ABSTRACT
When renal failure occurs, it generally follows one of three well-defined patterns (Figure 20.1)30. Abbreviated acute renal failure occurs after an isolated insult, results in a peak in serum creatinine around the fourth postoperative day, and generally has a favorable prognosis if no other events occur. The second pattern is similar to the first, except that the acute insult is accompanied by prolonged circulatory failure. This pattern runs a longer course, with recovery typically occurring in the second or third week after injury, in tandem with improvements in cardiac output. The final pattern begins like the second, but recovery is complicated by a second insult such as sepsis, massive gastrointestinal bleeding or myocardial infarction. As fluid overload with renal failure may precipitate respiratory and cardiac failure, there has been a trend towards early application of continuous arteriovenous hemofiltration (CAVH) and related techniques to remove excess fluid13. There is speculation that aggressive fluid removal may reduce tissue edema and intraabdominal pressure, thus improving renal perfusion pressure and consequently renal function. Other speculation involves the role of renal replacement techniques in removing circulating cytokines, but there are few data proving that cytokine removal results in better outcome.
