title: Determination of preload-recruitable stroke work and elastance by the relationship of arterial blood flow velocity to left ventricular area.
abstract: OBJECTIVE
  The authors investigated the feasibility of an online sampling and display of LV flow-area loops for the determination of LV elastance and preload-recruitable stroke work (PRSW). Automated LV area measurements by echocardiography may be combined with flow velocity measurements in the internal carotid artery to construct LV flow-area loops as estimates of the systolic pressure-volume relationship.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Open chest model.
  
  
  METHODS
  Eight anesthetized minipigs.
  
  
  METHODS
  Inferior vena cava occlusion was performed to simultaneously obtain parameters of the LV flow-area relationship and the LV pressure-area relationship.
  
  
  RESULTS
  Parameters were obtained at baseline and during sequential administration of dobutamine (5 microg/kg/min) and halothane (0.8 vol%). Linear regression analysis and analysis of variance were performed to investigate an underlying linear relationship between the corresponding variables. Highly linear elastance and PRSW curves were derived from the flow-area and pressure-area loops (n = 24, R >/= 0.85). Changes of the curve slopes indicated inotropic changes as well as model independent dP/dt(max). Elastance from the pressure-area relationship was expressed by elastance from the flow-area relationship by the term y = 0.52 + 0.04. x (R(2) = 0.84; p < 0.0001). Linear regression of PRSW as derived from the flow-area relationship with PRSW as derived from the pressure-area relationship was expressed by y = 0.43 + 0.02. x (R(2) = 0.77; p < 0.0001).
  
  
  CONCLUSIONS
  Indices of the LV pressure-area relationship can be derived from real-time loops constructed from arterial flow velocity and LV area.
authors.affiliation: Department of Anesthesiology, University of Wuerzburg, Josef-Schneider-Strasse 2, D-97080 Wuerzburg, Germany. jbroscheit@anaesthesie.uniwuerzburg.de
authors.forename: Jens A
authors.initials: JA
authors.lastname: Broscheit
authors.forename: Clemens A
authors.initials: CA
authors.lastname: Greim
authors.forename: Manuel
authors.initials: M
authors.lastname: Kessler
authors.forename: Frank
authors.initials: F
authors.lastname: Weidemann
authors.forename: Norbert
authors.initials: N
authors.lastname: Roewer
mesh_terms: D018685:Anesthetics, Inhalation / Q000494:pharmacology; D000818:Animals; D001783:Blood Flow Velocity; D002316:Cardiotonic Agents / Q000494:pharmacology; D002343:Carotid Artery, Internal; D004280:Dobutamine / Q000494:pharmacology; D015150:Echocardiography, Doppler; D004548:Elasticity; D004562:Electrocardiography; D006221:Halothane / Q000494:pharmacology; D009200:Myocardial Contraction / Q000187:drug effects; D013318:Stroke Volume; D013552:Swine; D013556:Swine, Miniature; D018608:Ultrasonography, Doppler; D016277:Ventricular Function, Left; D017725:Ventricular Pressure
chemical_list: D018685:Anesthetics, Inhalation; D002316:Cardiotonic Agents; D004280:Dobutamine; D006221:Halothane