title: Buffer capacity of 4% succinylated gelatin does not provide any advantages over acidic 6% hydroxyethyl starch 130/0.4 for acid-base balance during experimental mixed acidaemia in a porcine model.
abstract: OBJECTIVE
  Four percent gelatine is an alkaline compound due to NH2 groups, whereas 6% hydroxyethyl starch 130/0.4 (HES130) has acidic features. We investigated whether these solutions lead to differences in acid-base balance in pigs during acidaemia and correction of pH.
  
  
  METHODS
  Anaesthetized pigs were randomized to HES130 or gelatine infusion (n = 5 per group). Animals received acid infusion (0.4 M solution of lactic acid and HCl diluted in normal saline) and low tidal volume ventilation (6-7 mL kg(-1), PaCO2 of 80-85 mmHg, pH 7.19-7.24). Measurements were made before and after induction of acidaemia, before and after correction of pH with haemofiltration (continuous venovenous haemofiltration) and tris-hydroxymethylaminomethane infusion. We measured parameters describing acid-base balance according to Stewart's approach, ketone body formation, oxygen delivery, haemodynamics, diuresis and urinary pH.
  
  
  RESULTS
  Acid-base balance did not differ significantly between the groups. In HES130-treated pigs, the haemodilution-based drop of haemoglobin (1.4 +/- 1.0 g dL(-1), median +/- SD) was paralleled by an increase in the cardiac output (0.5 +/- 0.4 L min(-1). Lacking increases in cardiac output, gelatine-treated pigs demonstrated a reduction in oxygen delivery (149.4 +/- 106.0 mL min(-1)). Tris-hydroxymethylaminomethane volumes required for pH titration to desired values were significantly higher in the gelatine group (0.7 +/- 0.1 mL kg(-1) h(-1) vs. HES130: 0.5 +/- 0.2 mL kg(-1) h(-1)).
  
  
  CONCLUSIONS
  The buffer capacity of gelatine did not lead to favourable differences in acid-base balance in comparison to HES130.
authors.affiliation: Universitätsmedizin Berlin, Charité Campus Virchow-Klinikum, Department of Experimental Medicine (FEM), Berlin, Germany. veraesche@yahoo.de
authors.forename: V
authors.initials: V
authors.lastname: Esche
authors.forename: M
authors.initials: M
authors.lastname: Russ
authors.forename: S
authors.initials: S
authors.lastname: Melzer
authors.forename: B
authors.initials: B
authors.lastname: Grossmann
authors.forename: W
authors.initials: W
authors.lastname: Boemke
authors.forename: J K
authors.initials: JK
authors.lastname: Unger
mesh_terms: D000138:Acidosis / Q000473:pathology / Q000628:therapy*; D000818:Animals; D002021:Buffers; D003102:Colloids / Q000737:chemistry; D005780:Gelatin / Q000737:chemistry*; D006439:Hemodynamics; D006440:Hemofiltration; D006863:Hydrogen-Ion Concentration; D006895:Hydroxyethyl Starch Derivatives / Q000737:chemistry*; D006935:Hypercapnia; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D023421:Models, Animal; D010100:Oxygen / Q000378:metabolism; D013552:Swine
chemical_list: D002021:Buffers; D003102:Colloids; D006895:Hydroxyethyl Starch Derivatives; D019344:Lactic Acid; D005780:Gelatin; D010100:Oxygen