Early management and prevention of acute renal failure.

Abstract

Despite major advances in nutritional support, membrane technology and dialytic techniques, the mortality of patients with acute renal failure (ARF) who require dialysis is still almost 50% (1). Increased patient age and co-morbidity confer a poorer prognosis, and the condition is certainly commoner in this patient group. Hence, one study showed that the age-related annual incidence of ARF increased from 17 per million in adults under 50 years to 949 per million in the 80-89 age group (2). Over 60% of cases of ARF ultimately result from renal hypoperfusion and consequent intra-renal ischaemic damage, which leads to acute tubular necrosis (ATN) (3). Ischaemic ARF may thus result from a diversity of systemic and intra-renal circulatory stresses including acute losses of blood and extra-cellular fluids, from low cardiac output states such as following ischaemic or toxic myocardial damage, and even from drug-induced renal perfusion shutdown (ACE inhibitors, non-steroidal anti-inflammatory agents). Many cases of ARF have a multi-factorial aetiology (e.g. post-surgical sepsis with hypovolaemia, hypotension and injudicious antibiotic use), and these patients, who often have other organ failure, fit into the poorer prognostic category. A large number of patients with ischaemic ARF pass through a phase of potentially reversible pre-renal oliguria; early recognition and prompt, appropriate treatment of these pre-renal factors can prevent progression to established ARF, with the genuine prospect of improved patient morbidity and mortality, and this is the main scope of this article. Early diagnosis in other patients with ARF, such as those with acute inflammatory renal disease (e.g. vasculitis) or urinary tract obstruction, will allow appropriate prompt treatment and the possibility for reversal of the ARF. The following account, which is composed of personal experience, that of colleagues, and the literature (1,4), is not intended to provide a comprehensive guide to the management of ARF, but seeks to highlight important common pitfalls and fundamental principles in the recognition and subsequent preventive treatment of these patients.