title: Is using an open-reservoir cardiopulmonary bypass circuit after 6 days on standby safe?
abstract: OBJECTIVE
  To investigate the sterility and biocompatibility of a stored open-reservoir cardiopulmonary bypass circuit maintained on standby.
  
  
  METHODS
  A total of four cardiopulmonary bypass circuits were assembled, primed and left to recirculate. One unit was placed in a positive-pressure operating room and the other three were placed in the intensive care unit. The primed solutions, which employed Ringer's acetate, hydroxyethylated starch and hydrate steroid, were sampled after 0, 24, 48, 72, 96, 120 and 144 h in all cardiopulmonary bypass circuits to measure the bacteria count, endotoxin count and chemical substances within the primed solution. Chemical substances were detected by assessing the following: the total organic carbon by the combustion oxidation infrared spectrometry, and molecular weight spread by gel permeation chromatography. The environments were left unattended and were uncovered during the storage period to mimic the clinical scenario.
  
  
  RESULTS
  There were no bacteria in any of the primed solutions, and only very minute concentrations of endotoxins were detected, both in the operating room and in the intensive care unit. The total organic carbon concentration was slightly more concentrated in the 144-h samples when compared with that in the 0-h samples. However, the molecular weight spread of the 0-h sample was identical to that in the 144-h sample.
  
  
  CONCLUSIONS
  With regard to the presence of bacteria and endotoxins, we noted that the hardshell reservoirs in the cardiopulmonary bypass circuit were effectively sealed and not invaded by bacteria. With regard to the presence of chemical substances, we noted that an increase in total organic carbon concentration was caused by bedewing, and that there was no release of chemical substances such as a polymer-coating agent, or other molecular materials in the primed solution.
  
  
  CONCLUSIONS
  There was no contamination or release of chemical substances in 6-day old cardiopulmonary bypass circuits maintained on standby, confirming that they are safe to use in terms of sterility and biocompatibility.
authors.affiliation: Department of Medical Engineering, National Hospital Organization Kure Medical Centre and Chugoku Cancer Centre, Hiroshima, Japan tagayam@kure-nh.go.jp.
authors.forename: Masashi
authors.initials: M
authors.lastname: Tagaya
authors.affiliation: Department of Internal Medicine, National Hospital Organization Kure Medical Centre and Chugoku Cancer Centre, Hiroshima, Japan.
authors.forename: Morihiro
authors.initials: M
authors.lastname: Matsuda
authors.affiliation: Division of Cardiovascular Surgery, National Hospital Organization Kure Medical Centre and Chugoku Cancer Centre, Hiroshima, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ryugo
authors.affiliation: Division of Cardiovascular Surgery, National Hospital Organization Kure Medical Centre and Chugoku Cancer Centre, Hiroshima, Japan.
authors.forename: Taiichi
authors.initials: T
authors.lastname: Takasaki
authors.affiliation: Department of Anesthesiology, Critical Care and Pain Medicine, National Hospital Organization Kure Medical Centre and Chugoku Cancer Centre, Hiroshima, Japan.
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Kurita
authors.affiliation: Department of Medical Engineering, National Hospital Organization Kure Medical Centre and Chugoku Cancer Centre, Hiroshima, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Handa
authors.affiliation: Department of Medical Engineering, National Hospital Organization Kure Medical Centre and Chugoku Cancer Centre, Hiroshima, Japan.
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Hara
mesh_terms: D002315:Cardiopulmonary Bypass / Q000295:instrumentation*; D004867:Equipment Design; D005500:Follow-Up Studies; D006801:Humans; D009873:Operating Rooms; D010107:Oxygenators, Membrane; D013242:Sterilization; D013997:Time Factors
keywords: Cardiopulmonary bypass; Coating; Contamination; Extracorporeal membrane oxygenator; Polymer; Standby