The Effect of the dose of local anesthetics and other influential factors on the spread of epidural block in elders

Objective To evaluate the effect of the influential factors including the dose of local anesthetics,gender and puncture site on the spread of epidural block.Methods Three thousand elders,above 65 years old,were studied retrospectively.Multiple regression was used.Results The multiple regression equation of the spread of epidural block for elders above 65 years old is: Y(dermatome levels blocked)=3.719 0+0.080 4·X1(age)-0.823 0·X2(puncture site)-0.014 0·X3(height)+0.145 7·X0.854(initial dose).The order of the extent of the factors' effect was be agedoseheightpuncture site.The rectificatory parameters may include other influential factors that were not counted in this study.Conclusion The relation between anesthetic dose for epidural block and spread of block is represented as an exponential correlation.The effect of each influential factor had different extent.The equation got from this study can provide some guidance in clinical practice.