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Abstract
The process of cardiopulmonary bypass [CPB] is essential for many cardiac procedures. A major risk of cardiac surgery is the risk of postoperative infection, specifically surgical site infections [SSI], which lead to increased patient morbidity and mortality, increased length of hospital stay, and increased cost of surgical procedures. In order to prevent SSI and hospital-acquired infection [HAI], sterile technique is used throughout the processes of assembling, priming, and storing circuits used for CPB. Safe CPB circuit storage is a multi-faceted process, and it is the responsibility of the perfusionist to ensure that these processes have been carried out in sterile fashion.
The purpose of this study had three aims, and took place at Aurora St. Luke’s Medical Center in Milwaukee, Wisconsin. The first aim was to analyze potential contaminants in a primed circuit from the initial time of priming until seven days of standby. The second aim was to analyze potential contaminants on a sterile gown, which was used and re-used to cover stored CPB circuits for seven days. Additionally, potential contaminants were enumerated from an uncovered CPB circuit at the time of assembly and after 24 hours. The final aim was to assess circuit vulnerability to contaminants by determining the air quality in both the perfusion room and operating room [OR]. All contaminants were measured by counting colony forming units [CFU] on tryptic soy agar [TSA], and appropriate statistical analysis was performed on the data.
Results illustrated that the CPB circuit on standby for seven days was free of microbiological contaminants. All sampling points resulted in 0 CFU, indicating that the circuit was safe for use in terms of sterility. The sterile gown was free of contaminants at the first sampling point, but after 24 hours tested for significant levels of contamination [20.4 ± 2.97 CFU/100 µL, p less than 0.001]. However, data from an uncovered CPB circuit were not significant after 24 hours. Finally, environmental sampling indicates that time was a significant factor in the number of CFU in the perfusion room [p=0.006], but not in the operating room [p=0.44]. Additionally, in the perfusion room, CFU increased from 1.3 ± 0.52 to 4.2 ± 4.2 at the 15-minute and 30-minute sampling points. This study not only demonstrates that an open CPB circuit is safe for use after seven days on standby, but the study also addresses concerns pertaining to CPB circuit storage. For storage of CPB circuits, a new, sterile cover should be used immediately after assembly. Furthermore, any open medical device should not be used after 15 minutes of exposure to the perfusion room environment.