Continous human blood-flow monitoring system using optical sensor array

Abstract

Monitoring of flap after transplant surgery is important because occurrence of thrombosis bringing about compromised circulation demands immediate salvage surgery. The risk of thrombosis lasts for one week thus laying heavy burden on staffs. Continuous blood-flow monitoring device not only relieves staffs, but also increases rescue rate of salvage surgery due to its early detection. We propose a flexible sensor array that monitors multipoint flap condition by three quantitative on-site indications: pulse wave, skin color and temperature. Superior to conventional methods with huge devices, we implement small phototransistors and thermistors on flexible substrate which maps large-area flap conditions without disturbing patients. Instead of calculating blood volume, we designed an algorism that assesses blood-flow automatically by observing shift of pulse wave power. Signal obtained from volunteers (5 subjects) during resting-state, ischemia, and congestion demonstrated the effectiveness (p<0.005) of our flap failure detection, and it is expected to judge compromised circulation continuously.