The Glasgow Coma Scale (GCS) is a standardised clinical scoring system used to describe and monitor a patient’s level of consciousness following brain injury or any condition affecting neurological function. It was developed by Teasdale and Jennett at the University of Glasgow in 1974 and is now one of the most widely used neurological assessment tools in emergency medicine and intensive care worldwide.
The GCS assesses three components of behaviour: eye opening (scored 1 to 4), verbal response (scored 1 to 5), and motor response (scored 1 to 6). The three scores are added to give a total between 3 (indicating deep unresponsiveness) and 15 (fully conscious and alert). A GCS of 8 or below is generally used as the threshold for defining coma and indicates the need for airway protection, typically by endotracheal intubation.
In the intensive care unit following cardiac arrest, GCS is used to monitor neurological recovery as sedation is gradually reduced. Prognostication after cardiac arrest requires serial neurological assessments including GCS, pupillary responses, and other clinical tests, conducted no earlier than 72 hours after rewarming from targeted temperature management. This delay is necessary because residual sedative and analgesic drugs can suppress GCS scores independently of actual brain injury.
Families in the ICU are often given GCS scores as a way of describing their loved one’s responsiveness. It is important to understand that GCS alone does not predict final outcome after cardiac arrest. Early low GCS scores do not necessarily indicate permanent severe disability, and the brain can continue to recover over weeks and months as sedation is weaned and inflammation resolves.
« Back to Glossary Index