title: Effect of phenylephrine bolus administration on left ventricular function during postural hypotension in anesthetized patients.
abstract: OBJECTIVE
  To investigate the effect of intravenous (IV) phenylephrine (PHE) bolus administration on left ventricular function in patients who developed postural hypotension during isoflurane anesthesia in the head-up tilt (reverse Trendelenburg) position.
  
  
  METHODS
  Prospective "before-after" trial.
  
  
  METHODS
  Operation theater of a university medical center.
  
  
  METHODS
  15 ASA physical status I and II patients without cardiovascular disorders.
  
  
  METHODS
  The anesthetized patients were tilted from a supine horizontal to a 30-degree reverse-Trendelenburg position. Once a steady state was achieved, PHE 3 micrograms/kg was administered as an IV bolus dose.
  
  
  RESULTS
  Transesophageal echocardiography was used to assess left ventricular function. We measured blood pressure (BP); heart rate; left ventricular end-systolic and end-diastolic area, diameter, and wall thickness; and ejection time at baseline and after tilt, immediately before and for a period of 3 minutes after PHE injection. We calculated fractional area change (FAC), mean velocity of circumferential fiber shortening (mVcf), and end-systolic wall stress. Head-up tilt caused a reduction of mean arterial pressure [from 68 to 54 mmHg (mean)], end-systolic and end-diastolic left ventricular area (from 9.7 to 6.5 cm2 and from 19.2 to 13.1 cm2, respectively) and end-systolic wall stress (from 56 to 33 10(3).dyne/cm2). FAC and mVcf remained unaltered. PHE administration restored baseline values or overcompensated the changes caused by tilt. FAC slightly decreased in response to PHE (from 0.51 to 0.43), end-systolic wall stress increased to 83 10(3).dyne/cm2, and mVcf remained unchanged.
  
  
  CONCLUSIONS
  PHE bolus administration effectively restored BP and cardiac filling, which were reduced after head-up tilt, without causing a relevant impairment of left ventricular function or an increase in end-systolic wall stress above the upper normal limit.
authors.affiliation: Department of Anesthesiology, University of Ulm Medical Center, Germany.
authors.forename: A W
authors.initials: AW
authors.lastname: Goertz
authors.forename: M
authors.initials: M
authors.lastname: Schmidt
authors.forename: K H
authors.initials: KH
authors.lastname: Lindner
authors.forename: C
authors.initials: C
authors.lastname: Seefelder
authors.forename: M
authors.initials: M
authors.lastname: Georgieff
mesh_terms: D000328:Adult; D000769:Anesthesia, Inhalation; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D007022:Hypotension / Q000188:drug therapy* / Q000209:etiology; D007275:Injections, Intravenous; D007530:Isoflurane; D008297:Male; D010656:Phenylephrine / Q000008:administration & dosage*; D011187:Posture / Q000502:physiology*; D011446:Prospective Studies; D016277:Ventricular Function, Left / Q000187:drug effects*
chemical_list: D010656:Phenylephrine; D007530:Isoflurane