title: Integrated electromyographic measurement of abdominal motor blockade during bupivacaine epidural anesthesia for lower abdominal and pelvic surgery.
abstract: The onset and regression of abdominal motor blockade was monitored with integrated electromyography in eighteen patients undergoing pelvic or lower abdominal surgery during lumbar epidural anesthesia using 0.75% bupivacaine with 1:200,000 epinephrine. The integrated electromyograph (EMG) was measured at the T-6, T-8, T-10 and T-12 dermatomes during a standardized head-raising test before anesthesia and at fixed time intervals thereafter for a minimum of four hours. Simultaneous measurements were made of abdominal sensory block (analgesia to Allis forceps pinch expressed in dermatomes) and lower limb motor blockade (Bromage scale). Motor block at a given dermatome level was defined as reduction of the integrated EMG amplitude to less than 20% of control. Mean maximum level of sensory block was T-4.2 +/- 0.6 (SEM) mean maximum level of motor block was T-8.8 +/- 0.5. The mean motor sensory differential varied between 4.5 +/- 0.6 and 5.3 +/- 0.9 segments over the 4-hr study period. Mean time to maximum abdominal sensory block was 28 +/- 3 min, and maximum abdominal motor block was 29 +/- 6 min. Mean time to two-segment regression of abdominal motor block was 94 +/- 18 min and to two-segment regression of abdominal sensory block, was 150 +/- 18 min.
mesh_terms: D000005:Abdomen / Q000601:surgery*; D000767:Anesthesia, Epidural / Q000379:methods*; D002045:Bupivacaine / Q000008:administration & dosage; D004576:Electromyography; D004837:Epinephrine / Q000008:administration & dosage; D005260:Female; D059685:Herniorrhaphy; D006801:Humans; D007045:Hysterectomy, Vaginal; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010052:Ovariectomy; D010388:Pelvis / Q000601:surgery*; D012002:Rectal Diseases / Q000601:surgery; D013126:Spinal Nerve Roots / Q000502:physiology
chemical_list: D002045:Bupivacaine; D004837:Epinephrine