The effect of cortisol suppression on interleukin-6 and white blood cell responses to surgery

The endocrine and immune changes associated with surgery are well documented, but the interaction between them has not been fully evaluated. Cortisol production during surgery can be suppressed by etomidate and we have used this to investigate the relationship between the cortisol response and immune changes in the perioperative period.

We have measured the cortisol, interleukin-6 and white cell responses to elective abdominal hysterectomy in 8 healthy female patients, who received etomidate 0.3 mg kg-1 for induction of anaesthesia. A control group of 8 subjects received thiopentone. Both groups of patients received vecuronium and fentanyl 2 micrograms kg-1 and anaesthesia was maintained with nitrous oxide in oxygen and isoflurane 0.5-1.0%. Venous blood samples were collected before and during surgery and up to 24 h in the postoperative period.

Serum interleukin-6 values were significantly greater at 6 and 12 h (P < 0.05) in those patients who received etomidate. Inhibition of the serum cortisol response to surgery in the etomidate group was also associated with less marked lymphopenia at 4 h (P < 0.05). There was no significant difference in neutrophil granulocyte counts between the two groups.

In conclusion, endogenous corticosteroids modulate the interleukin-6 response to surgery.