Effects of the extradural administration of morphine or bupivacaine, on the metabolic response to upper abdominal surgery.

The influence of thoracic extradural local anaesthetics (0.5% bupivacaine) or extradural morphine on the metabolic response to upper abdominal surgery was compared with the administration of morphine i.v. in the period after operation. The extradural local anaesthetic group had significantly lower blood glucose and plasma FFA concentrations and consistently, but not significantly, lower blood glycerol and lactate concentrations than both the other groups. At 4 h both extradural groups had significantly lower plasma FFA and blood 3-hydroxybutyrate concentrations than the control group. Blood alanine concentration decreased in all three groups with a minimum at 24 h. There were no differences in serum insulin concentrations between the groups. It is concluded that thoracic extradural morphine differs from thoracic extradural local anaesthetics in being much less able to suppress the metabolic response associated with upper abdominal surgery.