Heat and moisture exchanger: protection against lung infections? Pilot study

The aim of this study was to conduct a bacteriological research comparing the aqueous heated humidification systems (HH) and filter heat and moisture exchanger (FHME) and to bacterial colonization and the incidence of respiratory infection in patients undergoing mechanical ventilation. It is a prospective, controlled trial, in that 15 intensive care unit (ICU) patients were divided into two groups. The first made use of HH (n=7) and the other, FHME (n=8). We collected samples of tracheal secretions, and condensate circuit FHME at admission in the fourth and eighth day and bacteriological analysis of the same place. Regarding the anthropometric characteristics, no differences were observed between the groups. The prevalence of ventilator associated pneumonia (VAP) was 57.1% in the HH and 62.5% in FHME. When performing quantitative bacteriological analysis between the group and HH and FHME, differences were not observed, suggesting no variation in the prevention of VAP between the humidification systems, but the presence of these bacteria in the tracheal and condensate and in the absence of these membrane FHME may indicate that the main source of contamination is the patient himself.

respiration, artificial; humidity; ventilators, mechanical; pneumonia, ventilator-associated; respiratory protective devices