BACKGROUND: Refractory edema in some patients with advanced heart failure or renal failure will not respond to diuretic therapy. In this setting, the ex- cess fluid can be removed by continuous hemofiltration either by continuous arteriovenous hemofiltration (CAVH) or continuous venovenous hemofiltration (CVVH). Careful monitoring is required to prevent life-threatening hypotension due to continued production of large ultrafiltrate. To overcome these disadvantages of CVVH, we attempted to perform daytime 1VVH as an alternative therapeutic modality to CVVH. METHODS: We performed venovenous hemofiltration for eight hours in the daytime in dialysis unit and repeated intermittently at 1 or 2 days interval if further treatment is required. We called this intermittent venovenous hemofiltration(IVVH). From October 1992 through November 1997, we prospectively studied the efficacy and usefulness of IVVH in 42 patients with refractory edema. RESULTS: Underlying disorders which required IVVH were renal insufficiency in 28 patients and nephrotic syndrome in 14 patients. The mean duration of treatment was 17.0+/-8.4 hours. Total UFR was 26.1+/-153L and mean UFR/hr was 1.5+/-2.2L. Edema was successfully controled with only one time treatment of IVVH in 12(28.6%), two in 17(40.5%), three in 7(16.6%), four in 4(9.5%), and five in 2(4.8%), Mean number of IVVH treatments per patient was 2.2+/-0.4 to complete the treatment of refractory edema. Changes in blood chemistry and hemodynamics before and after IVVH were not significantly different. Body weight and abdominal girth decreased significantly after IVVH(p<0.001). No major complications occurred during these trials. There were only two episodes(5.1%) of transient hypotension, and each one episode(2.6%) of bleeding at access site and arrhythmia, respectively. CONCLUSION: These results stongly suggest that IVVH is a simple, safe and effective method in the treatment of refractory edema not responding to diuretic therapy.