THE ADDITION OF PHENYLEPHRINE CONTRIBUTES TO THE DEVELOPMENT OF TRANSIENT NEUROLOGIC SYMPTOMS AFTER SPINAL-ANESTHESIA WITH 0.5-PERCENT TETRACAINE

Background Recent reports indicate that transient neurologic symptoms commonly occur after single-injection spinal anesthesia with lidocaine . Information regarding tetracaine has been limited to a single case r eport. In addition, little is known about the cause of these symptoms or the cofactors that affect their occurrence. The present study sough t to determine whether the presence of phenylephrine or the concentrat ion of glucose in the anesthetic solution affects the incidence of tra nsient neurologic symptoms after spinal anesthesia with 0.5% tetracain e. Methods: One-hundred sixty patients classified as American Society of Anesthesiologists physical status I or II who were scheduled for el ective surgery on a lower limb or perineum were sequentially assigned to one of four equal groups to receive intrathecal 0.5% tetracaine in 7.5% or 0.75% glucose, with or without 0.125% phenylephrine. Patients were evaluated on postoperative day one for the presence of pain, dyse sthesia, or both in the legs or buttocks by an investigator unaware of the drug given. Results: Symptoms were present in 10 patients (12.5%) receiving a spinal anesthetic containing phenylephrine, but in only o ne patient (1.3%) receiving spinal anesthesia without phenylephrine. T here was no significant difference in the incidence of symptoms betwee n groups receiving 7.5% glucose and those receiving 0.75% glucose (8.8 % and 5% of patients, respectively). Conclusions: These results sugges t that adding phenylephrine to tetracaine for spinal anesthesia increa ses the potential for transient neurologic symptoms, but that the conc entration of glucose does not affect their occurrence.