title: Experimental contamination of a closed endotracheal suction system: 24 h vs 72 h.
abstract: OBJECTIVE
  To ascertain the desirability of replacing closed suction systems after 72 h rather than after 24 h (manufacturer's recommendations) because it is possible that a reduction in the frequency of manipulations might reduce the risk of exogenous nosocomial pneumonia. We investigated the presence of time-dependent differences (after 24 h and 72 h) in pathogen survival/growth in artificially contaminated closed suction catheters (OptiFlo).
  
  
  METHODS
  The trial simulated bacterial contamination of the airways using a suspension of 2 x 10(3) CFU/ml of Staphylococcus aureus or Pseudomonas aeruginosa. Contamination was performed on a total of 80 catheters. Forty were contaminated a total of eight times every 45-60 min. Another 40 catheters underwent the same procedure 24 times over three consecutive days. Microbiological analysis of the catheters took place after 24 h and 72 h, respectively.
  
  
  RESULTS
  The mean S. aureus load was 9.4 CFU/catheter after eight suction procedures and 6.2 CFU/catheter after 24 suction procedures (3 days). Mean growth of P. aeruginosa was 5.3 CFU/catheter, and 8.2 CFU/catheter after 3 days. There was no statistically significant difference between day 1 and 3 for S. aureus (p = 0.474), but there was for P. aeruginosa (p = 0.004).
  
  
  CONCLUSIONS
  Our findings show that, from an experimental point of view, it remains controversial whether routine change of closed suction catheters can be extended from 24 h to 72 h. However, clinical evidence suggests that prolonged use of a closed suctioning system is safe.
authors.affiliation: Department of Environmental Health Sciences, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Meyer
authors.forename: M
authors.initials: M
authors.lastname: Schuhmacher
authors.forename: W
authors.initials: W
authors.lastname: Ebner
authors.forename: M
authors.initials: M
authors.lastname: Dettenkofer
mesh_terms: D002404:Catheterization; D015169:Colony Count, Microbial; D003428:Cross Infection / Q000517:prevention & control*; D004864:Equipment and Supplies / Q000382:microbiology*; D006801:Humans; D050296:Microbial Viability; D018410:Pneumonia, Bacterial / Q000517:prevention & control*; D011550:Pseudomonas aeruginosa / Q000254:growth & development* / Q000302:isolation & purification; D013211:Staphylococcus aureus / Q000254:growth & development* / Q000302:isolation & purification