Figure 6

Representative case presentation of a patient with and without impaired blood flow. (a) Raw signal data for each measured parameter. In the case where the tissue had normal blood flow (left), the pulse wave signal was strong, the colour signal was stable, and the temperature was stable within 1° or 2°. In the case of impaired blood flow (right), the pulse wave signal was weak, the colour signal varied substantially, and the temperature varied by 2°–3°. (b) Comprehensive risk rate calculated from the raw data. In the normal case (top), the risk rate was close to zero throughout the postoperative week. However, in the case which tissue circulation was compromised (bottom), the calculated risk rate increased in all four sensor channels. The system identified the risk of circulation deficiency 13 h prior to medical staff reporting the change.