title: Prophylactic angiotensin II infusion during spinal anesthesia for elective cesarean delivery.
abstract: BACKGROUND
  Angiotensin II may prove useful in treating regional anesthesia-induced hypotension in obstetric patients, because it causes less uterine vasoconstriction than do other vasoconstrictor drugs (such as phenylephrine). This study compared (1) maternal blood pressure and heart rate and (2) fetal status at delivery in parturients given either prophylactic angiotensin II or ephedrine infusion during spinal anesthesia for elective cesarean delivery.
  
  
  METHODS
  Fifty-four women were randomized to receive either angiotensin II or ephedrine infusion intravenously during spinal anesthesia for elective cesarean section delivery. Simultaneous with subarachnoid injection, infusion of angiotensin II (2.5 microg/ml) or ephedrine (5 mg/ml) was initiated at 10 ng x kg(-1) x min(-1) and 50 microg x kg(-1) x min(-1), respectively. The rate of each infusion was adjusted to maintain maternal systolic blood pressure at 90-100% of baseline.
  
  
  RESULTS
  Cumulative vasopressor doses (mean+/-SD) through 10, 20, and 30 min were 150+/-100, 310+/-180, and 500+/-320 ng/kg in the angiotensin group and 480+/-210, 660+/-390, and 790+/-640 microg/kg in the ephedrine group. Maternal heart rate was significantly higher (P < 0.001) during vasopressor infusion in the ephedrine group than in the angiotensin group. Umbilical arterial and venous blood pH and base excess were all significantly higher (P < 0.05) in the angiotensin group than in the ephedrine group.
  
  
  CONCLUSIONS
  Angiotensin II infusion maintained maternal systolic blood pressure during spinal anesthesia without increasing maternal heart rate or causing fetal acidosis.
authors.affiliation: University of Alabama at Birmingham, 35233-6810, USA. robert.vincent@ccc.uab.edu
authors.forename: R D
authors.initials: RD
authors.lastname: Vincent
authors.forename: C F
authors.initials: CF
authors.lastname: Werhan
authors.forename: P F
authors.initials: PF
authors.lastname: Norman
authors.forename: G H
authors.initials: GH
authors.lastname: Shih
authors.forename: D H
authors.initials: DH
authors.lastname: Chestnut
authors.forename: T
authors.initials: T
authors.lastname: Ray
authors.forename: E L
authors.initials: EL
authors.lastname: Ross
authors.forename: J A
authors.initials: JA
authors.lastname: Bofill
authors.forename: D B
authors.initials: DB
authors.lastname: Shaw
mesh_terms: D000136:Acid-Base Equilibrium; D000328:Adult; D000773:Anesthesia, Obstetrical / Q000009:adverse effects*; D000775:Anesthesia, Spinal / Q000009:adverse effects*; D000804:Angiotensin II / Q000008:administration & dosage / Q000627:therapeutic use*; D001784:Blood Gas Analysis; D002585:Cesarean Section; D004809:Ephedrine / Q000008:administration & dosage / Q000627:therapeutic use; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D006801:Humans; D007022:Hypotension / Q000209:etiology / Q000517:prevention & control*; D007231:Infant, Newborn; D011247:Pregnancy; D014662:Vasoconstrictor Agents / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D004809:Ephedrine