Director's Award

Pegah Safavi | College of Engineering

Connect: pegah.safavi@uky.edu

Poster: "Continuous Monitoring of Cerebral Blood Flow and Oxygenation Responses to Intermittent Hypoxia in Neonatal Rats"

Background: Intermittent hypoxia (IH) may result in hypoxic/ischemic stresses on the brains of preterm neonates. To address the need for wearable techniques, we adapted an innovative, fiber-free, wearable diffuse speckle contrast flow-oximetry (DSCFO) device for continuous monitoring of both cerebral blood flow (CBF) and oxygenation in neonatal rats.

Methods: A miniaturized DSCFO probe was assembled consisting of two small laser diodes as focused-point and a tiny NanEye camera to detect spatial fluctuation of diffuse laser speckles for CBF, and light intensity attenuations for cerebral oxygenation measurements, including oxy- and deoxy-hemoglobin concentrations ([HbO2] and [Hb]). The DSCFO probe was attached gently to the head of neonatal rats (7 days old) under 1.25% isoflurane anesthesia. Neonatal rats in the IH group received repetitive transient hypoxia-hyperoxia challenges (10 cycles of 2-minute 8% O2 in N2 and 2-minute 100% O2), while the sham group underwent a 10-minute normoxic baseline monitoring.

Results: The IH group (n = 8) demonstrated significant increases in CBF (1.268% ± 0.767, p = 0.041) and [HbO2] (3.346% ± 1.946, p = 0.003), and a significant decrease in [Hb] (0.98% ± 2.340, p = 0.018) during the last 2 minutes of recovery. In contrast, the sham group (n = 6) exhibited minor variations in CBF, HbO2, and Hb over the monitoring period.

Conclusions: This study demonstrated the feasibility of DSCFO as a low-cost wearable sensor for continuous monitoring of multiple cerebral hemodynamic parameters. The findings underscore the importance of multi-parameter measurements for gaining deeper insights into cerebral regulation during IH events.