title: Changes in stroke volume induced by passive leg raising in spontaneously breathing patients: comparison between echocardiography and Vigileo/FloTrac device.
abstract: BACKGROUND
  Passive leg raising (PLR) is a simple reversible maneuver that mimics rapid fluid loading and increases cardiac preload. The effects of this endogenous volume expansion on stroke volume enable the testing of fluid responsiveness with accuracy in spontaneously breathing patients. However, this maneuver requires the determination of stroke volume with a fast-response device, because the hemodynamic changes may be transient. The Vigileo monitor (Vigileo; Flotrac; Edwards Lifesciences, Irvine, CA, USA) analyzes systemic arterial pressure wave and allows continuous stroke volume monitoring. The aims of this study were (i) to compare changes in stroke volume induced by passive leg raising measured with the Vigileo device and with transthoracic echocardiography and (ii) to compare their ability to predict fluid responsiveness.
  
  
  METHODS
  Thirty-four patients with spontaneous breathing activity and considered for volume expansion were included. Measurements of stroke volume were obtained with transthoracic echocardiography (SV-TTE) and with the Vigileo (SV-Flotrac) in a semi-recumbent position, during PLR and after volume expansion (500 ml saline). Patients were responders to volume expansion if SV-TTE increased > or = 15%.
  
  
  RESULTS
  Four patients were excluded. No patients received vasoactive drugs. Seven patients presented septic hypovolemia. PLR-induced changes in SV-TTE and in SV-Flotrac were correlated (r2 = 0.56, P < 0.0001). An increase in SV-TTE > or = 13% during PLR was predictive of response to volume expansion with a sensitivity of 100% and a specificity of 80%. An increase in SV-Flotrac > or =16% during PLR was predictive of response to volume expansion with a sensitivity of 85% and a specificity of 90%. There was no difference between the area under the ROC curve for PLR-induced changes in SV-TTE (AUC = 0.96 +/- 0.03) or SV-Flotrac (AUC = 0.92 +/- 0.05). Volume expansion-induced changes in SV-TTE correlated with volume expansion-induced changes in SV-Flotrac (r2 = 0.77, P < 0.0001). In all patients, the highest plateau value of SV-TTE recorded during PLR was obtained within the first 90 s following leg elevation, whereas it was 120 s for SV-Flotrac.
  
  
  CONCLUSIONS
  PLR-induced changes in SV-Flotrac are able to predict the response to volume expansion in spontaneously breathing patients without vasoactive support.
authors.affiliation: Service d'Anesthésie Réanimation 1, Hôpital Pellegrin, CHU Bordeaux, Place Amélie Raba-Léon, 33076 Bordeaux Cedex, France. matthieu.biais@chu-bordeaux.fr
authors.forename: Matthieu
authors.initials: M
authors.lastname: Biais
authors.forename: Lionel
authors.initials: L
authors.lastname: Vidil
authors.forename: Philippe
authors.initials: P
authors.lastname: Sarrabay
authors.forename: Vincent
authors.initials: V
authors.lastname: Cottenceau
authors.forename: Philippe
authors.initials: P
authors.lastname: Revel
authors.forename: François
authors.initials: F
authors.lastname: Sztark
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D004452:Echocardiography / Q000379:methods*; D015150:Echocardiography, Doppler / Q000379:methods*; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000379:methods; D009043:Motor Activity / Q000502:physiology*; D015588:Observer Variation; D011184:Postoperative Period; D011187:Posture; D012372:ROC Curve; D012119:Respiration; D013318:Stroke Volume / Q000502:physiology*