Validity of the FOUR score coma scale in the medical intensive care unit

To evaluate the validity of the FOUR (Full Outline of UnResponsiveness) score (ranging from 0 to 16), a new coma scale consisting of 4 components (eye response, motor response, brainstem reflexes, and respiration pattern), when used by the staff members of a medical intensive care unit (ICU).

This interobserver agreement study prospectively evaluated the use of the FOUR score to describe the condition of 100 critically ill patients from May 1, 2007, to April 30, 2008. We compared the FOUR score to the Glasgow Coma Scale (GCS) score. For each patient, the FOUR score and the GCS score were determined by a randomly selected staff pair (nurse/fellow, nurse/consultant, fellow/fellow, or fellow/consultant). Pair wise weighted kappa values were calculated for both scores for each observer pair.

The interrater agreement with the FOUR score was excellent (weighted kappa: eye response, 0.96; motor response, 0.97; brainstem reflex, 0.98; respiration pattern, 1.00) and similar to that obtained with the GCS (weighted kappa: eye response, 0.96; motor response, 0.97; verbal response, 0.98). In terms of the predictive power for poor neurologic outcome (Modified Rankin Scale score, 3-6), the area under the receiver operating characteristic curve was 0.75 for the FOUR score and 0.76 for the GCS score. The mortality rate for patients with the lowest FOUR score of 0 (89%) was higher than that for patients with the lowest GCS score of 3 (71%).

The interrater agreement of FOUR score results was excellent among medical intensivists. In contrast to the GCS, all components of the FOUR score can be rated even when patients have undergone intubation. The FOUR score is a good predictor of the prognosis of critically ill patients and has important advantages over the GCS in the ICU setting.