During this stage, the excretion of urea and other nitrogenous compounds lags behind that of salt and water as reflected by the continual rise in the concentrations of these substances for several days after the onset of the diuresis The reason is the incomplete recovery of GFR. Nevertheless the tubular function also not well recovered the kidney still work as a simple filter. Salt and water loss could occur and lead to dehydration, hypokalemia and hyponatremia 3939 During this stage, the excretion of urea and other nitrogenous compounds lags behind that of salt and water as reflected by the continual rise in the concentrations of these substances for several days after the onset of the diuresis. The reason is the incomplete recovery of GFR. Nevertheless, the tubular function also not well recovered, the kidney still work as a simple filter. Salt and water loss could occur and lead to dehydration, hypokalemia and hyponatremia