Abstract Intra-arterial blood pressure (ABP) monitoring is essential for the diagnosis and management of hypertension, hypotension, and altered hemodynamics but is less commonly used in neonates due to its invasiveness and associated risks. While commonly used in the neonatal intensive care unit (NICU), intermittent oscillometer BP monitoring lacks precision and reliability, especially in hemodynamically unstable infants. Cuff-based continuous non-invasive arterial blood pressure (CNAP) devices used in adults are not precise at low blood pressure and are not recommended for use in young infants. On the other hand, cuffless devices employing optical sensors (photoplethysmography, PPG) are increasingly being explored as a potentially promising technology but with limited applications in newborns. This underscores the urgent need for safe and accurate CNAP monitors tailored for the neonatal population. We have recently built a low-cost, wearable wireless LED-based Near Infra-Red Spectroscopy (NIRS) device, called FlexNIRS, able to acquire pulsatile signals at a large source-detector separation (NIRS-PPG) with a high signal-to-noise-ratio (SNR) at a 266 Hz sampling rate. Using this device in adults, we demonstrated that the time derivative of the optical pulse waveforms, d/dt(NIRS-PPG), is related to pulsatile blood flow, and specific morphological features of the d/dt(NIRS-PPG) signal collected on the forehead showed a strong correlation with changes in blood pressure. Preliminary data collected in newborns show that the NIRS-PPG signals and their time derivatives have similar morphological features to the ones measured in adults. Using the head as a measuring site has the advantage of avoiding common issues like motion artifacts and peripheral influences in limb-based measurements. This project aims to develop a neonatal wearable optical device (CNAP-FlexNIRS) able to collect high temporal resolution NIRS-PPG pulsatile waveforms. We will test the device in 20 NICU inpatients of different gestational ages, races, ethnicities, and medical conditions, undergoing intra-arterial blood pressure monitoring for clinical care. Finally, we will optimize the NIRS-PPG waveform analysis by training and testing deep-learning models for blood pressure estimation. The ultimate goal is to develop a reliable, low-cost continuous non-invasive arterial blood pressure monitor for both hospital and at-home use in at-risk neonates. This device has the potential to revolutionize neonatal care by eliminating high-risk invasive procedures and providing real-time data for prompt intervention. This technology will empower clinicians with safe and reliable vital information to personalize management for infants at risk of blood pressure fluctuations, leading to improved outcomes.

Project Narrative In newborns, while monitoring blood pressure is very important for managing conditions like hypertension and hypotension, especially for fragile preterm babies, current methods are either invasive or inaccurate. Our proposal introduces a wearable wireless device, called FlexNIRS, which uses LED light applied to the head to measure blood pressure continuously without invasive procedures. By developing and testing this device in the NICU, we aim to provide a reliable and safe solution for monitoring blood pressure in newborns, ultimately improving their clinical care.