Mechanical Ventilation With or Without 7-day Circuit Changes. A Randomized Controlled Trial

Ann Intern Med. 1995 Aug 1;123(3):168-74. doi: 10.7326/0003-4819-123-3-199508010-00002.


Objective: To determine whether a practice of not routinely changing ventilator circuits in patients who require prolonged mechanical ventilation is associated with an increased incidence of nosocomial pneumonia.

Design: Randomized controlled trial.

Setting: Intensive care units in two university-affiliated teaching hospitals.

Patients: 300 patients admitted to an intensive care unit who required mechanical ventilation for more than 5 days.

Intervention: Patients were randomly assigned to receive either no routine ventilator circuit changes or circuit changes every 7 days.

Measurements: The primary outcome measure was the incidence of ventilator-associated pneumonia. Other outcome measures included duration of mechanical ventilation, length of hospital stay, and hospital mortality.

Results: 147 patients were randomly assigned to receive no routine ventilator circuit changes, and 153 patients were randomly assigned to receive circuit changes every 7 days. The two groups were similar at the time of randomization with regard to demographic characteristics, intensive care unit admission diagnoses, and severity of illness. Ventilator-associated pneumonia was seen in 36 patients (24.5%) receiving no routine changes and in 44 patients (28.8%) receiving changes every 7 days (relative risk, 0.85 [95% CI, 0.55 to 1.17]). No statistically significant differences for hospital mortality, intensive care unit mortality, death during mechanical ventilation, death in patients with ventilator-associated pneumonia, or mortality directly attributed to ventilator-associated pneumonia were found between the two treatment groups (P > or = 0.11). Patients receiving changes every 7 days had 247 circuit changes costing a total of $7410; patients receiving no routine changes had a total of 11 circuit changes costing $330.

Conclusion: The elimination of routine ventilator circuit changes can reduce medical care costs without increasing the incidence of nosocomial pneumonia in patients who require prolonged mechanical ventilation.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Cross Infection / etiology
  • Cross Infection / mortality
  • Cross Infection / prevention & control*
  • Female
  • Hospital Mortality
  • Hospitals, University
  • Humans
  • Incidence
  • Logistic Models
  • Male
  • Middle Aged
  • Odds Ratio
  • Pneumonia / etiology
  • Pneumonia / mortality
  • Pneumonia / prevention & control*
  • Respiration, Artificial / adverse effects
  • Respiration, Artificial / economics
  • Respiration, Artificial / instrumentation*
  • Respiration, Artificial / mortality
  • Time Factors