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Plenary
Lecture
Creatinaemia in neonates: from biochemical
quantification to clinical interpretation
Dr Karel Allegaert
Neonatal Intensive Care Unit
University Hospitals Leuven
BELGIUM
E-mail:
karel.allegaert@uzleuven.be
Abstract: Recognition of acute renal failure (ARF)
in neonates is of relevance to adapt medical treatment
and as prognostic indicator during neonatal stay. The
incidence of ARF in neonates however is extremely
variable due to the absence of a robust definition of
renal impairment in neonates and due to the use of fixed
cut off values for serum creatinine (Scr) despite
maturational differences within the preterm age. We
therefore aimed to describe postnatal Scr trends and its
covariates in a cohort of extreme low birth weight (ELBW,
i.e. < 1000 g) infants.
Serum creatinine (Scr) reflects to a certain extent
glomerular filtration rate in neonates, but also depends
on the technique used to quantify Scr [Jaffe colorimetry
or enzymatic quantification].We compared observations of
maternal-neonatal ELBW samples in whom Jaffe or
compensated Jaffe (maternal) and enzymatic
quantification (neonate) were applied. Finally, in an
attempt to quantify differences between these
techniques, we compared postnatal Scr trends in two
consecutive cohorts of extremely low birth weight (ELBW)
neonates before and following a switch from Jaffe to
enzymatic Scr quantification. Postnatal Scr (day
1,2,3,4,5,6,7,14,21,28,42) in a cohort of 151 ELBW
neonates (Jaffe) was compared to 116 more recently
admitted ELBW neonates (enzymatic).
Firstly, ELBW neonates display trends similar to heavier
neonates, but peak Scr is higher, the subsequent
decrease slower. Raised creatinemia in ELBW neonates
reflects both immaturity (the lower GA, the higher the
peak Screa and the slower the subsequent decrease) and
morbidity (ventilation, Apgar, ibuprofen). Secondly, the
quantification method affect the paradigm that
creatinaemia at birth is similar to maternal
creatinaemia. Creatinaemia values in mothers and
neonates depend on the method used. Method-specific
reference values are needed. Finally, while clinical
characteristics were similar, median postnatal Jaffe Scr
(66,88,96,95,86,82,77,68,60,54 and 49 mmol.l-1) remained
significantly higher compared to enzymatic
quantification (51,64,80,77,72,70,65,49,39,36 and 31
mmol.l-1, all at least p<0.001) throughout postnatal
life (day 1,2,3,4,5,6,7,14,21,28,42). The difference in
within-day median values fluctuated between 11-24
mmol.l-1. It was therefore concluded that there is no
fixed absolute difference between both techniques. A
similar comparison between Jaffe and enzymatic
quantification (pre)term neonates with a birth weight
above 1 000 g confirms these findings.
Consequently, clinicians and researchers should use the
appropriated age-dependent references values, dependent
on the quantification technique used and Scr centiles
(dependent on gestational and postnatal age) should be
used to evaluate individual observations.
Brief biography of the speaker:
Karel Allegaert, MD, PhD graduated from the Katholieke
Universiteit Leuven as medical doctor (1994), with a
subsequent training in Pediatrics/Neonatology (2001) and
Clinical Pharmacology (2005). Following the presentation
of his PhD defence (neonatal analgesia: towards an
integrated approach), he further combined clinical care
as a consultant of the neonatal intensive care unit,
University Hospitals Leuven with clinical research with
specific emphasis on perinatal clinical pharmacology
(special populations, including preterm neonates and
pregnancy). He was appointed as associated professor of
the Katholieke Universiteit Leuven in 2005, and
subsequently further developed these research
activities, currently reflected in about 200
publications in national and international journals,
conference proceedings and chapters in book. His
clinical research has (FWO clinical doctoral grant) and
still is supported by a Fundamental Clinical
Investigatorship (2009-2013) of the FWO Vlaanderen. This
research also resulted in several awards of the Belgian
Academy of Medicine and Sciences (Govaerts award for
Clinical Toxicology 2006-2008, and Heymans Award
Clinical Pharmacology 2002-2004), the Belgian Pain
Society (2005),and the Galenus price, clinical research
pharmacology, Belgium (2009).
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