INFLUENCE OF BARICITY ON THE OUTCOME OF SPINAL-ANESTHESIA WITH BUPIVACAINE FOR LUMBAR SPINE SURGERY

Background and Objectives. Although the majority of elective lumbar sp ine surgical procedures are performed under general anesthesia, succes sful use of spinal and epidural anesthesia has been reported. This stu dy was designed to evaluate the influence of baricity on the performan ce of spinal anesthesia for lumbar spine surgery. Methods. The study w as performed on 53 demographically similar American Society of Anesthe siologists status 1 and 2 patients who were randomly assigned to recei ve spinal anesthesia with 15 mg of bupivacaine along with 0.2 mg of ep inephrine as either 3 mL 0.5% plain bupivacaine (I group) or 2 mL 0.75 % bupivacaine (Sensor-caine Spinal, Astra, Westborough, MA) premixed i n 8.25% glucose (H group). All blocks were placed with a 22-gauge Quin cke needle (Becton Dickinson, Franklin Lakes, NJ) at the L3-L4 intersp ace with the patient in the sitting position. Subsequent data, collect ed by a blinded observer, included onset of motor and sensory anesthes ia, highest sensory level achieved, maximum changes in heart rate and blood pressure, need for treatment of heart rate or blood pressure dec reases, failed blocks, and need for supplemental local anesthetic inje ction to complete incision or wound closure. Results. The time to onse t for complete motor and sensory block was significantly longer in the I group. The maximum sensory level achieved was higher in the H group , and the maximum drop in blood pressure and number of interventions t o treat heart rate and blood pressure were greater in the H group. The re were two failed blocks, which were repeated successfully, in the H group. The need for local anesthetic infiltration of the wound with in cision and closure was greater in the H group. Conclusions. Plain bupi vacaine is superior to hyperbaric bupivacaine for spinal anesthesia fo r elective lumbar spine surgery.