An 18-Year- Old Girl Is Brought to the ER After

An 18-year- old girl is brought to the ER after a motor vehicle collision. She has a traumatic brain injury. In ER, the patient is comatose with no response or movement and GCS is 3. Her blood pressure is 108/68
And pulse is 114/min . Pupils are miotic and reactive to light . and there is an ecchymosis behind the ears. an intubation is done . On noncontrast CT scan shows bifrontal contusions and basilar skull fracture . On the next morning, a repeat head CT scan demonstrates diffuse cerebral edema.why should you adjust ventilatory respiratory rate to keep PaCO₂ level around 26-30 mmHg. ?

A) Decreased brain metabolic demand
B) Increased cerebral perfusion
C) Increased cerebral blood volume
D) Increased cerebral vascular resistance
E) Increased displacement of cerebrospinal fluid into the thecal sac