Liquid Oximeter
In a clinical study, a team from Massachusetts General Hospital (MGH) and Beth Israel Deaconess Medical Center (BIDMC) confirmed the practicality and accuracy of an oxygen-sensitive liquid dressing that measures the oxygen concentration in the transplanted tissue. A study published in the journal Science Advances compared the characteristics of a new applied bandage made of phosphorescent materials with a ViOptix wired oximeter – a standard for monitoring tissue oxygenation – in women who underwent breast reconstruction surgery after cancer.
The study showed that a transparent liquid bandage determines tissue oxygenation in the same way as an oximeter, but the wired device is less convenient for patients, it makes it difficult to visually inspect tissues and can give false indications depending on the lighting conditions and the patient's movement.
About 5% of reconstructive operations with a free flap may fail within 48 hours after transplantation if blood flow to the transplanted tissue is disrupted or insufficient. By controlling how much oxygen gets into the transplanted tissue, surgeons can quickly detect a vascular problem and intervene to save the transplant.
The study included five women who underwent breast reconstruction from March to September 2017. A 1x1 cm liquid bandage was applied to seven transplanted flaps (two women had both breasts reconstructed). A wired oximeter was also placed on each flap, and tissue oxygenation was evaluated within 48 hours after surgery. The dressing measures the amount of oxygen entering the tissue, while ViOptix reads the amount of oxygen in the blood using near–infrared spectroscopy - a less direct measurement of blood flow in the graft.
In this study, medical researchers photographed the bandage after surgery using a digital camera with customizable filters. The camera flash activated phosphorescent material in the bandage, which then glowed in the range from red to green depending on the amount of oxygen present in the tissue. After completing the study, the authors refined the bandage by developing a battery-powered sensor head, which eliminates the need for a camera and makes the bandage completely autonomous.
For all seven flaps, the rate of tissue oxygenation change measured by the bandage correlated with the oximeter data, and all seven flaps healed successfully. Currently, the authors are planning a clinical study to study how well a bandage can detect a flap that is healing poorly due to oxygen deficiency.
The clinical use of oxygen-sensitive dressing includes monitoring of healing after tissue transplantation for injuries, burns, diseases of peripheral arteries and chronic ischemia. The technology can also detect important tissue changes in patients with heart disease and other chronic diseases, warning about the progression of the disease in time.
Article by H.Marks et al. A paintable phosphorescent bandage for postoperative tissue oxygen assessment in DEEP flap reconstruction is published in the journal Science Advances.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of Massachusetts General Hospital: Liquid bandage detects tissue oxygenation without the drawbacks of wired oximeters.