Sympathetic-Block Persistence After Spinal or Epidural Analgesia

A PATIENT who had received an epidural block for a surgical procedure was observed to have gained return of both motor and sensory functions, so was permitted to become ambulatory. However, the patient fainted when he stood up. A possible explanation of this phenomenon is that sympathetic function, which might have produced vasoconstriction and prevented pooling of blood in the lower extremities, was still blocked. To learn whether or not this might have been true, a series of measurements of duration of loss of motor, sensory, and sympathetic functions following blocks of the lower part of the body were made. Method Ninety-six patients who were to have regional analgesia for surgical procedures were studied. Forty-two of these had epidural anesthesia, and 54 had spinal blocks. The psychogalvanic reflex (PGR), which "is a definite indication of whether or not a sympathetic nerve block, either chemical or surgical has been obtained,"1,2