Demetriades et al developed a discriminant function to predict mortality in a patient with isolated head injury. The authors are from the University of Southern California Los Angeles.
Parameters:
(1) Glasgow coma score (GCS)
(2) head AIS injury
(3) type of injury
(4) age in years
|
Parameter |
Finding |
Points |
|
Glasgow coma score |
3 |
1 |
|
|
4 to 8 |
2 |
|
|
9 to 12 |
3 |
|
|
13 to 15 |
4 |
|
head AIS injury |
1 or 2 |
1 |
|
|
3 |
2 |
|
|
4 |
3 |
|
|
5 |
4 |
|
type of injury |
blunt |
0 |
|
|
penetrating |
1 |
|
age of the patient |
<= 55 years |
0 |
|
|
> 55 years |
1 |
Z =
= (-2.740 * (points for GCS)) + (1.306 * (points for head AIS)) + (2.73 * (points for type of injury)) + (1.096 * (points for age)) + 1.04686
probability of death =
= 1 / (1 + EXP((-1) * Z))
where:
• I suspect that the constant in the equation should be (-1.04686) but the above expression is how it is given in the paper.
A second discriminant function was defined for patients with a GCS from 4 to 8:
X =
= (-0.741 * (GCS)) + (1.036 * (points for head AIS)) + (2.375 * (points for type of injury)) + (1.415 * (points for age)) - 0.56219
probability of death =
= 1 / (1 + EXP((-1) * X))
Specialty: Surgery, orthopedic, Emergency Medicine, Critical Care, Surgery, general
