title: Acid-base and electrolyte balance following administration of three crystalloid solutions in dogs undergoing elective orthopaedic surgery.
abstract: OBJECTIVE
  To compare acid-base balance and incidence of hyperchloraemic metabolic acidosis following administration of three crystalloid solutions to dogs undergoing anaesthesia for orthopaedic surgery.
  
  
  METHODS
  Prospective, randomised, clinical study.
  
  
  METHODS
  Sixty dogs.
  
  
  METHODS
  During a non-standardised anaesthetic, 0.9% saline (S), Hartmann's solution (H) or a polyionic glucose-free maintenance solution (M) was administered IV at 10 mL kg(-1)  hour(-1) . Venous blood pH, PCO2 , PCV, total protein, urea, sodium, potassium and chloride concentrations were measured at induction of anaesthesia (T0) and after 2 hours of fluid therapy (T2). Base excess (BE), bicarbonate, corrected chloride concentration (corrCl), osmolality, change in plasma volume (PV) and strong ion gap (SIG) were calculated. Changes in variables within groups (1-sample Student's t-test/Wilcoxon signed rank test) and between groups (1-way anova/Kruskal-Wallis) were assessed. Data are presented as median (interquartile range). Significance was set at p < 0.05.
  
  
  RESULTS
  No significant differences existed between groups for pH, PCO2 , PCV, total protein, urea, potassium, corrCl, PV and SIG. Potassium significantly increased in all groups. Significant differences existed between groups S and M for BE, sodium, chloride, bicarbonate and osmolality, and between groups H and M for sodium and osmolality. Chloride concentration significantly changed from 116 (114-117) to 117 (116-119) mmol L(-1) in group S, 116 (115-118) to 115 (113-117) mmol L(-1) in group H and 116 (115-118) to 114 (113-118)  mmol L(-1) in group M. In groups H and M, sodium and osmolality decreased, and BE and bicarbonate concentration increased significantly. Plasma volume increased by 28 (14-44)%, 25 (5-40)% and 24 (13-33)% in groups S, H and M, respectively.
  
  
  CONCLUSIONS
  Hyperchloraemic metabolic acidosis did not develop after intraoperative 0.9% saline, Hartmann's solution or maintenance solution at 10 mL kg(-1)  hour(-1) for 2 hours in dogs undergoing elective orthopaedic surgery. Bicarbonate and BE increased after Hartmann's and maintenance solutions. Increases in potassium concentration were unexplained.
authors: School of Veterinary Science, University of Liverpool, Liverpool, UK. elliew@liv.ac.uk
authors: Eleanor
authors: E
authors: West
authors: Rob
authors: R
authors: Pettitt
authors: Ronald S
authors: RS
authors: Jones
authors: Peter J
authors: PJ
authors: Cripps
authors: Martina
authors: M
authors: Mosing
mesh_terms: D000136:Acid-Base Equilibrium / Q000187:drug effects*; D000818:Animals; D000077324:Crystalloid Solutions; D004285:Dogs; D005260:Female; D007552:Isotonic Solutions / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D019637:Orthopedic Procedures / Q000662:veterinary*; D014882:Water-Electrolyte Balance / Q000187:drug effects*
chemical_list: D000077324:Crystalloid Solutions; D007552:Isotonic Solutions
keywords: acid-base; anaesthesia; electrolytes; fluid therapy; hyperkalaemia