Individualized Factors Affecting The Diffusion Of Continuous Epidural Anesthesia In Labor Analgesia

Objective: To investigate the main individualized factors affecting the sensory block level of continuous epidural anesthesia during labor analgesia by measuring the general factors and lumbar dural sac dimensions of parturients.Methods: A total of 162 parturients who met the inclusion criteria for labor analgesia were included in this study.Continuous epidural anesthesia was performed in L2-L3 intervertebral space,and an electronic infusion pump containing sufentanil(0.4ug/ml) and 0.08% ropivacaine was connected.The efficacy of labor analgesia was evaluated by visual analogue scale(VAS),and the upper bound of sensory block level was tested by acupuncture,alcohol cotton and cotton swab.The age,height,weight,BMI(body mass index),abdominal circumference,uterine height,spinal length,amniotic fluid index,newborn weight,lumbar dural sac dimensions(diameter,length,surface area and volume of dural sac)were recorded in 160 parturients.According to whether the maternal VAS score can decline to 3 points within 30 minutes,the parturients are divided into two groups: "ideal analgesia" and "non-ideal analgesia",and compare the groups by t test to screen out statistically different variables to enter the next step of analysis.Bivariate linear correlation analysis was used to analyze the correlation between sensory block level and six predictive indexes,such as height,BMI,spine length,dural sac length,dural sac surface area and dural sac volume.Multiple linear regression analysis was used to establish a model for predicting the peak sensory block level.Results: The height,BMI,abdominal circumference,spinal length,dural sac diameter,dural sac length,dural sac surface area and dural sac volume were significantly different between the "Ideal analgesia" group and "unsatisfactory analgesia" group(P<0.05). Linear correlation analysis showed that height,BMI,spine length,dural sac length,dural sac surface area and dural sac volume were significantly correlated with the sensory block level during continuous epidural anesthesia(P<0.05).Multiple linear regression analysis showed that:(1)Dural sac length,BMI and dural sac surface area were important predictors of the peak pain block level(P<0.05);(2)Dural sac length,BMI and dural sac volume were important predictors of the peak temperature block level(P<0.05);(3)Dural capsule length and BMI were important predictors of the peak tactile block level(P<0.05).Conclusion:(1)The sensory block level of maternal continuous epidural anesthesia was negatively correlated with height,spine length,dural sac length,dural sac surface area and dural sac volume,and positively correlated with BMI.(2)The maternal BMI,dural sac length,dural sac surface area and dural sac volume have higher clinical predictive value for the sensory block level during continuous epidural anesthesia.