Background and Goal of Study: Fluid management strategies have shown to improve postoperative outcomes in major surgery1. French guidelines recommend to titrate intraoperative volume expansion (VE) by measuring stroke volume index (SVI)2. We compared a new non-invasive pulse contour device using photoplethysmography (ClearSight) with a minimally invasive one (Pulsioflex) to measure SVI and its changes after VE during major surgery 
Materials and Methods: Adult patients undergoing elective major surgery requiring continuous invasive arterial pressure with monitoring of cardiac output were included. Cardiac index (CI), SVI, SVI variation, blood pressure (BP) and VE-induced changes in SVI were measured. SVI measured by Pulsioflex after auto-calibration was used as the reference. Absolute accuracy was assessed with Bland-Altman plots. Agreement between Pulsioflex and ClearSight to track changes of SVI after VE was assessed with Cohen’s kappa coefficient. 
Results and Discussion: After informed consent, thirty patients were included in the study with 6 087 pairs of measures analyzed and 62 VE. Bias and limits of agreements for SVI were 0.02 ± 19.8 mL for ClearSight compared to Pulsioflex (Figure). Considering the response of VE, the coefficient of agreement between the two devices was strong (κ = 0.81, p< 0.05). In responder patients (10-percent increase for SV), VE induced a similar increase in SV between Clearsight and Pulsioflex (7±4 mLvs 9±4 mL, p< 0.05) (Table). 
Conclusion(s): In comparison with Pulsioflex, ClearSight, a non-invasive pulse contour device, was reliable for tracking VE-induced changes in SVI during major surgery. 
References:
1Corcoran T. et al., Anesth Analg 2012
2Vallet B. et al. Ann Fr Anesth Reanim 2013
Acknowledgements:This study was funded by the University Hospital of Poitiers

Comparison of non-invasive (ClearSight®) and invasive (Pulsioflex®) pulse contour analysis to measure stroke volume during major surgery