Thyroxine has been shown to have a beneficial effect on renal function in cases of impending renal failure in ani-mal studies.'5 Studies of the use of thyroxine in humans in impending renal failure are scarce. The aim of this study was to assess the effect of oral thyroxine on the renal function of asphyxiated term neonates who often have renal impairment.
A randomised control trial was conducted, involving 30 term asphyxiated neonates. The study group (n=15) was given thyroxine (50 pg) orally on days 1, 2 and 3 of life and placebo was given to the control group (n=15). Renal function was studied on day 1 and day 4 of life. The two groups did not differ significantly as regards gestational age, birth weight, severity of asphyxia, preg-nancy or delivery complications, fluids administered and drugs used. There was no significant difference in urine output, creatinine clearance and fractional excretion of sodium on day 1 but there was a trend towards a worse renal function on day 1 in the treatment group. The creatinine clearance was significantly better in the treat-ment group on day 4 (p = 0.017). Urine output and fractional excretion of sodium on day 4 were better in the treatment group but the differences did not reach statistical significance (p = 0.14 and 0.057 respectively). Statistical analysis on the differences between day 4 and day 1 showed statistical significance only for creatinine clearance: creatinine clearance day 4 minus creatinine clearance day 1 was 52.6 (±32.4) for the thyroxine group and 7.3 (±7.8) for the controls (p= 0.006).
These data support the hypothesis that thyroxine may have a significant beneficial effect on the renal function in term neonates with perinatal asphyxia. Thyroxine may be proven useful in future for patients with impending renal failure.