Filtration Rate In Children Research Articles

Effect of cyclosporin A on glomerular filtration rate in children with minimal change nephrotic syndrome.

Cyclosporin A (CyA) is now commonly used in the management of children with steroid-dependent nephrotic syndrome. In order to assess nephrotoxicity related to CyA therapy, we measured glomerular filtration rate (GFR) on 123 occasions in 24 children with minimal change nephrotic syndrome receiving CyA. GFR was estimated from the plasma clearance of 51chromium-EDTA every 3 months during CyA therapy of up to 27 months duration. There was a significant reduction in GFR after 3 months of CyA therapy [118 +/- 33 (SD) to 93 +/- 24 ml/min per 1.73 m2] but no further fall thereafter, although the reduction in GFR was sustained for the duration of CyA therapy. This reduction in GFR appeared to be reversible upon cessation of CyA, but careful monitoring of renal function is necessary in such patients to prevent the development of longer term nephrotoxic sequelae.

A Comparison of Single Blood Sample and Multiple Blood Sample Methods to Measure GFR in a Pediatric Population

Several single-sample, Cr-51 EDTA based methods of estimating glomerular filtration rate in children have been proposed. The authors retrospectively reviewed our experience in 467 pediatric patients using Tc-99m DTPA and 4 ultrafiltered serum samples drawn 2-4 hours postinjection. The authors used the 2-hour specimens for the single-sample method. Regression analysis of the 2 techniques revealed significant scatter. Mathematically, it was shown that the error of the single-sample method was minimized when the clearance t 1/2 equalled the sampling time x 0.693. This model predicted a 300% error when the t 1/2 was varied to its observed extremes. The observed error of the single-sample method fit this theoretical prediction very well. Analysis of a two-sample method versus the four-sample method showed no improvement in results. In a subset of 18 unfiltered plasma samples, the glomerular filtration rate was falsely low in 12 patients. The authors conclude that multiple blood samples and serum ultrafiltration are required to accurately measure glomerular filtration rate when using Tc-99m DTPA.

Serum Creatinine, Height, and Weight Do Not Predict Glomerular Filtration Rate in Children with IDDM

To assess the validity of two equations: K x height/serum creatinine (KL/Cr; K = 0.55 for females 1-18 yr of age and 0.7 for males 12-18 yr of age) and (140 - age) x weight/72 x creatinine (x0.85 for women; Cockroft-Gault) in estimating glomerular filtration rate in children and adolescents with IDDM. From the records of the Children's Hospital Diabetes Clinic, we selected 70 patients with GFR determined by 99mTc-labeled DTPA plasma clearance, stable renal function, and simultaneous measurements of height, weight, blood pressure, HbA1c, and plasma creatinine. We compared DTPA-GFR with estimated GFR from KL/Cr and Cockroft-Gault equations for three groups: all patients, patients with DTPA-GFR < or = 140 ml.min-1 x 1.73 m-2, and patients with DTPA-GFR > 140 ml.min-1 x 1.73 m-2. For all patients, mean values for DTPA-GFR = 147 (95% confidence interval, 139-155), for KL/Cr = 118 (110-125), and for Cockroft-Gault = 84 ml.min-1 x 1.73 m-2 (78-90). For patients with DTPA-GFR < or = 140, DTPA-GFR = 123 (117-128), KL/Cr = 110 (100-119), and Cockroft-Gault = 92 (82-102). For patients with DTPA-GFR > 140, DTPA-GFR = 167 (158-177), KL/Cr = 125 (114-136), and Cockroft-Gault = 77 (71-84). Linear regression analysis showed significant (P < 0.05) relationships for KL/Cr only in patients with DTPA-GFR < or = 140 (r = 0.29), for Cockroft-Gault in all patients (r = -0.46), and for patients with DTPA-GFR < or = 140 (r = -0.31). Determination of a revised K for use in KL/Cr from individual calculations of K (DTPA-GFR x Cr/L) yielded an average value of 0.70 (SD = 0.11). With the use of K = 0.7, the mean KL/Cr value for patients with DTPA-GFR < or = 140 ml.min-1 x 1.73 m-2 was 125 +/- 27 (95% confidence interval, 115-135), compared with a DTPA-GFR value of 123 +/- 14 (95% confidence interval, 117-128). KL/Cr and Cockroft-Gault do not accurately estimate DTPA plasma clearance. We recommend the use of K equal to 0.70 when estimating GFR in children and adolescents with IDDM and DTPA-GFR < or = 140 using KL/Cr and do not recommend the use of the KL/Cr (for patients with DTPA-GFR > 140) or the Cockroft-Gault equation in this population.

Expressing glomerular filtration rate in children

We have reviewed the studies that provide the current standards of reference for glomerular filtration rate (GFR) in normal children from 14 days to 12 years of postnatal age. These standards currently are presented as ml/min per 1.73 m2, i.e., adjusted to average adult body surface area. Children from birth to 1 year of age have adjusted values below the adult range, making comparisons of observed to reference values difficult. Currently, there is no accepted way of obtaining reference values that vary smoothly with age. An analysis of the absolute GFR values in normal children taken from published studies led to an equation that estimates average GFR in relation to weight and term-adjusted age from -2 months (7 months gestational age) to 12 years in children at least 14 days post delivery. When these data are transformed to percentage of normal (% nl) for age and weight (i.e., percentage of the estimated average), it is possible to describe approximate apparent lower limits of normal GFR as is now done for adults and older children. For children with loss of renal mass, GFR expressed as % nl for age and weight provides a convenient standardization which has several useful applications. First, results expressed as % nl for children of different ages, particularly under 1 year of age, can be combined with those of older children for summary purposes. Second, the course of GFR measured serially in children is more appropriately described using this method for expressing GFR. Reporting GFR in absolute values is also useful, particularly in patients whose body mass is significantly distorted or whose absolute GFR is low.

