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New calibration methods and improved knowledge for reducing fatalities caused by dosage errors

The project  

Completed EMPIR project Metrology for drug delivery (18HLT08, MeDDII) improved dosing accuracy and enabled traceable measurements of volume, flow and pressure of existing drug delivery devices and inline sensors operating at very low flow rates (lower than 100 nL/min). This was achieved through the development of new calibration methods and improved metrological infrastructures. The influence of fast changing flow rates was investigated along with the physical properties of the infused fluids (e.g. viscosity), and occlusion phenomena in multi-infusion systems.

Special issue of journal

The journal Biomedical Engineering has recently published a special issue focusing on medical flow and dosing measurement metrology in drug delivery, with most of the contributions based on results from this EMPIR project. The Guest Editorial is written by project coordinator Elsa Batista from IPQ, along with project collaborators Hugo Bissig (METAS) and Stephan Klein (Technische Hochschule Lübeck).

As explained in the Guest Editorial, drug delivery is a critical aspect in health safety because infusion therapy is the most used form of therapy in hospitals and clinical environments. Accurate flow and dosing measurements are essential to ensure that the correct prescribed dose is delivered to the patient in hospitals or at home care by self-operated drug delivery devices preventing incorrect drug deliveries and improving significantly patient safety. This is particularly important for the cases where critical drugs are delivered at very small flow rates or administering very low doses for neonates.

The papers included in the special issue are:

• Metrology in health: challenges and solutions in infusion therapy and diagnostics
• Calibration methods for flow rates down to 5 nL/min and validation methodology
• Measurement of internal diameters of capillaries and glass syringes using gravimetric and optical methods for microflow applications
• In-line measurements of the physical and thermodynamic properties of single and multicomponent liquids
• Assessment of drug delivery devices working at microflow rates
• Calibration of insulin pumps based on discrete doses at given cycle times
• Development of a microfluidic electroosmosis pump on a chip for steady and continuous fluid delivery
• Effect of non-return valves on the time-of-arrival of new medication in a patient after syringe exchange in an infusion set-up
• Holographic PIV/PTV for nano flow rates–A study in the 70 to 200 nL/min range
• Unexpected dosing errors due to air bubbles in infusion lines with and without air filters

Project coordinator Elsa Batista from IPQ said

‘This project allowed the development and validation of new flow calibration methods down to 5 nL/min and a better understanding of drug delivery devices performance. This knowledge is now available in a special issue of the journal Biomedical Engineering and was also disseminated through workshops and training courses organised online and onsite for health professionals, scientists and metrologists with very good feedback from the attendees. Several Calibration and Measurement Capabilities were published in the BIPM Key Comparison Database and new flow calibration services are now available for manufacturers and end users. A predictive model for multi-infusion setups was extended to multiple flows, different viscosities, effects of air bubbles and check valves. This software can now be used by the medical community. Finally, the project supported the development of standards incorporating robust calibration procedures, equipment, and conditions, capable of supporting accurate drug delivery results and reduced risks of adverse patient incidents.’

This EMPIR project is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR Participating States.

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