Effectiveness of Air Purifiers in Intensive Care Units :
an intervention study

IAQS wants to highlight this interesting interventional study evaluating the indoor microbial load inside the ICUs and in the immediate surrounding of ICU patients, and to evaluate how effective the air purifiers installed in the ICUs are in filtering microbial load and preventing ICU infections. The authors reported a significant positive correlation between the number of colonies detected and the rate of hospital-acquired infections (HAI) in both ICUs. They found that the micro-organism concentration detected in the intervention ICU was lower than that in the control ICU. The authors concluded that using air purifiers in addition to the hospital HVAC system may be an effective way to reduce the microbial load in the air and on surfaces to reduce HAIs.

Full reference of article: Effectiveness of air purifiers in intensive care units: an intervention study Journal of Hospital Infection 2022; 120:14-22

The article in bullet points : what you need to know

  • When ICU patients are infected with micro-organisms resistant to antimicrobials, their hospital stay may be prolonged and their treatment costs may be increased, eventually causing higher morbidity and mortality rates.
  • Immediate preventive measures to minimize the entry and spread of micro-organisms in hospital settings should be the first step in the fight against these infections.
  • Two general-type ICUs with similar bed capacities, patient requirements, room areas and hospital-acquired infection rates (based on previous year) were selected for the study. These ICUs shared a central HEPA filtration system. The facilities were maintained through routine cleaning procedures.
  • Microbiological samples were collected from indoor ICU air and the immediate surroundings of ICU patients in the intervention and control ICUs. All samples were collected when the staff were least active in their regular functions
  • Hospital-acquired infection diagnoses were made based on European Centres for Disease Control and Prevention criteria 
  • The majority of the organisms isolated were found to be resistant to many of the antibiotics and these pathogens were causing HAIs according to the infection control surveillance data Over the total study period, regardless of sampling days, in Phase 1, CFUs in the air and on surfaces were found to be higher in the control ICU than in the intervention ICU.
  • There was a significant positive correlation between the rate of hospital-acquired infections and the incidence density rate of hospital-acquired infections (Figure 3).
  • There was a significant positive correlation between the number of colonies detected and the rate of hospital-acquired infections.
  • In conclusion, the micro-organism concentration decreased more rapidly during the first week when the air purifiers were installed in the ICUs. 

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