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Pharmacokinetics and pharmacokinetic-dynamic modelling of rocuronium in infants and children
J M Wierda1, O A Meretoja, T Taivainen
1Department of Anaesthesiology, University Hospital, Groningen, The Netherlands.
Insights
This study analyzed rocuronium pharmacokinetics in infants and children, revealing significant differences in clearance and distribution volume. These findings are crucial for optimizing neuromuscular blockade in pediatric anesthesia.
Area of Science:
- Pharmacology
- Pediatric Anesthesiology
- Clinical Pharmacokinetics
Background:
- Rocuronium is a widely used neuromuscular blocking agent.
- Understanding its pharmacokinetics in pediatric populations is essential for safe and effective use.
- Previous studies have shown age-related differences in drug disposition.
Purpose of the Study:
- To determine the pharmacokinetics and pharmacokinetic-pharmacodynamic (PK-PD) relationship of rocuronium in infants and children.
- To compare PK-PD parameters between infant and pediatric patient groups.
- To inform optimal dosing strategies for rocuronium in different pediatric age groups.
Main Methods:
- Pharmacokinetic and pharmacodynamic analysis of rocuronium in infants (0.1-0.8 yr) and children (2.3-8 yr) undergoing ICU ventilation.
- Intravenous administration of rocuronium to achieve 85% neuromuscular block, monitored via EMG.
- Plasma concentration measurements using HPLC and PK-PD modeling (Sheiner model, Hill equation).
Main Results:
- Infants exhibited lower plasma clearance and a larger volume of distribution compared to children.
- Mean residence time was longer in infants than in children.
- Differences were observed in the concentration at 50% block and the slope of the concentration-effect relationship between the groups.
- Calculated ED90 values were 0.26 mg kg-1 for infants and 0.34 mg kg-1 for children.
Conclusions:
- Significant pharmacokinetic differences exist between infants and children for rocuronium.
- These variations necessitate age-specific dosing considerations for rocuronium in pediatric anesthesia.
- Further research may refine dosing guidelines to improve clinical outcomes.
Abstract:
We have determined the pharmacokinetics and pharmacokinetic-pharmacodynamic relationship of rocuronium in infants and children. We studied infants (n = 5, 0.1-0.8 yr) and children (n = 5, 2.3-8 yr), ASA II, in the ICU while undergoing artificial ventilation under i.v. anaesthesia with an arterial cannula in situ and the EMG of the adductor pollicis muscle was monitored. Rocuronium 0.06 (infants) and 0.09 (children) mg kg-1 min-1 was given i.v. over +/- 5 min until 85% neuromuscular block was obtained. Arterial blood samples were obtained over 240 min. Plasma concentrations were measured by HPLC. Pharmacokinetic-dynamic variables were calculated using the Sheiner model and the Hill equation. Statistical analysis was performed using the Mann-Whitney U test (P < 0.05). The mean administered dose was 0.32 (SD 0.08) mg kg-1 and 0.4 (0.1) mg kg-1 for infants and children, respectively. Infants differed from children in plasma clearance (4.2 (0.4) vs 6.7 (1.1) ml min-1 kg-1), distribution volume at steady state (231 (32) vs 165 (44) ml kg-1), mean residence time (56 (10) vs 26 (9) min), concentration in the effect compartment at 50% block (1.2 (0.4) vs 1.7 (0.4) mg litre-1) and the slope of the concentration-effect relationship (5.7 (1.3) vs 3.9 (0.5)). Calculated mean ED90 values were 0.26 and 0.34 mg kg-1 for infants and children, respectively. The time course of neuromuscular block after equipotent doses did not differ.