modified_fisher_grade: Modified Fisher Grading Scale for Subarachnoid Hemorrhage

In cliot: Clinical Indices and Outcomes Tools

Modified Fisher Grading Scale for Subarachnoid Hemorrhage

Description

Calculates the Modified Fisher Grade, an updated radiographic scale for predicting the risk of delayed cerebral ischemia (vasospasm) following subarachnoid hemorrhage. Unlike the original Fisher scale, this version specifically accounts for the presence of intraventricular hemorrhage (IVH) and thick cisternal blood separately.

Usage

modified_fisher_grade(sah_present, ich_ivh_present, clot_thickness_ge_1mm)

Arguments

sah_present	Numeric (0 or 1). Is subarachnoid hemorrhage present? (1 = Yes).
ich_ivh_present	Numeric (0 or 1). Is intraventricular hemorrhage (IVH) present? (1 = Yes).
clot_thickness_ge_1mm	Numeric (0 or 1). Is the SAH clot thick (>= 1 mm)? (1 = Yes).

Value

A list containing:

Modified_Fisher_Grade	The calculated grade (0-4).
CT_Findings	Description of the radiographic pattern.
Symptomatic_Vasospasm_Risk	Estimated risk percentage.

References

Claassen J, Bernardini GL, Kreiter K, et al. Effect of cisternal and ventricular blood on risk of delayed cerebral ischemia after subarachnoid hemorrhage: the Fisher scale revisited. Stroke. 2001;32(9):2012-2020. doi:10.1161/hs0901.095677

Examples

# Example 1: Highest Risk (Grade 4)
# Thick SAH (1), IVH (1)
modified_fisher_grade(1, 1, 1)

# Example 2: Intermediate Risk (Grade 2)
# Thin SAH (0), IVH (1)
modified_fisher_grade(1, 1, 0)

cliot documentation built on Dec. 1, 2025, 1:06 a.m.