The purpose of the study was to compare the protective role of different anaesthetic techniques against surgical stress. Sixty patients undergoing elective
laparotomy were randomly divided into six groups of ten patients each: Group I was given 0.65 MAC
nitrous oxide (66 per cent inspired) and 0.65 MAC
isoflurane (0.75 per cent end-expired); Group II was given 0.65 MAC
nitrous oxide and 1-1.2 MAC
isoflurane (1.2-1.4 per cent end-expired); Group III was given the same anaesthetic management as patients in Group I but with the addition of
fentanyl (2 micrograms X kg-1) before the skin incision and 1/8 of the initial dose every 15 minutes during surgery; Group IV was treated as patients in Group I with an additional infusion of
lidocaine (30 micrograms X kg-1 X min-1); Groups V and VI were given 0.65 MAC of
nitrous oxide and
fentanyl, 7.5 and 15 micrograms X kg-1, respectively, before skin incision with 1/8 of the initial dose every 15 minutes during the operation;
diazepam, 5 mg IV each hour of surgery, was given to prevent
intraoperative awareness.
Cortisol concentration was determined by radioimmunoassay method and
catecholamines were measured by high performance liquid gas chromatography in blood samples taken at different stages perioperatively. All patients had satisfactory haemodynamic courses of anaesthesia. Statistically significant increases in both
epinephrine and
norepinephrine concentrations were observed during the immediate postoperative period in Group I patients only. Haemodynamic stability was maintained despite a two- to three-fold increase in
cortisol which occurred during the operation and immediate postoperative period.(ABSTRACT TRUNCATED AT 250 WORDS)