Population Pharmacodynamic Modeling without Plasma Concentrations of Rocuronium in Children

Abstract

Using the pharmacodynamic model without plasma concentrations described by Bragg et al, an individual approach resulted in highly variable parameters for rocuronium. Using a population approach of the model, the time course of the effect of an IV bolus dose of 400, 600, and 800 microg/kg of rocuronium was studied. Response was measured by accelerometry (TOF-Guard) in 45 low-risk surgical children, ages 2 to 14 years, who were receiving general anesthesia with isoflurane. Using a Bayesian approach and the software P-PHARM, response (the first twitch of the TOF) was modeled. The apparent rate constant of elimination, the rate constant for equilibrium between plasma and the effect compartment, the sigmoidicity factor of the relationship between drug concentration in the effect compartment and the effect, and the infusion rate that produces 50% of the effect at steady state were obtained. Population and individual post hoc parameters were similar among groups and variability was reduced.

Meta‐analysis of the Differences in the Time to Onset of Action Between Rocuronium and Vecuronium

“…In our meta‐analysis, similar results were obtained with AMG and MMG methods. The complete time‐course of the effect of rocuronium monitored by AMG was studied previously through a pharmacodynamic model without plasma concentrations without any problem related to the potential noise that may be generated by the AMG 34,37,38 . Therefore, we consider that the AMG can be used as a suitable alternative to MMG for evaluating the onset of action of NBA.…”

Effect of mivacurium 200 and 250 μg/kg in infants during isoflurane anesthesia: a randomized controlled trial [ISRCTN07742712]

“…However, it is not yet accepted as a monitor of definitive studies of neuromuscular blocking agents in anesthesia probably because it does not register the neuromuscular function in a continuous fashion, and can generate "noise" in the measurement of the effect [20]. Previously, we utilized it to evaluate the pharmacodynamics of rocuronium [6,28]. When used for rocuronium, data acquisition every 5 min in the recovery period was enough to model the recovery phase.…”

The effects of general anaesthesia on memory in children

“…Accidental disconnections have been reported with this device, with the manufacturers describing their intent to improve product instructions to prevent further disconnection [1][2][3]. However, despite there having been two previous reports of blockage [4,5] in addition to the defect described above, it is unclear whether the manufacturer's have investigated these problems further.…”

“…First, the duration of action of rocuronium [2], and hence the duration of anaesthesia, is much longer than the duration of the anticipated surgery; could I ask, therefore, what was the rationale for the dose of 1 mg.kg À1 ? Second, I wonder when and why the atracurium infusion was started following the rocuronium?…”