Effect Of Acute Hypervolemic Hemodilution On Plasma Electrolytes And Acid-base Equilibrium

Objective: To investigate the effect of acute hypervolemic hemodilution (AHHD) on plasma electrolytes and acid-base equilibrium.Methods:Fourteen ASA Ⅰ Ⅱ patients(6 male,8 female) undergoing elective orthopedic surgery were entered in this study. After induction of anesthesia the patients received 10ml·kg^-1 Ringer's solution and 6% HES [predicted volume of infusion= predicted blood volume × (Hct_{before AHHD}-Hct_{after AHHD})/ Hct_{after AHHD}] within 20-30min . Arterial blood samples were taken every 10 minute for determination of the plasma electrolytes, acid-base equilibrium and the degree of hemodilution. And during the hemodilution the heart rate (HR),mean arterial blood presure (MAP) and central vein pressure (CVP) were continuoused to monitor.Results:After AHHD the plasma sodium concentration, chloride concentration and CVP increased (p≤0.05 ),but the lactate concentration bicarbonate concentration,Hct, Hb and BE decreased (p<0.05) .The pH value drcreased slightly but without statistical meaning.The other values did not change during the hemodilution. Conclusion: 1) After AHHD ,the Hct value can decreased to the predicted value(Hct=0.26). AHHD with the formula[ predicted volume of infusion= predicted blood volume X (Hct_{before AHHD}- Hct_{after AHHD})/ Hct_{after AHHD}] was effective and safe .2)AHHD can chang the plasma electrolytes slightly but can not induce the acid-base unequal.The colloid with more "physiologic" composition could be the key of keeping the balance of acid-based during the AHHD.