Background
The microcirculation is the circulation of the blood in the smallest blood vessels in the body, comprising arterioles, capillaries and venules. The main functions of the microcirculation are the delivery of oxygen and nutrients and the removal of carbon dioxide. It also serves to regulate blood flow and tissue perfusion thereby affecting blood pressure and responses to inflammation. Microvascular blood flow and function are therefore very important to study and quantify in health and disease. The microvasculature does, however, present a particular challenge in physiological measurement because the blood vessel structure is spatially inhomogeneous and perfusion can exhibit high variability over time (Allen & Howell, 2014).
Often optical-based techniques are used for the microvascular assessment and the Newcastle upon Tyne Microvascular Diagnostics Service (MDS) in the UK provides a comprehensive array of optical and thermal non-invasive technologies for this purpose. The author’s main roles are the development and management of a state-of-the-art clinical microvascular, thermal imaging assessment facilities, and associated patient clinical measurement services. Measurement technologies are mostly imaging-based and currently include thermal imaging, capillaroscopy, laser Doppler perfusion imaging and flowmetry, photoplethysmography, tissue oxygen spectroscopy, fluorescence spectroscopy, venous physiology, invasive muscle tissue perfusion, autonomic function assessment, skin heating and iontophoresis vasodilatation, and tissue objective colour spectrophotometry. Many patient groups can potentially benefit, including those with Raynaud’s phenomenon, connective tissue disease, diabetes, chronic exertional muscle compartment syndrome, inflammation, chronic fatigue, burn wounds, and patients with endothelial and/or autonomic dysfunction. The measurement facility gives capability for both routine clinical measurements and provides an excellent resource for undertaking collaborative and clinically focused research and development work. The author is founder of the measurement facility and has worked with national experts to develop business plans, to procure the specialist measurement room, to introduce microvascular technologies, and also to introduce local associated measurement protocols in the form of standard operating procedures (SOP) (Allen, 2012).
This chapter summarizes the history and development of the MDS, the routine clinical services offered, and also the research and development currently undertaken. The aim of this chapter is also to emphasize the many potential opportunities for collaboration and innovation in this specialist field.