Valerie Chock, MD, MS Epi
The first seven days of life is critical for premature infants, especially for those born prior to 29 weeks gestation. During this time, these infants are most at risk for intraventricular hemorrhage and other brain injuries.
Associate Professor of Pediatrics Valerie Chock, MD, MS Epi, investigates cerebral oxygenation levels in babies and has worked to determine the “just-right” range for healthy neurodevelopment. If oxygen levels are too low, the risk of mortality increases, but if oxygen levels are too high, other injuries, like chronic lung disease and retinopathy of prematurity, may crop up.
In a recent paper in the Journal of Pediatrics, Dr. Chock and colleagues defined any cerebral oxygenation below 50% as dangerous; oxygen levels under this threshold were predictive of adverse outcomes. According to a large European clinical trial, the optimal range of cerebral oxygenation in preterm infants is 55-85%.
Faculty Scholar award targets healthy cerebral oxygenation
So, what can be done if a baby’s brain oxygen levels begin to dip into dangerous territory? It’s a question Dr. Chock aims to answer with MCHRI funding. Earlier in 2020, Dr. Chock was named the Arline and Pete Harman Endowed Faculty Scholar and will receive $100,000 per year for three years.
Building on her previous work, Dr. Chock’s latest research involves a non-invasive tool known as near-infrared spectroscopy (NIRS). To use NIRS, a clinician applies a small sensor directly to an infants’ forehead to measure brain oxygen levels. Over the last five years, this form of neuromonitoring has been used more frequently within the neonatal population thanks to research efforts that have demonstrated its efficacy at the bedside.
Dr. Chock has overseen the use of NIRS at Lucile Packard Children’s Hospital Stanford (LPCH). “We are the only NICU in the country that has a NIRS device available at every bedside,” she says. “I think we're so fortunate to have that capacity.”
Her Faculty Scholar research will measure infants’ cerebral oxygenation via NIRS during their first week of life. Timely enrollment efforts will be critical. She estimates most of her MCHRI funding will go toward supporting a research coordinator who can be available to consent and enroll families to this study shortly after birth or even before delivery.
To target healthy cerebral oxygenation, Dr. Chock plans to develop an algorithm that takes into account many different organ systems and in what order they should be assessed. For instance: What’s the baby’s systemic oxygen level? What’s the baby’s blood pressure? Is the baby anemic? “All these factors that contribute to brain oxygen levels, we have to address and think about,” Dr. Chock says. “It's great because it gets people to think very physiologically about what's going on with a baby at the bedside.”
A focus on optimizing neurologic and developmental outcomes
The Neuro Neonatal Intensive Care Unit (NeuroNICU), which is part of the Level III Intensive Care Nursery at LPCH, will support the babies enrolled in Dr. Chock’s study. Established in 2013 by Professor of Pediatrics Krisa Van Meurs, MD, the NeuroNICU is staffed by a specially trained team that uses the latest neurodiagnostic techniques and treatments to care for infants, both term and preterm, who suffer from mild to severe neurological problems. Dr. Chock credits Dr. Van Meurs with helping to guide her research and promoting the use of NIRS monitoring in the neonatal population.
Dr. Chock also considers Professor of Pediatrics Susan Hintz, MD, MS Epi, as a mentor, saying Dr. Hintz’s longitudinal research on neurodevelopmental outcomes in preterm infants paved the way for her own studies. Dr. Hintz received the MCHRI Harman Faculty Scholar award (2009-2015) to determine if neonatal neuroimaging, including cranial ultrasound and magnetic resonance imaging, could predict cognitive development difficulties at two years of age, and again at six or seven years of age, in children born preterm.
“There are so many different ways you can look at the brain. What combination of techniques is going to help us the most? That's what we're still trying to figure out,” Dr. Chock says.
This story is a complimentary piece to a larger article. To read the article, click here.
BY LAURA HEDLI
Laura Hedli is a writer for the Division of Neonatal and Developmental Medicine in the Department of Pediatrics and contributes stories to the Stanford Maternal and Child Health Research Institute.