[Renal tubular dysfunction in open pediatric heart surgery--preventive effect of haptoglobin]

Preventive effect of haptoglobin (Hb) for renal tubular dysfunction was studied in 16 pediatric patients undergoing open heart surgery under extracorporeal circulation (ECC). The patients were divided into two groups; Hp(+) group consisting of 7 patients administered haptoglobin (100 U/kg) in priming of ECC, and Hp(-) group of 9 patients not administered haptoglobin. As parameters of renal tubular function, urinary alpha 1-microglobulin-index (U-alpha 1m.I), urinary beta 2-microglobulin-index (U-beta 2m.I), urinary N-acetyl-beta-D-glucosaminidase-index (U-NAG.I), fractional clearance of alpha 1m (Fc-alpha 1m) and beta 2m (Fc-beta 2m), as well as Free-Hb, were measured just before start of ECC and then at periodical time after ECC to the 7th day. The results obtained are as follows. (1) Maximum Free-Hb in Hp(+) group was significantly less (p < 0.05) than that in Hp(-) group. (2) Every parameter of renal tubular function were shown a peak at the end of ECC. Maximum values of U-alpha 1m.I, U-NAG.I and Fc-alpha 1m in Hp(+) group were significantly less (p < 0.05) than those in Hp(-) group. Maximum U-beta 2m.I and Fc-beta 2m in Hp(+) group were less than those in Hp(-) group, although there was no significant difference. These results indicate that administration of haptoglobin suppresses the increase of Free-Hb and is useful for prevention of renal tubular dysfunction during ECC.