Therapeutic hypothermia is protective for the brain by reducing cerebral perfusion needs.

“when you're doing uh certain types of heart surgery you can actually cool the patient to 19° C at least back when I was training was The Sweet Spot I don't know if what the temperature is today but if you were um basically doing anything where you had to cross-clamp the aorta um and prevent cerebral profusion you would you know you would you would cool the patient literally have ice around their head the anesthesiologist would cool the patient um and obviously that was very protective”