In a medical emergency, minutes and seconds count.

The right thing for witnesses of such an event to do is call 995, the number of the Singapore Civil Defence Force's emergency ambulance and fire service, immediately. Do not hesitate. Leave it to the paramedics to make the call which hospital the patient should be transferred to (Can patients go to any hospital in an emergency?, by Mr Frank Yeo Yong Chong; Oct 26).

The paramedics will be able to initiate life-saving resuscitation at the scene, and then take the patient to the most appropriate public hospital.

In the vast majority of cases, this will be the nearest of the six general public hospitals which receive emergency ambulances, because it is vital that a sufferer of a life-threatening medical emergency receive treatment as soon as possible.

There are some exceptions, such as paediatric cases and burns, for which the paramedics will judge on a case-by-case basis if the patient is stable enough to be transported slightly farther to a children's hospital, or the Singapore General Hospital, which is a burns centre.

All six public hospitals have 24-hour emergency departments which are capable of resuscitating and stabilising all emergency cases, including heart attacks and strokes.

In certain situations, after the patient's condition has been stabilised, doctors may decide that the patient be transferred to another hospital for further care. Unstable patients are not transferred between hospitals, owing to the risk of deterioration and death en route.

In cases where the sufferer is not breathing normally and may be the victim of cardiac arrest, the caller should also be prepared, if physically able, to follow the step-by-step instructions given by the ambulance dispatcher on the other end of the line to perform CPR (cardiopulmonary resuscitation), until the ambulance arrives.

An immediate call to 995 and the readiness to perform CPR could mean the difference between life and death.

The number 995 is to be dialled only in the case of a fire or a medical emergency. For non-emergency medical cases in which transport is required to hospital, dial 1777.

Joanna Chan Shi-En (Dr)