Abstract

To combat the unmet need of early detection and monitoring of postpartum hemorrhage (PPH), the leading cause of maternal death, a wearable short-wave infrared (SWIR) photoplethysmography (PPG) sensor was developed for real-time detection and monitoring of hemodilution, a compensatory response to PPH. The device uses wavelengths at 900 and 1300 nm, ideal for monitoring hemoglobin and water contributions in blood, respectively. These wavelengths minimally absorb melanin, which has been shown to bias PPG results in pulse oximetry. High signal-to-noise PPG signals have been acquired from both the 900 nm and 1300 nm channels in human volunteers. Further, the hemodilution sensing capabilities were tested by flowing sheep blood through a pulsatile flow phantom. The ratio of the peak amplitudes of the PPG waveforms from both LEDs showed a linear correlation, demonstrating feasibility to detect hemodilution and provide a low-cost, fully wireless, continuous monitoring tool for early diagnosis and monitoring of PPH.

Hannah Gruensfelder, Kimberly Branan, Francesca Bonetta-Misteli, Madison Carlgren, Laura Brown, Justin McMurray, Gerard Cote, Kelly Liang, Xiyan Li, Leonid Shmuylovich, and Christine M. O’Brien, “Wearable short-wave infrared device to detect and monitor hemodilution during postpartum hemorrhage (Conference Presentation),” Proc. SPIE PC12850, Optical Diagnostics and Sensing XXIV: Toward Point-of-Care Diagnostics, PC128500D (13 March 2024); https://doi.org/10.1117/12.3000996