Generality
The Glasgow scale is a neurological rating scale, which serves to describe the level of consciousness in people who are victims of severe trauma (especially brain), in those who are in a coma and in those whose conditions require hospitalization in the ICU.
According to the Glasgow scale, to estimate the state of consciousness it is necessary to evaluate 3 functions of an individual: the opening of the eyes in response to a stimulus, the motor response to a certain command and, finally, the verbal response to a certain vocal stimulus .
The Glasgow scale includes a very precise range of values, ranging from 3 (minimum value, equivalent to complete unconsciousness) to 15 (maximum value, equivalent to semi-normal consciousness).
What is the Glasgow scale?
The Glasgow scale is the best known scoring system for describing the level (or state) of consciousness, in people who are victims of severe brain or non-brain trauma, in those who are in a coma and, finally, in all subjects. admitted to intensive care.
OTHER NAMES
The Glasgow scale is also known by the English definition of Glasgow Coma Scale and with the acronym GCS.
WHO INVENTED IT?
The first publication of the Glasgow scale dates back to 1974 and the credit for its invention goes to Graham Teasdale and Bryan J. Jennett, two professors of neurosurgery at the Institute of Neurological Sciences of the University of Glasgow and the Southern General Hospital.
As "it is easy to understand, the name" Glasgow staircase "is linked to the seat of the University to which the two aforementioned professors belong.
HISTORY
Originally, the Glasgow scale was only used to estimate the state of consciousness in people who have been victims of severe head trauma or in those who have been in a coma for at least 6 hours.
Over time, its fields of use have expanded and, today, doctors also use it to estimate the level of consciousness of all ICU patients and those who have suffered severe and acute physical trauma (but not necessarily in the brain).
Features
The Glasgow scale describes the state of consciousness, through a numerical score that derives from the sum of the evaluations, also expressed as a number, of three specific functions of a human being. These functions - which are then equivalent to the parameters on which it is based the Glasgow scale - are:
- The opening of the eyes in response to an ocular stimulus (eye opening);
- The motor response to a given command (motor response);
- The verbal response to a certain vocal stimulus (verbal response).
Named GCS index (from Glasgow Coma Scale), the sum of the numerical evaluations assigned to each of the aforementioned parameters can range from a minimum of 3 to a maximum of 15. Therefore, the Glasgow scale includes a range of possible scores between 3 and 15, where the minimum value 3 equals to complete unconsciousness (or deep coma), while the maximum value 15 corresponds to a semi-normal state of consciousness; the intermediate values clearly correspond to intermediate situations, characterized by a progressively greater degree of consciousness as one moves away from the value e 3 (and approaches the value 15).
EVALUATION OF PARAMETERS
The creators of the Glasgow scale have assigned to each of the 3 parameters, which are used to estimate the level of consciousness, a precise numerical evaluation interval (*).
To understand:
- The parameter "eye opening”Has a numerical evaluation range from 1 to 4. 1 (one) indicates complete absence of eye opening; it is the most severe level. 4 (four), on the other hand, indicates spontaneous eye opening; equates to normality.
Intermediate values correspond to intermediate situations. - The parameter "motor response to a given command”Has a numerical evaluation range from 1 to 6. 1 (one) indicates complete absence of motor response to any command; it is the most severe level. 6 (six), on the other hand, signals maximum motor obedience to any command; corresponds to normality.
Values between 1 and 6 represent intermediate situations. - The parameter "verbal response to a certain vocal stimulus”Has a numerical evaluation range from 1 to 5. 1 (one) indicates complete absence of response to any type of verbal stimulus; it is the most severe level. 5 (five), on the other hand, indicates maximum attention, normal language skills and ability to respond to any stimulus of a verbal nature; represents normality.
As in the previous cases, the values included between 1 and 5 are equivalent to intermediate situations.
As stated, the estimate of an individual's level of consciousness is the result of the sum of the numerical evaluations of each parameter. For example, if in a "medical survey," eye opening, motor response to a command, and verbal response to a vocal stimulus each total the minimum allowed (i.e. 1), the final sum of the three parameters - hence the level of consciousness - is equal to 3, that is a state of complete unconsciousness (or deep coma).
* N.B: the numerical evaluation of each parameter is up to the medical staff, who has the patient under observation.
THRESHOLD
Within the range of scores that characterize the Glasgow scale, c is a value, located approximately in the middle, which represents the borderline between the state of unconsciousness and the state of consciousness. This value is 8 and takes the name of the threshold value of the Glasgow scale.
In light of this, therefore, when the sum of the parameters of the Glasgow scale is greater than 8 (GCS index> 8), the individual is more or less conscious; on the contrary, when the sum of the parameters of the Glasgow scale is equal or less than 8 (GCS index = or <of 8), the subject is more or less unconscious.
Interpretations of a brain injury, based on the Glasgow scale:
- It is serious if the GCS index is less than or equal to 8;
- It is moderate if the GCS index is between 9 and 12 (N.B: some experts maintain that the most appropriate range is between 9 and 13);
- It is mild if the GCS index is greater than or equal to 13.
Pros and criticisms
The Glasgow scale is a valid and reliable level of consciousness rating system.
However, it has a limit: it is unsuitable if the patient is a child under 36 months of age.
The reason is very simple: the Glasgow scale considers the verbal response, which in young children is not yet present.
