title: Observer variability in serial noninvasive measurements of stroke index using pulsed Doppler flowmetry.
mesh_terms: D001011:Aorta; D001783:Blood Flow Velocity; D002302:Cardiac Output; D004452:Echocardiography / Q000379:methods*; D006801:Humans; D012212:Rheology; D013318:Stroke Volume; D014463:Ultrasonography