Comparison of the relative analgesic efficacies of epidural or intramuscular diamorphine following total knee arthroplasty.

BACKGROUND AND OBJECTIVES: Debate has proliferated as to the true site of action of opioids when placed in the epidural space. The aim of this study was to compare the analgesic effects of a bolus of diamorphine given by the epidural or intramuscular route. METHODS: Sixty patients having elective primary total knee replacements were recruited and randomized to receive epidural or intramuscular diamorphine. A lumbar epidural catheter was sited and 10 mL of bupivacaine 0.5% wt vol-1 was injected. Patients subsequently received diamorphine 5 mg into the epidural space or as an intramuscular injection. Patient-controlled analgesia with intravenous morphine was used for postoperative analgesia. The primary outcome measures included time to first patient-controlled analgesia use and total morphine consumption in 24 h. Secondary end-points considered possible treatment complications. RESULTS: All primary end-points showed significant differences in favour of epidural diamorphine. Medians for times to first patient-controlled analgesia use and total 24 h morphine requirements were significantly different (P < 0.001) at 418 vs. 198 min and 11 vs. 39 mg, respectively. There were no significant differences in secondary end-points. CONCLUSIONS: This study has shown the superior analgesic efficacy of epidural diamorphine when compared to intramuscular injection.

Primary pulmonary hypertension in pregnancy; a role for novel vasodilators.

We describe the case of a 28-week pregnant woman presenting with severe primary pulmonary hypertension (PPH). She had an elective Caesarean section under general anaesthesia at 32 weeks gestation. Pulmonary artery pressures (PAP) measured from a pulmonary artery catheter before anaesthesia were in excess of 100 mm Hg. Intraoperative nitric oxide was used to reduce PAP. After the delivery of a healthy infant PAP was controlled with nebulized iloprost and a prostacyclin infusion. Seven days later she was discharged from intensive care taking an oral calcium antagonist and warfarin. She developed intractable right heart failure and died 14 days after delivery. Despite increasing experience in the use of drugs to reduce PAP, the clinical course of pregnancy complicated by severe PPH is usually fatal.