The brain-preserving cooling treatment known as therapeutic hypothermia is rarely being used in patients who suffer cardiac arrest while in the hospital, despite its proven potential to improve survival and neurological function, researchers from the Perelman School of Medicine at the University of Pennsylvania report in the June issue of Critical Care Medicine. 

The authors suggest that scarce data about in-hospital cardiac arrest patients and guidelines that only call for health care providers to consider use of therapeutic hypothermia, rather than explicitly recommending it, may explain the study's results.

In a prospective study between 2003 and 2009 of over 530 hospitals in the United States, the Penn team found that 98 percent of over 67,000 patients who went into cardiac arrest in the hospital received only conventional post-resuscitation care—leaving just 2 percent who received therapeutic hypothermia, which has been credited with saving the lives of a growing number of patients who arrest outside hospitals.

"We know it's being used in patients who went into cardiac arrest in their homes, at work, or anywhere else outside of a hospital, but little was known about how often it's used in patients who arrest in the hospital," said Mark E. Mikkelsen, MD, MSCE, assistant professor in the division of Pulmonology, Critical Care and Allergy at Penn Medicine. "We found that even though most hospitals have the capability to treat these patients with therapeutic hypothermia, it's not being used. And even when it was used, in nearly half the cases, the correct target temperature was not being achieved.

"Several factors could explain this: there is little data, which is often conflicting, to support its use for patients in the hospital, and we have national guidelines that only have clinicians considering its use, which may lead to hesitation and lack of institutional protocol."

Cooling the body down to about 89.6 degrees after cardiac arrest protects it against neurological damage initiated by the lack of blood flow and oxygenation, several studies of out-of-hospital cardiac arrest patients have shown. It has also been shown to improve survival – a welcome development, since cardiac arrest survival statistics remain grim, with less than 10 percent of patients surviving in most cities across the U.S.

More than 300,000 people who go into cardiac arrest out of the hospital die each people each year in the United States; thousands of others are left neurologically devastated.

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