Potential Risk for Bacterial Contamination in Ventilator Systems
Condition: Contaminated Medical or Biological Substances; Environmental-Pollution-Related Condition
Study type: Observational [Patient Registry]

Summary: 
      Background: Few studies have investigated the difference of bacterial contamination between
      conventional reused ventilator systems and disposable closed ventilator-suction systems. The
      aim of this study was to investigate the bacterial contamination rates of the reused and
      disposable ventilation systems, and the association between system disconnection and
      bacterial contamination of ventilator systems.

      Methods: The enrolled patients used a conventional reused ventilator system and a disposable
      closed ventilator-suction system, respectively, for a week; specimens were then collected
      from the ventilators' internal system to evaluate human and environmental bacterial
      contamination. The sputum specimens from patients were also analyzed in this study.

      Results: The detection rate of bacteria in the conventional reused ventilator system was
      substantially higher than that in the disposable system. The inspiratory and expiratory limbs
      of disposable closed ventilator-suction system had higher bacterial concentrations than the
      conventional reused ventilator system. The bacterial concentration in the heated humidifier
      (HH) of the reused system was significantly higher than that in the disposable system.
      Positive associations existed among the bacterial concentrations at different locations in
      the reused and disposable ventilator systems, respectively. The predominant bacteria
      identified in the reused and disposable ventilator systems included Acinetobacter spp.,
      Bacillus cereus, Elizabethkingia spp., Pseudomonas spp., and Stenotrophomonas (Xan)
      maltophilia.

      Conclusion: Both the reused and disposable ventilation systems had high bacterial
      contamination rates after one week of use. Disconnection of the ventilator systems should be
      avoided during system operation for decreasing the risks of environmental pollution and human
      exposure, especially for the disposable system.
    

Detailed description: 
      The intubated and mechanically ventilated patients were enrolled from the Intensive Care Unit
      of Chang Gung Memorial Hospital, Taiwan. The experimental study group was assigned to a
      disposable ventilator system combined with an auto-filled heated humidifier (HH), a closed
      suction catheter, and a closed aerosol therapy procedure with a valved T-adaptor. According
      to clinical commonly used system, the control study group was assigned to use with
      conventional reused ventilator system, combined with a manually filled HH, an open suction
      catheter, and a conventional aerosol therapy procedure. Every patient was use above both
      ventilator systems.
    

Intervention name(s): Disposable ventilator system; Conventional reused ventilator system
Intervention type(s): Device; Device
Observational model: Other
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        A total of 16 patients (10 men and 6 women, aged between 20 and 91 years) were included for
        the final analysis. Patients had been on a mechanical ventilator for 17-46 days, and had a
        primary diagnosis of sepsis, septic shock, cardiac arrest, pneumonia (CAP or HAP), chronic
        obstructive pulmonary disease, respiratory failure, acute respiratory distress syndrome, or
        lung contusion.
      
Keywords: Nosocomial infection; Ventilator system; Closed suction system; Open suction system; Bacterial contamination