Preoperative assessment: the excretory system

The majority of anesthetics are nephrotoxic in that they depress, usually temporarily, renal hemodynamics and functions. The author briefly reviews renal anatomy and physiology; the relevance of laboratory data associated with excretory function; the effects of abnormal values on the body including electrolytes, cardiac status and acid base balance; and the overall impact of these alterations on the anesthetic management of the surgical patient.