Tobiasen et al developed a regression equation for predicting mortality in burn patients. They used this to develop an abbreviated burn severity index. The authors were from the University of Virginia in Charlottesville.
NOTE: This is a derivative of the Burn Severity Risk Index.
Parameters used for equations:
(1) sex
(2) age
(3) inhalation injury
(4) presence of full thickness burn
(5) percent of body surface area (BSA) burned
where:
• I am assuming that the percent of BSA burned is that involved by second (partial thickness) and third degree (full thickness) burns
|
Parameter |
Finding |
|
|
sex |
female |
1 |
|
|
male |
0 |
|
age |
0-20 years |
1 |
|
|
21-40 |
2 |
|
|
41-60 |
3 |
|
|
61-80 |
4 |
|
|
81-100 |
5 |
|
inhalation injury |
yes |
1 |
|
|
no |
0 |
|
presence of full thickness burn |
yes |
1 |
|
|
no |
0 |
|
percent BSA burn |
1-10% |
1 |
|
|
11-20% |
2 |
|
|
21-30% |
3 |
|
|
31-40% |
4 |
|
|
41-50% |
5 |
|
|
51-60% |
6 |
|
|
61-70% |
7 |
|
|
71-80% |
8 |
|
|
81-90% |
9 |
|
|
91-100% |
10 |
from Table 4, page 230
S =
= (0.86 * (points for sex)) + (1.08 * (points for age)) + (1.02 * (points for presence of full thickness burn)) + (1.20 * (points for inhalation injury)) + (0.95 * (points for percent BSA burned)) – 9.01
probability of mortality =
= 1 / (1 + EXP((-1) * S))
abbreviated burn severity index =
= SUM(points for the 5 variables)
Interpretation:
• minimum abbreviated burn severity index: 2
• maximum abbreviated burn severity index: 18
• The higher abbreviated burn severity index, the greater the mortality risk.
• The R^2 for the equation was 0.569
|
Abbreviated Burn Severity Index |
Threat to Life |
Probability of Survival |
|
2-3 |
very low |
>= 99% |
|
4-5 |
moderate |
98% |
|
6-7 |
moderately severe |
80-90% |
|
8-9 |
serious |
50-70% |
|
10-11 |
severe |
20-40% |
|
>= 12 |
maximum |
<= 10% |
Specialty: Emergency Medicine, Critical Care
