Evaluation of Acute Kidney Injury in Intensive Care Unit

Abstract

Acute kidney injury (AKI), impairment of kidney function requires special attention in intensive care unit’s (ICU), because if multiorgan failure affect the kidney, it carries a greater risk for worse outcome and furthermore survivors have higher risk then normal population for chronic renal failure. It was reported that they also have higher mortality and morbidity rates compared to normal population (Kellum, 2008 & Shiffle, 2006). Acute tubular necrosis (ATN) is the primary causes of AKI in hospital and ICU and sepsis, ischemic or toxic insults were reported as the most common reason for ATN. The rates of AKI have been reported in hospitalized patients to be between 3.2%-20% and in ICUs this rate rises up to 22% and even to 67% depending on the population studied and the definition used (Murugan 2011). Based on the administrative data, the incidence of severe AKI (defined requiring dialysis) from 1988 to2002 has increased from 4 to 27 per 100000 population. But fortunately in hospital mortality, has decreased from 41.3 to28 % (p<0.001) (Waikar, 2008). Likewise a progressive 2.8% annual increase in incidence of AKI and progressive 3.8% annual decrease in AKI associated mortality(95%CI:-4.7 to-2.12:p<0.001) was observed from 1996-2005 in a large database in Australia and New Zealand (Pisoni, 2008&Bagshaw, 2007). Despite the fact that mortality might be decreasing in ICU patients with AKI, it is still high and reported to be up to 43-88%. Mortality rate becomes even higher when patients require renal replacement therapy (Kellum, 2008). Interestingly, it was reported that irreversible AKI requiring chronic dialysis therapy increased from 3.7% in 1984 to 18.2% in 1995 in surviving patients. Even higher number of patients (33-68%) at discharge whose kidney failed to recover and who needed long term dialysis. This changing renal outcome in the survivors of ICU acquired AKI cases might be related to increasing number of older patients, several co morbid conditions, more severe AKI cases than before and in addition, complication of the more aggressive renal replacement therapies currently used (Shiffle, 2006). Since AKI in critical ill patients have high mortality rate and even if patients survive, they are at risk for End Stage Renal Disease (ESRD) and higher mortality than the normal population, it is important to recognize the clinical picture of AKI and to institute prevention as early as possible. Thus, physician should be alarmed and be ready for early intervention in this particular group of patients. With the introduction of the RIFLE