Prevention of postoperative lymphopenia and granulocytosis by epidural analgesia

Blood leucocyte-counts, cortisol, and glucose were measured in twelve healthy premenopausal women undergoing elective abdominal hysterectomy during either general anaesthesia (six women) or epidural analgesia (T4 to S5) (six women). Surgery during general anaesthesia caused significant lymphopenia 6 and 9 h after skin incision and significantly increased granulocyte-counts 6, 9, and 24 h after skin incision. Epidural analgesia prevented lymphopenia and reduced granulocytosis to about 40% of that seen in the group receiving general anaesthesia. The normal increase in plasma glucose and cortisol during and after surgery was abolished by epidural analgesia. These results indicate that neurogenic stimuli from the surgical area, probably through their influence on adrenal hormones (cortisol and adrenaline), are the main mediators of postoperative lymphopenia and are partly responsible for postoperative granulocytosis. Inhibition of the endocrine-metabolic response to surgery may prevent postoperative immunodepression.