High-flow Hemofiltration as an Adjunctive Therapy in Sepsis

Abstract

Almost ten years ago, standard hemofiltration was often provided at 1 or 2 l/h of ultrafiltration and only in pre-dilution mode. However, practice began to change as results from new studies were published in the early 2000s demonstrating a beneficial effect on outcome of increasing the ultrafiltration rate to 35 ml/kg/h in patients with acute kidney injury (AKI). Two methods of high volume hemofiltration (HVHF), with different underlying concepts and results, became prevalent: Continuous high volume hemofiltration (CHVH) providing 50 to 70 ml/kg/h 24 hours a day, and intermittent high volume hemofiltration (IHVH) with brief, very high volume treatment at 100 to 120 ml/kg/h for 4 to 8 hours (previously called ‘pulse’ HVHF). Two recently published studies [1, 2] highlight the crucial role of adequate dosage of continuous venovenous hemofiltration (CVVH), demonstrating that, in critically ill patients with renal failure, a dose of 35 ml/kg/hour was associated with dramatic improvement in survival of nearly 20 %. The incorporation of the results from these studies into daily clinical practice can now be deemed to be urgent, although the results of other ongoing confirmatory (or not) studies are awaited. In a world increasingly guided by evidence based medicine, two level I studies lead to a Grade A recommendation, and this intervention should, therefore, be applied by every intensivist instigating continuous hemofiltration, while awaiting the results of the ongoing studies. Nevertheless, the implementation process is exposed to a number of potential difficulties. These encompass items such as blood flow requirements, vascular access problems, pre-and post-dilution policy, type of membranes used, as well as restitution fluid and the possible need for associated dialysis. Implementation of these findings will necessitate a collaborative network between medical staff members and the entire nursing staff.