INFLUENCE OF D PA ON THE ANALGESIC EFFECT OF ACUPUNCTURE

Wang Sulin, Ma Lihua, Hu Shulan, Wang Kuan

(The third Hospital, Beijing Medical College, Beijing)

D-phenylalanine (D-PA), an inhibitor of peptidase (injected intraventricularly) may enhance analgesic effect of acupuncture in mice and rabbits by reducing the rate of disintegration of enkephalin. We used D-PA as premedication to surgery under acupuncture anesthesia and its influence on the analgesic effect of acupuncture was studied.

Method and Material

D-PA premedication was used in 20 cases of anterior route discectomy with bone grafting, in 27 cases of thyroidectomy, 10 cases of tubal ligation, totalling 57. 29 patients "were given D-PA double-blindly and placebo was given in 28 cases.

D-PA was given in 0.5 g. on the day before surgery at 2:00 p.m. and 7:00 p. m., and another 1.0 g. was added an hour before surgery. The overall dosage was 2.0 g. The same dosage applied to the placebo. 57-9A electronic skin analgometer was used to study the changes of painful and pain tolerance thresholds of the incisional area before premedication, before acupuncture, 20 minutes after induction and after intravenous injection of 0.1 mg of fentanyl respectively, and the painful reaction of major procedures of the operation and pain after surgery was analyzed,

Results

1) The pain threshold seemed to be enhanced after induction of acupuncture in the enhanced after induction of acupuncture in the group with D-PA premedication and the results of over-all assessment of analgesic effect of acupuncture in the D-PA group also seemed to be superior to those of the controls though the difference did not have statistical significance (T-test).

2) The average pain index was lower in the D-PA premedicalion group than that in the placebo group, when the results were studied in the anterior route discectomy with bone grafting, thyroidectomy and tubal ligation separately. T-test showed no difference of statistical significance.

3) No difference in postoperative analgesic effect was observed in patient receiving anterior route discectomy with bone grafting and tubal ligation. However, in patients undergoing thyroid operation the postoperative analgesic effect was more distinct in D-PA group than that in the placebo group, which had statistical significance. (P<0.01)

Larger dosage of D-PA was given (=3.0g) in 18 patients undergoing thyroid surgery using double-blind method for further assessment. Eight patients were given D-PA and 10 placebo. No significant increase of analgesic effect was detected in these premedication groups and the control one as to the painful and pain tolerance thresholds before acupuncture, after induction and after application of 0.1 mg of fentanyl, and pain index of major operation procedures and postoperative analgesic effect.

Conclusion

D-PA given double-blindly before surgery under acupuncture anaesthesia did not seem to increase the analgesic effect of acupuncture.