Could Air Filtration Systems be to Blame for Hospital-Acquired Infections in the COVID-19 Era?

    The advent of COVID-19 has everyone taking extra precautions to prevent contamination through both social distancing and self-quarantine. But the recent discovery that airborne transmission of the virus can occur in indoor spaces through microscopic respiratory droplets is a glaring reminder of just how dangerous hospitals, in particular, can be for patients at this time.

    In a hospital setting, contaminants can be easily spread throughout the operating room from certain devices that have internal fans. Although hospitals across the country have set up specific floors and strict operating rooms for COVID-19 patients, these measures in and of themselves may not always be enough to ensure safe air quality. In fact, any operating room device that requires internal air movement to maintain a specific temperature for a computer processing unit (CPU) may contain the virus for two to three days if the material is plastic or stainless steel. These devices constantly move air across their CPUs to maintain a low temperature, and over time, may build up the COVID-19 virus if not properly disinfected.

    Having recently conducted field research on this subject, I can safely conclude that failure to diligently monitor, clean, and maintain operating room devices with internal fans may potentially increase the risk of transmission, exposure, and surgical site infection to patients undergoing surgical procedures. The good news is that some surgical equipment with internal fans can actually be used to positively affect airflow in an operating room.

    In this article, I’ll walk you through a few operating room devices that pose specific air quality dangers, review tell tale signs that a patient’s hospital-acquired infection originated from poor operating room ventilation, and outline what the proper standard of care should be for maintaining safe air quality in hospital operating rooms in the post-COVID-19 world.

    Operating Room Devices That Threaten Safe Air Quality

    Some of the biggest culprits of operating room air contamination are forced-air warming blower devices. Forced-air warming blowers intake air directly from the ground level and force the air into a half body or full body blanket beneath or above the patient on the surgical table. Studies have shown that microbial buildup and emissions are very possible from these devices.

    In the context of COVID-19, surgical infection within the operating room may be most notably caused by the forced-air warming blower, the Bair Hugger. Back in 2015, the FDA issued a safety alert for the 3M Bair Hugger, a multi-position upper body warming blanket. This heating device is typically used under a sterile drape, causing most of the device’s air to blow to the ground. However, air from the Bair Hugger can, in fact, recirculate above the patient as it is released from the device.

    Our studies have shown that the Bair Hugger has the greatest effect on airflow over the surgical table, directing upward and dispersing airflow, as well as causing recirculation. Therefore, any pathogen that gets caught in the Bair Hugger’s airflow can recirculate right above the sterile field. This may increase the risk of exposure to COVID-19 or a surgical site infection. Furthermore, when airflow in the operating room is sent parallel to the exhaust vents, the Bair Hugger is able to push potentially contaminated air up to the ceiling, where it’s able to linger due to limited airflow.

    Other evidence suggests that some infection complications—including Nontuberculous Mycobacteria (NTM) infections—following open-heart procedures have been linked to the discharge fans of surgical equipment, most notably the Sorin LivaNova 3T. In 2014, the FDA circulated a safety communication regarding LivaNova 3T (a device that is used to warm or cool a surgical patient) indicating that the heater-cooler device was discovered to be associated with a higher patient risk for mycobacterial infections.

    How to Tell if a Patient’s Infection Originated from Poor Operating Room Ventilation

    The mycobacterium found in patients who have been infected by poor operating room ventilation is relatively easy to identify using bacterial cultures. Unlike staph bacteria, for example, these mycobacteria are not native to the human body. They are slow-growing and typically found in soil and water. When an infection is discovered in a patient, hospital staff will perform a culture to determine the type of infection. Based on the results, it’s usually fairly easy to determine where the patient picked up the infection based on the characteristics of the pathogen, be it bacteria or virus.

    Proving causation between an instance of post-surgical COVID-19 and negligent ventilation or heater-cooler unit failure may be more challenging at the onset, in that there are many variables to consider in a hospital setting (i.e. the number of people entering or leaving the operating room, etc.) However, in an otherwise sterilized operating room environment, the origin of a post-surgical case of COVID-19 may be the intake and discharge vents of ventilation equipment, especially if associated staff also test positive.

