Therapeutic Hypothermia Increases Survival in ‘Non-Shockable’ Heart Patients

October 6th, 2016

AURORA, CO – Survival rates and brain function are increased when body temperature is lowered for cardiac arrest patients – even if they have “non-shockable” heart rhythms.

That’s according to a new study, published recently in the journal Circulation. While previous studies have indicated that therapeutic hypothermia (TH) can improve survival and neurological function, it usually is recommended only for patients with "shockable" rhythms such as ventricular fibrillation.

A study team lead by University of Colorado School of Medicine researchers suggests that therapeutic hypothermia might also benefit comatose cardiac arrest patients with "non-shockable" heart rhythms who don’t respond to defibrillation because of a lack of pulse or electrical activity in the heart.

For the study, researchers examined data from 519 patients who had a cardiac arrest due to a non-shockable heart rhythm in the Penn Alliance for Therapeutic Hypothermia (PATH) registry between 2000 and 2013.

Those who received therapeutic hypothermia were 2.8 times more likely to survive after cardiac arrest and 3.5 times more likely to have better neurologic recovery compared to those who were not cooled, according to the results.

"Neurologic injury after cardiac arrest is devastating," said lead author Sarah Perman, MD, of the University of Colorado. "We have one chance to give some form of neuroprotection, and that's immediately after the arrest.

"Our resources right now are not extensive and our outcomes are still fairly grim,” she added. “Therapeutic hypothermia is one therapy we do have in our arsenal, and if a patient is comatose after arrest, it's very important to consider applying this therapy, specifically in patients who are neurologically injured.”

Background information in the study points out that, despite established guidelines for the use of therapeutic hypothermia in patients who suffer cardiac arrest, use is low, especially for in-hospital cardiac arrest patients and those who arrest with initial non-shockable rhythms.

"The perception that there is no benefit to patients who have an initial non-shockable rhythm has hindered application," Perman said.

“Using propensity score matching, we found patients with non-shockable initial rhythms treated with TH had better survival and neurologic outcome at hospital discharge than those who did not receive TH,” study authors conclude. “Our findings further support the use of TH in patients with initial non-shockable arrest rhythms.”