MAINTAINING LOW CONCENTRATIONS OF PLASMA BETA(2)-MICROGLOBULIN THROUGH CONTINUOUS SLOW HEMOFILTRATION

As a first step in the development of a future wearable artificial kidney, we conducted three forms of treatment with continuous haemofiltration (CHF) on a group of 10 patients in an attempt to determine what plasma values of small molecules and beta(2)-microglobulin (beta(2)-M) could be maintained. In the first system, one ordinary 4-h haemodialysis, followed by 7-day CHF with 51 exchange per day, was repeated. The second system consisted of CHF with 51 exchange/day and thrice weekly slow nocturnal dialysis. The third system used CHF with 101 exchange per day. The first, second and third systems were used with three, four and four patients, respectively, for at least 4 weeks each. PAN-DX and FH-66 haemofilters were used eight and three times, respectively, with continuous infusion of heparin at 500-700 units/h. In the first system, the pre-CHF plasma beta(2)-M was 45.5 +/- 3.1 mg/l, against a much lower 18.8 +/- 1.0 mg/l 4 weeks later. With the second system, this decrease was from 43.5 +/- 5.7 mg/l to 18.1 +/- 1.1 mg/l with 4 weeks treatment, and from 44.7 +/- 3.4 mg/l to 18.1 +/- 1.4 mg/l with 3 weeks treatment. Pre-haemodialysis treatment levels of urea nitrogen, plasma creatinine and uric acid in the first system were greater than ordinary pre-haemodialysis levels. On the second system, these were kept at -54 +/- 8.3%, -52.2 +/- 6.7% and -47.6 +/- 4.4% of the ordinary pre-haemodialysis levels, respectively. After 4 weeks on the third system, these same levels were maintained at -32.1 +/- 3.1%, -56.7 +/- 2.1% and -59.2 +/- 5.4%, respectively. Although with the first system the serum Na, Cl and Ca were within the normal range, the pre-dialysis plasma K concentration was high. Plasma P-i was greater than normal in the first and second systems, but was maintained within the normal range in the third system.