ABSTRACT
Urine output forms the basis for assessment of intravascular volume status and for diagnosis of multiple diseases. The arginine vasopressin (AVP) plays a major role in maintaining the urine concentrating ability of the kidney along with the countercurrent mechanism and urea recycling. In Brain–Kidney crosstalk category, there are multiple diseases such as syndrome of inappropriate antidiuretic hormone (SIADH), cerebral salt-wasting syndrome (CSWS), and central neurogenic diabetes insipidus (CNDI) arising out of trauma to the hypothalamus and pituitary either directly or indirectly. When a patient with SIADH comes to the operating room for any surgical procedure, fluids are managed by measuring the central volume status by central venous pressure (CVP), pulmonary artery lines, or the cross-sectional left ventricular area at end diastole on transesophageal echocardiography and by frequent assays of urine osmolarity, plasma osmolarity, and serum sodium, including the period immediately after the surgical procedure.
