Ventilatory effects of epidural clonidine during the first 3 hours after caesarean section

Abstract

Many authors have shown the analgesic efficacy of 150-800 micrograms of epidural clonidine in the postoperative period. Its use as an analgesic after caesarean section has recently been studied with higher dosages (400-800 micrograms). Our study aimed at assessing the analgesic and ventilatory effects of two smaller doses of epidural clonidine (150 and 300 micrograms), which were compared to the effects of 10 mg of parenteral morphine (M) during the first 3 h after caesarean section. The duration of the analgesic effect was longest with 150 micrograms of epidural clonidine. Arterial blood pressure decreased from 30 min after the injection to the end of the study in both epidural clonidine groups. A marked sedation was observed in patients receiving 300 micrograms of epidural clonidine and was frequently associated with snoring, obstructive apnoea and episodes of arterial oxygen desaturation. We conclude that 150 micrograms of epidural clonidine provides better and longer analgesia after caesarean section than 10 mg of parenteral morphine, and seems preferable to higher doses (300 micrograms) in this setting, since 300 micrograms of epidural clonidine may produce unacceptable respiratory obstructive disturbances.