title: Randomized clinical trial of extended use of a hydrophobic condenser humidifier: 1 vs. 7 days.
abstract: OBJECTIVE
  To determine whether extended use (7 days) would affect the efficiency on heat and water preservation of a hydrophobic condenser humidifier as well as the rate of ventilation-acquired pneumonia, compared with 1 day of use.
  
  
  METHODS
  Prospective, controlled, randomized, not blinded, clinical study.
  
  
  METHODS
  Twelve-bed intensive care unit of a university hospital.
  
  
  METHODS
  One hundred and fifty-five consecutive patients undergoing mechanical ventilation for > or = 48 hrs.
  
  
  METHODS
  After randomization, patients were allocated to one of the two following groups: a) heat and moisture exchangers (HMEs) changed every 24 hrs; b) HMEs changed only once a week. Devices in both groups could be changed at the discretion of the staff when signs of occlusion or increased resistance were identified.
  
  
  RESULTS
  Efficient airway humidification and heating were assessed by clinical variables (numbers of tracheal suctionings and instillations required, peak and mean airway pressures). The frequency rates of bronchial colonization and ventilation-acquired pneumonia were evaluated by using clinical and microbiological criteria. Endotracheal tube occlusion, ventilatory support variables, duration of mechanical ventilation, length of intensive care, acquired multiorgan dysfunction, and mortality rates also were recorded. The two groups were similar at the time of randomization. Endotracheal tube occlusion never occurred. In the targeted population (patients ventilated for > or = 7 days), the frequency rate of ventilation-acquired pneumonia was 24% in the HME 1-day group and 17% in the HME 7-day group (p > .05, not significant). Ventilation-acquired pneumonia rates per 1000 ventilatory support days were 16.4/1000 in the HME 1-day group and 12.4/1000 in the HME 7-day group (p > .05, not significant). No statistically significant differences were found between the two groups for duration of mechanical ventilation, intensive care unit length of stay, acquired organ system derangements, and mortality rate. There was indirect evidence of very little, if any, change in HME resistance.
  
  
  CONCLUSIONS
  Changing the studied hydrophobic HME after 7 days did not affect efficiency, increase resistance, or altered bacterial colonization. The frequency rate of ventilation-acquired pneumonia was also unchanged. Use of HMEs for > 24 hrs and up to 7 days is safe.
authors.affiliation: Intensive Care Unit and Trauma Center, Nord Hospital, Marseilles University Hospital System, Marseilles School of Medicine, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Thomachot
authors.forename: Marc
authors.initials: M
authors.lastname: Leone
authors.forename: Karim
authors.initials: K
authors.lastname: Razzouk
authors.forename: François
authors.initials: F
authors.lastname: Antonini
authors.forename: Renaud
authors.initials: R
authors.lastname: Vialet
authors.forename: Claude
authors.initials: C
authors.lastname: Martin
mesh_terms: D004867:Equipment Design; D005260:Female; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D007442:Intubation, Intratracheal; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000209:etiology; D011446:Prospective Studies; D013997:Time Factors; D012122:Ventilators, Mechanical