The Proper Way to Measure a Patient's Glasgow Coma Score

It has good interobserver reliability and ease of use when measured properly.  GCS has been linked to prognosis prediction for traumatic brain injury, subarachnoid hemorrhage, and bacterial meningitis. 

Intubation and use of sedating drugs interfere with its utility, so it is best to obtain a GCS prior to these interventions.

 The GCS grades coma severity according to three categories of responsiveness: eye opening, motor, and verbal responses.

Eye 

1: No eye opening

2:  Eye opening in response to pain stimulus

–A peripheral pain stimulus (such as squeezing a patient’s fingernail is more effective than a central stimulus such as a trapezius squeeze, due to a grimacing effect.)

3:  Eye opening to speech

–(awakening a sleeping person does not count.  Those pts get a 4)

4.  Eyes opening spontaneously

Eye opening in response to pain should be tested by a stimulus in the limbs, because the grimacing associated with supraorbital or jaw-angle pressure may cause eye closure.

Most comatose patients will eventually open their eyes.  Less than 4% of head-injured patients never open their eyes before they die.

Verbal

 1:  No verbal response

2:  Incomprehensible sounds

3:  Inappropriate words

4:  Confused

5:  Oriented

 Incomprehensible sounds refer to moaning and groaning without any recognizable words.  Incomprehensible sounds is rudimentary vocalization that does not necessitate awareness and is thought to depend upon subcortical function.  Anencephalic children and vegetative patients can have this type of vocalization.

 Motor

1:  No motor response

2:  Extension to pain (decerebrate response)

3:  Abnormal flexion to pain (decorticate response)

4:  Flexion/withdrawl to pain

5:  Localizes to pain

6:  Obeys commands

1^st attempt to see if the patient follows commands.  If the patient can follow commands he/she gets a 6.  If the patient can’t follow commands, apply a painful stimulus. 

 When applying a painful stimulus: 

◦1) First, squeeze the patients nailbed.  If the patient flexes…

◦2)  Apply pressure to supraorbial ridge, pinch the trapezius or sternal rub

–A) Localization:  patient crosses the midline to attempt to remove the painful stimuli (5)

–B) Withdrawal Flexion:  rapid flexion of the elbow associated with abduction of the shoulder (4)

–C) Abnormal Flexion (slower sterotyped flexion of the elbow with adduction of the shoulder that can be achieved when stimulated at other sites) ((3)

–D) Extension (2)

from Dr. John Cull