this large fluid requirement is owing to a combination of a change in vascular compliance after excision of a pheochromocytoma , the residual effects of specific preoperative medications ( phenoxybenzamine and alpha-methyl-p-tyrosine ) and the loss of fluid into the retroperitoneal compartment ( third space ) produced by extensive dissection .
C0031511
pheochromocytoma
C0031441
phenoxybenzamine