Purpose: This study aims to use curves generated from the ViOptix T.Ox tissue oximetry device to create a mathematical model to identify and predict venous congestion in patients undergoing free tissue transfer.
Methods: We obtained IRB approval for a prospective in vivo venous occlusion test (VOT) to simulate tissue venous congestion. Healthy individuals >18 years old from Atrium Health Wake Forest Baptist were selected through convenience sampling, with exclusion criteria for major cardiac disease, peripheral vascular disease, neurologic conditions, and pain syndromes.
Data collection involved connecting subjects to ViOptix T.Ox terminal for baseline StO2% measurements on the volar forearm using a fiber optic sensor, along with recording baseline blood pressure. During VOT the blood pressure cuff was inflated to 20mmHg below baseline diastolic pressure and blood pressure was monitored every 5 minutes during the 20-minute VOT. Five minutes of rebound StO2% was recorded. Data analysis and modeling were performed using Microsoft Excel.
Results: Each subject’s StO2% during VOT was plotted against time. The combined trend is characterized by the equation y = 80.81e-0.019x, R2 =0.9872. Baseline and rebound StO2% measurements were recorded. The average decline in StO2% across all subjects was 1.23% per minute.
Conclusion: Venous congestion of tissue can be successfully characterized with this venous occlusion model. Venous occlusion is described by the curve y = 80.81e-0.019x. Identifying specific patterns of venous congestion may lead to earlier detection of tissue compromise in a clinical setting.