[Plasma-antidiuretic hormone level as indicator of postoperative stress (part II) (author's transl)].

For a period of five days serum levels of antidiuretic hormone (ADH) have been investigated postoperatively in a group of 20 patients with upper abdominal surgery. In addition serum electrolytes (Na+, K+) and plasma osmolality have been controlled regularly. Patients in group A (n = 10) received Fentanyl epidurally (0.1-0.2 mg diluted with 0.9% saline solution) for treatment of postoperative pain, whereas in group B (n = 10) systemic opiate therapy was performed by intramuscular application of piritramide (Dipidolor, 15-25 mg). There was a significant increase in ADH in all patients, whereas serum electrolytes (Na+, K+) and plasma osmolality stayed within normal range. ADH-levels in group A (epidural opiate), however, were significantly lower than mean values in group B (systemic opiate application). The postoperative increase in ADH is interpreted as a reaction to stress and trauma, being less pronounced, when epidural opiate therapy is performed for postoperative pain treatment.