What is an Emergency?

The Departments of Emergency Medicine (DEM) attend to a wide variety of patients. Because the resources of all DEMs are finite, there is a need to prioritise patients upon arrival to receive emergency medical care. Acuity (or severity) would naturally form the basis for such prioritisation.

The assessment of patient with the aim of prioritizing is called Triage. In all the emergency departments, this is carried out by a triage nurse. After getting information about the patient's problems and initial assessment of the vital signs, the triage nurse will assign a PACS (or simply P) status:

The 4-point Singapore Patient Acuity Category Scale (PACS) is as follows :

PACS Classification
PAC Scale 1	These are patients who are either already in a state of cardiovascular collapse or in imminent danger of collapse and would therefore be required to be attended to without a moment's delay. They would likely require the maximum allocation of staff and equipment resources for initial management. e.g. Acute Myocardial Infarction, Cardiac Arrest, Major Trauma
PAC Scale 2	These patients are ill and non-ambulant and in various forms of severe distress. They would appear to be in a stable state on initial cardiovascular examination and are not in danger of imminent collapse. The severity of their symptoms requires very early attention, failing which early deterioration of their medical status is likely. e.g. Stroke, Long Bone Fractures, Asthma
PAC Scale 3	These patients have acute symptoms, but are ambulant, have mild to moderate symptoms and require acute treatment which will result in resolution of symptoms over time. e.g. Cuts with bleeding, Mild to moderate injury, High Fever
PAC Scale 4	These are non-emergency patients. They should not be presenting to DEM in the first place and should more appropriately be managed in a primary health care setting such as in family practice or public polyclinics. They may have an old injury or condition that has been present for a long time. They do not require immediate treatment. There is no immediate threat to their life or limb. e.g. Chronic Low Back Pain, High Cholesterol, Acne