Spectroscopy for blood perfusion monitoring

• Research type

  Research Study

• Full title

  Spectroscopy for blood perfusion monitoring

• IRAS ID

  195717

• Contact name

  Benny Lo

• Contact email

  benny.lo@ic.ac.uk

• Sponsor organisation

  Imperial College London

• Duration of Study in the UK

  3 years, 9 months, 1 days

• Research summary

  Summay of Research
  Monitoring of tissue health through blood perfusion.

  Proper blood perfusion (or blood circulation throughout tissue) is crucial to ensure tissue healthiness, however, current monitoring is not continuous and requires hospital or GP appointments. In particular, after reconstructive skin transplantation surgery, the current protocol for monitoring the healthiness (or viability) of transplant is not standardized across hospitals. It is mostly based on the nurses and surgeons experience, as they assess the transplanted skin (called flap) visually, with palpation and/or with a hand-held Doppler (device to monitor blood circulation). Each assessment lasts about 5 minutes and should be iterated every hour for at least a week following surgery.

  To provide a more constant and continuous assessment, an optical (light) sensor was developed; allowing the monitoring of the viability of tissue by measuring different parameters (such as oxygen level: increase or constant oxygen level means the tissue is healthy). Multiple sensors can be placed, to remain on patients who undergo reconstructive surgery or who need blood perfusion monitoring (e.g. diabetes) for a week at maximum (see study protocol). Providing real-time measurements and visualization of blood perfusion, the device's lifetime is sufficient for the clinical team to have an overall view of the viability evolution of the tissue.

  Divided into two steps, the study firstly aims to assess the reliability and robustness of the device in a real environment. To do so, our device can be compared with a gold standard machine currently used in hospitals to assess tissue viability; measurements are recorded to be analysed (following statistical analysis) - in case of no gold standard machine available on site, only the investigated device will be used. The second step is the classification of the investigated device: measuring its sensitivity and specificity. It is necessary for telling how well this device is able to monitor tissue health.

  Summary of Results
  Free tissue transfer (FTT) surgery for breast reconstruction following mastectomy has become a routine operation with high success rates. Although failure is low, it can have a devastating impact on patient recovery, prognosis, and psychological well-being. Continuous and objective monitoring of tissue oxygen saturation (StO2) has been shown to reduce failure rates through rapid detection time of postoperative vascular complications.
  In this study, we investigate the feasibility of using our pervasive wearable wireless near-infrared spectroscopy (NIRS) to continuously monitor FTT via StO2 measurement. The goal of the study was to demonstrate that the device can reliably detect StO2 variations in a clinical setting: 14 patients were recruited. Advanced data analysis was performed on the StO2 variations, the relative StO2 gradient change, and the classification of the StO2 within different clusters of blood occlusion level (from 0% to 100% at 25% step) based on previous studies made on a vascular phantom and animals. The outcomes of the clinical study concur with previous experimental results and the expected biological responses. This suggests that the device is able to correctly detect perfusion changes and provide real-time assessment on the viability of the FTT in a clinical setting

• REC name

  London - Bromley Research Ethics Committee

• REC reference

  16/LO/1584

• Date of REC Opinion

  20 Dec 2016

• REC opinion

  Further Information Favourable Opinion