Abstract
Baricity of a drug delivered via the subarachnoid space greatly affects the onset and spread of spinal anesthesia. Hyperbaric bupivacaine, which contains glucose, is heavier than water and cerebrospinal fluid, and the spread of spinal anesthesia using hyperbaric bupivacaine is significantly affected by gravity. Plain bupivacaine, which does not contain glucose, is heavier than water and lighter than cerebrospinal fluid. When intrathecal injection of plain bupivacaine is performed at L2/3 or L3/4, the range of the cephalad spread is great. On the other hand, when the injection is made at L4/5, the range of the cephalad spread is less than that at L2/3 or L3/4, and the spread of anesthesia is suitable for hip surgery in elderly patients.
