Although hypothermia reduces intracranial hypertension, a randomized trial in the New England Journal of Medicine found that hypothermia did not improve functional recovery as compared with standard care alone:
The trial was stopped early because the results suggested that outcomes were actually worse with hypothermia.
The accompanying editorial points out the obvious. Treating traumatic brain injury is complicated…
“Unlike the successes for almost every other organ, resuscitation of the brain has been a fitful pursuit, punctuated by enthusiasm in early trials and subsequent disappointment.
The ostensible purpose of using hypothermia was its fairly dependable effect in reducing intracranial pressure, and it has been thought to have an additional neuroprotective effect. Interpretation of these disappointing results is, as usual, complicated.
Would the benefit have been more favorable for hypothermia in the Eurotherm3235 Trial if only patients who did not have an adequate response to what the authors term “stage 2” treatments (e.g., hyperosmolar therapy) had been enrolled?
The effects on mortality and functional outcome of all the treatments we currently use — hypothermia, craniectomy, drainage of cerebrospinal fluid, hyperventilation, and even hyperosmolar therapy — are probably smaller than we think, because severe head injury is an overwhelming and complex process involving neurons, glia, and vasculature. It may be that raised intracranial pressure compresses cerebral veins and creates a self-regenerating cycle of even higher pressure so that medical management becomes futile. This is not an excuse to allow elevated intracranial pressure to go unchecked, but it is an admonition to be discerning in the use of medical and surgical treatment, especially hypothermia. Given the diversity of protocols and treatments for severe head injury in different centers (e.g., the limited use of hypothermia in the United States as compared with Europe), the study by Andrews and colleagues is useful when interpreted with its limitations. Completely new approaches are needed for the control of intracranial pressure in order to design trials and treatments for severe traumatic brain injury.”
Because I’ve recently read this interesting book:
I’ve added a new category to this blog, “Medical Reversals.”
According to these Prasad and Cifu, a problem with this study on hypothermia is using a “surrogate” endpoint (ICP) to treat TBI patients, when what we are really concerned about is the effect of hypothermia on mortality and functional outcome.
This is how medical reversal happen. A small non-randomized, uncontrolled report is published. The treatment appears logical. We jump on the bandwagon. The treatment is adopted as “Evidenced Based.” Then a randomized trial is conducted and a medical reversal occurs. It may turn out that the treatment not only has no effect, but worse, it is HARMFUL. Unfortunately, it takes years before a reversal truly eliminates the flawed treatment.