M. Brause

Effect of filtration volume of continuous venovenous hemofiltration in the treatment of patients with acute renal failure in intensive care units.

ObjectiveWe evaluated the variable Kt/V, which has become established in the therapy of end-stage renal disease in acute renal failure, to assess the influence of the filtration volume of continuous venovenous hemofiltration on Kt/V. We measured the variables of acid-base balance and uremia control. DesignProspective interventional pilot study. SettingMedical intensive care unit of a university hospital. PatientsFifty-six patients with acute renal failure and continuous venovenous hemofiltration treatment. InterventionsThe patients were consecutively treated with a filtration volume of either 1 L/hr (group 1) or 1.5 L/hr (group 2). Measurements and Main ResultsPatients with a filtration volume of 1.5 L/hr achieved a Kt/V of 0.8 per day, which was significantly higher than in the patient group treated with 1 L/hr (0.53, p < .05). The filtration volume of 1.5 L/hr led to a markedly better control of blood urea nitrogen concentrations, 69.3 ± 6.6 mg/dL vs. 52.1 ± 5.2 (p < .05), and to a much quicker and longer lasting compensation of acidosis. Both groups had acidotic pH at the beginning of therapy (group 1, 7.29 ± 0.02; group 2, 7.29 ± 0.02, nonsignificant). In group 2, a significantly higher pH value than in group 1 was measured after 24 hrs of continuous venovenous hemofiltration (p < .001; 7.39 ± 0.02 vs. 7.31 ± 0.02). The pH values in group 1 did not normalize until after 4 days. The filtration volume of 1.5 L/hr led to a quicker increase in bicarbonate concentrations after 24 hrs of therapy (group 1, 2.8 ± 3.2 mmol/L; group 2, 6.5 ± 3.1 mmol/L, p < .001). ConclusionsThe standardized urea clearance Kt/V is a valuable tool in the treatment of acute renal failure. Higher Kt/V levels were associated with a better control of uremia and acid-base balance. However, there were no differences in the clinical course, patient survival, percentage of patients with or without renal failure who were transferred from the intensive care unit, or Acute Physiology and Chronic Health Evaluation III scores.

Cytokine Removal in Septic Patients with Continuous Venovenous Hemofiltration

Despite the progress that has been made in intensive care medicine, multiple organ failure is still associated with high mortality. Apart from the prevention of infectious complications, numerous efforts are being made to improve the treatment of sepsis through adequate antibiotic therapy, the development of new respirator therapies, better control of the hemodynamic situation, and adequate renal replacement therapy. Some authors advocate continuous renal replacement therapy not only for acute renal failure but also for the elimination of inflammatory molecules such as cytokines. Continuous renal replacement therapy improves the cardiovascular hemodynamics in patients with multiple organ failure. Therapeutic options such as volume control, clearance of uremic toxins, correction of acid base disturbances and temperature control are improved. Suitable renal replacement therapy improves not only cardiovascular hemodynamics but also patient survival. In current practice, continuous renal replacement therapy is not used to eliminate mediators such as cytokines. In patients with multiple organ failure and compromised cardiovascular hemodynamics, renal replacement therapy should be carried out as early as possible. In the following review, experimental and clinical findings concerning mediator elimination by continuous and intermittent renal replacement therapy are summarized.