Clinical impact of continuous renal replacement therapy on multiple organ failure

Because continuous renal replacement therapy (CRRT) may enhance inflammatory mediator removal, this review assesses its impact on multiple organ failure (MOF). Regarding MOF with acute renal failure (ARF), the overall mortality of 2313 CRRT patients (43 studies) was 62.8% compared with 59.1% (p = 0.046) in 961 intermittent hemodialysis (IHD) patients (12 other studies). Of 13 CRRT studies with an IHD comparison group, 3 showed that the groups had a similar risk, but IHD mortality was higher; 1 noted that CRRT had lower mortality (risk not stated); and 4 showed similar mortality and greater CRRT risk. Aggregate mortality was IHD 69.5% and CRRT 63.9% (p = 0.02). Of the six studies with matched groups (age and APACHE II scores), IHD mortality was higher (70.9% vs. 60.1%, p = 0.01). CRRT pulmonary gas exchange, hemodynamic instability, azotemia control, fluid overload, and nutritional support were better. Regarding MOF without ARF, of 14 CRRT studies (14.5 patients per study), only 4 had comparison groups. Patient conditions were as follows: acute respiratory distress syndrome, six studies; sepsis, three studies; septic shock, two studies; pancreatitis, one study; critically ill patients, one study; and cardiac surgery with respiratory failure, one study. Of the three studies with a control group, the mortality was the same. There was minimal evidence that CRRT improved pulmonary gas exchange or hemodynamic instability. For MOF patients with ARF, there is compelling evidence that CRRT provides better survival than IHD and more improvement in pulmonary gas exchange, hemodynamic instability, azotemia control, fluid overload, and nutritional support. In patients with MOF and no renal failure, there is little evidence that CRRT enhances survival, oxygenation, or perfusion. Controlled trials demonstrating a CRRT benefit are necessary before CRRT can be recommended for MOF without ARF.