SummaryThe incidence of side-effects occurring with epidural diamorphine (0.05 mg.ml ¹1 ), fentanyl (2.0 mg.ml ¹1 ), methadone (0.1 mg.ml ¹1 ), morphine (0.05 mg.ml ¹1 ) and pethidine (1.0 mg.ml ¹1 ) used by infusion in combination with bupivacaine has been compared. One hundred and sixty patients were studied, 32 receiving each opioid. The incidence of nausea and vomiting was significantly greater with morphine than fentanyl (p ¼ 0.0097) and pethidine (p ¼ 0.0021). The incidence of pruritis was significantly greater with morphine and diamorphine than with methadone (p ¼ 0.012) and pethidine (p ¼ 0.027). Morphine was also associated with a significantly greater incidence of urinary retention than pethidine (p ¼ 0.012) and methadone (p ¼ 0.025).

CPB produces changes in the blood-gas partition coefficient dependent on the prime used and temperature. Fortunately, the overall effect for hypothermic CPB and a crystalloid prime is only +2%. A volatile agent started during hypothermic CPB takes longer to equilibrate and agents already in use need to re-equilibrate, potentially changing the depth of anaesthesia, until equilibration is complete. As these agents are metabolized to a small degree and washout is fast, the duration of action is not prolonged after CPB.

No abstract