Spread of Epidural Anesthesia

Abstract

  The spread of epidural anesthesia is highly variable among individuals. A large number of studies have attempted to clarify the reason for this variability. Some of the variability is intrinsic to the patient, and is not dependent on variations in technique or the drugs administered. Some intrinsic factors, such as age, are poorly correlated with the spread of anesthesia. The author proposed the hypothesis that differences in the surface area of the lumbosacral dura, epidural fat volume, and epidural venous plexus velocity might explain the variability in the extent and duration of epidural anesthesia with ropivacaine. According to the results of the study performed by the authors, the dural surface area may influence the spread of epidural anesthesia with ropivacaine, and posterior fat volume may influence the duration of epidural anesthesia in healthy patients within a narrow age range.