Treating Neurologic Injury With Hypothermia

Cooling in the Right Context
Although hypothermia has beneficial effects on neurologic outcome, “a treatment can only be effective if the other aspects of intensive care are good,” cautioned Dr. Polderman. Therefore, “context matters. It’s not just about cooling.”

When using hypothermia, temperature should be lowered rapidly, but rewarming should be done very slowly, noted Dr. Polderman. “If you do it rapidly, you could lose some or all of the protective effects of hypothermia,” he warned.

In addition, physicians should consider other aspects of ICU treatment, such as prevention of hypo- and hypercapnia, electrolyte disorders, hyperglycemia, and hypoglycemia. “All these things matter, and they may make all the difference,” he said. “Without getting that right, hypothermia can be an ineffective or even dangerous therapy.”

“The idea of context applies even more strongly to areas like severe TBI,” he asserted. “Speed and duration of cooling are important.” For patients with TBI who receive hypothermia, longer duration of cooling (ie, greater than 48 hours) and slow rewarming protocols are associated with better outcome. He noted that one way to determine the optimal duration of cooling in individual patients is to measure intracranial pressure. Intracranial pressure is both a marker of ongoing brain injury and a potential cause of additional injury.

“The use of hypothermia is not risk-free. There are severe side effects, which we should take into account, but the good news is that these can be fairly easily managed,” concluded Dr. Polderman.