Investigation of Impulse Oscillometry for the Detection of Extravasations using Design of Experiments and an Infusion...

Extravasation is a phenomenon that occurs when the infusion solution misses the vein and enters the surrounding tissue. We developed a sensor prototype utilising impulse oscillometry to detect extravasations at an early stage. A hydraulic impulse is injected into the infusion line to observe and analyse its progress. The aim of this study was to determine the tissue parameters that might influence the sensor measurement signal and signal changes during extravasation. We developed a simulator that simulates infusions and extravasations to test the prototype. Tissue-specific parameters can be adjusted independently. The effects of the tissue parameters, including blood pressure, blood flow, blood density, blood viscosity, vein diameter, venous wall thickness, and tissue modulus of elasticity, were investigated using the design of experiments method. The parameter values were varied between two levels and tested across 16 experiments. Blood pressure, blood viscosity, vein diameter, and venous compliance demonstrated the greatest impact on the sensor signal (p < .001). The other parameters showed negligible effects. Significant differences (p = .006) in the pressure signal of the sensor could be observed when the catheter changed from the venous position to the extravasal position.