Grading scales used in the management of aneurysmal subarachnoid hemorrhage: a critical review.

The use of grading scales to predict clinical outcomes following aneurysmal subarachnoid hemorrhage (aSAH) is commonplace. In recent times management of aSAH patients has developed such that surgical intervention is taking place earlier in the course of the illness. Given the complex and multifactoral clinical picture of these patients, there is an increased impetus to examine and reevaluate the relative merits and predictive characteristics of grading scales. The measurement characteristics and predictive power of the following instruments were reviewed: Fisher Scale (FS), Glasgow Coma Scale (GCS), Glasgow Outcome Score (GOS), Hunt and Hess (HH) Scale, Karnovsky Performance Scale (KPS), and the World Federation of Neurological Surgeons (WFNS) Scale. No uniformly conclusive findings were found when the HH Scale, GCS, and WFNS Scale were used to predict clinical outcomes. No instrument consistently outperformed any other across age or severity. Contradictory findings were reported. Difficulties were encountered in comparing instruments because of administration, scoring schemes, timing of assessments, and psychometric properties, such as interrater reliability. Reports on newly developed instruments often lacked the replication data necessary to effectively compare measures currently in use. The timing of measurements and the use of serial measures emerged as important factors in the prediction of clinical outcomes. Assessments taken close to the time of surgical intervention were found to have superior predictive abilities.