent study by Luo et al (2020) found the role of absolute humidity in the transmission of COVID-19 has not yet been established, and their results suggest it will not necessarily lead to declines.
Memarzadeh’s (2011) ‘Engineering Perspective on The Envrioment of Care and Health Care-Associated Infections’ for ASHE also concluded that there is still insufficient evidence that temperature and relative humidity influence transmission. However, studies have shown that increasing the mean relative humidity from 35% to 50% may accelerate the removal of infectious Influenza A Virus and help prevent or reduce infection.
The AIIR should be provided with both temperature and relative humidity monitoring, but other areas of the hospitals will not have this level of monitoring. It is typical for humidity to be measured at a common exhaust from the area. However, with IoT sensors, it is now more widely available to provide room level monitoring of these parameters. This provides a more detailed analysis for facilities and infection control teams to identify areas where humidity might have an impact on bacteria (high humidity) or viruses (lower humidity).
5. Ensure suitable filtration and clean status
As mentioned, the particle size of these viruses is very small and suitable filtration is needed to ensure they are not just moved from one area to another. The air from an AIIR should not be recirculated, but rather exhausted directly outdoors. Yet, filtration is still needed.
High-Efficiency Particle Air (HEPA) filters are needed to remove the very small particles. For healthcare, they need to remove 0.3µm or larger and be monitored and maintained. The facilities team should ensure they are changing these filters as needed based on dirty status from sensors monitoring the pressure drop across the filter. ASHRAE also provides guidance to apply personnel safety procedures when changing filters. Depending on the types of organisms and other contaminants collected on the used media, a risk assessment should be carried out.
6. Provide resilient power supplies
The need to ensure these systems work continuously is critical for the safety of patients and staff. Having redundancy for systems is needed as defined by the UK’s Healthcare Technical Memorandum (HTM) 04-01: “Appropriate standby provision should be identified (for example connection to the essential power supply or uninterruptible power supplies) to enable continuity of supply should a mains power failure occur”.
For healthcare facilities that do not have enough AIIR’s, the patient should be isolated in exam rooms with doors closed and moved to a facility that can accommodate them as quickly as possible. Some healthcare facilities have triage rooms that can be mechanically changed into negative rooms when potential pandemic situations like this occur. This requires a well-engineered mechanical ventilation system. All monitoring and control principles previously mentioned need to be adopted. For those facilities that cannot adjust their mechanical systems, other engineering controls and interim safety measures need be applied. Where patients are placed in examination rooms awaiting transfer, the CDC recommends isolating them and ensuring the air from that room is not recirculated. It may need a temporary exhaust system to provide the negative pressure in this situation.
The response and measures that are taken must be carefully coordinated with HCP and the infection control team to ensure all members of the hospital are working safely and to the correct measures. Training and education are important, so every member knows the impact of leaving a door open or not washing hands. In 2018, airborne isolation room air flow (EC.02.05.01 EP15) was the 11th most cited incidence by the Joint Commission. This is where technology can support healthcare facilities, by utilizing EcoStruxure for Healthcare facilities can:
- Ensure the correct operation of ventilation systems to achieve the needed air changes and pressure regime using EcoStruxure Building Operation
- Provide critical alerts to facility and clinical staff when safety might be compromised through EcoStruxure Building Operation
- Continuously record and analyse the performance of critical areas with EcoStruxure Building Advisor and plan for maintenance on filters
- Manage access and movement of people through the facility using EcoStruxure Security Expert
- Ensure power availability through digitized electrical distribution and uninterruptible power supplies with EcoStruxure Power
As health systems around the world take measures to control and isolate this disease, healthcare facilities can assist by ensuring proper operations and maintenance.
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Additional Bibliographic Resources
- ASHRAE 170 Ventilation. ASHRAE
- Cole, E. C. & Cook, C. E. 1998 Characterisation of infectious aerosols in healthcare facilities: an aid to effective engineering controls and preventative strategies. Am. J. Infect. Control 26, 453 –464. (doi:10.1016/S0196-6553(98)70046-X)
- Memarzadeh, F. The Environment of Care and Health Care-Associated Infections. An Engineering Perspective. 2011. American Society of Healthcare Engineers
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