Abstract
Fourteen adult non-diabetic patients undergoing elective major abdominal surgery were divided into 2 groups. One group received epidural and general anesthesia, and a mixture of 0.125% bupivacaine and 2mg of morphine was administered epidurally about 30 minutes before the end of general anesthesia for relief of post surgical pain. The other control group received general anesthesia only with nitrous oxide, oxygen and enflurane.
Flow directed pulmonary arterial and radial arterial catheters were inserted preoperatively, and hemodynamic and respiratory variables were measured serially. Blood was drawn serially and catecholamines, cortisol, aldosterone, insulin, blood sugar, free fatty acid and ketone bodies were measured. The data were compared before and after recovery stage of general anesthesia.
In control group, epinephrine level at the recovery stage of anesthesia increased about 5 times compared to the anesthetic stage. Oxygen consumption and oxygen extraction ratio were increased and mixed venous oxygen saturation was decreased significantly. There was a close linear correlation between oxygen consumption (Y) and epinephrine (X) level. That is, Y=285.7X+90.5 (p<0.01), and correlation coefficient was 0.72.
On the other hand, plasma epinephrine, oxygen consumption and mixed venous oxygen saturation did not change significantly in epidural analgesia group at the recovery stage of general anesthesia. There was also a close linear correlation between oxygen consumption (Y) and oxygen delivery (X). That is, Y=0.22X-32.0 (p<0.01), and correlation coefficient was 0.89. It was demonstrated that oxygen supply demand balance was kept smoothly.
We consider that the pain induced by surgical stress and the subsequent increase in plasma epinephrine may seriously influence tissue oxygenation and metabolic variables, and that epidural analgesia at the recovery period of anesthesia may have favorable effect in maintaining stable conditions.
