Fig. 1
From: Pearls and pitfalls in comprehensive critical care echocardiography
Accurate stroke volume (SV) estimation: SV = LVOTarea × LVOTVTI. a Accurate SV assessment = [0.785 × 2.1 cm2] × 27.2 cm = 94 ml. LVOTarea estimation: use of zoomed in parasternal long-axis view of the aortic valve with LVOT diameter measured at mid-systole at the site of aortic valve cusp entry along with accurate Doppler settings for LVOT VTI assessment using high sweep speed, low wall filters and reduced gain for modal velocity estimation (brightest portion of spectral tracing) as well as seeing the aortic valve closing click. b Inaccurate SV assessment = [0.785 × 2.4 cm2] × 32.7 cm = 148 ml. Potential pitfalls leading to inaccurate SV estimation include mistakes in 2D image acquisition as well as Doppler pitfalls: estimating LVOTarea from non-zoomed aortic valve analysis, foreshortened or oblique plane of LVOT interrogation in 2D mode and LVOT spectral Doppler VTI assessment with the sample volume in a wrong position or being too large, with too high gain or too high wall filter settings, low sweep speed and baseline inappropriately low. Note overestimation or underestimation of SV assessment with inappropriate measures