title: Hemodynamic perturbations during robot-assisted laparoscopic radical prostatectomy in 45° Trendelenburg position.
abstract: BACKGROUND
  Robot-assisted laparoscopic radical prostatectomy has gained widespread use. However, circulatory effects in patients subjected to an extreme Trendelenburg position (45°) are not well characterized.
  
  
  METHODS
  We studied 16 patients (ASA physical status I-II) with a mean age of 59 years scheduled for robot-assisted laparoscopic radical prostatectomy (45° head-down tilt, with an intraabdominal pressure of 11-12 mm Hg). Hemodynamics, echocardiography, gas exchange, and ventilation-perfusion distribution were investigated before and during pneumoperitoneum, in the Trendelenburg position and, in 8 of the patients, also after the conclusion of surgery.
  
  
  RESULTS
  In the 45° Trendelenburg position, central venous pressure increased almost 3-fold compared with the initial value, with an associated 2-fold increase in mean pulmonary artery pressure and pulmonary capillary wedge pressure (P<0.01). Mean arterial blood pressure increased by 35%. Heart rate, stroke volume, cardiac output, and mixed venous oxygen saturation were unaffected during surgery, as were echocardiographic heart dimensions. After induction of anesthesia, isovolumic relaxation time was prolonged, with no further change during the study. Deceleration time was normal and stable. In the horizontal position after pneumoperitoneum exsufflation, filling pressures and mean arterial blood pressure returned to baseline levels. Pneumoperitoneum reduced lung compliance by 40% (P<0.01). Addition of the Trendelenburg position caused a further decrease (P<0.05). Arterial blood acid-base balance was normal. End-tidal carbon dioxide tension increased whereas arterial carbon dioxide was unaffected with unchanged ventilation settings. Pneumoperitoneum increased PaO2 (P<0.05). Ventilation-perfusion distribution, shunt, and dead space were unaltered during the study.
  
  
  CONCLUSIONS
  Pneumoperitoneum and 45° Trendelenburg position caused 2- to 3-fold increases in filling pressures, without effects on cardiac performance. Filling pressures were normalized immediately after surgery. Lung compliance was halved. Gas exchange was unaffected. No perioperative cardiovascular complications occurred.
authors.affiliation: Department of Anesthesiology and Intensive Care, Karolinska University Hospital, S-141 86 Stockholm, Sweden.
authors.forename: Melinda
authors.initials: M
authors.lastname: Lestar
authors.forename: Lars
authors.initials: L
authors.lastname: Gunnarsson
authors.forename: Lars
authors.initials: L
authors.lastname: Lagerstrand
authors.forename: Peter
authors.initials: P
authors.lastname: Wiklund
authors.forename: Suzanne
authors.initials: S
authors.lastname: Odeberg-Wernerman
mesh_terms: D000368:Aged; D000768:Anesthesia, General; D002248:Carbon Monoxide / Q000097:blood; D004452:Echocardiography; D018475:Head-Down Tilt / Q000502:physiology*; D006333:Heart Failure / Q000517:prevention & control; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010100:Oxygen / Q000097:blood; D011028:Pneumoperitoneum, Artificial; D011184:Postoperative Period; D011468:Prostatectomy / Q000379:methods*; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012121:Respiration, Artificial; D012371:Robotics; D013318:Stroke Volume; D013815:Thermodilution; D014692:Ventilation-Perfusion Ratio / Q000502:physiology
chemical_list: D002248:Carbon Monoxide; D010100:Oxygen