Level of sensory block and baricity of bupivacaine 0.5% in spinal anesthesia.

INTRODUCTION Bupivacaine is anesthetic often used in spinal anesthesia in the hyperbaric form (with factory-made incorporated 8.25% glucose), and in isobaric form without additives, (so-called "plain"). Baricity manipulation of local anesthetic is made for the better match of necessary and achieved level of sensor block. Too high block is unnecessary and can compromise the patient's hemodynamic status. OBJECTIVE To compare gained height and coherence of sensor block using hyperbaric and isobaric 0.5% bupivacaine. PATIENTS AND METHODS Sixty patients were subjected to the elective operating orthopedic, urological or gynecological surgery in spinal anesthesia. Randomly selected thirty patients received 3 ml of hyperbaric 0.5% bupivacaine, while thirty others received 3 ml of isobaric 0.5% bupivacaine by an identical protocol. After application of anesthesia, the development of all modalities of the block was checked. Finally, after 20 minutes, the height of sensor blocks were determined by an insulin needle (pin-prick test) and that value was taken as the final. RESULTS All blocks were sufficient to perform surgery. In the hyperbaric group the highest recorded level of the block was first thoracic segment-T1 (3.33%) and the lowest level was seventh thoracic segment T7 (6.66%). In the isobaric group the highest recorded level was T5 (3.33%) and the lowest was L2 (3.33%). Modus as the most frequent value in the series of the hyperbaric group was T5, and in the isobaric T10 (p < 0.01). CONCLUSION Hyperbaric 0.5% bupivacaine because of the amount of the block may be adequate for all operational procedures that are made in the spinal anesthesia, but sometimes gives unnecessary high block that can give significant changes in the pressure and in the pulse. Isobaric 0.5% bupivacaine gives a very comfortable anesthesia for surgeries in which sensory block of T10 is sufficient.