Survivors of cardiac arrest who remain in comas have better survival and neurological outcomes when their body temperatures are lowered, according to a US study.
They noted that previous research has shown that therapeutic hypothermia can be effective for protecting the brain in patients with so-called “shockable” heart rhythms like ventricular fibrillation.
“We have one chance to give some form of neuroprotection, and that’s immediately after the arrest”
But researchers from the University of Colorado say they have now demonstrated that it is also effective for patients with “non-shockable” rhythms, when there is no pulse and the patient is in a coma.
Author Dr Sarah Perman, an assistant professor of emergency medicine, said: “Prior to our study, there was minimal data to support the use of this treatment on patients with non-shockable rhythms. As a result, the therapy was not widely used with these patients.”
She and her colleagues looked at data from 519 patients who had non-shockable heart rhythms between 2000 and 2013.
They found those who received therapeutic hypothermia were 2.8 times as likely to survive to be discharged and 3.5 times more likely to have better neurological outcomes – returning to their baseline mental state – than those who did not have the therapy.
The technique employed cooling wraps to drop the patients’ temperature from approximately 37 degrees Celsius to 33 degrees Celsius.
Landmark trials in 2002 studying shockable patients found 49% of those who received therapeutic hypothermia had good neurological outcomes, as opposed to 26% who did not receive the treatment. Another trial showed 55% of patients with good neurological outcome against 39% who did not have the therapy.
Dr Perman said: “Neurologic injury after cardiac arrest is devastating. We have one chance to give some form of neuro-protection, and that’s immediately after the arrest.”
She called for therapeutic hypothermia to be more widely used in comatose patients to protect neurological function.
“We know that patients benefit from this therapy,” she said. “One of our next challenges is to tailor the hypothermia treatment to the patient’s specific injury in order to improve outcomes further.”
The study was published in the latest edition of the journal Circulation.