chip_head_injury_rule: CHIP Prediction Rule for CT in Head Injury Patients

In cliot: Clinical Indices and Outcomes Tools

CHIP Prediction Rule for CT in Head Injury Patients

Description

Applies the CHIP (CT in Head Injury Patients) Prediction Rule to determine the need for a CT scan in patients with minor head injury (GCS 13-15). The rule identifies patients at high risk for intracranial complications requiring neurosurgical intervention.

Usage

chip_head_injury_rule(age, gcs, vomiting, amnesia, skull_fracture_signs,
                      neurological_deficit, seizure, coagulopathy,
                      dangerous_mechanism)

Arguments

age	Numeric. Patient age in years. (>= 60 years is a risk factor).
gcs	Numeric. Glasgow Coma Scale score. (< 15 is a risk factor).
vomiting	Numeric (0 or 1). Any episode of vomiting. (1 = Yes).
amnesia	Numeric (0 or 1). Post-traumatic amnesia (anterograde > 4 hours) or retrograde amnesia (> 30 minutes). (1 = Yes).
skull_fracture_signs	Numeric (0 or 1). Clinical signs of skull fracture (depressed, basal, or penetrating). (1 = Yes).
neurological_deficit	Numeric (0 or 1). Any focal neurological deficit. (1 = Yes).
seizure	Numeric (0 or 1). Post-traumatic seizure. (1 = Yes).
coagulopathy	Numeric (0 or 1). History of coagulopathy or use of anticoagulant medication (e.g., warfarin). (1 = Yes).
dangerous_mechanism	Numeric (0 or 1). High-energy mechanism of injury (e.g., Pedestrian/cyclist vs vehicle, ejection from vehicle, fall from elevation > 1m/5 stairs). (1 = Yes).

Value

A list containing:

Recommendation	"CT Head Indicated" or "CT Head Not Indicated".
Risk_Factors_Present	A list of the specific criteria met that triggered the indication for CT.

References

Smits M, Dippel DW, Steyerberg EW, et al. Predicting intracranial traumatic findings on computed tomography in patients with minor head injury: the CHIP prediction rule. Ann Intern Med. 2007;146(6):397-405. doi:10.7326/0003-4819-146-6-200703200-00004

Examples

# Example 1: High Risk (Age)
# 70yo, GCS 15, no other symptoms
chip_head_injury_rule(70, 15, 0, 0, 0, 0, 0, 0, 0)

# Example 2: Low Risk
# 30yo, GCS 15, minor mechanism, no symptoms
chip_head_injury_rule(30, 15, 0, 0, 0, 0, 0, 0, 0)

# Example 3: High Risk (Vomiting)
# 25yo, GCS 15, Vomiting present
chip_head_injury_rule(25, 15, 1, 0, 0, 0, 0, 0, 0)

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