title: Hemodynamic changes during displacement of the beating heart by the Utrecht Octopus method.
abstract: BACKGROUND
  Coronary bypass grafting of posterior circumflex branches requires full displacement of the heart (apex pointing ventrally), which, in the beating heart, results in an arterial pressure drop. We analyzed its origin.
  
  
  METHODS
  To facilitate displacement, the Utrecht "Octopus" method was applied in 8 anesthetized beta-blocked pigs and the beating heart was fully retracted.
  
  
  RESULTS
  Displacement decreased stroke volume from 75 +/- 17 mL (mean +/- standard deviation) to 43 +/- 13 mL (p < 0.001), a 44% +/- 3% decrease that resulted in a decrease in cardiac output by 32% +/- 5% (mean +/- standard error of the mean; p < 0.001), a decrease in mean arterial pressure by 26% +/- 5% (p < 0.01), and an increase in heart rate by 26% +/- 6% (p < 0.01). Right ventricular end-diastolic pressure increased from 5 +/- 1 to 8 +/- 1 mm Hg (p < 0.01). Twenty degrees head-down tilt normalized cardiac output and mean arterial pressure. Right ventricular end-diastolic pressure increased to 10 +/- 2 mm Hg (p < 0.001) and left ventricular end-diastolic pressure to 11 +/- 3 mm Hg (p < 0.01).
  
  
  CONCLUSIONS
  Displacement of the beating heart in the pig induced a 44% drop in stroke volume, which is attributed to biventricular interference with pump function. The Trendelenburg maneuver reestablished the control circulatory status at the expense of augmented right and left ventricular preloads and an increased heart rate.
authors.affiliation: Department of Cardiology, Utrecht University Hospital, the Netherlands. exp.cardio@hli.azu.nl
authors.forename: P F
authors.initials: PF
authors.lastname: Gründeman
authors.forename: C
authors.initials: C
authors.lastname: Borst
authors.forename: J A
authors.initials: JA
authors.lastname: van Herwaarden
authors.forename: H J
authors.initials: HJ
authors.lastname: Mansvelt Beck
authors.forename: E W
authors.initials: EW
authors.lastname: Jansen
mesh_terms: D000818:Animals; D001794:Blood Pressure; D002302:Cardiac Output; D001026:Coronary Artery Bypass / Q000295:instrumentation* / Q000379:methods*; D018475:Head-Down Tilt; D006439:Hemodynamics; D019060:Minimally Invasive Surgical Procedures / Q000295:instrumentation / Q000379:methods; D013318:Stroke Volume; D013552:Swine; D017725:Ventricular Pressure