Determination of preload-recruitable stroke work and elastance by the relationship of arterial blood flow velocity to left ventricular area.
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.
Broscheit
Jens A
JA
Department of Anesthesiology, University of Wuerzburg, Josef-Schneider-Strasse 2, D-97080 Wuerzburg, Germany. jbroscheit@anaesthesie.uniwuerzburg.de
Greim
Clemens A
CA
Kessler
Manuel
M
Weidemann
Frank
F
Roewer
Norbert
N
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
D018685:Anesthetics, Inhalation; D002316:Cardiotonic Agents; D004280:Dobutamine; D006221:Halothane