A Florida neurosurgeon, Dr. Rohit Khanna, received a patent last week on a system for chilling the human brain.
As it turns out, keeping the brain cool is a good way to limit brain damage in cases of severe trauma or stroke. For now, the most common methods for keeping the brain cool work only indirectly, by chilling the entire body.
Generally, cooling of the brain has been accomplished through whole body cooling with use of a cooling blanket, immersing the patient in ice, or cooling the blood through a cardiopulmonary bypass machine.
But chilling the entire body ("systemic hypothermia"), while good for the brain, can cause serious problems elsewhere.
[T]he significant side effects that occur from induced systemic hypothermia . . . include infection, cardiac arrhythmias, coagulopathy, renal failure, as well as rewarming shock.
"Cooling helmets" have been tried, but according to the new patent, they don't work that well because people have a "thick skull."
The system described in Dr. Khanna's patent (8,123,789) gets past that thick skull. It uses a catheter (5) inserted directly into the brain, with its tip reaching into one of the brain's fluid-filled ventricles (3). Once the catheter is in place, a coolant circulates through it to cool off the brain's own fluid (cerebrospinal fluid). The coolant itself stays inside the catheter.
One problem is that the catheter should be pretty narrow (when it comes to holes in the head, smaller is better) but a very small tip wouldn't be very effective at cooling a large volume of brain. The solution described in the patent is a tip that is "capable of expanding like a balloon." To expand the tip, just crank up the pressure of the coolant. Once the tip is expanded, the brain can be kept cool more effectively, since more of the brain's fluid comes in contact with the coolant-filled tip.
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