What is new in microcirculation and tissue oxygenation monitoring?

Abstract

Ensuring and maintaining adequate tissue oxygenation at the microcirculatory level might be considered the holy grail of optimal hemodynamic patient management. However, in clinical practice we usually focus on macro-hemodynamic variables such as blood pressure, heart rate, and sometimes cardiac output. Other macro-hemodynamic variables like pulse pressure or stroke volume variation are additionally used as markers of fluid responsiveness. In recent years, an increasing number of technological devices assessing tissue oxygenation or microcirculatory blood flow have been developed and validated, and some of them have already been incorporated into clinical practice. In this review, we will summarize recent research findings on this topic as published in the last 2 years in the Journal of Clinical Monitoring and Computing (JCMC). While some techniques are already currently used as routine monitoring (e.g. cerebral oxygenation using near-infrared spectroscopy (NIRS)), others still have to find their way into clinical practice. Therefore, further research is needed, particularly regarding outcome measures and cost-effectiveness, since introducing new technology is always expensive and should be balanced by downstream savings. The JCMC is glad to provide a platform for such research.

A proof of concept for microcirculation monitoring using machine learning based hyperspectral imaging in critically ill patients: a monocentric observational study

“…HSI shares some technological capabilities and limitations of near infrared spectroscopy (NIRS), which has been extensively studied as a microcirculatory monitoring tool. Besides the use of different spectral ranges between NIRS and HSI, a major difference is that NIRS is continuous whereas HSI represents an intermittent optical monitoring method [ 29 , 30 ]. The use of ML to analyze HSI data is growing, improving diagnostic accuracy and disease classification in a variety of medical fields, including gastric, brain, and skin cancer detection, as well as eye disease or image-guided surgery [ 7 , 31 – 33 ].…”

Dietary nitrate, aging and brain health: the latest evidence

“…This raises the intriguing possibility that nitrate could help divert blood to the specific parts of the brain where it is most likely to be needed, which could be related to an increased reduction of nitrite into nitric oxide (and therefore nitric oxide-dependent vasodilatory signaling) under hypoxic conditions. A number of subsequent studies went on to demonstrate beneficial effects of nitrate on other measures of cerebral blood flow/ oxygenation [e.g., via use of near-infrared spectrometry (NIRS), a noninvasive spectroscopic method that uses near-infrared light to monitor concentration changes in oxy-and deoxyhemoglobin to determine oxygenation and blood flow/volume in tissue, including the brain [23,24]] and showed improvements in certain measures of cognitive function, including simple reaction time, response time during a Stroop test, and serial 3 s subtraction task performance (for review, see ref. [8]).…”

Multimodal imaging device to comprehensively assess infection, oxygenation, and wound analytics—A pilot study

“…State‐of‐the‐art imaging‐based devices provide a rapid alternative against the traditional techniques like swab culture, needle aspiration, and tissue biopsies for wound infection detection 9 . Correspondingly, microvascular or tissue oxygenation is the most reliable measure of blood perfusion to the tissue 13 . Existing devices measure tissue oxygenation by computing transcutaneous oxygen pressure (TcPO 2 ), 14,15 tissue oxygen saturation (StO 2 ), 16 or regional oxygen saturation (rSO 2 ) 17 .…”

“…9 Correspondingly, microvascular or tissue oxygenation is the most reliable measure of blood perfusion to the tissue. 13 Existing devices measure tissue oxygenation by computing transcutaneous oxygen pressure (TcPO 2 ), 14,15 tissue oxygen saturation (StO 2 ), 16 or regional oxygen saturation (rSO 2 ). 17 However, there is no single device, operated at a point of care, which can enable measurement of these critical wound assessment parameters.…”