Effect Of Limb Ischemic Reperfusion Injury On Blood Coagulation By Thrombelastography

Objective To investigate the effect of limb ischemic reperfusion injury on blood coagulation by thrombelastography and the hemodynamic changes during the operation of knee arthroscopy under epidural anesthesia.Methods Eighteen patients scheduled for unilateral knee arthroscopy surgery under epidural anesthesia were involved in this study, ASAⅠ~Ⅱ. The limb ischemic reperfusions were achieved by the inflatable tourniquet during the operation. The operation were performed by the same group of surgeons. Pentobarbital sodium 0.1g and atropine 0.5mg were given by intramuscular injection as premedication 30 min before surgery. Ringer lactate was infused at the speed of 0.2 ~ 0.25 ml/kg/min before anesthesia. At the same time epidural puncture was performed and 1% lidocaine 3ml was given as test dose. When the liquid was infused to 12ml/kg, the mixture with 1% lidocaine and 0.375% ropivacaine was applied to adjust the upper block field about in T8. The limb ischemic reperfusions were achieved by the inflatable tourniquet before the surgery. The inflate pressure was 2 times systolic blood pressure. Venous bloods were drawn at following timepoints: before tourniquet inflated (T1), 30min after tourniquet inflated (T2), 3min after tourniquet deflated (T3) and 30min after tourniquet deflated (T4). Then the blood coagulation parameters were measured by thrombelastography with kaolin as activating agent. The reaction time (R), the coagulation time (K), alpha angle (α), maximal amplitude (MA) and fibrinolytic activity index (LY30) were recorded. Heart rate (HR), mean arterial pressure (MAP), respiratory rate (RR) and pulse oxygen saturation (SpO2) were also recorded at the same time. If the patients' hemodynamic was instability, such as MAP was less than 55 mmHg, 10mg ephedrine was given as vasoactive drugs to improve the blood pressure.Results Compared with those at T1, MAP increased significantly (P <0.05) and HR decreased significantly (P <0.05) at T3. There were no significant difference in RR and SpO2 among the four timepoints. Only one case was needed ephedrine 10 mg iv for the MAP less than 55mmHg. There were a hypercoagulable tendency of low R, low K, high MA and increaseαin TEG at T3, but this kind of change was in the normal range. There were no significant difference among the four time points (P>0.05).Conclusion Limb ischemic reperfusion injury can affect pateiens'hemodynamics. But it has no singnificant effect on and blood coagulation. Objective To investigate the effect of progressive haemodilution with two kinds of hydroxyethyl starch (HES130/0.4 and HES200/0.5) on blood coagulation in vitro .Methods Twenty-four patients scheduled for surgery were involved in this study, ASAⅠ~Ⅱ. All patients were randomly assigned to two groups: HES130/0.4 group and HES200/0.5 group with 12 each. Pentobarbital sodium 0.1g and atropine 0.5mg were given by intramuscular injection as premedication 30min before surgery. After entering the operating room, upper limb vein was opened and venous blood samples were obtained. Blood samples were diluted to different concentration(s25%, 50% and 75% ) with different Hydroxyethyl starch. Blood coagulation parameters were measured by thrombelastography with Kaolin as activating agent. The reaction time (R), the coagulation time (K), alpha angle (α), maximal amplitude (MA) and fibrinolytic activity index (LY30) were recorded.Results Parameters were not affected by 25%dilution(P>0 05) in both groups. Compared to those in HES 130/0.4 group, R and K at 50% dilution were significantly longer and angleαand MA were significantly lower in HES 200/0.5 group (P <0.05). Compared to those in HES 130/0.4 group, R and K were significantly much longer while angleαand MA were significantly much lower at 75%dilution in HES 200/0.5 group (P<0.01). LY30 data had not statistical difference at various concentrations between two groups.Conclusion Mild hemodilution with HES 130/0.4 and HES 200/0.5 have no effect on blood coagulation. Moderate and severe hemodilution with HES 130/0.4 and HES200/0.5 have significant influence on blood coagulation. The influence caused by HES 130/0.4 is significantly less than that by HES 200/0.5.