title: Renal effects of hypotensive anaesthesia in combination with acute normovolaemic haemodilution with hydroxyethyl starch 130/0.4 or isotonic saline.
abstract: BACKGROUND
  Hypotensive anaesthesia (HA) and acute normovolaemic haemodilution (ANH) are used separately to decrease per-operative blood loss. Reducing blood viscosity by adding ANH to HA may appear profitable in a situation with lowered perfusion pressure and concern about organ ischemia. The aim of this study was to clarify the influence of HA in combination with ANH using crystalloid or colloid as replacement fluid on renal function.
  
  
  METHODS
  Hypotensive anaesthesia was induced in 11 patients referred to major spine surgery using sevoflurane in combination with fentanyl/remifentanil. Acute normovolaemic haemodilution was carried out by drawing venous blood into standard blood bags and replacing it by isotonic saline 0.9% (Group S) or HES 130/0.4 (Group V). Renal function was evaluated before, during and up to 8 h after hypotension as the glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) by means of 51Cr-EDTA and 125I-Hippuran clearances.
  
  
  RESULTS
  Lowering mean arterial blood pressure decreased GFR and ERPF in both groups. During hypotension ERPF was lower in Group S (n = 5) than Group V (n = 6). Renal function was normalized postoperatively. We found a positive but non-significant correlation between the relative GFR change and the duration of hypotension.
  
  
  CONCLUSIONS
  In conclusion, our study demonstrated that renal function, assessed by GFR and ERPF, is transiently reduced during the combination of hypotensive anaesthesia and acute normovolaemic haemodilution. A colloid-based fluid regime (HES 130/0.4) used for haemodilution may preserve renal function to a greater extent than a crystalloid-based regime (0.9% saline).
authors.affiliation: Department of Anaesthesiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: C
authors.initials: C
authors.lastname: Fenger-Eriksen
authors.forename: C
authors.initials: C
authors.lastname: Hartig Rasmussen
authors.forename: T
authors.initials: T
authors.lastname: Kappel Jensen
authors.forename: E
authors.initials: E
authors.lastname: Anker-Møller
authors.forename: J
authors.initials: J
authors.lastname: Heslop
authors.forename: J
authors.initials: J
authors.lastname: Frøkiaer
authors.forename: E
authors.initials: E
authors.lastname: Tønnesen
mesh_terms: D000328:Adult; D000368:Aged; D000758:Anesthesia; D016063:Blood Loss, Surgical / Q000517:prevention & control*; D000077324:Crystalloid Solutions; D005919:Glomerular Filtration Rate; D006438:Hemodilution; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000494:pharmacology*; D007023:Hypotension, Controlled; D007552:Isotonic Solutions; D008875:Middle Aged; D010952:Plasma Substitutes / Q000494:pharmacology; D012079:Renal Circulation; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D000077324:Crystalloid Solutions; D006895:Hydroxyethyl Starch Derivatives; D007552:Isotonic Solutions; D010952:Plasma Substitutes; D012965:Sodium Chloride