title: Non-invasive assessment of fluid responsiveness using CNAP™ technology is interchangeable with invasive arterial measurements during major open abdominal surgery.
abstract: BACKGROUND
  Dynamic variables of fluid responsiveness (FR), such as pulse pressure variation (PPV), have been shown to predict the response to a fluid challenge accurately. A recently introduced non-invasive technology based on the volume-clamp method (CNAP™) offers the ability to measure PPV continuously (PPVCNAP). However, the accuracy regarding the prediction of FR in the operating room has to be proved.
  
  
  METHODS
  We compared PPVCNAPwith an invasive approach measuring PPV using the PiCCO technology (PPVPiCCO). We studied 47 patients undergoing major open abdominal surgery before and after a passive leg-raising manoeuvre and i.v. fluid resuscitation. A positive response to a volume challenge was defined as ≥15% increase in stroke volume index obtained with transpulmonary thermodilution. Bootstrap methodology was used with the grey zone approach to determine the area of inconsistency regarding the ability of PPVPiCCOand PPVCNAPto predict FR.
  
  
  RESULTS
  In response to the passive leg-raising manoeuvre, PPVPiCCOpredicted FR with a sensitivity of 81% and a specificity of 72% [area under the curve (AUC) 0.86] compared with a sensitivity of 76% and a specificity of 72% (AUC 0.78) for PPVCNAPRegarding the volume challenge in the operating room, PPVPiCCOpredicted FR with a sensitivity of 87% and a specificity of 100% (AUC 0.97) compared with a sensitivity of 91% and specificity of 93% (AUC 0.97) for PPVCNAPThe grey zone approach identified a range of PPVPiCCOvalues (11-13%) and PPVCNAPvalues (7-11%) for which FR could not be predicted reliably.
  
  
  CONCLUSIONS
  Non-invasive assessment of FR using PPVCNAPseems to be interchangeable with PPVPiCCOin patients undergoing major open abdominal surgery.
  
  
  BACKGROUND
  NCT02166580.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany jochen.renner@uksh.de.
authors.forename: J
authors.initials: J
authors.lastname: Renner
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Gruenewald
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hill
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Mangelsdorff
authors.affiliation: Department of General and Thoracic Surgery, University Hospital Schleswig-Holstein, Christian-Albrechts-University, Kiel, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Aselmann
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Marienhospital Stuttgart, Stuttgart, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Ilies
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Steinfath
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Broch
mesh_terms: D000005:Abdomen / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D005260:Female; D005440:Fluid Therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
keywords: anaesthesia; arterial pressure; equipment; general; haemodynamics; measurement; pulse pressure