title: The correlation between the Trendelenburg position and the stroke volume variation.
abstract: BACKGROUND
  The stroke volume variation (SVV), based on lung-heart interaction during mechanical ventilation, is a useful dynamic parameter for fluid responsiveness. However, it is affected by many factors. The aim of this study was to evaluate the effects of SVV on Trendelenburg (T) and reverse Trendelenburg (RT) position and to further elaborate on the patterns of the SVV with position.
  
  
  METHODS
  Forty-two patients undergoing elective surgery were enrolled in this study. Fifteen minutes after standardized induction of anesthesia with propofol, fentanyl, and rocuronium with volume controlled ventilation (tidal volume of 8 ml/kg of ideal body weight, inspiration : expiration ratio of 1 : 2, and respiratory rate of 10-13 breaths/min), the patients underwent posture changes as follows: supine, T position at slopes of operating table of -5°, -10°, and -15°, and RT position at slopes of operating table of 5°, 10°, and 15°. At each point, SVV, cardiac output (CO), peak airway pressure (PAP), mean blood pressure, and heart rate (HR) were recorded.
  
  
  RESULTS
  The SVV was significant decreased with decreased slopes of operating table in T position, and increased with increased slopes of operating table in RT position (P = 0.000). Schematically, it was increased by 1% when the slope of operating table was increased by 5°. But, the CO and PAP were significant increased with decreased slopes of operating table in T position, and decreased with increased slopes of operating table in RT position (P = 0.045, 0.027).
  
  
  CONCLUSIONS
  SVV is subjected to the posture, and we should take these findings into account on reading SVV for fluid therapy.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Myongji Hospital, Goyang, Korea.
authors.forename: Jin Hye
authors.initials: JH
authors.lastname: Min
authors.affiliation: Department of Anesthesiology and Pain Medicine, Myongji Hospital, Goyang, Korea.
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Lee
authors.affiliation: Department of Anesthesiology and Pain Medicine, Myongji Hospital, Goyang, Korea.
authors.forename: Hong Sik
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Department of Anesthesiology and Pain Medicine, Myongji Hospital, Goyang, Korea.
authors.forename: Young Keun
authors.initials: YK
authors.lastname: Chae
authors.affiliation: Department of Anesthesiology and Pain Medicine, Myongji Hospital, Goyang, Korea.
authors.forename: Yong Kyung
authors.initials: YK
authors.lastname: Lee
authors.affiliation: Department of Anesthesiology and Pain Medicine, Myongji Hospital, Goyang, Korea.
authors.forename: Yoo
authors.initials: Y
authors.lastname: Kang
authors.affiliation: Department of Anesthesiology and Pain Medicine, Myongji Hospital, Goyang, Korea.
authors.forename: Ui Jin
authors.initials: UJ
authors.lastname: Je
keywords: Fluid therapy; Reverse Trendelenburg position; Stroke volume variation; Trendelenburg position