title: Experimental validation of frequently-used echocardiographic right-ventricular impedance parameters.
abstract: BACKGROUND
  Aim of the study was to validate commonly used bedside right-ventricular (RV) impedance parameters, which are utilized in determining heart-lung interactions during mechanical ventilation.
  
  
  METHODS
  Fifteen pigs were equally assigned to either an open or a closed pericardium group. In all animals, an inflatable vascular occluder and a flow probe were placed around the main pulmonary artery, which allowed for a gradual increase in pulmonary vascular impedance with banding of the pulmonary artery. A median sternotomy was performed for the open pericardium group, and a lateral thoracotomy was performed for the closed pericardium group.
  
  
  RESULTS
  In the open pericardium group, mean acceleration time (ACmean) and the slope of the pulmonary artery flow correlated significantly with Poiseuille resistance over the banding (r=0.67 and r=0.65, respectively). In the closed pericardium group, the ratio of the right to left ventricular area, eccentricity index, and tricuspid annular plane systolic excursion did not correlate with resistance over the banding, only the ACmean showed a significant correlation with resistance over the banding (r=0.88).
  
  
  CONCLUSIONS
  ACmean is a reliable parameter of RV impedance that can be used to study the heart-lung interactions during mechanical ventilation.
authors.affiliation: Department of Intensive Care, Erasmus Medical Centre, Rotterdam, The Netherlands - d.dosreismiranda@erasmusmc.nl.
authors.forename: D
authors.initials: D
authors.lastname: Reis Miranda
authors.forename: A H
authors.initials: AH
authors.lastname: Marco Knook
authors.forename: F
authors.initials: F
authors.lastname: Paalvast
authors.forename: A
authors.initials: A
authors.lastname: Rossi
authors.forename: W
authors.initials: W
authors.lastname: Hop
authors.forename: F
authors.initials: F
authors.lastname: Oei
authors.forename: J
authors.initials: J
authors.lastname: Van Bommel
authors.forename: D
authors.initials: D
authors.lastname: Gommers
mesh_terms: D000818:Animals; D004452:Echocardiography / Q000592:standards*; D011651:Pulmonary Artery / Q000503:physiopathology; D034421:Sus scrofa; D013552:Swine; D014655:Vascular Resistance; D018497:Ventricular Dysfunction, Right / Q000503:physiopathology; D016278:Ventricular Function, Right