Simulating Radial Pressure Waveforms with a Mock Circulatory Flow Loop to Characterize Hemodynamic Monitoring Systems

Mock circulatory loops (MCLs) can reproducibly generate physiologically relevant pressures and flows for cardiovascular device testing. These systems have been extensively used to characterize the performance of therapeutic cardiac devices, but historically MCLs have had limited use for assessing patient monitoring systems. Here, we adapted an MCL to include peripheral components and evaluated its utility for qualitative and quantitative benchtop testing of hemodynamic monitoring devices.

An MCL was designed to simulate three physiological hemodynamic states: normovolemia, cardiogenic shock, and hyperdynamic circulation. The system was assessed for stability in pressure and flow values over time, repeatability, waveform morphology, and systemic-peripheral pressure relationships.

For each condition, cardiac output was controlled to the nearest 0.2 L/min, and flow rate and mean arterial pressure remained stable and repeatable over a 60-s period (n = 5, standard deviation of ± 0.1 L/min and ± 0.84 mmHg, respectively). Transfer function analyses showed that the systemic-peripheral relationships could be adequately manipulated. The results from this MCL were comparable to those from other published MCLs and computational simulations. However, resolving current limitations of the system would further improve its utility. Three pulse contour analysis algorithms were applied to the pressure and flow data from the MCL to demonstrate the potential role of MCLs in characterizing hemodynamic monitoring systems.

Overall, the development of robust analysis methods in conjunction with modified MCLs can expand device testing applications to hemodynamic monitoring systems. Properly validated MCLs can create a stable and reproducible environment for testing patient monitoring systems over their entire operating ranges prior to clinical use.