chapter  7
Renal support therapy
ByDavid Selwyn & James Low
Pages 12

Despite vast improvements in the understanding of renal

failure in critically ill surgical patients, the incidence of acute

renal impairment requiring dialysis remains at 50-200 cases

per million population.1,2 Modest degrees of acute renal

failure (ARF) not resulting in dialysis treatment have been

reported as increasing the risk of death approximately five-

fold.3 Specific surgical conditions are related to a higher

incidence of ARF: for example, after cardiac surgery it has

been reported to be as high as 30 per cent,4 whereas abdom-

inal aortic surgery is associated with an incidence of oliguric

renal failure of 2-7 per cent and an associated mortality of

Compounding the exact incidence are imprecise defin-

itions of ARF, for example: ‘An acute and usually reversible

deterioration of renal function, which develops over a

period of days or weeks, and results in uraemia’. Although a

marked reduction in urine volume is usual it is not invari-

able, and clearly, in the surgical population, if established

acute renal failure is left untreated the patient will die. The

mortality associated with the condition in isolation is 8 per

cent; unfortunately, the patients who develop ARF while on

the critical care unit do so as a part of generalized multiple

organ failure (MOF), when the mortality increases to between

60 and 90 per cent.