| Objetive : To investigate the effects of acute hypervolemic hemodilution(AHHD) with 6% hydroexythyl starth 200/0.5 on platelet glycoprotein Ilb/IIIa Complex, GMP-140 and Von Willebrand Factor .Methods: Forty patients, ASA grade I-II, undergoing elective esophageal carcinoma surgery were randomly divided into hemodilution group(n=20) and control group (n=20). Patients with cardiac, pulmonary, renal, and hepatic diseases were excluded. The mean age of the patients was 52.73+7.13yr, the mean weighing was 64.26 +8.3kg. Their bleeding time , clotting time and blood routine were in normal range preoperatively. The patients were premedicated wjth intramuscular atropine O.Olmg/kg and diazepam 0.2mg/kg before operation. Anesthesia was induced with IV thiopentone 4-6 mg/kg, fentanyl 2-4 ug/kg and scoline 1-2 mg/kg in both groups. After tracheal intubation, the patients were mechanically ventilated. Anesthesia was maintained with 2.0%-2.5% isoflurane and 0.5 L/min 02, injecting boluses of musle relaxant as required intermittent intravenous,and measuring BP, MAP, HR SPO2, and ECG were continuously measured in the whole operation. Internal jugular vein was cannulated for CVP monitoring and blood sampling. The concentration of PETCO2 was mainteined at 30-40 rnmHg. Before anesthesia 5% glucose-normal saline 8-10 mg/kg was infused compensated for food and water fasting overnight. 6% HES 200/0.5 15 ml/kg was infused in the hemodilution group after anesthesia was stable in 25-20 minutes, and the rate of infusion was adjusted by BP, MAP, HR and CVP to avoid circulatory overload. During operation blood loss was replaced with equal volume 6% HES, replacing of others fluid loss with glucose-normal saline. Blood routine, prothrombin time (PT) and activated partial thromboplastin time (APTT) were checked at 30 minutes before and after hemodilution in hemodilution group. The blood samples were analyzed before operation, beginning operation, 1 hour after operation and the end operation using the flow cytometric assay to measure the platelet surface glycoprotein Ilb/IIIa Complex, GMP-140 and Von Willebrand factor. At the same time PT and APTT were also checked.Results: There were not significantly changes on the year, the weighing, the types and time of operation and blood loss in both groups. In hemodilution group, the level of Hct and concentration of hemoglobin decreased from 41.16+3.85 to 29.70 + 4.37 and from 135.91 + 11.04 to 107.62+10.81respectively. Hb, Hct and PLT decreased significantly after AHHD as compared- with those before AHHD, CVP increased significantly after AHHD, but in normal range. There were not siginificantly changes between HR and MAP during operation in two groups. PT was significantly prolonged after hemodilution, but there was not significantly change in APTT with only a few of prolongation, during operation, the shortening of PT and APTT were significant in both groups, which were aslo significant in respective group. During operation the expressions of GP Ilb/IIIa, vWF and GMP-140 on the platelet membrane surface glycoprotein were significantly increased, whereas the expressions were significantly decreased in hemodilution group.Conclusions: AHHD with 6% HES 200/0.5 inhibits the expressions of the platelet membrane glycoproteins Ilb/IIIa, vWF and GMP-140, and platelet activation, adhesion and aggregation, which may contribute to the impairment of platelet function, whereas the coagulation state is not influenced as shown by PT and APTT; AHHD is a safe and effective method with 6% HES 200/0.5 as expander, because the blood transfusion can be decreased and the hemodynamic is stable; The mechanism of depressing the activating of platelet by AHHD will be further studied in the future.
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