The effect of pH adjustment of 1% lidocaine on the onset of sensory and motor blockade of epidural anesthesia in nonpregnant gynecological patients

Abstract

Using a double-blind randominzed study protocol, we examined the distribution of sensory blockade and the quality of motor blockade after epidural anesthesia with 1% lidocaine with or without bicarbonate in nonpregnant gynecological patients. Alkalinization significantly decreased the time to onset of sensory blockade. However, there were no statistically significant differences between the low-pH and high-pH groups with respect to motor blockade or the distribution of sensory blockade. We conclude that pH-adjusted 1% lidocaine offers the advantage of a more rapid onset of sensory blockade, while motor blockade and the distribution of anesthesia are unaffected by pH change in epidural anesthesia. © 1994 JSA.