By ECRI
Do ventilators that are used to treat COVID-19 patients need to be disinfected after use – and if so, how, and how often? Surprisingly, this late in the pandemic the answers still are not clear cut. Guidance from device manufacturers is inconsistent from one vendor to the next; and recommendations from the U.S. Centers for Disease Control and Prevention (CDC) are not completely clear about which ventilator components, if any, are covered. ECRI offers its guidance to help reduce the confusion.
COVID-19 patients who have difficulty breathing or maintaining adequate blood oxygen levels may need to be placed on mechanical ventilation. Ventilating such patients raises infection control concerns, however: Droplets and aerosols in the patient’s exhaled air travel through, and are exhausted from, the ventilator, potentially allowing the SARS-CoV2 virus to contact device components (e.g., the exhalation valve, the expiratory flow sensor) and be spread into the room. This raises two key questions:
- How can health care facilities minimize the risk of contaminating ventilator components and the surrounding environment? The use of filters in the breathing circuit can help. ECRI cautions, however, that filters are not a cure-all.
- What steps are required to clean and disinfect the ventilator before using the device on another patient? Unfortunately, recommendations from ventilator vendors vary. ECRI offers its guidance to help clarify the issue for health care facilities.
The Use of Filters in the Breathing Circuit
When ventilating a patient with a known or suspected airborne pathogen, ECRI recommends using a filter in the breathing circuit between the patient and the exhalation valve of the ventilator – either at the patient wye or between the circuit and the exhalation valve. The exact type of filter needed for a given patient depends on the known or suspected pathogen, as well as other factors.
The primary purpose of this filter is to limit the spread of the disease through the atmosphere. As for protecting the ventilator: “Using a filter is not sufficient to prevent cross-contamination,” warns Brad Bonnette, a senior project officer in ECRI’s Device Evaluation group. “But it can help.” Placing the filter upstream of the exhalation valve can help limit contamination of the valve and other reusable ventilator components.
Generally, if a heated humidifier is in use, the filter should be located between the breathing circuit and exhalation valve. If a heat/moisture exchanger (HME) is being used for humidification, using one with a filter (i.e., a heat/moisture-exchanging filter [HMEF]) precludes the need for an additional filter.
When a filter is to be used, ECRI recommends:
- Checking the filter before use and replacing it when necessary, such as if the filter has become saturated with condensate or if the manufacturer-recommended replacement interval has been reached.
- Verifying that the filter is correctly and securely installed so that it does not contribute to any risk of disconnection of any portion of the breathing circuit or misconnection of components.
- Installing the filter before performing manual pre-use checks and automatic ventilator breathing-circuit compliance tests.
- Following manufacturer recommendations and hospital policies for emptying water traps to minimize infection risks while ensuring that the trap does not overfill into the filter.
- Using care in handling and disposing of the contaminated filter.
- During ventilation, watching for signs of obstruction or increased exhalation resistance. One way to do this is to monitor the peak expiratory flow and the duration and slope of the exhaled breath on the waveform display. Alternatively, if no waveform display is available, exhalation pressure can be checked during an expiratory hold maneuver.
- Considering the use of a heated-wire circuit or an HME, if appropriate, to minimize the moisture in the breathing circuit and therefore the moisture load on the filter.
“It’s important to note that adding any new component in a ventilator breathing circuit can introduce new risks,” cautions ECRI’s Bonnette. With filters, the greatest risk is that moisture accumulating in the filter could cause increased exhalation resistance or an obstruction, possibly resulting in decreased ventilation effectiveness or pneumothorax. Misconnection or disconnection of breathing-circuit components may also be possible.
The Case for Disinfection
Whenever possible, single-use items should be used to reduce the risk of cross-contamination. But for reusable ventilator components, health care organizations require guidance about whether and how such components are to be disinfected. Unfortunately, ventilator vendors are inconsistent in their recommendations. For example:
Some vendors – but not all – explicitly recommend that, after every patient, facilities perform high-level disinfection on the exhalation valve and any other components that are in the path of exhaled gases.
Some vendors provide detailed cleaning and disinfecting information but make no specific recommendations on how often these tasks should be performed.
Some vendors informally instruct clients that a filter in the breathing circuit, either at the patient wye or between the circuit and the exhalation valve, will be sufficient to prevent pathogens from finding their way onto reusable components and thereby becoming a potential source of cross-contamination. (But to ECRI’s knowledge, no vendor has included such a recommendation in their user manuals.)
This can cause confusion about what measures are necessary to keep patients safe, especially in facilities that have a mixed fleet of ventilators.
CDC’s Guideline for Disinfection and Sterilization in Healthcare Facilities (2008) states, in recommendation 3.b., “Provide, at a minimum, high-level disinfection for semicritical patient-care equipment (e.g., gastrointestinal endoscopes, endotracheal tubes, anesthesia breathing circuits, and respiratory therapy equipment) that touches either mucous membranes or nonintact skin.” However, it is not completely clear which ventilator components, if any, are covered by this recommendation.
While the endotracheal tube clearly touches mucous membranes, the ventilator components do not touch them directly. On the other hand, airway secretions (and ventilator condensate, which contains secretions) are a possible vector by which the patient’s mucous membranes could contaminate ventilator components.
As Bonnette explains: ECRI believes that airway secretions, and ventilator condensate that contains secretions, “should be considered to be just as potentially infectious as mucous membranes.” Therefore, ECRI recommends that facilities generally treat any reusable ventilator components that may come into contact with exhaled patient gas as semicritical equipment and perform high-level disinfection or greater on those components between patients. “This applies regardless of whether a filter is used.”
Components to disinfect include internal exhalation valves on most intensive care ventilators, many subacute ventilators and some transport ventilators. External exhalation valves, which are present on the majority of transport ventilators, should also be given this level of reprocessing, if they are reusable (most aren’t).
For most intensive care ventilators, this means the exhalation valve or cartridge should be removed between patients and sent for processing as described in the user manual. For convenience, consider keeping two exhalation valves or cartridges for each device to minimize turnover time between patients.
Additionally, the external surface of the ventilator should receive at least low-level disinfection between patients. If reusable breathing circuits are used, they should receive at least high-level disinfection between patients.
To Learn More
This article is adapted from ECRI’s “Safe Cleaning and Disinfection of Ventilators: ECRI’s Recommendations” (Device Evaluation 2021 Oct 6). The complete article is available to members of ECRI’s Capital Guide, Device Evaluation, and associated programs. To learn more about membership, visit www.ecri.org/solutions/evaluation-and-comparison, or contact ECRI by telephone at (610) 825-6000, ext. 5891, or by e-mail at clientservices@ecri.org.