A Novel Wearable Device for Continuous Temperature Monitoring & Fever Detection.

Objective: Continuous temperature monitoring in high-risk patients can enable healthcare providers to remotely track patients' temperatures, promptly detect fevers and timely intervene to improve clinical outcomes. We evaluated if a novel wearable, continuous temperature monitor (Verily Patch) can reliably estimate body temperature and early detect fevers in an outpatient setting in patients at a high risk of febrile neutropenia (FN) who recently underwent chemotherapy and autologous stem cell transplantation (ASCT). Methods: 86 patients at a high risk for FN were prospectively enrolled at Mayo Clinic, MN. Patients wore the device in their axilla region for 7 days post ASCT and recorded self-measured oral temperatures every 3 hours. Patients were also followed using clinical standard-of-care procedures with daily oral temperature assessment. The clinic- and patient-assessed oral temperatures were used to develop and evaluate Verily Patch's body temperature and early fever detection algorithms using a K-fold cross-validation approach. Results: The Verily Patch reliably measured body temperatures with an error of 0.35 ± 0.88°F in comparison to clinic- and patient-assessed oral temperatures. The sensitivity and specificity of the patch in detecting clinic-assessed fever episodes was 90.2% and 87.8%. The patch detected 14.3 times the number of clinic-assessed fever episodes with a median lead time of 4.3 hours. Conclusion: Patient self-monitoring of temperature and fever incidents suffers from low accuracy and is impractical for extended periods of time. Continuous temperature monitoring by a wearable device (such as Verily Patch) has the potential to overcome these challenges resulting in better patient clinical outcomes and more cost-effective care.

Radiation testing of the AeroForm CO2-based breast tissue expander implant.

BACKGROUND: Tissue expanders are used in breast reconstruction after mastectomy to stretch the remaining tissue to create space for placement of permanent breast implants. The AeroForm™ Tissue Expander, developed by AirXpanders™ Inc., contains electronic components designed to activate the release of carbon dioxide from an internal reservoir to inflate the expander. Breast cancer patients who undergo mastectomy and tissue expander/implant-based breast reconstruction may require radiation therapy at doses up to 50-60 Gy while the expander is in place. The ionizing radiation used in postmastectomy radiation therapy interacts with electronic components in medical implants, which may cause degradation in performance above certain levels. Most commercial electronic components used in medical devices, such as complementary metal-oxide semiconductor or bipolar integrated circuits can withstand radiation levels in the 50 Gy range without any performance degradation. Beyond this level, the performance may still be sufficient to guarantee functionality, but this needs to be confirmed at the system and electronic circuit level. We assessed the impact of radiation levels up to 75 Gy on 32 AeroForm™ Tissue Expanders (AirXpanders, Inc., Palo Alto, CA USA) and on the associated internal printed circuit assemblies. FINDINGS: The electronics inside the AeroForm™ Tissue Expander implant continued to function properly after exposure to radiation levels up to 75 Gy, which is well above the maximum total dose level typically used in postmastectomy radiation therapy. CONCLUSIONS: Standard postmastectomy radiation therapy doses do not damage or affect the functionality of the AeroForm™ Tissue Expander.

Real-time, continuous, fluorescence sensing in a freely-moving subject with an implanted hybrid VCSEL/CMOS biosensor.

Performance improvements in instrumentation for optical imaging have contributed greatly to molecular imaging in living subjects. In order to advance molecular imaging in freely moving, untethered subjects, we designed a miniature vertical-cavity surface-emitting laser (VCSEL)-based biosensor measuring 1cm(3) and weighing 0.7g that accurately detects both fluorophore and tumor-targeted molecular probes in small animals. We integrated a critical enabling component, a complementary metal-oxide semiconductor (CMOS) read-out integrated circuit, which digitized the fluorescence signal to achieve autofluorescence-limited sensitivity. After surgical implantation of the lightweight sensor for two weeks, we obtained continuous and dynamic fluorophore measurements while the subject was un-anesthetized and mobile. The technology demonstrated here represents a critical step in the path toward untethered optical sensing using an integrated optoelectronic implant.