Mobilising Oedema in the Oedematous Critically Ill Patient with ARDS: Do We Seek Natriuresis Not Diuresis?

In the treatment of the acute respiratory distress syndrome in the intensive care unit, one of the aims is to achieve a negative fluid balance. Traditional use of sole-agent loop diuretics such as furosemide often results in the loss of free water, dehydration, hypernatraemia and metabolic alkalosis, with therapeutic failure once water is replaced. A more rational approach is to induce natriuresis with loss of sodium in the urine to reduce extracellular and interstitial fluid volume, not total body water. Polypharmacy with a loop diuretic combined with other weak diuretics to prevent tubules modifying glomerular filtrate, promotes natriuresis with large volume urinary losses and minimal electrolyte disturbance, and the excretion of urine with a composition comparable to plasma.