title: Hemodynamic effect of the prone position during anesthesia.
abstract: We studied 21 patients undergoing lumbar spinal surgery under halothane anesthesia on a convex saddle frame, in order to determine the hemodynamic effect of the prone position. A thermodilution pulmonary arterial catheter was placed in 14 patients (Group PA-1: n = 8; and Group PA-2: n = 6), and an inferior vena caval catheter in the remaining seven patients (Group IVC). Group PA-1 and Group IVC patients were placed in the prone position on a convex saddle frame. In the prone position, the cardiac index (CI) decreased significantly from 3.1 +/- 0.5 to 2.5 +/- 0.3 (l.min-1.m-2, mean +/- s.d., P less than 0.01) without accompanying significant changes in the other hemodynamic variables in Group PA-1. The postural change in Group IVC did not exert a significant effect on the inferior vena caval pressure. Group PA-2 were initially placed in the flat prone position on a flat saddle frame, which produced no significant changes in the hemodynamic variables. Then the convex curvature of the frame was adjusted to the grade appropriate for surgery, which produced a significant reduction in CI (from 2.9 +/- 0.3 to 2.4 +/- 0.4, P less than 0.05). We conclude that the prone position itself may not interfere with the circulatory function. The prone position using a convex saddle frame causes significant reductions in CI, but little change in the other hemodynamic variables.
authors.affiliation: Department of Anesthesiology and Orthopedic Surgery, Kochi Medical School, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yokoyama
authors.forename: W
authors.initials: W
authors.lastname: Ueda
authors.forename: M
authors.initials: M
authors.lastname: Hirakawa
authors.forename: H
authors.initials: H
authors.lastname: Yamamoto
mesh_terms: D000769:Anesthesia, Inhalation; D002302:Cardiac Output / Q000502:physiology; D006221:Halothane; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008875:Middle Aged; D016684:Prone Position / Q000502:physiology; D013318:Stroke Volume / Q000502:physiology; D016683:Supine Position / Q000502:physiology; D013523:Surgical Equipment; D014655:Vascular Resistance / Q000502:physiology; D014682:Vena Cava, Inferior / Q000502:physiology
chemical_list: D006221:Halothane