Low-Cost Tissue Oximetry Using Discrete Light-Emitting Diodes

Tissue oxygen saturation
$(\text{StO}_{2})$
is an important biomarker used to monitor patients after a surgical intervention.
$\text{StO}_{2}$
is often measured using various techniques that require expensive, bulky, and complicated instrumentation. We propose a low-cost instrument design to measure
$\text{StO}_{2}$
level using discrete light-emitting diodes (LED) and a photodiode receiver. The instrument was tested using a liquid tissue phantom to verify the operation of the system in vitro during hemoglobin deoxygenation. A commercial spectrometer was used as a reference device. Furthermore, we tested the device in vivo by measuring skin
$\text{StO}_{2}$
during a brachial artery occlusion test. The results of these experiments suggest that the device is capable of measuring
$\text{StO}_{2}$
with sufficient accuracy and could provide a low-cost alternative to spectrometer-based tissue oximetry in clinical use.