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What are the new findings?
Current near-infrared spectroscopy (NIRS) and visible light spectroscopy devices are expensive, cumbersome, wired and have a large footprint, limiting their use in clinical practice.
This study proposes the use of a novel NIRS device, which is small, wireless and inexpensive, overcoming current physical and technological barriers to other spectroscopy device uptake.
How might it impact on healthcare in the future?
The real-time assessment of tissue perfusion may detect ischaemia earlier than in current clinical practice, especially in high-risk patients.
Future work should include large-scale prospective studies using wireless, real-time NIRS monitoring to determine its impact on outcomes in acute limb ischaemia.
Introduction
Acute limb ischaemia is a vascular emergency threatening both life and limb, with estimated mortality rates of 9%–22%,1 and 30-day extremity amputation rates of 10%–30%.2 3 Timely identification of the acutely ischaemic limb is pivotal.4 Conventional methods of assessing limb ischaemia rely on repeated clinical examination, serial assessment of Doppler signals and imaging technology such as duplex ultrasound, digital subtraction angiography, CT angiography and MR angiography. While able to assess arterial compromise, these technologies are limited as they provide data for only a single time point, and imaging modalities are high in cost and low in portability. The ability to non-invasively and continually monitor for limb ischaemia could enable identification of compromised tissue earlier, prompting faster revascularisation and reducing complications associated with prolonged ischaemia.
A growing interest in the role of the microcirculation in tissue perfusion5 has led to the use of near-infrared spectroscopy (NIRS) devices in the evaluation of limb ischaemia.4 6 NIRS is a non-invasive spectroscopy method of obtaining regional tissue oxygen saturation (StO2), using light wavelengths in the red and near-red range of the spectrogram. NIRS-based devices can reliably identify the ratio of oxygenated haemoglobin (HbO2) and deoxyhaemoglobin (HHb) present in tissue, and as such are able to …
Footnotes
Contributors The study was conducted by MG, MB, PSa and LG. SO, PSt, JS and AD provided specialist input to the study. The novel sensor was developed by MB at the Hamlyn Centre, Imperial College London. The article was drafted by MG, with all coauthors providing feedback prior to submission.
Funding At the time of conducting the study, MG was an Academic Clinical Fellow at Imperial College London funded by NIHR and Imperial BRC.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.