title: The microbiologic effect of gas filtration.
abstract: BACKGROUND
  Air and expansile gases commonly are injected into the eye in both vitreoretinal surgery and anterior segment surgery. Although the halogenated gases are filtered routinely before injection, air often is not prepared in this manner. This study was designed to investigate the effect of filtration on the microbiology of gas mixtures.
  
  
  METHODS
  Two separate studies were conducted, one examining medical grade perfluoropropane gas (C3F8), and the other evaluating air collected from an ophthalmic operating room or emergency room. Aliquots of air or gas were collected through a 0.22-micron filter before and after filtration. The filter discs were cultured for bacterial and fungal organisms.
  
  
  RESULTS
  Of 514 samples collected, none grew either bacterial or fungal organisms. There was no difference with regard to recovered microbes between filtered and unfiltered air or C3F8, nor was there a difference between operating room air and emergency room air. Positive controls using aerosolized microorganisms yielded heavy growth.
  
  
  CONCLUSIONS
  Based on results obtained in this study and available information on the concentration of airborne microbes, the microbiologic effect of gas filtration is of little significance for volumes routinely injected in ophthalmic surgery.
authors.affiliation: Wilmer Ophthalmological Institute, Ocular Microbiology Laboratory, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: T L
authors.initials: TL
authors.lastname: Schneider
authors.forename: A M
authors.initials: AM
authors.lastname: Maguire
authors.forename: T P
authors.initials: TP
authors.lastname: O'Brien
mesh_terms: D000388:Air; D000391:Air Microbiology; D004340:Drug Contamination; D005374:Filtration; D005466:Fluorocarbons; D006801:Humans
chemical_list: D005466:Fluorocarbons; C042852:perflutren