The clearance of iohexol as a measure of the glomerular filtration rate in children with chronic renal failure

The plasma clearances of technetium-99m-labelled DTPA ([99Tcm]-DTPA) and the non-ionic contrast medium iohexol were estimated in 11 children with chronic renal failure for determination of the glomerular filtration rate (GFR). Equal values were obtained with the two substances provided plasma sampling was simultaneous, but when plasma was sampled within 3.5 h after injection of iohexol and [99Tcm]-DTPA the GFR was overestimated by more than 50%. For clearance values below 20 ml min-1 1.73 m-2, valid GFR estimates were obtained both from two plasma samples taken 3 h and 24 h after the injection of iohexol and from a single plasma sample taken 24 h after the injection.

Expressing glomerular filtration rate in children

Expressing glomerular filtration rate in children

Measurement of glomerular filtration rate in children with insulin-dependent diabetes mellitus

51Cr-EDTA, inulin and creatinine clearances were measured simultaneously in 11 diabetic children and 12 healthy young adults. The clearances in all individuals were 115 ± 24 ml/min per 1.73 m 2SA for 51Cr-EDTA, 118 ± 25 ml/min per 1.73 m 2SA for inulin and 157 ± 35 ml/minper 1.73 m 2SA for creatinine. Values were higher in the diabetic children but the differences were not significant. 51Cr-EDTA clearance significantly underestimated that of inulin by a mean of — 7.4 ± 2.5 (SEM) ml/min per 1.73 m 2SA ( p < 0.01) and creatinine clearance significantly overestimated that of inulin by 37.6 ± 3.3 (SEM) ml/min per 1.73 m 2SA ( p < 0.0001). Similarly, the mean ratio of 51Cr-EDTA to inulin clearance was 0.94 (95% CI 0.90–0.98) and that of creatinine to inulin clearance was 1.32 (95% CI 1.27–1.37); the differences between diabetics and controls were not significant. Correlation coefficients were 0.93 between 51Cr-EDTA and inulin clearances, and 0.95 between inulin and creatinine clearances. The pooled coefficient of variation between clearances within an individual was higher with inulin, 10.3 ± 6.5% (SD), than 51Cr-EDTA, 7.3 ± 5.1% ( p < 0.001, t test). These results show that 51Cr-EDTA clearance underestimates that of inulin to a similar extent in both diabetic children and healthy controls and creatinine clearance overestimates inulin clearance to a greater but similar extent in both groups. The methodological variation in 51Cr-EDTA measurement is less than with the other 2 methods. Therefore, we recommend the use of the renal clearance of 51Cr-EDTA for the measurement of GFR in diabetic children.

Measurement of glomerular filtration rate in children after renal transplantation

Inulin clearance (C In ) has long been accepted as the standard method for measurement of glomerular filtration rate (GFR) in normal subjects [1–3]. In renal transplant recipients and donors, however, Rosenbaum et al [4] showed a significant decrease in standard C In relative to the standard clearances of other markers of GFR such as iothalamate (C Io ) and creatinine (C Cr ). This phenomenon was seen within a week of transplantation and persisted in one patient up to 14 years. Heller, Horacek, and Hollyova [5] reported a similar discrepancy in transplanted dogs but only as a transient phenomenon. At 6 months after transplantation C In and C Cr in these dogs were identical. To our knowledge, there is no corresponding information in children.

Glomerular filtration rate in children with advanced chronic renal failure: methods of determination and clinical applications.

The rationale, significance and pitfalls of currently available methods for the determination of glomerular filtration rates in children with advanced chronic renal diseases are reviewed. Normal renal clearances in infants and children from birth to adulthood are presented. Methods of serial measurements of renal function, especially by the reciprocals of serum creatinine concentrations, are evaluated. They are applied clinically to monitor the effectiveness of conservative and new modalities of treatment, such as dietary supplementation with essential amino acids plus their keto analogues, and to determine that 1,25-dihydroxyvitamin-D3 treatment of renal osteodystrophy does not accelerate the deterioration of renal function in children with chronic renal insufficiency.

A Simple Estimate of Glomerular Filtration Rate in Children Derived From Body Length and Plasma Creatinine

Based on statistical analysis of data in 186 children, a formula was derived which allows accurate estimation of glomerular filtration rate (GFR) from plasma creatinine and body lenght (GFR(ml/min/1.73 sq m) = 0.55 length (cm)/Per (mg/dl). Its application to clearance data in a separate group of 223 children reveals excellent agreement with GFR estimated by the Ccr (r = .935) or Cin (r = .905). This formula should be useful for adjusting dosages of drugs excreted by the kidney and detecting significant changes in renal function.

A Simple Method for Accurate Assessment of the Glomerular Filtration Rate in Children

A Simple Method for Accurate Assessment of the Glomerular Filtration Rate in Children

A Simple Method for Accurate Assessment of the Glomerular Filtration Rate in Children

In 30 children with all degrees of reduced renal function, the total plasma clearance of [51Cr]EDTA (Cl) determined after an intravenous bolus injection was compared to the [51Cr]EDTA plasma clearance calculated from the final slope of the plasma curve (Cl1), from the final slope and the first part of the plasma curve (Cl2), and from the first part of the plasma curve (Cl3). The determination of Cl3, which demands the drawing of five blood samples within the first two hours after the injection, was found to be the most accurate one of the three simplified single injection methods for assessment of the glomerular filtration rate. The short duration is also of importance for the applicability of the method.