title: Use of an inspiratory impedance threshold device on a facemask and endotracheal tube to reduce intrathoracic pressures during the decompression phase of active compression-decompression cardiopulmonary resuscitation.
abstract: BACKGROUND
  Use of an inspiratory impedance threshold device (ITD) significantly increases coronary perfusion pressures and survival in patients ventilated with an endotracheal tube (ETT) during active compression-decompression cardiopulmonary resuscitation. We tested the hypothesis that the ITD could lower intratracheal pressures when attached to either a facemask or ETT.
  
  
  METHODS
  An active and sham ITD were randomly applied first to a facemask and then to an ETT during active compression-decompression cardiopulmonary resuscitation in 13 out-of-hospital cardiac arrest patients in a randomized, double-blinded, prospective clinical trial. The compression-to-bag-valve ventilation ratio was 15:2. Airway pressures (surrogate for intrathoracic pressure) were measured with a pressure transducer. A sham and an active ITD were used for 1 min each in a randomized order, first on a facemask and then on an ETT. Statistical analyses were made using Friedman's and Wilcoxon's rank-sum tests.
  
  
  RESULTS
  For the primary end point, mean +/- sd maximum negative intrathoracic pressures (mm Hg) during the decompression phase of cardiopulmonary resuscitation were -1.0 +/- 0.73 mm Hg with a sham vs. -4.6 +/- 3.7 mm Hg with an active ITD on the facemask (p = .003) and -1.3 +/- 1.3 mm Hg with a sham ITD vs. -7.3 +/- 4.5 mm Hg with an active ITD on an ETT (p = .0009). Decompression phase airway pressures with the facemask and ETT were not statistically different.
  
  
  CONCLUSIONS
  Use of an active ITD attached to a facemask or an ETT resulted in a significantly lower negative intratracheal pressure during the decompression phase of active compression-decompression cardiopulmonary resuscitation when compared with controls. Airway pressures with an ITD on either a facemask or ETT were similar. The ITD-facemask combination was practical and enables rapid deployment of this life-saving technology.
authors.affiliation: Department of Anesthesiology and Critical Care, Lariboisière University Hospital, Paris, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Plaisance
authors.forename: Christian
authors.initials: C
authors.lastname: Soleil
authors.forename: Keith G
authors.initials: KG
authors.lastname: Lurie
authors.forename: Eric
authors.initials: E
authors.lastname: Vicaut
authors.forename: Laurent
authors.initials: L
authors.lastname: Ducros
authors.forename: Didier
authors.initials: D
authors.lastname: Payen
mesh_terms: D002307:Cardiography, Impedance; D016887:Cardiopulmonary Resuscitation / Q000295:instrumentation* / Q000379:methods; D004632:Emergency Medical Services; D005260:Female; D006323:Heart Arrest / Q000628:therapy*; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D008397:Masks; D008875:Middle Aged