title: Changing the priming solution from Ringer's to Hartmann's solution is associated with less metabolic acidosis during cardiopulmonary bypass.
abstract: OBJECTIVE
  Previously, it was noted that changing the solutions used for priming and intravascular volume replacement from Hartmann's to Ringer's resulted in a more profound metabolic acidosis developing during cardiopulmonary bypass (CPB). The aim of this study was to examine the effects of changing the solutions back to Hartmann's on metabolic acidosis that develops during CPB in patients undergoing heart surgery.
  
  
  METHODS
  Two groups of patients were studied sequentially: the first received Ringer's (n = 63) and the second Hartmann's solution (n = 66). Arterial blood samples were taken before induction of anaesthesia and towards the end of CPB. Samples were analysed in a blood gas analyser.
  
  
  RESULTS
  Hydrogen ion concentration increased from 38 (4) to 41 (7)mmol/L in the Ringer's group, but decreased from 38 (5) to 36 (6) mmol L(-1) in the Hartmann's group. Changes in PaCO2 (0.77, p < 0.001) and volume of fluid administered (r= 0.23, p <0.01) were significant univariate correlates of change in hydrogen ion concentration, but haemoglobin concentration was not (r < 0.01, p = 0.97). Analysis of variance for repeated measures found significant between subject effects on the change in hydrogen ion concentration during CPB caused by the choice of intravascular solution used (p < 0.001) and PaCO2 (p = 0.001), but not as a result of the volume of solution administered (p > 0.10).
  
  
  CONCLUSIONS
  Changing the solutions used for priming and intravascular volume replacement from Ringer's to Hartmann's was associated with a reduction in metabolic acidosis that developed during CPB.
authors.affiliation: Department of Anaesthesia, Critical Care and Pain Medicine, Royal Infirmary of Edinburgh, Edinburgh, UK. peter.alston@ed.ac.uk
authors.forename: R P
authors.initials: RP
authors.lastname: Alston
authors.forename: C
authors.initials: C
authors.lastname: Theodosiou
authors.forename: K
authors.initials: K
authors.lastname: Sanger
mesh_terms: D000138:Acidosis / Q000517:prevention & control*; D000368:Aged; D002315:Cardiopulmonary Bypass; D005260:Female; D006331:Heart Diseases / Q000601:surgery*; D006801:Humans; D007552:Isotonic Solutions; D008297:Male; D011522:Protons; D012189:Retrospective Studies; D000077325:Ringer's Lactate; D000077331:Ringer's Solution
chemical_list: D007552:Isotonic Solutions; D011522:Protons; D000077325:Ringer's Lactate; D000077331:Ringer's Solution