Volume Kinetics Of Ringer's Solution During Induction Of Anesthesia

OBJECTIVESTo investigate volume kinetics of Ringer's solution during induction of general anesthesia or epidural anesthesia, implore whether the age is an affective factor on the volume kinetics of Ringer's solution and observe whether the volume infusion could prevent the hypotension in anesthesia .METHODSThe kinetics of an i.v. Infusion of 1000ml of Ringer's solutions over 60 min was studied in fifty-three ASA 1-2 elective surgical patients undergoing epidural (EA) or general (GA) anaesthesia. Group EA was divided into the aged group (EA1, aged 67-86, 11 cases) and the young aged group (EA2, aged 28-62, 11 cases). Group GA was also divided into the aged group (GA1, aged 66-85, 15 cases) and the young aged group (GA2, aged 24-60, 16 cases). Patients in EA group were induced 10 min and in GA were 20 min after the i.v. infusion. Arterial blood (2.0ml) was collected before the i.v infusion and every 5 min during the study period of 60 min. We used blood gas analyzer Istat to measure the B-Hb concentration and calculated the plasma dilution, volume increase, volume retained and volume expansion with volume equation. The patients were monitored with SAP/DAP,MAP,HR and SPO₂.The SPSS2.0 software was used to analyze these data.RESULTSIn EA groups,the pressure had no significant change between each recorded time and the basline(p>0.05).ln GA,the MAP had statistically significant change from the induction time(25 min after infusion) till the study end(p<0.01). There were statistically significant MAP reduced between GA and EA under the young aged group or aged group(p<0.05).. After the i.v. infusion of 1000 ml of Ringer's solution, the kinetic parameters such as the plasma dilution (P<0.01), the fluid retained in vessel (P<0.05) and volume expansion were more than in patients of EA group.The induction resulted in similar changes in volume kinetic parameters in different age patients under the same anesthesia (P>0.05).CONCLUSIONSThe age did not affect the effect of volume expansion of Ringer's solution. The induction of general anesthesia resulted in significant changes in volume kinetic parameters than epidural anesthesia. Volume expansion of infusion of Ringer's solution in this study could possibly prevent arterial hypotension in epidural anesthesia.