title: Pre-eclampsia: the effect of intravenous fluid preload on atrial natriuretic peptide secretion during caesarean section under spinal anaesthesia.
abstract: BACKGROUND
  The haemodynamic effect of volume load at elective Caesarean delivery may be modulated by atrial natriuretic peptide (ANP) especially in pre-eclamptic women in whom basal ANP levels are increased.
  
  
  METHODS
  We followed the haemodynamic parameters and determined the peripheral venous levels of ANP before and after an intravenous volume preload of 1000 ml of Ringer's acetate solution, followed by a further load of the same volume under spinal anaesthesia in 7 healthy and in 6 pre-eclamptic women.
  
  
  RESULTS
  During the preload period the median ANP level increased more (from 14.8 to 22.1 pmol/l, P = 0.03) in pre-eclamptic than in healthy women (from 8.0 to 8.5 pmol/l, NS); while an increment in central venous pressure (CVP) was also greater in pre-eclamptic than in healthy women. The increase in the concentrations of ANP correlated significantly (P < 0.05) with the increase in CVP in the total study group. A significant increase in ANP levels in healthy pregnant women was not seen until during the second infusion period under spinal anaesthesia; in pre-eclamptic women the levels increased further during that period.
  
  
  CONCLUSIONS
  These findings concur with the theory that atrial stretch is a stimulus for ANP release. An exaggerated release of ANP in response to volume loading may aid in the adaptation of maternal circulation to volume load at elective Caesarean delivery in pre-eclamptic women.
authors.affiliation: Department of Obstetrics and Gynaecology, Oulu University Central Hospital, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Pouta
authors.forename: J
authors.initials: J
authors.lastname: Karinen
authors.forename: O
authors.initials: O
authors.lastname: Vuolteenaho
authors.forename: T
authors.initials: T
authors.lastname: Laatikainen
mesh_terms: D000328:Adult; D000773:Anesthesia, Obstetrical; D000775:Anesthesia, Spinal; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001810:Blood Volume; D002496:Central Venous Pressure; D002585:Cesarean Section; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D011225:Pre-Eclampsia / Q000378:metabolism*; D011247:Pregnancy
chemical_list: D009320:Atrial Natriuretic Factor