triss_trauma_score: Trauma Score - Injury Severity Score (TRISS)

In cliot: Clinical Indices and Outcomes Tools

Trauma Score - Injury Severity Score (TRISS)

Description

Calculates the probability of survival for a trauma patient using the TRISS methodology. This method combines anatomical injury severity (ISS), physiological status (Revised Trauma Score), patient age, and the mechanism of injury to estimate outcomes.

Usage

triss_trauma_score(age, mechanism, gcs, systolic_bp, respiratory_rate, iss)

Arguments

age	Numeric. Patient age in years.
mechanism	String. Mechanism of injury. Options: "blunt" or "penetrating".
gcs	Numeric. Glasgow Coma Scale score (3-15).
systolic_bp	Numeric. Systolic blood pressure in mmHg.
respiratory_rate	Numeric. Respiratory rate in breaths per minute.
iss	Numeric. Injury Severity Score (Range 1-75).

Details

The Revised Trauma Score (RTS) is calculated first using coded values for GCS, SBP, and RR with standard weights:

RTS = 0.9368 \times GCS_c + 0.7326 \times SBP_c + 0.2908 \times RR_c

The probability of survival (P_s) is then calculated using logistic regression coefficients derived from the Major Trauma Outcome Study (MTOS):

P_s = \frac{1}{1 + e^{-b}}

b = b_0 + b_1(RTS) + b_2(ISS) + b_3(AgeIndex)

Where AgeIndex is 1 if Age >= 55, else 0. Coefficients vary by mechanism (Blunt vs. Penetrating).

Value

A list containing:

TRISS_Probability_Survival	Estimated percentage probability of survival.
RTS_Calculated	The calculated Revised Trauma Score used in the model.

References

Boyd CR, Tolson MA, Copes WS. Evaluating trauma care: the TRISS method. Trauma Score and the Injury Severity Score. J Trauma. 1987;27(4):370-378. Champion HR, Sacco WJ, Copes WS, et al. A revision of the Trauma Score. J Trauma. 1989;29(5):623-629.

Examples

# Example 1: Blunt Trauma, Young, Stable
# Age 30, Blunt, GCS 15, SBP 120, RR 18, ISS 15
triss_trauma_score(30, "blunt", 15, 120, 18, 15)

# Example 2: Penetrating Trauma, Older, Unstable
# Age 60, Penetrating, GCS 10, SBP 85, RR 32, ISS 30
triss_trauma_score(60, "penetrating", 10, 85, 32, 30)

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