INTRATHECAL DIAMORPHINE FOR ANALGESIA AFTER CESAREAN-SECTION - A DOSE-FINDING STUDY AND ASSESSMENT OF SIDE-EFFECTS

Eighty women undergoing elective Caesarean section under spinal anaest hesia using hyperbaric bupivacaine 0.5% were randomly allocated to rec eive, in addition, intrathecal diamorphine 0.125, 0.25 or 0.375 mg or saline. Postoperative morphine requirements, measured using a patient- controlled analgesia system, were reduced in a dose-dependent manner b y diamorphine. Pain scores were significantly lower at 2 and 6 h follo wing the two larger doses of diamorphine. Less supplemental analgesia was required intra-operatively if intrathecal diamorphine had been giv en. The incidences of vomiting and pruritus were also dose-related. No respiratory rates of less than 14 breath.min(-1) were recorded and th e incidence of oxygen saturation readings less than 95% and 90% did no t differ between groups. There were no adverse neonatal effects. Intra thecal diamorphine in the present study was found to be safe in doses of up to 0.375 mg following Caesarean section. However, minor side-eff ects were frequently observed.