Laboratory Study of a Waste Anesthetic Gas Mask Scavenging System to Reduce Airborne Pathogen Exposure for Health Care Workers in Post Anesthesia Care Units

Introduction A scavenging oxygen mask system (SOMS) utilizing house vacuum has been demonstrated to significantly reduce exposure of post anesthesia care unit (PACU) health care workers (HCWs) to waste anesthetic gases (WAGs). Therefore, it was proposed that the same system could also be used to protect HCWs in the PACU by reducing Infectious Respiratory Particles (IRPs) spread from patients who may harbor airborne infective pathogens, such as Mycobacterium tuberculosis, certain strains of influenza, and SARS-CoV-2. Methods A life-like adult manikin head equipped with a bio-aerosol Collison nebulizer was set up to simulate patients exhausting pathogenic droplets. Further evaluation of a mask involved using a SOMS for case trials and comparing to control conditions without the SOMS. The nebulizer atomized several types of respirable surrogate pathogens (bacteria, including a bioluminescent reporter strain, and viruses) representing different sizes to evaluate the scavenging system’s ability to capture a range of pathogens likely to be found in infectious patients. Microbes were entrained by vacuum of the SOMS, while microbes that escaped the SOMS were captured using liquid impingers. Results In most of the trials, the SOMS reduced bacterial escape with greater than 94% reduction when compared to a control system of no mask. The filter equipped with the SOMS significantly prevented pathogens from breaking through into the house vacuum (P ≤ .05). Substituting high efficiency particulate air (HEPA) filters in the SOMS further reduced the number of viruses exiting the system. The SOMS proved to reduce the exposure to the smallest viruses (27 nm) by 93.2% and the largest bacteria (3 µm) by as much as 99.9998%. Low-light imaging shows where the bioluminescent bacteria accumulated in the SOMS during use by a simulated patient. Conclusion The results of this laboratory research underscore the potential benefit of the SOMS to significantly mitigate airborne pathogen exposure among HCWs. This is particularly pertinent for nurses operating in high-risk environments for pathogen exposure such as the PACU, intensive care unit (ICU), and potentially general nursing care areas. The integration of SOMS within these settings could markedly enhance occupational safety and health by providing a significant layer of defense against airborne pathogens.