ARTICLE | doi:10.20944/preprints202105.0062.v1
Subject: Medicine & Pharmacology, Allergology Keywords: creatinine; cystatin C; asphyxia; whole body hypothermia; acute kidney injury; renal clearance; kidney function.
Online: 5 May 2021 (13:27:42 CEST)
Many neonates undergoing whole body hypothermia (WBH) following moderate to severe perinatal asphyxia suffer from renal impairment. While recent data suggest a WBH-related reno-protection, the differences in serum creatinine (Scr) patterns to reference patterns were not yet reported. We therefore aimed to document Scr trends and patterns in asphyxiated neonates undergoing WBH, and compared these to centiles reference Scr dataset of non-asphyia neonates. Using a systematic review strategy, reports on Scr trends (mean ± SD, or median and range) were collected (day 1-7) in WBH cohorts, and compared to centiles of an earlier reported reference cohort of non-asphyxia cases. Based on 13 papers on asphyxia+WBH cases, a pattern on postnatal Scr trends in asphyxia+WBH cases was constructed. Compared to the reference cohort, mean or median Scr values at birth (>90th centile) and the first two days of WBH (>75th centile) remained clinical relevantly higher in asphyxia+WBH cases, with a subsequent decline to reach at best high or high normal creatinine values (all >50th centile, but mainly >75th centile) from day 4 onwards. Such patterns are valuable to anticipate average changes in renal clearance capacity relevant for pharmacotherapy, but do not yet cover the relevant inter-patient variability observed in WBH cases.
ARTICLE | doi:10.20944/preprints202208.0135.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: physiologically based pharmacokinetic modelling; propofol; low cardiac output; pharmacokinetics; neonate; developmental pharmacology; asphyxia; hypothermia; pediatrics; pharmacokinetics
Online: 8 August 2022 (06:12:36 CEST)
Background: pathophysiological changes like low cardiac output (LCO) impact pharmacokinetics, but its extent may be different throughout pediatrics compared to adults. Physiologically based pharmacokinetic (PBPK) modelling enables further exploration. Methods: A validated propofol model was used to simulate the impact of LCO on propofol clearance across age groups using the PBPK platform, Simcyp® (version 19). The hepatic and renal extraction ratio of propofol was then determined in all age groups. Subsequently, dose explorations were conducted under LCO conditions, targeting a 3 µg/mL (80-125%) propofol concentration range. Results: Both hepatic and renal extraction ratios increased from neonates, infants, children to adolescents and adults. The relative change in clearance following CO reductions increased with age, with the least impact of LCO in neonates. The predicted concentration remained within the 3 µg/mL (80-125%) range under normal CO and LCO (up to 30%) conditions in all age groups. When CO was reduced by 40-50%, a dose reduction of 15% is warranted in neonates, infants and children, 25% in adolescents and adults. Conclusions: PBPK driven, the impact of reduced CO on propofol clearance is predicted to be age-dependent, proportionally greater in adults. Consequently, age group specific dose reductions for propofol are required in LCO conditions.