While intrathecal morphine in small doses has been effective in controlling postoperative pain, many patients have been suffered from the side effects. In recent studies, it has been suggested that small dose of propofol can attenuate these side
effects
of intrathecal morphine. We have studied the effect of propofol and tried to find the optimum dose that can reduce side effects of intrathecal morphine.
Sixty patients of ASA class 1 scheduled for anorectal surgery were allocated randomly to receive either a bolus dose of propofol 0.5 mg/kg followed by an infusion of 1 mg/kg/24hr(group P1) or 2 mg/kg/24hr(group P2) and no bolus dose followed by
1,000 ml
5% dextrose water(control group). In this study, postoperartive sedation, nausea, vomiting, pruritus and urinary retention were evaluated immediate postoperatively, 12 hour, 24 hour and 48 hour after spinal anesthesia using 1% tetracaine 5 mg
with
10%
dextrose water 5 ml and morphine 0.3 mg. As time passed, all the complications subsided significantly. However, there was no significant difference among 3 groups except pruritus. The incidence of pruritus was lower in the group P1 and group
P2(80%, 50%
respectively) than the control group(90%). In the 12 hour-after evaluation, there was no patient of grade 3 pruritus in the group P2 but 5 patients in the control group(p<0.001) and 3 patients in the group P1 had itching(p<0.05). The higher doses
of
propofol, the greater sedative effect observed. However, there was no clinically serious problem (e.g. respiratory depression, deep sedation).
In conclusion, we recommend that an adequate infusion dose of propofol for reducing the incidence and severity of pruritus is 2 mg/kg/24hr.(Korean J Anesthesiol 1995; 29: 701∼708)
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