The Glasgow Coma Scale Pupils Score (GCS-P) was described by Paul Brennan, Gordon Murray, and Graham Teasdale in 2018 as a strategy to combine the two key indicators of the severity of traumatic brain injury into a single simple index.
Calculation of the GCS-P is by subtracting the Pupil Reactivity Score (PRS) from the Glasgow Coma Scale (GCS) total score:
GCS-P = GCS – PRS
The Pupil Reactivity Score is calculated as follows.
Pupils unreactive to light - Pupil Reactivity Score
Both pupils - 2
One pupil - 1
Neither pupil - 0
The GCS-P score can range from 1 and 15 and extends the range over which early severity can be shown to relate to outcomes of either mortality or independent recovery.
The GCS-P is a useful predictor of 30-day mortality, although its usefulness for other clinical outcomes remains to be proven 1).