Continuous renal replacement therapy

Metabolic and Nutritional Aspects of Acute Renal Failure in Critically Ill Patients Requiring Continuous Renal Replacement Therapy

Acute renal failure (ARF) is rarely an isolated process but is often a complication of underlying conditions such as sepsis, trauma, and multiple-organ failure in critically ill patients. As such, concomitant clinical conditions significantly affect patient outcome. Poor nutritional status is a major factor in increasing patients' morbidity and mortality. Malnutrition in ARF patients is caused by hypercatabolism and hypermetabolism that parallel the severity of illness. When dialytic intervention is indicated, continuous renal replacement therapy (CRRT) is a commonly used alternative to intermittent hemodialysis because it is well tolerated by hemodynamically unstable patients. This paper reviews the metabolic and nutritional alterations associated with ARF and provides recommendations regarding the nutritional, fluid, electrolyte, micronutrient, and acid-base management of these patients. The basic principles of CRRT are addressed, along with their nutritional implications in critically ill patients. A patient case is presented to illustrate the clinical application of topics covered within the paper.

Role of routine blood cultures in detecting unapparent infections during continuous renal replacement therapy

OBJECTIVE

Continuous renal replacement therapy (CRRT) is frequently employed in the management of renal failure in unstable intensive care patients. At some centers, blood cultures are performed routinely while on CRRT to monitor for occult bacteremia. We questioned the role of routine blood cultures (RBC) in diagnosing underlying infections in these often afebrile patients.

DESIGN

Retrospective cohort study (1998-2003).

SETTING

Medical, surgical and pediatric intensive care units in a tertiary care teaching hospital. METHODS/MEASUREMENTS: We undertook a retrospective chart review of all 101 episodes of CRRT performed in our hospital since 1998. The primary endpoint of the study was the number of positive cultures that changed patient management. For each positive result, documented infection and parameters of sepsis were noted.

RESULTS

There were 101 treatments of CRRT in 98 patients. A total of 698 routine RBC bottles were drawn, a mean of 7.2+/-7 per patient; of those, 29 (4%) were positive in 17patients, documenting 11 bacteremias. Six positive cultures represented contaminants. In all but one case, infection was known or signs of sepsis were present prior to receipt of the culture result.

CONCLUSIONS

For patients on CRRT, RBC are rarely positive, and do not detect occult infection in the absence of clinical evidence of infection for the majority of patients. Because routine cultures utilize significant resources, and can result in false-positive results, RBC should not be performed in these patients. Careful clinical monitoring, with blood cultures performed at the first clinical suggestion of an infection, should detect all clinically relevant infections.