Tamara van Donge

Chapter 8 156 Table 1: Differences in serum creatinine concentration (mg/dL) calculated at the end of treatment period for three ibuprofen treatment periods starting at different postnatal ages and separated per gestational age group. Differences in creatinine concentration (mg/dL) Gestational age Period 1 (day 1 – 3) Period 2 (day 15 – 17) Period 3 (day 29 – 31) 24 weeks 0.030 0.010 0.006 27 weeks 0.026 0.008 0.005 29 weeks 0.025 0.007 0.005 32 weeks 0.023 0.006 0.004 0.3 0.5 0.7 0.9 1 7 14 21 28 35 42 Postnatal age (days) Scr concentration (mg/dL) Ibuprofen treatment Yes No GA (weeks) 24 27 29 32 Figure 1: Predicted serum creatinine concentration time profiles for four typical GA ELBW neonates, dotted lines represent serum creatinine concentration under ibuprofen treatment; solid line represents absence the of ibuprofen treatment. GA; gestational age, ELBW; extremely low birth weight. Focusing on the different gestational ages, the initial increase in serum creatinine concentrations as observed during the first days of life is most profound in the more immature neonates. This elevation of creatinine concentrations is the highest in extreme premature neonates (increase of 0.03 mg/dL for a 24-week old neonate) and decreases with gestational age (increase of 0.02 mg/dL for a 32-week old neonate, Table 1).