London, Nov 16 (IANS) Rapid cooling of the body after a cardiac arrest seems to improve chances of survival without damaging the victim's brain, a new study has found.

'We now have a method that is safe and can be started within minutes of cardiac arrest to minimise damage during this very critical period,' said study leader Maaret Castren, professor of emergency medicine at the Karolinska Institute, Stockholm.

For years, people hospitalised after cardiac arrest have been cooled to reduce damage to the brain and other tissues when blood circulation normalises after being temporarily halted.

In the Prince (Pre-Resuscitation Intra-Nasal Cooling Effectiveness) investigation, Castren and colleagues at 14 other centres across Europe used a new tool, RhinoChill, that cools the brain during ongoing cardiopulmonary resuscitation (CPR).

Researchers randomised 200 adults going into witnessed cardiac arrest to receive either standard resuscitation or resuscitation with cooling started as soon as possible during the arrest, with ongoing CPR.

All patients who survived until hospitalisation were further cooled according to standard criteria.

Eighteen patients were excluded from the analysis because a 'do-not-resuscitate' order was found or there was a non-cardiac reason for their cardiac arrest.

In the 182 patients reported, 83 (average age 66 years, 71 percent male) were randomised to receive nasal cooling (although two were not cooled because of user or device problems) and 99 (average age 64.8, 78 percent male) received standard care.

RhinoChill is a non-invasive device that introduces coolant through nasal prongs. The system is battery-powered and requires no refrigeration, making it suitable for emergency medical technicians to use while a person is receiving CPR.

In the total group, 46.7 percent of those cooled survived until hospital discharge, compared with 31 percent of those receiving standard care.

And 36.7 percent of those cooled were in good neurological condition on hospital discharge, compared with 21.4 percent of those receiving standard care, said a Karolinska Institute release.

In a time analysis, patients who received a combination of early CPR started within six minutes of collapse and cooling had the best outcomes.

These findings were presented at the American Heart Association's Scientific Sessions 2009.