Third-generation FloTrac/Vigileo does not reliably track changes in cardiac output induced by norepinephrine in critically ill patients

Abstract

Background: The ability of the third-generation FloTrac/Vigileo software to track changes in cardiac index (CI) induced by volume expansion and norepinephrine in critically ill patients is unknown. Methods: In subjects with circulatory failure, we administered volume expansion (20 subjects) and increased (20 subjects) or decreased (20 subjects) the dose of norepinephrine. We measured arterial pressure waveform-derived CI provided by the third-generation FloTrac/Vigileo device (CIpw) and transpulmonary thermodilution CI (CItd) before and after therapeutic interventions. Results: Considering the pairs of measurements performed before and after all therapeutic interventions (n=60), a bias between the absolute values of CI pw and CItd was 0.26 (0.94) litre min-1 m -2 and the percentage error was 54. Changes in CIpw tracked changes in CItd induced by volume expansion with moderate accuracy [n=20, bias=-0.-11 (0.54) litre min-1 m-2, r 2=0.26, P=0.02]. When changes in CItd were induced by norepinephrine (n=40), a bias between CIpw and CItd was 0.01 (0.41) litre min-1 m-2 (r2=0.11, P=0.04). The concordance rates between changes in CIpw and CItd induced by volume expansion and norepinephrine were 73% and 60%, respectively. The bias between changes in CIpw and CItd significantly correlated with changes in total systemic vascular resistance (r 2=0.41, P<0.0001). Conclusions: The third-generation FloTrac/Vigileo device was moderately reliable for tracking changes in CI induced by volume expansion and poorly reliable for tracking changes in CI induced by norepinephrine. © 2012 The Author. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved.