Narcotic analgesics may be added to spinal anesthetics solution to improve the quality of sensorimotor blockade and to produce postoperative pain relief. The opioid-related side effects of respiratory depression, pruritus, nausea, and urinary
retension
also occur with intrathecal administration and the effects are dose-related.
It is difficult to select morphine with spinal anesthetic solution due to fatal side- effect, respiratory depression. Intrathecal morphine dose used for our study was less than 1mg, thereby the risk of respiratory depression was decreased.
There was no report that the addition of morphine affected the motor block produced by the local anesthetics in spinal anesthesia. But in our study, we found that 0.9 mg of intrathecal morphine produced prolongation of optimal condition for
operation(more than 3 hours duration), and sufficient postoperative pain relief(for about 20 hours) without respiratory depression in 28 out of 30 spinal anesthesia cases. On the other hand, 0.5 mg or 0.7 mg of intrathecal morphine produced
sufficient
postoperative pain relief without respiratory depression(for about 20 hours), but insufficient prolongation of optimal condition for operation in each 30 cases of spinal anesthesia.(Korean J Anesthesiol 1995; 29: 881∼887)
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