title: Inferior vena cava distensibility as a predictor of fluid responsiveness in patients with subarachnoid hemorrhage.
abstract: BACKGROUND
  The objective of our study is to assess the reliability of the distensibility of the inferior vena cava (dIVC), as measured by ultrasound, as an indicator of fluid responsiveness in patients with subarachnoid hemorrhage.
  
  
  METHODS
  We enrolled 29 adult patients requiring advanced hemodynamic monitoring, sedation, and mechanical ventilation. Inferior vena cava diameter was measured during a single mechanical breath. The dIVC was calculated as (the diameter of the inferior vena cava on inspiration-the diameter on expiration)/the diameter on expiration. All the hemodynamic parameters were collected at baseline and after a fluid challenge (7 ml/kg) with 6% hydroxyethyl starch. A 15% increase of cardiac index was the standard criterion used to differentiate patients with and without a response to fluid therapy.
  
  
  RESULTS
  Apart from stroke volume variation (SVV) and dIVC, which were significantly higher in fluid responders (17 patients), the other baseline characteristics did not differ significantly between groups (responders versus non-responders). Significant changes in hemodynamic parameters after volume load were observed only in fluid responders. The area under the ROC curve was 0.779 (95% confidence interval 0.587-0.911) for SVV and 0.902 (95% confidence interval 0.733-0.979, P = NS) for dIVC. Central venous pressure was a less reliable indicator of fluid responsiveness than dIVC. A dIVC value of >16% yielded the most favorable balance of test characteristics, with 70.59% sensitivity and 100% specificity. There was a trend toward a lower incidence of delayed ischemic lesions in fluid responders (11.7 vs. 25%, P = NS).
  
  
  CONCLUSIONS
  dIVC proved to be a reliable predictor of fluid responsiveness in ICU patients with subarachnoid hemorrhage.
authors.affiliation: Department of Anesthesia and Critical Care, Ospedale SS Antonio e Biagio e Cesare Arrigo, via Venezia n 16, 15100, Alessandria, Italy. rmoretti@ospedale.al.it
authors.forename: Riccardo
authors.initials: R
authors.lastname: Moretti
authors.forename: Barbara
authors.initials: B
authors.lastname: Pizzi
mesh_terms: D000328:Adult; D019540:Area Under Curve; D001810:Blood Volume; D002496:Central Venous Pressure; D016001:Confidence Intervals; D005260:Female; D006439:Hemodynamics; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D010952:Plasma Substitutes / Q000008:administration & dosage; D011237:Predictive Value of Tests; D012372:ROC Curve; D012119:Respiration; D012121:Respiration, Artificial; D012680:Sensitivity and Specificity; D013345:Subarachnoid Hemorrhage / Q000503:physiopathology*; D014463:Ultrasonography; D014664:Vasodilation; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D014882:Water-Electrolyte Balance
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes