title: Use of heat and moisture exchanging (HME) filters in mechanically ventilated ICU patients: influence on airway flow-resistance.
abstract: OBJECTIVE
  To investigate the flow-resistance of a new generation of Heat Moisture Exchanging Filters (HME filters) during 24 h of clinical use.
  
  
  METHODS
  Before-after trial.
  
  
  METHODS
  A general Intensive Care Unit of a university hospital.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Surgery, Anaesthesiology and Intensive Care, University of Pavia, Varese, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Chiaranda
authors.forename: L
authors.initials: L
authors.lastname: Verona
authors.forename: O
authors.initials: O
authors.lastname: Pinamonti
authors.forename: L
authors.initials: L
authors.lastname: Dominioni
authors.forename: G
authors.initials: G
authors.lastname: Minoja
authors.forename: G
authors.initials: G
authors.lastname: Conti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000403:Airway Resistance / Q000502:physiology; D003422:Critical Care; D005260:Female; D005374:Filtration / Q000295:instrumentation*; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D008297:Male; D008875:Middle Aged; D012121:Respiration, Artificial / Q000295:instrumentation*; D012131:Respiratory Insufficiency / Q000209:etiology / Q000503:physiopathology* / Q000628:therapy*