title: Massive aspiration past the tracheal tube cuff caused by closed tracheal suction system.
abstract: BACKGROUND
  Aspiration past the tracheal tube cuff has been recognized to be a risk factor for the development of ventilator-associated pneumonia (VAP). This study investigated the effect of closed tracheal suctioning on aspiration of fluid past the tracheal tube cuff in an in vitro benchtop model.
  
  
  METHODS
  High-volume low pressure tube cuffs of 7.5 mm internal diameter (ID) were placed in a 22 mm ID artificial trachea connected to a test lung. Positive pressure ventilation (PPV) with 15 cm H₂O peak inspiratory pressure and 5 cm H₂O positive end-expiratory pressure (PEEP) was used. A closed tracheal suction system (CTSS) catheter (size 14Fr) was attached to the tracheal tube and suction was performed for 5, 10, 15, or 20 seconds under 200 or 300 cm H₂O suction pressures. Amount of fluid (mL) aspirated along the tube cuff and the airway pressure changes were recorded for each suction procedure. Fluid aspiration during different suction conditions was compared using Kruskal-Wallis and Mann-Whitney test (Bonferroni correction [α = .01]).
  
  
  RESULTS
  During 10, 15, and 20 seconds suction, airway pressure consistently dropped down to -8 to -13 cm H₂O (P < .001) from the preset level. Fluid aspiration was never observed under PPV + PEEP but occurred always during suctioning. Aspiration along the tube cuff was higher with -300 cm H₂O than with -200 cm H₂O suction pressure (P < .001) and was much more during 15 and 20 seconds suction time as compared to 5 seconds (P < .001).
  
  
  CONCLUSIONS
  Massive aspiration of fluid occurs along the tracheal tube cuff during suction with the closed tracheal suction system.
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Zurich, Switzerland. mital.dave@kispi.uzh.ch
authors.forename: Mital H
authors.initials: MH
authors.lastname: Dave
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Zurich, Switzerland.
authors.forename: Angela
authors.initials: A
authors.lastname: Frotzler
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Zurich, Switzerland.
authors.forename: Caveh
authors.initials: C
authors.lastname: Madjdpour
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Zurich, Switzerland.
authors.forename: Nelly
authors.initials: N
authors.lastname: Koepfer
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Zurich, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Weiss
mesh_terms: D019544:Equipment Failure Analysis; D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D008962:Models, Theoretical; D053717:Pneumonia, Ventilator-Associated / Q000209:etiology / Q000517:prevention & control*; D053120:Respiratory Aspiration / Q000209:etiology / Q000517:prevention & control*; D013396:Suction / Q000295:instrumentation / Q000379:methods