A new study suggests that survival rates of adults who suffer cardiac arrest are not improved by the lowering of their body temperature prior to hospital arrival. This is according to a study published in JAMA.

Cardiac arrest occurs when the heart stops pumping blood around the body. The most common cause of the condition is an irregular heart rhythm known as ventricular fibrillation (VF).

Share on Pinterest Researchers say that pre-hospital cooling for patients who suffer cardiac arrest does not improve their outcomes.

According to the researchers from Harborview Medical Center in Seattle, WA, led by Francis Kim, cardiac arrest can cause brain injury and because of this, many patients do not awake after resuscitation.

Putting the body into a state of hypothermia (lowering of the body temperature) can help the brain recover from cardiac arrest, the investigators note.

It is thought that better outcomes occur when body cooling is carried out as soon as patients show the return of spontaneous circulation – the resumption of sustained cardiac activity – prior to hospital arrival.

To see how pre-hospital body cooling impacts patients’ survival rates, the researchers analyzed 1,359 patients, of which 583 had ventricular fibrillation and 776 did not.

All patients suffered pre-hospital cardiac arrest and were resuscitated by paramedics. Patients were randomly assigned to receive standard care with or without pre-hospital cooling.

The pre-hospital cooling was carried out by infusing the patients with up to 2 liters of normal saline (sterile solution of sodium chloride) at 4°C as soon as the patient showed return of spontaneous circulation.

The investigators note that almost all of the patients who were resuscitated from VF and admitted to the hospital received hospital cooling regardless of which group they were randomized to.