Relationship between plasma creatinine concentration and glomerular filtration in preterm newborn infants

Abstract

Fluid management and dosage regimens of drugs in preterm infants should be based on the glomerular filtration rate. The current methods to determine glomerular filtration rate are invasive, time-consuming, and expensive. In contrast, creatinine clearance can be easy obtained and quickly determined. The purpose of this study was to compare plasma creatinine on the third and seventh day of life in preterm newborn infants, to evaluate the influence of maternal creatinine, and to demonstrate creatinine clearance can be used as a reliable indicator of glomerular filtration rate. We developed a prospective study (1994) including 40 preterm newborns (gestational age < 37 weeks), average = 34 weeks; birth weight (average) = 1840 g, in the first week of life. Inclusion criteria consisted of: absence of renal and urinary tract anomalies; O2 saturation >/= 92%; adequate urine output (>1ml/kg/hr); normal blood pressure; absence of infections and no sympathomimetic amines in use. A blood sample was collected to determine plasma creatinine (enzymatic method) on the third and seventh day of life and creatinine clearance (CrCl) was obtained using the following equation: [formula: see text], k = 0.33 in preterm infant All plasma creatinine determinations showed normal values [third day: 0.78 mg/dl +/- 0.24 (mean +/- SD)and seventh day: 0.67 mg/dl +/- 0.31 - (p>0.05)]. Also all creatinine clearance at third and seventh day of life were normal [third day: 19.5 ml/min +/- 5.2 (mean +/- SD) and seventh day: 23.8 ml/min +/- 7.3 - (p>0,05)]. All preterm infants developed adequate renal function for their respective gestational age. In summary, our results indicate that, for clinical practice, the creatinine clearance, using newborn length, can be used to estimate glomerular filtration rate in preterm newborn infants.

Reference values of serum cystatin C in very low‐birthweight premature infants

“…In children, variability of muscle mass, age, gender, diet, glomerular and tubular secretion precludes Cr to be a valuable tool for GFR assessment . Moreover, serum Cr in neonates reflects maternal Cr even up to third day after delivery .…”

Changes in Serum Creatinine Levels and Natural Evolution of Acute Kidney Injury with Conservative Management of Hemodynamically Significant Patent Ductus Arteriosus in Extremely Preterm Infants at 23–26 Weeks of Gestation

“…Fluid therapy and drug dosing in premature infants need to be adjusted according to renal function, i.e., GFR [3,4,45,46]. Considering our results, which showed greater and delayed peak of sCr and very high prevalence of AKI stage 3 at the first two postnatal weeks in these peri-viable EPT with HS PDA, judicious fluid restriction might be prerequisite for the success of non-interventional treatment for HS PDA [2,48,49].…”

“…Assessing kidney function is crucial for meticulous fluid, electrolyte, and nutritional support, and the adjustment of medication dosage in extremely preterm infants (EPT) [1][2][3][4]. Serum creatinine level (sCr) is a commonly used in evaluating renal function and could also be applied in assessment of glomerular filtration rate (GFR) in neonates and infants [4][5][6][7].…”

“…Assessing kidney function is crucial for meticulous fluid, electrolyte, and nutritional support, and the adjustment of medication dosage in extremely preterm infants (EPT) [1][2][3][4]. Serum creatinine level (sCr) is a commonly used in evaluating renal function and could also be applied in assessment of glomerular filtration rate (GFR) in neonates and infants [4][5][6][7]. However, the use of sCr for renal function assessment in preterm infants is problematic as their sCr at birth reflects maternal levels [8,9], and sCr is quite variable according to gestational age (GA), birth weight, and chronological age [4,7,10,11].…”

“…Serum creatinine level (sCr) is a commonly used in evaluating renal function and could also be applied in assessment of glomerular filtration rate (GFR) in neonates and infants [4][5][6][7]. However, the use of sCr for renal function assessment in preterm infants is problematic as their sCr at birth reflects maternal levels [8,9], and sCr is quite variable according to gestational age (GA), birth weight, and chronological age [4,7,10,11]. Limited data are available on how sCr is affected by gestational age and birth weight and how this value changes over time, especially in the peri-viable EPT [5,7,10,[12][13][14].…”