Glasgow Coma Scale
Glasgow Coma Scale (GCS) is a tool designed to monitor and assess the level of consciousness and to determine the prognosis after traumatic brain injury. Developed in 1974 by Irish neurosurgeons Graham Teasdale and Bryan J. Janet, it quickly became the most widely used scale for assessing the level of consciousness. Currently, in addition to use in a medical emergency setting, the Glasgow Coma Scale is also used in hospitals, especially for monitoring chronic patients in the ICU.
Calculation of GCS score
Glasgow coma scale consists of three sections: motor, verbal and ocular. For each of these answers is assigned a certain number of points. Number of points for each of the three responses generates a GCS score. The minimum number of points - 3 points, is attributed to patients in a coma. Healthy people gain maximum score - 15 points.
- Ocular response (eye opening) (O)
- Do not open his eyes = 1 point
- Opens eyes in response to painful stimuli = 2 points (pain caused by compression of the nail, pressing the orbital arcade or jaw)
- Opens eyes on verbal command = 3 points
- Opens his eyes spontaneously = 3 points
- Verbal response (V)
- No verbal response = 1 point.
- Strange sounds (moans) = 2 points
- Gabbling (exclamations or unrelated words) = 3 points
- Confused answer = 4 points (Answers to questions coherently but with some delay and disorientation)
- Adequate verbal reaction = 5 points.
- Motor response (M)
- Lack of motor response (not reactive) = 1 point
- Extensor response to pain (reaction of decerebration) = 2 points (abduction of the arm, the internal rotation of the shoulder, forearm pronation, extension at the wrist joint).
- Flexor response to pain (reaction of decortication) = 3 points
- Uncoordinated flexion / retraction of limb at pain = 4 points (on compression of the orbital arcade - elbow flexion, supination of the forearm, flexion at the wrist joint; on compression of the nail is added arm retraction)
- Localizes pain = 5 points. (movement directed to the painful stimulus)
- Executes instructions = 6 points
Interpretation of the results
Interpretation of the results is done for each response separately and for the total score. Numerical description of the results is as follows: GCS 9 = O2 V4 M3.
Being used to evaluate the prognosis of traumatic brain injury (TBI), Glasgow scale divides it into three categories:
- Severe TBI, GCS = 8 points
- Moderate TBI, GCS 9-12 points
- Mild TBI, GCS =13
- Glasgow Coma Scale is useful in assessing the coma, the correlation in this case being:
- GCS = 8 => I stage coma
- GCS = 7-6 => II stage coma
- GCS = 5-4 => III stage coma
- GCS = 3 => IV stage coma
If the patient is intubated or there is palpebral edema, assessment of verbal and eye response, respectively, is not possible. In this case, for these responses is assigned 1 point with the notice: O 1c and V 1e, where "c" - "closed" and "e" - "endotracheal tube."
Aplication of Glasgow Coma Scale
Glasgow Coma Scale was used to assess the level of consciousness in comatose patients, to assess the status and prognosis in patients with traumatic brain injury and to monitor the effectiveness of treatment in the ICU.
Glasgow Coma Scale is used as an indicator of therapeutic interventions, the most known example being the assessment of the need for intubation. It is recommended that patients with Glasgow Coma Scale score 8 points or less to be intubated because they are unable to control and protect their airway.
Limitations of Glasgow Coma Scale
Despite the wide application of Glasgow Coma Scale, it has some limitations, which often cause a number of troubles and attempts to create an alternative to it. One of the frequently cited limitations is the inability to use the scale to assess bulbar reflexes. Many researchers do not agree with Tisdale and Jennet in that ocular response would be sufficient for the recognition of the activation of the brain stem and developed rating scales that include brain stem responses. Thus, "The Comprehensive Level of Consciousness Scale" among eye, verbal and motor responses, evaluates the position of the eyeballs in the resting state, abnormal eye movements, pupillary reflexes, and overall reactivity.
Glasgow Coma Scale is accused of not completely fair assessment of the level of consciousness and of the prognosis in patients with medium scores on the GCS (9-12 points). Inequality of points between the three responses (O-4, V-5 and M-6) is another contentious issue, referring to the maximum contribution of the motor response and minimum contribution of ocular response on overall GCS score. However, this approach seems to be justified more and more lately, being established that motor response has the highest predictive value in patients with traumatic brain injury.
The timing of assessment is equally important. Tisdale recommends assessment of GCS score 6 hours after traumatic brain injury, to avoid overestimation of the severity of brain damage, due to shock or respiratory failure.