Predictability of the respiratory variation of stroke volume varies according to the definition of fluid responsiveness.

1 Boly CA, Reesink KD, van den Tol MP, et al. Minimally invasive intraoperative estimation of left-ventricular end-systolic elastance with phenylephrine as loading intervention. Br J Anaesth 2013; 111: 750–8 2 Westerhof N, Stergiopulos N, Noble MIM. Snapshots of Hemodynamics. New York, Dordrecht, Heidelberg, London: Springer, 2010 3 van Geldorp IE, Delhaas T, Hermans B, et al. Comparison of a noninvasive arterial pulse contour technique and echo Doppler aorta velocity–time integral on stroke volume changes in optimization of cardiac resynchronization therapy. Europace 2011; 13: 87–95 4 Burkhoff D, Mirsky I, Suga H. Assessment of systolic and diastolic ventricular properties via pressure–volume analysis: a guide for clinical, translational, and basic researchers. Am J Physiol Heart Circ Physiol 2005; 289: H501–12 5 Senzaki H, Chen C. Single-beat estimation of end-systolic pressure– volume relation in humans: a new method with the potential for noninvasive application. Circulation 1996; 94: 2497–506 6 Chen CH, Fetics B, Nevo E, et al. Noninvasive single-beat determination of left ventricular end-systolic elastance in humans. J Am Col Cardiol 2001; 38: 2028–34 7 Guarracino F, Cariello C, Danella A, et al. Effect of levosimendan on ventriculo-arterial coupling in patients with ischemic cardiomyopathy. Acta Anaesthesiol Scand 2007; 51: 1217–24 8 Kjørstad KE, Korvald C, Myrmel T. Pressure–volume-based singlebeat estimations cannot predict left ventricular contractility in vivo. Am J Physiol Heart Circ Physiol 2002; 282: H1739–50