Spinal anesthesia with 0.5% isobaric bupivacaine (Marcaine^® spinal)

Abstract

The effects of spinal anesthesia with 0.5% isobaric, hyperbaric bupivacaine solutions (Marcaine^® spinal) and 0.5% isobaric tetracaine solutions were investigated in 35 patients undergoing operations of lower abdomens and lower extremities. The patients who received isobaric bupivacaine solutions had a slower onset and cephalad spread of analgesia (T₇-T₈), which lasted longer (3-4h) and was accompanied by less hypotension than those who received hyperbaric bupivacaine solutions. The degree of motor paralysis in the isobaric bupivacaine solutions was also more intense than that in the hyperbaric bupivacaine solutions. 0.5% isobaric tetracaine solutions had effects similar to that of 0.5% isobaric bupivacaine solutions. The hyperbaric bupivacaine solutions with good muscle relaxations are suitable for lower abdominal surgery lasting about 2h, while the isobaric bupivacaine and tetracaine solutions that produced a less hypotension could be useful for relatively older patients undergoing longer operations of lower extremities and urological surgery lasting about 3h.