Wound assessment should not stand on StO2 alone - Use SnapshotNIR to fill the gaps
SnapshotNIR is the only near-infrared spectroscopy (NIRS) device on the market today with the unique 4-panel Hemoglobin View (Hgb View). With SnapshotNIR you can use the deoxyhemoglobin (Deoxy Hgb) values and oxyhemoglobin (Oxy Hgb) values in Hgb View to identify and document wound healing and underlying diseases that may contribute to patient outcomes.
SnapshotNIR on the hemoglobin view 4-frame screen. Top left is StO2, bottom left is total hemoglobin, top right is deoxyhemoglobin and bottom right is oxyhemoglobin.
wound healing 101 and snapshotnir
Wound healing 101 teaches the necessity of oxygen and blood flow. However, adequate oxygen delivery and uptake to a limb with a wound can be more complicated than it may sound.
Using a NIRS imaging device, like SnapshotNIR, to visualize the tissue oxygen saturation (StO2) and hemoglobin levels in the wound and peri-wound can provide a thorough understanding of tissue healing capacity.
SnapshotNIR has multiple views to compare and interpret patient’s data. StO2 images can be compared with the color image of a wound or a clinician can view oxygen saturation, deoxy-, oxy- and total hemoglobin.
What does hemoglobin have to do with wound healing?
Depiction of red blood cells, oxygen and hemoglobin molecules. Image courtesy of Healthwise.
Hemoglobin is a molecule that binds to oxygen in our red blood cells as it travels throughout the body. Each hemoglobin molecule can carry four molecules of oxygen.
When oxygen is bound to hemoglobin, it is called oxyhemoglobin (oxyHgb), and when it is unbound, it is deoxyhemoglobin (deoxyHgb). Total hemoglobin includes both deoxy and oxy.
The oxygen molecules are bound to hemoglobin in our lungs and transported to our tissues where it is unloaded, depending on need of the cells in our tissues.
What hemoglobin trends should you expect to see as your patient heals?
On SnapshotNIR, the relative amounts of deoxyHgb and oxyHgb will spread further apart during wound healing. As a general rule of thumb, as a patient heals, deoxyhemoglobin will decrease, and oxyhemoglobin will increase.*
What else could impact StO2 and hemoglobin levels?
Venous insufficiency
Peripheral arterial disease (PAD)
Anemia
Smoking
Obesity and metabolic syndrome
Conditions and circumstances where clinicians and physicians can use hemoglobin view:
Wound healing
Pre- and post-debridement
Determining hyperbaric oxygen therapy candidacy and effectiveness
Offloading effectiveness
Compression therapy
CAMPs and CTPs progression
Ultrasound therapy
Shock therapy
PAD assessments
Candidacy for revascularization
When viewing skin perfusion and tissue oxygen saturation, it is essential to keep in mind that there are underlying reasons and conditions that will be masked by what is considered a ‘normal’ StO2.
Monitoring trends using hemoglobin view on SnapshotNIR may be the difference between a non-healing wound requiring an amputation and limb preservation.
*Each patient and individual may present differently in their disease presentation. This is not to be taken as medical advice or to replace the standard of care. This information is to be used in conjunction with a clinician’s medical assessment of the individual patient.
References:
Attia ABE, Moothanchery M, Li X, Yew YW, Thng STG, Dinish US, Olivo M. Microvascular imaging and monitoring of hemodynamic changes in the skin during arterial-venous occlusion using multispectral raster-scanning optoacoustic mesoscopy. Photoacoustics. 2021 Apr 20;22:100268. doi: 10.1016/j.pacs.2021.100268. PMID: 34026491; PMCID: PMC8122174.8.
Dilworth L, Facey A, Omoruyi F. Diabetes mellitus and its metabolic complications: the role of adipose tissues. International journal of molecular sciences. 2021 Jul 16;22(14):7644.
Lee YS, Olefsky J. Chronic tissue inflammation and metabolic disease. Genes Dev. 2021 Mar 1;35(5-6):307-328. doi: 10.1101/gad.346312.120. PMID: 33649162; PMCID: PMC7919414.
Rhodes CE, Denault D, Varacallo M. Physiology, Oxygen Transport. [Updated 2022 Nov 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538336/