Kidney Sodium Content in Cardiorenal Patients

"We will measure kidney sodium content in patient with cardiorenal syndrome. we will inject within the week of this first measurement furosemide only in patient who will be resistant to diuretics (Based on these parameters, diuretic response will be defined as:~* A reduction in fractional spot urinary sodium~* An increase in urinary volume~* A \>1 kg reduction in body weight within 24 hours from diuretic administration (extrapolation of guidance on management of acute HF) and we will do another measurement of kidney sodium content after furosemide injection."