Clinical Study On Volume Monitoring And Fluid Therapy In Patients Undergoing Craniotomy

Volume therapy is an integral part of clinical anesthesia; the correct volume treatment is based on the accurate volume monitoring. The traditional indicator of volume monitoring is static monitoring indicators, such as central venous pressure, pulmonary artery wedge pressure.These monitoring indicators susceptible to circula-tory function, anesthesia, stress and other factors, have a certain imperfect and hyste-resis. Stroke volume variation (stroke volume variation, SVV) is one of the function-al hemodynamic monitoring parameters, which turn out to be a sensitive indicator on predicting the volume status and fluid responsiveness. FIoTrac/Vigileo(?) monitoring system measured SVV in real time and dynamically, is a simple, less invasive means of care, and a large number of studies have confirmed its effectiveness and accuracy.At present, there is a lot of controversy on fluid therapy strategy except volume monitoring. The timing of the infusion, dosage, species will affect the prognosis. The volume status of neurosurgery patients is not easy to accurately assess. The vo-lume status is often in a negative balance owing to preoperative fasting, vomitting and diuretics. Long operation time and a large amount of bleeding lead to intraoperative individual differences of volume status. Neurosurgeons advocate restrictive fluid therapy in order to avoid the occurrence of postoperative cerebral edema, but restric-tive fluid therapy easily lead to insufficient volume, which affect tissue perfusion and is not conducive to the recovery of patients. Infusion strategy of a fixed amount can prevent perioperative obvious shortage or excess volume, but did not consider indi-vidual differences and preoperative volume status and therefore can not meet the pe-rioperative changing demand for fluid. Choose the right treatment and the right kind of fluid is critical. Different transfusion strategies in neurosurgical patients should be further explored. Selecting appropriate treatment proposal and the right kind of fluid is critical. The effect on neurosurgical patients with different transfusion strategies should be further explored. Part I The consistency of change of stroke volume variation and blood volume change in assessing volume statusObjective:To study whether there is a consistency between the change of stroke vo-lume variation (SVV) and blood volume change, and confirm the effectiveness and accuracy of SVV guided volume therapy.Methods:Twenty ASA classification I-II patients of either sex aged20-60yr with BMI<30kg·m-2undergoing selective neurosuigery were enrolled.The patients were randomly divided into2groups(n=10each):group crystal(Plasma-Lyte A) and group colloid (6%hydroxyethyl starch130/0.4).Volume expanding is not applied before in-duction. After induction Plasma-Lyte A solution or6%hydroxyethyl starch solution15ml/kg was infused over30min followed by continuous infusion at0.1ml/kg dur-ing the next60min in both groups. Hb concentration and Hct were measured by radi-al artery blood sample every5min during the first30min and then every10min in the next60min and changes in blood volume amount were calculated, stroke volume variation(SW), central venous pressure(CVP), Heart rate(HR) and blood pressure(BP) were also recorded.Results:We found a negative correlation between ΔSVV and ABV/kg in Group Crystal(r=-0.964, P<0.001; Linear regression equation ΔBV/kg=-1.079ΔSVV-0.143,slope test P<0.001) and in Group Colloid (r=-0.956, P<0.001; Linear regres-sion equation ΔBV/kg=-1.330ΔSVV-0.434slope test P<0.001). After the end of the infusion, the blood volume of the crystal group decreased rapidly and SVV values rise rapidly; there is a slow decline in blood volume and a slow increase of SVV value in colloid group. Conclusion:There is a negative correlation between change of stroke volume varia-tion and blood volume change in assessing volume status, and SVV has a capacity of predicting the volume status. Colloidal blood volume expansion effect is better than crystal. Part II Clinical effect of different fluid therapy directed by SW in neurosurgical patientsObjective:To evaluate the effect of different protocols of fluid therapy directed by SVV on intracranial pressure, cerebral oxygen supply-demand balance, and get better fluid therapy strategies.Methods:Forty ASA grade I-II patients aged20-60years with BMI<30kg-m-2un-dergoing elective craniotomy were included in the study. The patients were randomly divided into2groups(n=20each):group crystal(Ringer’s lactate) and group colloid (6%hydroxyethyl starch130/0.4). After induction, patients were infused with Ringer’s lactate solution at a rate of4ml/kg/h in both groups. Fluid management was guided by SVV (Vigileo/FloTrac system). The aim was to maintain the SVV between10-12%using crystal or colloid in different group. At the six time point of To(after induc-tion),T1(after SVV stabilization),T2(before opening the dura),T3(after tumor resection), T4(after meningeal stitched),T5(before the end of surgery), heart rate(HR), mean ar-terial pressure(MAP), central venous pressure(CVP), cardiac output index(CI) were recorded. Blood sample from the radial artery and jugular bulb were collected for measurement and calculated for arterial-jugular oxygen content difference(CajvO2), cerebral oxygen uptake rate(CERO2), arterial-jugular vein glucose differ-ence(A-JvGD)and arterial-jugular vein lactate difference (A-JvGD). Brain relaxation was scored by the surgeon upon opening the dura. Total fluid infusion, urinary output, blood loss, blood transfusion, and use of vasoactive drugs were also recorded.Results:There was no significant difference in jugular bulb venous oxygen satura-tion(SjvO2), CajvO2, CERO2, A-JvGD Glu and A-JvLD among groups and different points of time(P>0.05). In both groups, compared with the SjVO2value at the moment of To, the value at the moment of T3decreased significantly(group crystal:P=0.016; group colloid:P=0.026); in group crystal, CajvO2significantly decreased after me-ningeal stitched and before the end of surgery(P<0.05and0.001, respectively); CERO2was significantly increased after tumor resection in both groups(group crystal: P=0.032; group colloid:P=0.009). There were no difference in brain relaxation, uri-nary output, blood loss, blood transfusion and vasoactive drugs use. Total volumes of fluid administered in group crystal was significantly higher than that in group collo-id(group crystal:3070±1138ml vs group colloid:2041±758ml, P=0.002).Conclusion:In this study, goal-directed therapy by SVV with crystalloids or colloids during neurosurgery have no different effect on intracranial pressure and cerebral oxygen supply-demand balance.