Postoperative hemodynamic changes in patients with pituitary tumors

Antidiuretic hormone (ADH) affects both diuresis and pressor functions, and recent studies have shown hemodynamic changes after its administration. The authors studied postoperative hemodynamic changes in 10 patients with pituitary tumors and examined the correlations among diabetes insipidus (DI), serum ADH, biochemical parameters, and hemodynamics. Systemic vascular resistance (SVR) was significantly lower in patients when they are in DI stage than in non-DI stage. On the other hand, the cardiac index (CI) was higher in patients when they are in DI stage. There were no significant differences between the two groups in central venous pressure or pulmonary capillary wedge pressure. Regardless of whether DI was temporary or permanent, the CI increased and SVR decreased immediately after surgery and, within a few days, returned to the preoperative status. These postoperative hemodynamic changes were the same as those routinely encountered after surgery. These results suggest that fluctuation in ADH after transsphenoidal surgery in patients with DI does not cause hemodynamic changes. Such changes are evidently prevented by various physiological autoregulatory mechanisms.