title: Evaluation of corrected flow time in oesophageal Doppler as a predictor of fluid responsiveness.
abstract: BACKGROUND
  Corrected flow time (FTc) by oesophageal Doppler is considered to be a 'static' preload index. We evaluated the ability of FTc to predict fluid responsiveness and compared this with the abilities of other preload indices, such as pulse pressure variation (PPV), central venous pressure (CVP), and left ventricular end-diastolic area index (LVEDAI).
  
  
  METHODS
  Twenty neurosurgical patients were studied. After induction of anaesthesia, FTc, PPV, LVEDAI, CVP, and stroke volume index (SVI) were measured before and 12 min after fluid loading with 6% hydroxyethyl starch solution (7 ml kg(-1)). Responders and non-responders were defined as those patients with an SVI increase >or= 10% or < 10% after fluid loading, respectively. Pearson's correlation was used to assess correlations between changes in SVI and initial haemodynamic variables. Receiver operating characteristic (ROC) curves were constructed and compared to evaluate the overall performance of preload indices (FTc, PPV, LVEDAI, and CVP) in terms of predicting fluid responsiveness.
  
  
  RESULTS
  FTc and PPV before fluid loading differed between responders (n = 11) and non-responders (n = 9), and correlated with changes in SVI (r = -0.515 and r = 0.696, respectively), which was opposite to that observed for CVP or LVEDAI. Areas under ROC curves for FTc [0.944 (SD 0.058)] and PPV [0.909 (0.069)] were significantly greater than those for CVP [0.540 (0.133), P < 0.001] and LVEDAI [0.495 (0.133), P < 0.001]. The optimal threshold value given by ROC analysis was 357 ms for FTc.
  
  
  CONCLUSIONS
  In this study, FTc predicted fluid responsiveness. However, FTc should be used in conjunction with other clinical information.
authors.affiliation: Department of Anaesthesiology, Seoul National University Hospital, 28 Yongon-Dong, Chongno-Gu, Seoul 110-744, Republic of Korea.
authors.forename: J-H
authors.initials: JH
authors.lastname: Lee
authors.forename: J-T
authors.initials: JT
authors.lastname: Kim
authors.forename: S Z
authors.initials: SZ
authors.lastname: Yoon
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Lim
authors.forename: Y
authors.initials: Y
authors.lastname: Jeon
authors.forename: J-H
authors.initials: JH
authors.lastname: Bahk
authors.forename: C S
authors.initials: CS
authors.lastname: Kim
mesh_terms: D000328:Adult; D001794:Blood Pressure; D002496:Central Venous Pressure; D017548:Echocardiography, Transesophageal / Q000379:methods*; D005260:Female; D005440:Fluid Therapy / Q000379:methods*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D011379:Prognosis; D012372:ROC Curve; D013318:Stroke Volume