Assessing the Utility of Outlet Filters in the Ventilators of ICU Patients OC16-OC21
Dr. Aditya Lal Vallath,
Intern, Bharati Vidyapeeth Medical College, Bharati Hospital and Research Centre, Pune-411043, Maharastra, India.
Introduction: Intensive Care Units (ICU) host a large percentage of all nosocomial infections in any hospital. The air quality in such an environment plays a pivotal role in the dissemination of such infections. Ventilated patients expel aerosols containing nosocomial infectious agents from the ventilator.
Aim: To assess the value of placing a Heat and Moisture Exchanger (HME) filter at the outlet of ventilators to reduce the Total Viable Count (TVC) in the air and improve air quality.
Materials and Methods: The study was conducted in two phases, of which Phase I was conducted without a filter and Phase II was conducted after placing HME filters in the outlet of the ventilators; while sampling locations remained the same. In both phases, active and passive sampling was done on a total of 120 samples which included 60 samples from each phase. The index of microbiological air contamination (passive sampling) and surface air sample TVC (active sampling) were calculated to assess the level of microbiological contamination.
Results: The mean results of passive sampling were 1547.41 CFU/dm2/hour in phase I and 761.49 CFU/dm2/hour in phase II. In active sampling, the mean results were 88.48 CFU/m3 in Phase I and 51.71 CFU/m3 in Phase II.
Conclusion: The placement of HME filters at the outlet of ventilators has significantly reduced TVC counts in both active and passive sampling in Phase II using the filters as compared to Phase I. Other measures should be undertaken to further reduce TVC counts to accepted safety standards.