Grading Scales for Subarachnoid Hemorrhage - Animal Models of Acute Neurological Injuries: Injury and Mechanistic Assessments - page 286

Classen et al. ( 21 ) attempted to correlate physiologic variables,
such as mean arterial blood pressure, sodium bicarbonate levels,
and arterio-alveolar gradients with radiographic fi ndings in SAH
patients. Those patients found to have abnormalities in physiologic
variables indeed had worse 3 month outcomes when compared to
the physiologically normal patients.
The WFNS scale condenses the 13 data points of the GCS to a
fi ve point scale, however, no grading axis existed in regards to
systemic disease or imaging fi ndings which have been shown to
play an important role in prediction of functional outcome. The
modifi ed WFNS ( 15 ) included seven additional axes to address
these points and include admission systolic blood pressure, history
of hypertension, presence of vasospasm at admission, clot thickness,
aneurysm location, patient's age, and aneurysm size. Unfortunately,
adding the additional data points have made the modifi ed WFNS
complex and unwieldy with only modest improvement in predic-
tive accuracy.
The Fisher scale as discussed above attempts to correlate non-
contrast head CT fi ndings with the likelihood for the development
of vasospasm. The development of vasospasm is a frequent cause of
neurologic defi cits that follow SAH and ultimate poor outcomes.
Gotoh et al. ( 22 ) attempt to utilize a clinical fi ndings (i.e., GCS
score) to predict vasospasm and ultimately outcome. They included
patients with GCS of 7-15 and found a strong relationship between
those patients with worse initial GCS and the development of symp-
tomatic vasospasm. As with the shortcomings of previous studies,
a continuum is evident as one moves toward the lower GCS scores
making it diffi cult to provide information on particular break points.
Although certainly of no guarantee, a high GCS or favorable
WFNS score at presentation has been shown to be predictive of a
good long-term functional outcome ( 22 ). It is often the middle to
poor grade SAH patient who has signifi cant neurologic derange-
ment, where the predictive tests would be most useful from both a
utilization of resources standpoint as well as providing realistic
information to the patient's family. The timing of when and what
scale provides the most valuable information has been examined
( 23 ) and that the worst clinical grade (either GCS or WFNS) was
most predictive of long-term neurologic outcome.
Lagares et al. ( 24 ) attempted to create an SAH outcome scale
that improved the breakpoints between each individual score. In
order to accomplish this, they examined 442 patients at a single
institution and found that by replacing the Hunt and Hess portion
of the MGH score with a WFNS point total were able to improve
the divisions of their breakpoints. A modifi cation of an existing
scale is a recurring theme and was demonstrated in this particular
patient population to be benefi cial for prediction, how this translates
in the larger scope of patients is yet to be determined.