Fig. 4From: The effect of tolvaptan on renal excretion of electrolytes and urea nitrogen in patients undergoing coronary artery bypass surgerySerial changes in potassium concentrations (upper) and FEK (lower) in patients receiving conventional diuretics plus tolvaptan (black symbols and solid lines) or conventional diuretics only (white symbols and dotted lines). FEK, fractional excretion of potassium; POD, postoperative dayBack to article page