The authors respond

Thank you for your question. Normal ICP measurements can range from 0 to 15 mm Hg,¹ with critical values greater than 20 mm Hg. Normal CPP range is 60 to 100 mm Hg.¹ Our neuro-surgeon’s practice is to allow permissive CPP ranges of 50 to 60 mm Hg, depending on the patient’s pathology.

In regard to hyperventilation, we use very “brief” trials of hyperventilation as a temporary measure in order to decrease ICP if it is dangerously elevated. We agree, this is not a common practice of late, but it is still (on rare occasions) used while monitoring patients. We support a PaCO₂range of 35 to 40 mm Hg. We listed several references that supported the options we presented in the article.