The Role Of Diuretics In The Intensive Care Unit: A Review

Diuretics are drugs which cause a net loss of sodium and water from the body by net action on the kidney. Their primary effect is to decrease the reabsorption of sodium and chloride from the filtrate, increased water loss being secondary to the increased excretion of salt. There are various classes of diuretics which differ considerably in chemical derivation, efficacy, sites of action, and mechanism of action; namely, their pharmacology and pharmacodynamics. Effective use of diuretics requires knowledge of the pharmacology of each diuretic agent coupled with an understanding of the pathophysiology of the patient's disease. Diuretics have various uses in clinical conditions including oedematous disorders and hypertension, treatment of hypercalcaemia with loop diuretics, treatment of diabetes insipidus or hypercalciuria with thiazide diuretics, treatment of glaucoma with carbonic anhydrase inhibitors, and treatment of cerebral oedema with osmotic agents. The use of diuretics in the acute care setting is an area of significant clinical and laboratory research. Diuretics represent one of the most commonly used agents in the intensive care unit and fluid balance occupies a significant amount of attention by the intensivist and the anaesthetist. The author's aim was to systematically review the literature regarding the use of diuretics in critically ill patients on the Intensive Care Unit. We searched MEDLINE (1966-2004), EMBASE (1974-2004) and the Cochrane Controlled Trials Register (CCTR) to identify randomised controlled trials, in order to review the risks and benefits of diuretics in four different groups of patients. These included subjects with acute renal failure, congestive heart failure, severe head injury and also preterm infants with respiratory distress syndrome.