Quantification of Bacterial Shedding from the Respiratory Tract of Health Care Workers Wearing PAPRs and Other Types of Air-Purifying Respirators on Sterile Conditions in a Simulated Operating Rooms (ORs)

Details

• Personal Author:
  Ajewole SO
• Description:
  The role of powered air-purifying respirators (PAPRs) in healthcare settings during infectious diseases outbreaks or use with highly contagious pathogens (e.g., SARS, HINI, and Ebola, etc.) has attracted much interest based on their many beneficial features. A common practice to minimize airborne contaminant exposure among healthcare workers has been using surgical masks (SMs) or N95 filtering facepiece respirators (FFRs). However, SMs have been shown to offer minimal respiratory protection. N95 filtering facepiece respirators (FFRs) have been shown to provide better protection than SMs; however, they have been found uncomfortable to use for prolonged periods. In current PAPR designs, exhaled air from the wearer is not filtered before release to the environment. This design suggests a potential for biocontamination if used in an operating room sterile field condition. The objective of this research is to evaluate the effect of bacterial shedding from the respiratory tract of healthcare workers wearing PAPRs and half-mask respirators on sterile conditions in operating rooms (ORs). Firstly, a pilot study was conducted in a laboratory setting to determine the appropriate sampling methodology to use in the sterile field setting. Both passive sampling (settle plate method) and active sampling (Andersen cascade impactor sampler and SKC Bio sampler impinger) were evaluated. Settling plates were used for a sampling period of 45 minutes, and both active sampling methods were used for 15 minutes. During sampling, two subjects, each donning an elastomeric half-mask, performed activities such as reading the rainbow passages and rotating around a simulated patient manikin while sampling was being done. The results suggest that active sampling with the use of Andersen N6 single-stage cascade impactor collected more colony-forming units when compared to the settling plates of the SKC Bio sampler. After the pilot study, a randomized, simulated workplace study was conducted to compare the bacterial shedding from respiratory tracts of 9 teams of 2 participants, each wearing six different types of respiratory protection devices (RPD), including an FDA approved surgical mask (SM), and five different NIOSH certified respirators. The NIOSH certified devices were two N95 filtering facepiece respirators (FFR), one with and one without an exhalation valve, an elastomeric half facepiece respirator (EHMR) equipped with an exhalation valve, and two PAPRs, one having an assigned protection factor (APF) of 25 and one with an APF of 1000. Sterile field contamination resulting from the use of the FDA-approved surgical mask was used as a baseline for comparison with the NIOSH-certified devices. Contamination was determined by active biological sampling using ' 'sheep's blood agar plates. Collected samples were incubated, and the resulting bacterial colony-forming units (CFU) were counted. The primary outcome was expressed as concentration, the number of CFU/m3 . Poisson regression analyses were used to evaluate the concentration of CFU/m3 resulting from the use of the surgical mask as compared to the other RPDs. A Bonferroni pairwise comparison was used to estimate the difference between the respirators. The study was conducted between February and March 2021 at the WV Simulation Training & Education for Patient Safety laboratory at Ruby Memorial Hospital, Morgantown, WV. Two identical simulated OR rooms were used. Each had a volume dimension of 13.'5' x 13.'5' x '8' with an air exchange rate (AER) of 25 per hour. 18 participants grouped into nine teams of two completed the study. The data analysis found that the bacterial contamination produced by a pair of subjects wearing the N95 FFR without exhalation valves, the PAPR with APF=25, and the PAPR with APF=1000 was not significantly different than the contamination resulting from wearing the SM. The bacterial contamination resulting from using the N95 FFR with exhalation valve and EHMR with exhalation valve was found to be significantly higher than the bacterial contamination resulting from wearing the SM. [Description provided by NIOSH]
• Subjects:
  Communicable Diseases Health Personnel Occupational Health Personal Protective Equipment Respiratory Protective Devices Safety
• Keywords:
  Active Sampling Author Keywords: Operating Room Bacteria Bacterial Shedding Colony-forming Units Exhaled Particles Health Care Workers Infectious Diseases N95 Filtering Facepiece Respirators Operating Rooms OR PAPR Powered Air-purifying Respirators Powered Air Purifying Respirator Respiratory Protection Sterile Field Contamination Surgical Mask Surgical Masks

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• Publisher:
  West Virginia University
• Document Type:
  Text
• Funding:
  Contract
• Genre:
  Dissertation
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-55
• NIOSHTIC Number:
  nn:20068876
• Citation:
  Morgantown, WV: West Virginia University, 2021 Dec; :1-55
• Federal Fiscal Year:
  2022
• Performing Organization:
  West Virginia University
• Peer Reviewed:
  False
• Source Full Name:
  Quantification of bacterial shedding from the respiratory tract of health care workers wearing PAPRs and other types of air-purifying respirators on sterile conditions in a simulated operating rooms (ORs)
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:724b840038567e6f41058dffa78ab92379f8d40e7564856806ff15ab7c86c273b7ab543e07ecb08c58e5699f3bd877386536da9e6b10ebee04fd01b93a5debc8
• Download URL:
  https://stacks.cdc.gov/view/cdc/207441/cdc_207441_DS1.pdf
• File Type:
  [PDF - 1.80 MB ]