Long-term mechanical ventilation with hygroscopic heat and moisture exchangers used for 48 hours: a prospective clinical, hygrometric, and bacteriologic study

Crit Care Med. 2003 Mar;31(3):823-9. doi: 10.1097/01.CCM.0000055382.87129.DD.


Objective: To determine whether use of a hygroscopic heat and moisture exchanger (HME) for 48 hrs without change affects its efficiency and the level of bacterial colonization in long-term mechanically ventilated medical intensive care unit patients.

Design: Prospective, randomized clinical study evaluating two hygroscopic HMEs.

Setting: Medical intensive care unit at a university teaching hospital.

Patients: Long-term mechanically ventilated medical intensive care unit patients, including chronic obstructive pulmonary disease patients.

Interventions: Patients were randomly allocated to one of the two HMEs studied (Hygrolife and EdithFlex) and changed every 48 hrs. Devices in both groups could be changed if hygrometric measurements indicated insufficient humidity delivery.

Measurements and main results: Daily measurements of inspired gas temperature and relative and absolute humidity. In addition, cultures of tracheal aspirations and both patient and ventilator sides of the device were performed after 48 hrs of use. Ventilatory variables and clinical indicators of efficient humidification were also recorded. Prolonged use of both HMEs was safe and efficient (no tracheal tube occlusion occurred). Mean duration of mechanical ventilation was 20 days. Both clinical indicators and hygrometric measurements showed that both devices performed well during 48 hrs. Absolute humidity with EdithFlex was significantly higher on day 0 and day 1 than with Hygrolife. Absolute humidity measured in chronic obstructive pulmonary disease patients was identical to that measured in the rest of the study population. Tracheal colonization and HME colonization were similar with both HMEs. Bacterial contamination of the ventilator side of both devices was markedly low.

Conclusions: These two purely hygroscopic HMEs provided safe and efficient humidification during a 48-hr period of use in long-term mechanically ventilated medical intensive care unit patients, including chronic obstructive pulmonary disease patients. In addition, they maintained ventilatory circuits clean, despite the absence of filtering media. The cost of mechanical ventilation is consequently reduced.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Colony Count, Microbial
  • Cost Control
  • Disposable Equipment / economics
  • Disposable Equipment / standards
  • Equipment Contamination / statistics & numerical data
  • Equipment Design / standards
  • Female
  • Humans
  • Humidity
  • Infection Control
  • Long-Term Care
  • Male
  • Middle Aged
  • Nebulizers and Vaporizers / economics
  • Nebulizers and Vaporizers / standards*
  • Prospective Studies
  • Pulmonary Disease, Chronic Obstructive / complications
  • Pulmonary Disease, Chronic Obstructive / therapy*
  • Respiration, Artificial / economics
  • Respiration, Artificial / instrumentation*
  • Respiratory Insufficiency / complications
  • Respiratory Insufficiency / therapy*
  • Safety
  • Sputum / microbiology
  • Time Factors
  • Trachea / microbiology
  • Treatment Outcome
  • Wettability