Source: Wilkes et al. Anesth Analg 2002; 94: 538-44.

Reviewer:  R. Prasad, MD

Summary:

• 21 healthy volunteers, 19-45yo, BMI 20-30 kg/m*m ASA I
• Hextend 10ml/kg over 20min
• Serum samples taken over 7-day period
• Early phase (distribution - first 8h) half-life 4.2h; half-life for 7-day study (elimination phase) was 38.2h
• Median volume of distribution, corrected for whole blood = 72ml/kg; shows HES mainly confined to intravascular space
• Most HES eliminated via kidneys
• Decreases in some plasma components c/w dilution by infused volume
• for 24-48h for Hgb, Hct, RBC, plt count, aPTT (all statistically signif but clinically unimportant changes)
• Fibrinogen, Factor VIII, vWFAg: mild-moderage decreases x 48h
• Decreases in plasma concentrations of others were greater than expected
• Bili, protein, ALT, GGT
• albumin, alk phos, AST, LDH, CPK - even greater decreases
• Increases in
• Amylase activity (it breaks down larger HES polymers)
• Plasma bicarb (from 25.9 to peak 28.1 at 6h, 27.8 at 48h) ... clinical significance?

• Good stuff!
• But they only gave 10ml/kg ... I'm not particularly concerned with volumes that low! Much more interesting would have been looking at the same data after infusions of >20 ml/kg:
• Do a larger study with separate groups receiving different volumes.
• Even better - bleed some volunteers (Red Cross donors?), give them Hextend, and see what happens!
• And, what would be really cool - formulate 5% albumin in LR instead of NS, and do studies comparing the 2 formulations of albumin and Hetastarch.