Identifying Potential Provider and Environmental Contamination on a Clinical Biocontainment Unit Using Aerosolized Pathogen Simulants

Abstract

The Johns Hopkins Hospital created a biocontainment unit (BCU) to care for patients with highly infectious diseases while assuring healthcare worker safety. Research to date for BCU protocols and practices are based on case reports and lessons learned from patient care and exercises. This study seeks to be the first to explore the influences of healthcare worker movement and personal protective equipment (PPE) doffing on the transport of simulant pathogen particles in a BCU. A cough device released 1 μm fluorescent polystyrene beads (PSLs) in the patient room. PSL transport was then examined under 2 scenarios: (1) PSL release only, no healthcare workers; and (2) PSL release during 5-minute simulated activity by healthcare workers. Airborne PSL concentrations were quantified every second for 30 minutes per scenario by 7 optical particle sensors located throughout the BCU. PSLs were not detected in the donning room at any time nor in the doffing room during the first test scenario where no healthcare worker was present. The main difference detected between the tested scenarios was the presence of PSLs in the doffing room when healthcare workers were removing PPE, potentially due to re-aerosolization of PSLs off the exterior PPE surface or opening of the patient room door. Future work will further explore the potential for re-aerosolization of particles off of PPE during doffing. The present study provides the groundwork for a systematic method for evaluating the BCU and doffing procedures for their respective safety, and it also pilots a systematic method for evaluating potential pathogen exposure pathways for BCU healthcare workers.

A novel personal protective equipment coverall was rated higher than standard Ebola virus personal protective equipment in terms of comfort, mobility and perception of safety when tested by health care workers in Liberia and in a United States biocontainment unit

“…This could provide safety data to better understand the potential advantages of PPE B compared with PPE A. 14 PPE A was tested first at both sites. The lack of randomization of PPE order in the study protocol may have introduced unintended biases toward one of the PPE ensembles.…”

Impact of air‐handling system exhaust failure on dissemination pattern of simulant pathogen particles in a clinical biocontainment unit

“…Therefore, the potential for HCW exposure to airborne pathogens is of concern in the doffing room due to multiple potential scenarios for this contamination. Thus far, between the present study and Drewry et al, these identified scenarios include HVAC exhaust failure, re‐aerosolization of particles deposited on the outside of HCW's PPE during doffing, and/or particle transport from the patient room after opening the door between the two spaces.…”

“…Drewry et al also noted the presence of simulant pathogen particles in the JH‐BCU doffing room following simulated patient care and doffing procedures. The key difference between the present study and the study of Drewry et al is that there were no HCWs in the present study; that is, particle dissemination was observed as a result of airflow patterns alone while manipulating HVAC condition. Therefore, the potential for HCW exposure to airborne pathogens is of concern in the doffing room due to multiple potential scenarios for this contamination.…”

“…Recently, Drewry et al presented a study to investigate the potential for healthcare worker (HCW) exposure to simulant airborne pathogens while working in the JH‐BCU. The goal was to develop a safe and effective method that could be used by BCUs to evaluate potential failure points of PPE to reduce the risk of exposure to infectious particles.…”

The role of dedicated biocontainment patient care units in preparing for COVID-19 and other infectious disease outbreaks

“…15 Of particular relevance to the current COVID-19 pandemic, the BCU team, in collaboration with the JH Applied Physics Lab, used a novel fluorescent microbead system to simulate the movement of infectious particles through a biocontainment environment and to assess the impact of environmental control systems and patient care protocols on the movement of these infectious simulants. 16,17 In partnership with HEIC, the BCU team combined these infectious simulants with more traditional methods to enhance the detection of selfcontamination during the doffing process, and to validate the use of a trained observer in the doffing process for viral hemorrhagic fevers. 18,19 The BCU team partnered with the JH Berman Bioethics Institute to explore the ethical, legal, and social implications of genomic research on containment care.…”