Derivations that enable the testing of fetal urine production as a method of fetal surveillance

Abstract

PurposeTo calculate the measurement error of the hourly fetal urine production rate (HFUPR) and evaluate the implication of different methods for measuring the HFUPR, i.e. ellipsoid versus sum-of-cylinders method.MethodsThe calculation was based on sonographic documentation of the increased bladder volumes during the filling phase, the bladder volume measurement error and the number and time points of bladder image capture.ResultsThe probability of a false pathological reading was excluded (0%) with the sum-of-cylinders method for gestational ages of ≥30 weeks. With the ellipsoid method, the risk was higher. The maximum changes which could be exclusively explained by measurement error were four to five times greater with the ellipsoid method compared with the sum-of-cylinders method.ConclusionsThe present paper illustrates a careful evaluation of the HFUPR measurement error and the implications of using different ultrasound methods for bladder volume estimations.Electronic supplementary materialThe online version of this article (doi:10.1007/s00404-009-1242-6) contains supplementary material, which is available to authorized users.

Determining the Uncertainty of Fetal Urine Production Rate Estimations

“…In 2010 our team described the calculation of measurement error of HFUPR estimations. The presentation was very theoretical and probably of limited value for the readers [19]. In the current paper an interactive program for estimating the HFUPR and SD HFUPR is presented and now illustrated by a practical example.…”

Renal Function and Urine Production in the Compromised Fetus

“…The implication of the volume measurement error was demonstrated in detail in a publication publication concerning the 2D technique and the sum-of-cylinders method. (Fagerquist et al, 2010).…”