1.
Acid-base changes caused by 5% albumin versus 6% hydroxyethyl starch solution in patients undergoing acute normovolemic hemodilution: a randomized prospective study
Rehm M, Orth V, Scheingraber S, Kreimeier U, Brechtelsbauer H, Finsterer U
Anesthesiology. 2000;93((5):):1174-83.
Abstract
BACKGROUND Preoperative acute normovolemic hemodilution (ANH) is an excellent model for evaluating the effects of different colloid solutions that are free of bicarbonate but have large chloride concentrations on acid-base equilibrium. METHODS In 20 patients undergoing gynecologic surgery, ANH to a hematocrit of 22% was performed. Two groups of 10 patients each were randomly assigned to receive either 5% albumin or 6% hydroxyethyl starch solutions containing chloride concentrations of 150 and 154 mm, respectively, during ANH. Blood volume (double label measurement of plasma and red cell volumes), pH, Paco2, and serum concentrations of sodium, potassium, chloride, lactate, ionized calcium, phosphate, albumin, and total protein were measured before and 20 min after completion of ANH. Strong ion difference was calculated as serum sodium plus serum potassium minus serum chloride minus serum lactate. The amount of weak plasma acid was calculated using a computer program. RESULTS After ANH, blood volume was well maintained in both groups. ANH caused slight metabolic acidosis with hyperchloremia and a concomitant decrease in strong ion difference. Plasma albumin concentration decreased after hemodilution with 6% hydroxyethyl starch solution and increased after hemodilution with 5% albumin solution. Despite a three-times larger decrease in strong ion difference after ANH with 6% hydroxyethyl starch solution, the decrease in pH was nearly the same in both groups. CONCLUSIONS ANH with 5% albumin or 6% hydroxyethyl starch solutions led to metabolic acidosis. A dilution of extracellular bicarbonate or changes in strong ion difference and albumin concentration offer explanations for this type of acidosis.
2.
Individualized hemodilution in acute brain infarct using a 20% albumin solution and physiological saline solution Dutch
Goslinga H, Eijzenbach V, Heuvelmans JH, van de Nes JC, Kurk RM, Bezemer PD
Nederlands Tijdschrift voor Geneeskunde. 1992;136((49):):2422-8.
Abstract
OBJECTIVE To determine the effect of normovolaemic haemodilution in patients after a cerebrovascular accident. DESIGN Prospective, randomized clinical trial. SETTING St Lucas Hospital, Amsterdam. METHOD Normovolaemic haemodilution was achieved by means of bloodletting and administration of a 20% solution of albumin plus crystalline infusion fluids under haemodynamic and rheological monitoring during the acute phase of the cerebral infarction. All patients were subjected to general intensive care and monitoring with a pulmonary artery catheter. This custom-tailored fluid therapy was guided by a pulmonary wedge pressure of 12 mm Hg (SD 3) and a haematocrit (Ht) of 0.32 l/l (SD 0.02). The control group only received individually dosed rehydration with crystalline infusion fluids. Endpoints of the study after 3 months were mortality and dependence/independence concerning everyday functioning. RESULTS The results in the total haemodilution group and the control group did not differ significantly. However, in the subgroup with normal Ht (< 0.45 l/l; n = 201) there was a significant reduction (p < 0.05) of the mortality after 3 months (27% and 16%, respectively) and an increase of independence at home (35% and 48%, respectively) due to a reduction of the viscosity by means of haemodilution with albumin (a specific viscosity effect in the normovolaemic group). In the control group with raised Ht (dehydration; Ht > or = 0.45 l/l; n = 50) there was a significant decrease (p < 0.005) of the mortality after 3 months (27% and 8%, respectively) and an increase of independence at home (35% and 59%, respectively) compared with the control group with normal Ht without signs of dehydration (Ht < 0.045 l/l; n = 102), due to rehydration exclusively with crystalline infusion fluids (a specific rehydration effect in the dehydrated group). CONCLUSION In cerebrovascular accident patients haemodilution should be adjusted individually; in normovolaemic patients haemodilution should be carried out with an albumin solution; the higher the Ht, the more rehydration with crystalline infusion fluids is to be carried out.