Modified Fisher Scale: Clinical Guide

Overview

Grades subarachnoid haemorrhage CT appearance to estimate risk of delayed cerebral ischaemia.

Clinical Significance

Higher grades generally indicate greater risk of symptomatic vasospasm, particularly grade 4.

When to Use

• Use as structured clinical decision support when the required data are available and reliable.

How It Is Calculated

• The displayed variables are combined using the published equation, decision rule or weighted point system.

Interpretation

• Higher grades generally indicate greater risk of symptomatic vasospasm, particularly grade 4.

Worked Example

Enter verified patient data in the displayed units; MedicalC applies the published model.

Limitations

• Risk and classification tools can be misapplied outside their validated population.
• Missing, estimated or non-contemporaneous data may materially change the result.

Clinical Pearls

• Document the input values, units, date and clinical setting with the result.
• Use serial scores only when the same instrument and measurement method are used consistently.

Common Mistakes

• Using the tool without confirming entry criteria.
• Using approximate or incorrectly converted laboratory values.
• Treating a prognostic score as a standalone treatment decision.

References

1. Frontera JA et al. Neurosurgery. 2006;59:21-27. — Primary or supporting reference for the implemented model.