INVESTIGATION OF PITUITARY-ADRENOCORTICAL FUNCTION IN THE ELDERLY DURING STANDARDIZED OPERATIONS AND POSTOPERATIVE INTRAVENOUS METYRAPONE TEST ASSESSED BY PLASMA CORTISOL, PLASMA COMPOUND S AND EOSINOPHIL CELL DETERMINATIONS

Twenty elderly subjects with an average age of 73.0 years (range 66–82) underwent standardized surgery (laparotomies). Thirteen younger subjects with an average age of 45.4 years (range 23–58) served as controls. Changes in plasma cortisol, plasma compound S and eosinophil cell count were checked throughout the first 24 hours after surgery. A maximum increase in the plasma cortisol concentration exceeding the spontaneous initial value by 150 and 110 per cent respectively was observed, in the young and elderly subjects. An insignificant rise only was seen in the plasma compound S concentration. The eosinophil cell count fell to less than 50 n/μl. The variations in the three parameters, observed in the geriatric group, indicate a less marked response to surgical stress although no evidence was found for the existence of any significant age difference. Between the fourth and eighth postoperative day, an intravenous metyrapone test was carried out in 13 elderly and 10 young subjects. The changes in the concentration of plasma cortisol and plasma compound S and in the eosinophil cell count were recorded. When exposed to an apparently identical stimulation of the feedback system during the postoperative phase, the elderly patients showed a much greater response than that seen in the younger patients. The possibility that the pituitary-adrenal system in the elderly develops a higher sensitivity following repeated exposures to stress, is discussed. Exhaustion of the pituitary-adrenal system during the postoperative phase was not demonstrated in the elderly.