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This article is part of the supplement: 33rd International Symposium on Intensive Care and Emergency Medicine

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Looking for the inflexion point of the Frank-Starling curve

HD Aya*, M Geisen, C Ebm, N Fletcher, M Grounds, A Rhodes and M Cecconi

  • * Corresponding author: HD Aya

Author Affiliations

St George's Healthcare NHS Trust, London, UK

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Critical Care 2013, 17(Suppl 2):P206  doi:10.1186/cc12144

The electronic version of this article is the complete one and can be found online at:

Published:19 March 2013

© 2013 Aya et al.; licensee BioMed Central Ltd.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Fluid responsiveness is defined based on an arbitrary increase of cardiac output (CO) or stroke volume (SV) of 10 to 15%. We hypothesise that the variation of heart efficiency (Eh) and the slope (S) defined by the relative increase of CO over the relative increase of mean filling pressure (Pmsa) can be used as alternative definitions of fluid responsiveness.


Patients admitted to the ICU were monitored with a calibrated LiDCOplus (LiDCO, UK) and Navigator (Applied Physiology, Australia) to estimate Pmsa and Eh (Pmsa -central venous pressure/Pmsa). A 250 ml fluid challenge was performed over 5 minutes. Categorical data were compared by Pearson chi-square test. Correlation was assessed by Kappa test. The inflexion point of S to define responders was obtained by ROC curve analysis.


A total of 104 fluid challenges were observed in 40 patients. ROC curve analysis reveals an area under the curve of 0.93 (95% CI = 0.85 to 1, P <0.001). The best cutoff or the slope was 0.76 (sensitivity 0.92, specificity 0.93). The proportions of responders identified by the ΔEh (Table 1) and by the slope method (Table 2) are smaller compared with the relative increase of SV method. Significant correlation was found between both methods and the ΔSV (ΔEh κ = 0.54, P <0.001; S κ = 0.55, P <0.001). See Figure 1.

Table 1. Distribution of events according to ΔSV and ΔEh

Table 2. Distribution of events according to ΔSV and the slope (S)


Moderate agreement is observed between new and current definitions of fluid responsiveness.


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