The Variation Of Inferior Vena Cava Guides Fluides Management In Patients Undergoing Lower Extremity Surgery

Objective: To explore the clinical application value and significance of inferior vena cava variability index(IVCV)in guiding intraoperative fluid management in patients undergoing mechanical ventilation under general anesthesia in lower extremity surgery in the supine position.Methods: A total of 60 patients who underwent lower limb surgery under general anesthesia in the supine position in our hospital from October 2021 to December 2022 were randomly divided into the experimental group(inferior vena cava variability group)and the control group(traditional rehydration group)with 30 cases in each group according to the surgical method performed during the operation.In the experimental group,the feasibility and clinical value of inferior vena cava variability index as the standard of intraoperative fluid management under mechanical ventilation under lower extremity general anesthesia were observed.In the control group,the traditional rehydration scheme was used for intraoperative fluid management under general anesthesia.In the experimental group,intraoperative fluid therapy was guided by the variability index of the inferior vena cava measured by ultrasound on the longitudinal axis of the subxiphian level.After anesthesia induction,ultrasound was performed every30 minutes to measure the variability of the inferior vena cava and intraoperative fluid management was carried out according to the fluid response of the patients.The mean arterial pressure(MAP),heart rate(HR),intraoperative vasoactive drug dosage,fluid intake,urine volume,blood loss,postoperative lactic acid value,incidence of tourniquet reaction and discharge time were compared between the two groups at every 15 minutes after induction(T1-T9).Results: There was no significant difference in the variation rate of mean arterial pressure between the two groups,but the average value of the experimental group was lower than that of the control group.The mean arterial pressure of the control group was higher than that of the experimental group at T1-T7,and the mean arterial pressure of the experimental group was more stable during the operation.The mean arterial pressure at different time points showed a trend of change with time,and there was an interaction effect between group and time.Comparison of heart rate variability between the two groups showed that there was a statistically significant difference in mean arterial pressure variability between the two groups,and the average value of the experimental group was lower than that of the control group.The heart rate of the control group was higher than that of the experimental group at T1-T7,and the heart rate level of the experimental group was more stable during the operation.The mean arterial pressure in the group changed with time at different time points,and there was an interaction effect between group and time.The volume of fluid intake,dosage of vasoactive drugs,postoperative lactic acid and discharge time were compared between the two groups.There was no significant difference in urine volume and bleeding volume between the two groups.The infusion volume and dosage of vasoactive drugs in the experimental group were lower than those in the control group,and the lactic acid value was higher,while there was no significant difference in urine volume and bleeding volume.The incidence of tourniquet reaction was lower in the experimental group.Conclusion: To a certain extent,the variability index of inferior vena cava measured by ultrasound can provide non-invasive,economical and reasonable fluid management during lower extremity surgery under general anesthesia and mechanical ventilation.It can reduce intraoperative fluid infusion and the dosage of vasoactive drugs under the premise of maintaining a stable circulation,and has certain clinical value.