    The New, Post-COVID-19, Standard of Care for Hospitals

    In the past, hospitals have been required to validate their HVAC systems on an annual basis. The Center for Disease Control (CDC) has specific infection control guidelines that cover how HVAC systems should be utilized within the hospital setting, especially air exchanges per hour (ACH). The CDC recommends that hospital ventilation measures should “maintain ≥ 15 ACH, of which ≥ 3 ACH should be fresh air”.

    Now, our findings indicate that the current HVAC air exchange rate might not be enough to remove contaminated air within the operating room. Moving forward, understanding airflow dynamics in the operating room can help hospital staff arrange the room to best minimize competition of devices and increase return vent exchange. Below are three steps hospital operating room personnel should be taking to reduce chances of contamination of sterile fields and protect surgical patients from contracting infections in the operating room—specifically, COVID-19.

    1) Change Intake Vent Direction

    Having all of the operating room equipment on simultaneously changes the airflow around the operating room. Therefore, utilizing equipment with internal fans to help direct and remove air will be critical in reducing the chances of contaminating sterile fields. Based on our findings, the direction of the intake vents in specific devices can change the direction of airflow and help possibly to remove air.

    2) Direct Heater-Cooler Unit Exhaust Outside the Operating Room

    Because the velocity of the heater-cooler unit exhaust fan is strong enough to expel contaminants into the surgical field, heater-cooler unit exhaust should be kept at an acceptable distance to prevent exhaust airflow from coming in contact with a provider’s face or eyes, the surgical table, or the surgical field. This can mitigate the risk of infection from heater-cooler units.

    3) Clean, Clean, Clean

    Because COVID-19 can live for days on stainless steel and plastic materials, healthcare providers should be taking extra care to clean equipment with internal fans as well as exhaust ports on devices with internal fans. In the instance that a perfusion monitor has an intake vent on the back panel and an exhaust port on the bottom panel, a hospital’s environmental services and biomedical department should be aware of the material these devices contain and ensure they are appropriately clean after a possible COVID-19 patient procedure.

    Especially due to the resurgence of COVID-19 in many states, hospitals that are not taking such precautions in their operating rooms could be subject to legal liability.

    How Experts in Cardiovascular Perfusion Can Help

    There is a large amount of electronic equipment in the operating room that requires internal fans, and the greatest danger with these devices is that they all have exhaust. In the new COVID-19 world, hospitals need to ensure that operating room ventilation equipment—including HVAC systems, forced air warming blowers, and heater-cooler devices—are being utilized safely and efficiently.

    As an expert in cardiovascular perfusion, I have recently collaborated with several colleagues on studies testing air quality in hospital settings. Our studies use fog machines to identify devices that have an effect on the airflow with the intention of reducing the risk of surgical site infections secondary to poor air quality. This methodology is helping identify the fundamental ways in which equipment disrupts the airflow patterns in the operating room, contributing to a greater understanding of contemporary hospital-acquired infections, and hopefully mitigating the spread of COVID-19 in hospital settings.

    Moving forward, experts in cardiovascular perfusion can help attorneys whose clients may have contracted COVID-19 or a mycobacterial infection through unsafe operating room ventilation systems. A cardiovascular perfusionist is familiar with the various areas of a hospital operating room (including surgical equipment, nursing equipment, anesthesia equipment, and perfusion equipment) and can help attorneys understand how vents should be directed in order to maintain a sterile environment for the patient and decrease the risk of contamination.

    Expert Witness Bio E-006942


    Location: CT
    BS, Biology, Northern Arizona University
    MS, Cardiovascular Science, Midwestern University
    MBA, Suffolk University
    Certified, Cardiovascular Perfusionist
    Certified, Advanced Cardiac Life Support
    Member, American Heart Association
    Former, Staff Perfusionist, Mayo Clinical Hospital
    Former, Assistant Provost, AmSECT University
    Former, Senior Perfusionist, Cardiac Surgery, Massachusetts General Hospital
    Current, Staff Perfusionist, a CT hospital
    Current, Adjunct Faculty, a major university

    This board-certified cardiovascular perfusion expert has over 10 years of experience in his field. He received his BS in biology from Northern Arizona University, followed by his MS in cardiovascular science from Midwestern University. He served formerly as a staff perfusionist at Mayo Clinical Hospital and as a senior perfusionist at Massachusetts General Hospital. He is a member of the American Heart Association and is also certified in advanced cardiac life support. He is currently a clinical perfusionist at a major hospital and is also very involved in academia as the program director of perfusion students.