Haematoma More Condition_treatment Why Can't A Lumbar Puncture Be Used In Someone Who Has A Subdural Haematoma?

Why can't a lumbar puncture be used in someone who has a subdural haematoma? - haematoma more condition_treatment

Or why not be used for a person with intracranial pressure in general? Please, could you explain the pressure changes occur, not the textbooks are clear on this point. Thank you.