INTRATHECAL ADDITION OF MORPHINE TO BUPIVACAINE IS NOT THE CAUSE OF POSTOPERATIVE NAUSEA AND VOMITING

Background and Objectives. Postoperative nausea and vomiting after ane sthesia is an distressing side effect. This study was undertaken to de termine to what extent spinal opioids contribute to postoperative naus ea and vomiting (PONV) and secondly to how effectively metoclopramide can reduce the incidence of PONV after intrathecal administration of m orphine. Methods. Patients were allocated to three groups all undergoi ng major joint surgery of the lower limb. In group 1 (n = 200), intrat hecal anesthesia was assessed by administration of 20 mg bupivacaine a nd 0.2 mg morphine. In Group 2 (n = 100) intrathecal anesthesia was as sessed in the same way and in addition, 20 mg metoclopramide intramusc ular during maintenence of anesthesia and a second dose of 20 mg metoc lopramide was administered intramuscular after arrival at the recovery room. Finally, in group 3 (n = 100), intrathecal anesthesia was asses sed after administration of 20 mg bupivacaine. Results, The maximum PO NV percentages were 41.1%, 32.7%, and 37% in groups 1, 2, and 3, respe ctively. The consumption of antiemetics was similar in all groups. The number of patients who needed one or more additional antiemetics duri ng the first 24 hours after surgery was 112 (56.6%), 57 (58%), and 60 (60%) in groups 1, 2, and 3, respectively. Conclusions. Administration of metoclopramide did not reduce the overall incidence of PONV. Our s tudy shows no relationship between the use of intrathecal morphine and the incidence of PONV during the first 24 hours postoperative.