It's good that you recognize that this is in a lower (more favorable) tier of treatment as compared to the others presented. However, hyperventilating this patient is suboptimal for several reasons. There's another better option from a lower tier that should be pursued before this one. Hyperventilation also only transiently provides benefit. It makes sense when someone is herniating and you need to buy time to get them to a definitive treatment like decompressive craniectomy. However, the patient already has a bone flap off, so there'd be no clear endpoint to hyperventilation-- people tend to feel uncomfortable about pulling it back when ICPs remain high, even though it's causing damage at that point.