Getting the right dose of antibiotic promptly is an important part of treating infections. Unfortunately, when an infection is severe (sepsis) the body changes how it processes antibiotics. Consequently, some people with severe infection retain antibiotics for too long (risking adverse effects), whilst others excrete antibiotics too quickly (risking under-treatment). Mathematical models can help researchers understand drug handling variability (known as pharmacokinetics) between people. These models require very accurate information about drug administration and drug blood concentration timings. Researchers usually rely on someone recording these timings, but recording errors can make models inaccurate. We would like to understand if using data from routinely used electronic drug infusion devices (recording the exact time of administration) can improve the accuracy of pharmacokinetic models. We intend to investigate this with an antibiotic (vancomycin) that clinicians already routinely monitor blood concentrations for. Adults and children treated at St George's Hospital intensive care units will be invited to participate in the study which will last for 28-days within a 14-month period. Participants will donate a small amount of extra blood and provide researchers access to their clinical data. Blood will be taken at special times during vancomycin treatment from lines placed as part of standard treatment, minimising any pain or distress. There will be no other changes to patient's treatment. In the future, data from this study might help change the way we dose antibiotics. The National Institute for Health and Care Research and Pharmacy Research UK are supporting the study with funding.
Study Type
OBSERVATIONAL
Enrollment
30
Intravenous vancomycin administration accuracy will be determined by comparing data obtained from drug infusion pumps with manually input administration times from the electronic Prescribing and Medicines Administration (ePMA) system.
St Georges University Hospitals NHS Foundation Trust
London, London, United Kingdom
Objective Function Value
Pharmacokinetic model fit determined quantitively by Objective Function Value (2.log likelihood) using vancomycin administration time data recorded by patient's bedside drug infusion devices compared to manually recorded data
Time frame: Within collection of 15 vancomycin serum concentrations or 28 days from first study recorded administration of vancomycin
Participant Vancomycin Volume of Distribution
Calculation of participant's vancomycin volume of distribution (litres) using non-linear mixed effects modelling methods from obtained non-protein bound and total vancomycin concentrations and patient's drug infusion device obtained administration time data
Time frame: Within collection of 15 vancomycin serum concentrations or 28 days from first study recorded administration of vancomycin
Participant Vancomycin Clearance
Calculation of participant vancomycin clearance (litres/hour) using non-linear mixed effects modelling methods using obtained non-protein bound and total vancomycin concentrations and participant's drug infusion device derived administration time data
Time frame: Within collection of 15 vancomycin serum concentrations or 28 days from first study recorded administration of vancomycin
Participant 24-hour Area Under the Vancomycin Concentration Time Curve (AUC)
Calculation of participant's AUC (milligrams.hour/litre) using obtained non-protein bound and total vancomycin concentrations and participant's drug infusion device derived administration time data
Time frame: Within collection of 15 vancomycin serum concentrations or 28 days from first study recorded administration of vancomycin
Participant 24-hour AUC:MIC Ratio
Calculation of the area under the 24-hour non-protein bound and total vancomycin concentration AUC/bacterial minimum inhibitory concentration (MIC) ratio using an empiric MIC of 1mg/L or MIC of obtained isolates (if available) using trapezial rule or vancomycin dose and calculated clearance
Time frame: Within collection of 15 vancomycin serum concentrations or 28 days from first study recorded administration of vancomycin
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