title: Assessment of operating room airflow using air particle counts and direct observation of door openings.
abstract: BACKGROUND
  The role of the operating room (OR) environment has been thought to contribute to surgical site infection rates. The quality of OR air, disruption of airflow, and other factors may increase contamination risks. We measured air particulate counts (APCs) to determine if they increased in relation to traffic, door opening, and other common activities.
  
  
  METHODS
  During 1 week, we recorded APCs in 5-minute intervals and movement of health care workers. Trained observers recorded information about traffic, door openings, job title of the opener, and the reason for opening.
  
  
  RESULTS
  At least 1 OR door was open during 47% of all readings. There were 13.4 door openings per hour during cases. Door opening rates ranged from 0.19-0.28 per minute. During this time, a total of 660 air measurements were obtained. The mean APCs were 9,238 particles (95% confidence interval [CI], 5,494- 12,982) at baseline and 14,292 particles (95% CI, 12,382-16,201) during surgery. Overall APCs increased 13% when either door was opened (P < .15). Larger particles that correlated to bacterial size were elevated significantly (P < .001) on door opening.
  
  
  CONCLUSIONS
  We observed numerous instances of verbal communication and equipment movement. Improving efficiency of communication and equipment can aid in reduction of traffic. Further study is needed to examine links between microbiologic sampling, outcome data, and particulate matter to enable study of risk factors and effects of personnel movement.
authors.affiliation: Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Teter
authors.affiliation: Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Isabella
authors.initials: I
authors.lastname: Guajardo
authors.affiliation: Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Tamrah
authors.initials: T
authors.lastname: Al-Rammah
authors.affiliation: Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Gedge
authors.initials: G
authors.lastname: Rosson
authors.affiliation: Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD; Department of Epidemiology, Johns Hopkins University, School of Public Health, Baltimore, MD.
authors.forename: Trish M
authors.initials: TM
authors.lastname: Perl
authors.affiliation: Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD. Electronic address: mmanahan@jhmi.edu.
authors.forename: Michele
authors.initials: M
authors.lastname: Manahan
mesh_terms: D000391:Air Microbiology; D000392:Air Movements; D006801:Humans; D019370:Observation; D009873:Operating Rooms; D052638:Particulate Matter
chemical_list: D052638:Particulate Matter
keywords: Air quality; Infection control; Operating room; Particulate matter; Surgery; Surgical site infection