Evaluation of stress response to surgery under general anesthesia combined with spinal analgesia

Each type of anesthesia has varying influence on the amount of catecholamine secretion during surgery. Epidural or spinal anesthesia can markedly suppress the increase of many of the stress hormones. Our purpose of this study is to evaluate metabolism change during surgery under anesthesia and to see whether general anesthesia combined with intraspinal anesthetic and narcotic is a better way to suppress such stress response.

Seventeen patients in fit physical condition (ASA class I) with normal biochemical screening scheduled for radical gastrectomy were studied. All patients were premedicated with diazepam and glycopyrrolate and an indwelling catheter was inserted into a radial artery under local anesthesia for monitoring blood pressure and obtaining blood samples for glucose and hormonal assays. A CVP line was set up via the right internal jugular vein for the administration of fluid (free of sugar). In the study group, a 32-G intraspinal catheter was placed via lumbar interspaces. Spinal blockade up to T4 by titrating 0.25% marcaine. Then anesthesia in both groups was induced with thiopental 5 mg/kg, followed by succinylcholine 1.5 mg/kg for intubation. Anesthesia was maintained with isoflurane, N2O, O2 and pancuronium. Blood samples for measurement cortisol, catecholamine and sugar were taken after induction and 30 min after surgical incision. Thirty min after skin incision all patients were subjected to glucose tolerance test, accomplished by giving 50% dextrose at 0.33 g/kg in 3 min. Arterial blood samples were then obtained at 1, 3, 5, 7, 10, 20, 30, 45 and 60 min intervals for plasma glucose determination.

No difference was evident in cortisol values, baseline, before and after surgical incision (p > 0.05) either intragroup or inter-group. Catecholamine and glucose were significantly higher in control group after surgical incision (p < 0.05, intra-gr and inter-gr). Following a glucose load the decay of plasma glucose was similar in both groups but glycemic level was higher in the control group.

Better control of stress response by general anesthesia combined with subarachnoid block was disclosed in this study.