Influence of epidural fentanyl on stress-induced elevation of plasma vasopressin (ADH) after surgery.

The role of techniques used for management of intra- and postoperative pain on plasma levels of antidiuretic hormone (ADH) was evaluated in 107 patients undergoing abdominal or thoracic surgery. Fifty-one patients had neurolept-anesthesia (NLA) intraoperatively followed by intramuscular piritramide, a long-lasting synthetic narcotic, for relief of postoperative pain. Fifty-six patients had a combination of epidural bupivacaine and NLA intraoperatively followed by epidural fentanyl for relief of postoperative pain. All patients had daily measurements of serum levels of potassium and sodium, plasma levels of ADH, and plasma osmolality for the first 5 postoperative days. In 67 patients arterial blood-gas tensions also were measured at similar times. There were no significant changes in serum electrolyte levels, plasma osmolality, or blood-gas tensions intra- or postoperatively. Plasma ADH levels increased postoperatively in all patients, but in patients given NLA followed by postoperative intramuscular narcotics, plasma levels of ADH were more than twice as great as in patients given epidural anesthesia followed by epidural fentanyl.