Development and validation of a wireless patch for post-surgical monitoring and electrotherapy of surgical flaps

PROJECT SUMMARY Despite the advances in microsurgery and tissue reconstruction, flap failures are still common due to the inability to accurately monitor flap health that might deteriorate by both vascular occlusions and surgical site infections (SSIs). Flap failures are costly and contribute >1 billion USD annually to the national economic burden, apart from causing severe trauma to the patients. More than 95% of flap failures occur within 72 h of surgery, the costliest failures occur at later stages, after the patients have been discharged from the hospital, when they do not have access to emergency medical care. Conventional strategies and devices to monitor flap health have the following limitations (i) only tissue oxygenation (StO2) is measured as an indicator of tissue viability, (ii) patients must stay in the hospital to be monitored, further increasing treatment costs. StO2, relative temperature of the adjacent healthy tissue to the transplanted flap, and edema can be indicative of vascular occlusion and SSIs. Currently, there is no single device available that allows measurement of all the above markers of tissue health and provides electrotherapy for wound healing. SageSpectra aims to overcome these limitations posed by the current paradigm of care by developing a unique wireless patch for combined real-time remote monitoring of relative flap and health tissue temperature, edema and StO2 along with pulsed electrical stimulation (PES) for wound healing. The patch will send patient’s data to a HIPAA-compliant cloud server every 5 minutes and alert the surgeons in case of any abnormal values, thus enabling swift medical attention. SageSpectra has developed their core StO2 measurement technology using multi-wavelength spectrometry. Furthermore, they have succeeded in temperature measurements utilizing an Analog Device temperature sensor, MAX30205. The current SBIR Phase I proposal focuses on the development of a novel prototype patch with combined StO2, edema and relative temperature measurement to aid in remote monitoring of the surgical flaps. SageSpectra will test the feasibility of the wireless patch system with two specific aims. Aim 1 will focus on the design and development of the patch for StO2, bioimpedance and relative temperature measurement along with PES using a redesigned Analog Devices patch platform MAXREFDES282. Once the patch system is designed and tested in vitro, the feasibility of the patch will be tested on Porcine Musculocutaneous Flap Models in Aim 2. SageSpectra believes that the feasibility of the proposed approach can bring a significant shift in the current paradigm of care, alerting the physicians well before flap failure occurs. With wireless patch technology that can send patient data to a HIPAA-compliant cloud server, patients can be monitored directly from home by their healthcare providers, decreasing flap failure rate, and reducing cost of flap salvage procedures. After the initial proof-of-concept studies in Phase I, SageSpectra will proceed to Phase II SBIR which will focus on efficacy studies for flap surgeries in mastectomy patients.