Implementation of a Pharmacokinetic Model to Estimate the Contribution of Infusion Systems to the Delayed Dosing of Morphine in Children

Sammanfattning: Infusion pumps administer medications like morphine to pediatric patients in order to manage pain. Drug delivery delays can be the result of flow rate variabilities in the infusion pump system. Due to the risk of over-or underdosing, this could have a high impact on the pediatric population. This study’s aim is to investigate the effect of drug dilution and dosing delays by investigating which factors affect the morphine concentration in the patient. Implementation of a previously developed population pharmacokinetic model was performed in MATLAB. Then combining it with a self-developed model of the infusion pump system, a model which included the infusion pump and the system between the pump and the patient. Simulations were performed to investigate the contributing factors. The results show that dosing delays decrease with an increasing patient’s age. There are larger morphine concentration variations with lower syringe flow rates. A decrease in dosage and a smaller syringe volume result in a shorter time of reaching a steady state concentration. Using the wrong syringe which is not compatible with the machine will lead to an increasing morphine concentration in the patient that does not reach a steady state. A limitation of the study was that no clinical data was used for the simulations. These results are useful for clinicians when making decisions regarding intravenous administration of morphine, potentially leading to fewer medication errors.