Pharmacokinetics of single intravenous bolus administration of propofol in preterm and term neonates
Bibliographic record
Abstract
The aim of this study is to describe maturational aspects of propofol pharmacokinetics following single intravenous bolus administration in childhood. Seventy propofol blood–time profiles were collected in nine neonates (mean weight 2.4, range 0.91–3.8 kg) by arterial blood samples up to 24 hours after administration of a single intravenous bolus of propofol (3 mg/kg over 10 s) before elective chest tube removal. Concentration–time curves obtained for every individual neonate were interpreted by two-stage analysis as two-compartment and three-compartment open models. These newly collected observations following intravenous bolus administration of propofol in preterm and term neonates ( n = 9) were combined with individual pharmacokinetic estimates in toddlers ( n = 12) and young children ( n = 10) [ 1 , 2 ]. Data were reported by the median and range. The Wilcoxon test or linear correlation were used to analyse the pharmacokinetic findings in neonates, toddlers and young children. The blood–concentration curves obtained for every individual patient were interpreted by two-stage analysis as a three-compartment open model in a cohort of 31 patients with a median weight of 11.2 (range 0.91–24) kg and a median postmenstrual age of 108 (range 27–405) weeks. The median clearance was 36.8 (range 3.7–78.1) ml/kg/min, the median apparent volume of distribution at steady state ( V ss ) was 7.6 (1.33–15.6) l/kg and the median final serum elimination half-life was 377 (range 27–1134) minutes. Median clearance was significantly lower in neonates compared with toddlers and older children ( P < 0.01) and these differences remained significant after allometric scaling (ml/kg 0.75/min). A significant correlation between V ss and postmenstrual age ( r = 0.61, 95% CI 0.32–0.8, P < 0.004) was observed. Propofol disposition is significantly different in neonates compared with toddlers and young children, reflecting both ontogeny and differences in body composition. Based on the reduced clearance of propofol, accumulation during repeated administration and longer recovery time are more likely to occur in neonates.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".