Use of heat and moisture exchanging (HME) filters in mechanically ventilated ICU patients: influence on airway flow-resistance

Intensive Care Med. 1993;19(8):462-6. doi: 10.1007/BF01711088.


Objective: To investigate the flow-resistance of a new generation of Heat Moisture Exchanging Filters (HME filters) during 24 h of clinical use.

Design: Before-after trial.

Setting: A general Intensive Care Unit of a university hospital.

Patients: A consecutive series of 96 patients undergoing mechanical ventilation for respiratory insufficiency of various etiology and severity.

Methods: The characteristics of the secretions collected by tracheal suctioning and the pressure/flow relationship of the HMEs before and after 24 h of clinical use were analyzed.

Results: The resistance of the HMEs when dry was 2 hPa/l.s, and it increased to a maximum of 1 hPa/l.s in 83% of the patients after 24 hours; in four patients with particularly heavy secretions HME resistance was 4-5 hPa/l.s. There were no significant modifications of the secretions within the investigation period, excluding, in particular, an increase in density with consequent tracheal tube obstruction.

Conclusion: The gas conditioning efficiency and design performance of the tested HMEs did not create a significant obstacle to airflow medium term mechanical ventilation; however, these devices should be cautiously used in patients with heavy bronchial secretions.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Airway Resistance / physiology
  • Critical Care
  • Female
  • Filtration / instrumentation*
  • Hot Temperature
  • Humans
  • Humidity
  • Male
  • Middle Aged
  • Respiration, Artificial / instrumentation*
  • Respiratory Insufficiency / etiology
  • Respiratory Insufficiency / physiopathology*
  • Respiratory Insufficiency / therapy*