title: The ability of pulse pressure variations obtained with CNAP™ device to predict fluid responsiveness in the operating room.
abstract: BACKGROUND
  Respiratory-induced pulse pressure variations obtained with an arterial line (ΔPP(ART)) indicate fluid responsiveness in mechanically ventilated patients. The Infinity® CNAP™ SmartPod® (Dräger Medical AG & Co. KG, Lübeck, Germany) provides noninvasive continuous beat-to-beat arterial blood pressure measurements and a near real-time pressure waveform. We hypothesized that respiratory-induced pulse pressure variations obtained with the CNAP system (ΔPP(CNAP)) predict fluid responsiveness as well as ΔPP(ART) predicts fluid responsiveness in mechanically ventilated patients during general anesthesia.
  
  
  METHODS
  Thirty-five patients undergoing vascular surgery were studied after induction of general anesthesia. Stroke volume (SV) measured with the Vigileo™/FloTrac™ (Edwards Lifesciences, Irvine, CA), ΔPP(ART), and ΔPP(CNAP) were recorded before and after intravascular volume expansion (VE) (500 mL of 6% hydroxyethyl starch 130/0.4). Subjects were defined as responders if SV increased by ≥15% after VE.
  
  
  RESULTS
  Twenty patients responded to VE and 15 did not. The correlation coefficient between ΔPP(ART) and ΔPP(CNAP) before VE was r = 0.90 (95% confidence interval [CI] = 0.84-0.96; P < 0.0001). Before VE, ΔPP(ART) and ΔPP(CNAP) were significantly higher in responders than in nonresponders (P < 0.0001). The values of ΔPP(ART) and ΔPP(CNAP) before VE were significantly correlated with the percent increase in SV induced by VE (respectively, r(2) = 0.50; P < 0.0001 and r(2) = 0.57; P < 0.0001). Before VE, a ΔPP(ART) >10% discriminated between responders and nonresponders with a sensitivity of 90% (95% CI = 69%-99%) and a specificity of 87% (95% CI = 60%-98%). The area under the receiver operating characteristic (ROC) curve was 0.957 ± 0.035 for ΔPP(ART). Before VE, a ΔPP(CNAP) >11% discriminated between responders and nonresponders with a sensitivity of 85% (95% CI = 62%-97%) and a specificity of 100% (95% CI = 78%-100%). The area under the ROC curve was 0.942 ± 0.040 for ΔPP(CNAP). There was no significant difference between the area under the ROC curve for ΔPP(ART) and ΔPP(CNAP).
  
  
  CONCLUSIONS
  A value of ΔPP(CNAP) >11% has a sensitivity of at least 62% in predicting preload-dependent responders to VE in mechanically ventilated patients during general anesthesia.
authors.affiliation: Service d'Anesthésie et de Réanimation 1, Hôpital Pellegrin, CHU Bordeaux, 33076 Bordeaux Cedex, France. matthieu.biais@chu-bordeaux.fr
authors.forename: Matthieu
authors.initials: M
authors.lastname: Biais
authors.forename: Laurent
authors.initials: L
authors.lastname: Stecken
authors.forename: Laetitia
authors.initials: L
authors.lastname: Ottolenghi
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Roullet
authors.forename: Alice
authors.initials: A
authors.lastname: Quinart
authors.forename: Françoise
authors.initials: F
authors.lastname: Masson
authors.forename: François
authors.initials: F
authors.lastname: Sztark
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000768:Anesthesia, General; D001794:Blood Pressure; D001795:Blood Pressure Determination / Q000295:instrumentation*; D015924:Blood Pressure Monitors; D002302:Cardiac Output; D002406:Catheterization, Peripheral; D004867:Equipment Design; D005260:Female; D005385:Fingers / Q000098:blood supply*; D005440:Fluid Therapy; D005602:France; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation*; D009010:Monte Carlo Method; D010952:Plasma Substitutes / Q000008:administration & dosage*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012119:Respiration; D012121:Respiration, Artificial; D013318:Stroke Volume; D013997:Time Factors; D014656:Vascular Surgical Procedures / Q000009:adverse effects
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes