When a child suffers a head trauma, medical professionals are in high gear to prevent further damage to a developing brain. Measuring and regulating the child's level of carbon dioxide is critical to ensuring the brain is getting enough blood oxygen to prevent a secondary brain injury. High carbon dioxide can increase intracranial pressure, while a low level is associated with poor brain circulation.
source https://medicalxpress.com/news/2019-08-refine-guidelines-pediatric-brain-injuries.html