In Singapore, over 1500 people will suffer an out-of-hospital cardiac arrest every year. Only 20 per cent of cardiac arrest victims received timely cardiopulmonary resuscitation (CPR) after collapsing.

The survival rate of out-of-hospital cardiac arrest cases is a dismal 2.7 per cent. For those who do survive, many will suffer irreversible damage to the vital organs and the brain.

However, a study by the Singapore General Hospital (SGH) may potentially change this bleak situation. SGH researchers have found that therapeutic hypothermia when used on patients immediately after resuscitation can reduce chances of death and brain damage.

Therapeutic hypothermia works by lowering a patient's core body temperature to about 33-34 degrees using an endovascular catheter inserted inside the body or wrapping water-based gels pads around the patient’s torso and legs. The unconscious patient will then be put into a medically-induced coma for the next 24 hours before gradually being restored to normal temperature. Hypothermia preserves the vital organs and prevents irreversible damage to the tissues at a cellular level.

“This study has the potential to significantly impact the current way we treat cardiac arrest patients. With therapeutic hypothermia, we are able to slow the patient’s metabolism and minimise damage to the brain that can be caused by the restored blood flow,” said Associate Professor Marcus Ong, Senior Consultant, Department of Emergency Medicine and lead investigator of the study.

The SGH study looked at the clinical outcomes of 40 cardiac arrest patients aged 18 to 80 years between October 2008 and December 2012. The patients were divided into two groups – with or without controlled therapeutic hypothermia. The findings show encouraging results that patients who were put on the new hypothermia treatment had a lower death rate and fared better.

“SGH sees between 150 and 200 cardiac arrests patients in the Emergency Department each year. As part of the Academic Healthcare Cluster, we want to not only treat patients but also study how we can increase patients’ chances of survival and improve clinical outcome,” added Prof Ong, who is also part of the teaching faculty at the Duke-NUS Graduate Medical School.

However, not every cardiac arrest patient is suitable or will benefit from the new treatment. The patient should have a stable blood pressure post resuscitation and the treatment is not suitable for traumatic cardiac arrests.

Therapeutic hypothermia has been adopted by a number of Emergency Departments overseas and is part of an ongoing clinical trial at SGH for treatment of cardiac arrest patients.