Noninvasive Neonatal Blood Gas Monitoring

Project Summary/Abstract Blood gas analysis plays a crucial role in the care of preterm and critically-ill infants in the Neonatal Intensive Care Unit (NICU). Premature infants have immature lungs frequently requiring prolonged mechanical ventilation that can lead to a host of challenges necessitating constant monitoring of blood oxygen and carbon dioxide levels. Neonates in the NICU often experience significant life-threatening illnesses that affect the lungs, heart, brain, and gut that require constant monitoring and vigilance by NICU physicians and nurses. Arterial blood gas (ABG) measurements are the gold standard for detecting and managing these conditions and is the only method for quantifying blood oxygen specifically, but sampling blood from neonates is challenging. Repeated vascular access via stab puncture is impractical, necessitating arterial line placement for continuous access. However, the vessels of these infants are both tiny and fragile and the motion of neonates can lead to arterial lines becoming pulled or dislodged. Indwelling blood gas catheters exist and can be placed in the larger arteries, including the umbilical artery, but these systems carry the potential for tissue and nerve damage, malperfusion, and trauma to the gut. Problematically, while frequent ABGs are needed to monitor serious conditions - up to two or three times per hour - neonates have limited blood supply such that critically-ill infants regularly reach the threshold for blood transfusion, which carries additional risks. While transcutaneous devices have been developed with the goal of measuring blood gas levels, current devices require significant heating of the skin up to 44°C. As these high temperatures lead to skin burning and damage, these monitors are often either cycled, resulting in infrequent measurements, or operated at lower temperatures, resulting in poor agreement with ABG readings. There is an urgent need for new tools to improve the frequency, accuracy, and safety of blood gas measurements in the NICU. The proposed program leverages highly-sensitive physiologic sensors developed at the Wellman Center for Photomedicine to create and validate Versatile, Instantaneous Tracking of ABG Levels (VITAL) sensors for com- pletely non-invasive, safe, accurate, and high-frequency blood gas analysis. Aim 1 will design, implement, and test small, self-contained, wireless, and battery-operated devices that adhere to the skin for continuous neonatal blood gas readings without the need for heating or blood draw. This device will be tested in preclinical piglet mod- els, where medical gas and ventilation challenges will enable side-by-side comparison of VITAL sensor results with ABG values. Aim 2 will translate these devices to a first-in-human study in the NICU, where VITAL sensors will be directly bench-marked against ABG readings in preterm and critically-ill infants. Neonates from a full range of gestational ages, extremely premature to term, will be included in the study to validate VITAL sensors across physiological parameters including neonate size, skin thickness, ventilation, temperature, and disease status. The goal will be to validate the developed devices and methodology so that this promising technology can be rapidly translated to point-of-care technologies for NICU patients in the near future.