[Significance of endocrine parameters of stress]

Thirty two male patients undergoing coronary bypass surgery were given low (group A, 0.01 mg/kg bw) and high dose (group B, 0.035 mg/kg bw) fentanyl anaesthesia. Haemodynamic and hormone responses were investigated from the beginning of anaesthesia until extracorporeal circulation (ECC) (group A: n = 16; group B: n = 16). Significant changes in haemodynamics occurred only in group A including an increase in heart rate (36%) and systolic arterial pressure (21%). Plasma vasopressin (ADH) levels rose significantly in both groups after the beginning or surgical procedure which was markedly less pronounced in patients with high fentanyl (group B). In group A (low dose) a second dose of fentanyl was given after sternotomy, which was followed by a significant decrease in ADH (80% from previous value). No significant variations could be demonstrated in plasma levels of cortisol, ACTH, and human growth hormone (HGH). The data stress the importance of plasma-vasopressin-levels in determining the endocrine stress response following trauma and operation. On the other hand there was a lack of correlation between trauma and pain and frequently reported patterns of the endocrine-metabolic stress response.