Effects Of Acute Hypervolemic Hemodilution On Body Environment In Patients Undergoing Abdominal Surgery

Objective: To compare the effect of acute hypervolemic hemodilution (AHHD) on hemodynamics, electrolytes and acid-base equilibrium by Voluven and Lactated Ringer's solution (LR) in patients undergoing abdominal surgery.Methods:32 patients undergoing abdominal surgery with ASA statusⅠ/Ⅱ, age from 30 to 68, hematocrit (HCT) above 36% and hemoglobin (HB) above 110g/L are selected. No hypertension, diabetes, water-electrolyte imbalance, acid-base imbalance and diuretics using recently could be detected when admitting. The patients were randomly assigned to receive either Voluven (Group V, n=16) and LR (Group R, n=16). All patients were received general anesthesia combined epidural anesthesia after routine preparations. Respiration was controlled during surgery. The patients were received 6-8mL/kg LR to supplement the lost body fluid before the operation and 6% HES [predicted volume of infusion= predicted blood volume x (HctbeforeAHHD-HctafterAHHD) /Hctafter AHHD] for hemodilution. The same volume Voluven and LR were infused before 20-40 minutes of surgery until HCT was 26%. Arterial blood sample were obtained at before AHHD (T1), after AHHD (T2),30min after AHHD (T3) for electrolytes, blood gas analysis and hemodynamics. Make a contrast analysis with the change of the criterions.Results:1. There were no significant differences in volume expansion time between group V and group R (p>0.05). Group V's volume expansion ratio is higher than group R's obviously (p<0.05). The blood volume increased obviously to 23.6±9.2% at 30min after AHHD.2. There were no significant differences in HR and MAP between group V and group R (p>0.05). All patients'CVP were higher than the criterions before AHHD (p<0.05). Group V's was higher than Group R's obviously.3. The change of electrolytes:Group V:Na+, Cl- increased (p<0.05). K+, Ca2＋decreased (p<0.05). K＋decreased to 3.6±0.8 mmol/L at 30min after AHHD.Group R: Na＋decreased (p<0.05). There were no significant differences in K+, Cl-and Ca2＋(p>0.05).4. The change of blood routine and acid-base equilibrium:Group V: B, PH, BE, HCT, HCO3-, LAC-, PaCO2 decreased (p<0.05).Group R:HCO3-, BE, HB, HCT decreased (p<0.05). There was no significant differences in PH and PaCO2. Lac- decreased after temporary increase.Conclusion:1. AHHD with Voluven is effective and safe. Hemodilution can be quick and accurate with Voluven. And Voluven is more reliable than LR in volume expansion effect obviously.2. CVP significantly increased after AHHD with Voluven. The patients who have poor cardiac compensation should use it cautiously and have a seriously examination about their heart function.3. K＋and Ca2＋decreased after AHHD with Voluven, and AHHD with Voluven can cause slight metabolic acidosis. These problems should be handled in time.