First of all, I don’t want to speculate at all about what might be happening. As I previously posted, hypothermia is a set protocol that is set in motion asap following a cardiac arrest. Our hospital continues this for 24 hours and this requires that the patient be fully sedated(drug induced coma). The neurologist is usually called in after this is completed, especially if the patient isn’t waking up. Obviously, the longer the patient requires CPR, the greater the risk for an anoxic brain injury. A non contrast Head CT is often done as it is a quick procedure but sometimes the patient is not stable enough for this early on. MRI testing is much harder to get in critically ill patients but is sometimes done if the results can help the neurologist in decision making. I worked at UC hospital during part of my residency. Excellent hospital. I’m sure he is getting top notch care.