HEMI and SPG soon to be finalized

The HEMI and SPG devices are currently being finalized for clinical trials. In the next phase we will investigate how these technologies can provide us with biomarkers for microcirculation function in a clinical setting.

The HEMI device is a multi-spectral optical system, which combines an LED light source, a miniature spectrometer and an adjustable finger cuff to measure photoplethysmography (PPG) and oscillometric blood pressure signals from the fingertip. From these signals, capillary pressure and vascular resistance in different vascular layers can be assessed, allowing the evaluation of the endothelial function and autoregulation. Earlier studies with healthy volunteers have shown that the HEMI device is able to assess microvascular status by measuring the hemodynamics from large and small arteries and the capillary bed.

The SPG device is a dual-wavelength device, which can measure photoplethysmography (PPG) and speckleplethysmography (SPG) signals from the finger. These signals give information on the blood volume and motion in the finger, in different depth layers. Therefore, it can give us information from both larger and smaller vessels. Tests on healthy volunteers showed good signal quality and responsiveness to changes in the circulation, which shows that our device is promising for measuring microvascular dysfunction.

The SPG device can easily be attached to a laptop, which powers the device and can give live feedback on the SPG and PPG signals that are recorded. As reference measures, ECG leads and a respiration belt can be attached. Measuring works by simply placing the finger on the device as shown in the image.