Comparison of Two NIRS Tissue Oximeters (Moxy and Nimo) for Non-Invasive Assessment of Muscle Oxygenation and Perfusion

Background: Near-infrared spectroscopy (NIRS) tissue oximeters enable non-invasive measurement of muscle oxygenation and perfusion. Several NIRS oximeters are currently available, particularly for muscle measurements. Aim: To evaluate the agreement of oxygenation and perfusion measurements obtained by two devices (Moxy, Fortiori Designs LLC, USA, and Nimo, Nirox, Italy) during an arterial occlusion test on the arm. Subject and Methods: Arterial occlusions were conducted at the arm of one individual for 10 min with 200 mmHg. Measurements were made twice a day on five different days. Both MRS devices were fixed at the arm (covering the muscles extensor carpi ulnaris, extensor digitorum, and flexor carpi ulnaris). Results: The experiment revealed that i) both devices could detect changes in muscle oxygenation and perfusion during the occlusion, but ii) the magnitudes and dynamic changes differed between the two devices. Discussion and Conclusion: Both devices had different performances with regard to the measurement of tissue oxygenation and perfusion. This study shows that it might be worthwhile to compare all NIRS tissue oximeters currently available for muscle measurement in a large systematic study to increase the comparability of measurements obtained with different devices.