title: Contrasting effects of colloid and crystalloid resuscitation fluids on cardiac vascular permeability.
abstract: BACKGROUND
  Fluid extravasation may lead to myocardial edema and consequent reduction in ventricular function. Albumin is presumed to interact with the endothelial glycocalyx. The authors' objective was to compare the impact of different resuscitation fluids (human albumin, hydroxyethyl starch, saline) on vascular integrity.
  
  
  METHODS
  In an isolated perfused heart model (guinea pig), Krebs-Henseleit buffer was augmented with colloids (one third volume 5% albumin or 6% hydroxyethyl starch 130/0.4) or crystalloid (0.9% saline). Perfusion pressure and vascular fluid filtration (epicardial transudate formation) were assessed at different flow rates. After global, stopped-flow ischemia (37 degrees C, 20 min), hearts were reperfused with the same resuscitation fluid additives. In a second series, the authors applied the respective perfusates after enzymatic digestion of the endothelial glycocalyx (heparinase, 10 U over 15 min).
  
  
  RESULTS
  Both 5% albumin and 6% hydroxyethyl starch decreased fluid extravasation versus saline (68.4 +/- 5.9, 134.8 +/- 20.5, and 436.8 +/- 14.7 microl/min, respectively, at 60 cm H(2)O perfusion pressure; P < 0.05), the corresponding colloid osmotic pressures being 2.95, 5.45, and 0.00 mmHg. Digestion of the endothelial glycocalyx decreased coronary integrity in both colloid groups. After ischemia, a transient increase in vascular leak occurred with Krebs-Henseleit buffer containing hydroxyethyl starch and saline, but not with albumin. The authors observed no difference between intravascular and bulk interstitial colloid concentration in the steady state. Notwithstanding, electron microscopy revealed an intact endothelial glycocalyx and no interstitial edema in the albumin group.
  
  
  CONCLUSIONS
  Ex vivo, albumin more effectively prevented fluid extravasation in the heart than crystalloid or artificial colloid. This effect was partly independent of colloid osmotic pressure and may be attributable to an interaction of albumin with the endothelial glycocalyx.
authors.affiliation: Clinic of Anesthesiology, Ludwig-Maximilians University Munich, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Jacob
authors.forename: Dirk
authors.initials: D
authors.lastname: Bruegger
authors.forename: Markus
authors.initials: M
authors.lastname: Rehm
authors.forename: Ulrich
authors.initials: U
authors.lastname: Welsch
authors.forename: Peter
authors.initials: P
authors.lastname: Conzen
authors.forename: Bernhard F
authors.initials: BF
authors.lastname: Becker
mesh_terms: D000418:Albumins / Q000494:pharmacology; D000818:Animals; D002199:Capillary Permeability; D003102:Colloids / Q000494:pharmacology; D003331:Coronary Vessels / Q000378:metabolism*; D000077324:Crystalloid Solutions; D005947:Glucose / Q000494:pharmacology; D006168:Guinea Pigs; D019763:Heparin Lyase / Q000494:pharmacology; D006895:Hydroxyethyl Starch Derivatives / Q000494:pharmacology; D007552:Isotonic Solutions / Q000494:pharmacology; D008297:Male; D009997:Osmotic Pressure; D012151:Resuscitation; D014325:Tromethamine / Q000494:pharmacology
chemical_list: D000418:Albumins; D003102:Colloids; D000077324:Crystalloid Solutions; D006895:Hydroxyethyl Starch Derivatives; D007552:Isotonic Solutions; C074097:Krebs-Henseleit solution; D014325:Tromethamine; D019763:Heparin Lyase; D005947:Glucose