title: Fluid responsiveness prediction using Vigileo FloTrac measured cardiac output changes during passive leg raise test.
abstract: BACKGROUND
  Passive leg raising (PLR) is a so called self-volume challenge used to test for fluid responsiveness. Changes in cardiac output (CO) or stroke volume (SV) measured during PLR are used to predict the need for subsequent fluid loading. This requires a device that can measure CO changes rapidly. The Vigileo™ monitor, using third-generation software, allows continuous CO monitoring. The aim of this study was to compare changes in CO (measured with the Vigileo device) during a PLR manoeuvre to calculate the accuracy for predicting fluid responsiveness.
  
  
  METHODS
  This is a prospective study in a 20-bedded mixed general critical care unit in a large non-university regional referral hospital. Fluid responders were defined as having an increase in CO of greater than 15 % following a fluid challenge. Patients meeting the criteria for circulatory shock with a Vigileo™ monitor (Vigileo™; FloTrac; Edwards™; Lifesciences, Irvine, CA, USA) already in situ, and assessed as requiring volume expansion by the clinical team based on clinical criteria, were included. All patients underwent a PLR manoeuvre followed by a fluid challenge.
  
  
  RESULTS
  Data was collected and analysed on stroke volume variation (SVV) at baseline and CO and SVV changes during the PLR manoeuvre and following a subsequent fluid challenge in 33 patients. The majority had septic shock. Patient characteristics, baseline haemodynamic variables and baseline vasoactive infusion requirements were similar between fluid responders (10 patients) and non-responders (23 patients). Peak increase in CO occurred within 120 s during the PLR in all cases. Using an optimal cut point of 9 % increase in CO during the PLR produced an area under the receiver operating characteristic curve of 0.85 (95 % CI 0.63 to 1.00) with a sensitivity of 80 % (95 % CI 44 to 96 %) and a specificity of 91 % (95 % CI 70 to 98 %).
  
  
  CONCLUSIONS
  CO changes measured by the Vigileo™ monitor using third-generation software during a PLR test predict fluid responsiveness in mixed medical and surgical patients withvasopressor-dependent circulatoryshock.
authors.affiliation: Department of Anaesthesia and Critical Care, Royal Blackburn Hospital, Haslingden Road, Blackburn, UK.
authors.forename: Anton
authors.identifier: 0000-0002-3415-4281
authors.initials: A
authors.lastname: Krige
authors.affiliation: Department of Anaesthesia and Critical Care, Royal Blackburn Hospital, Haslingden Road, Blackburn, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Bland
authors.affiliation: Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Fanshawe
keywords: Cardiac output monitoring; Edwards Vigileo FloTrac monitoring; Fluid responsiveness; Passive leg raising; Septic shock; Vasoplegic shock