Total Burn Surface (TBS) Index of Bhatia and Mukherjee for Predicting Survival in a Burn Patient

 

Body regions:

(1) face

(2) neck

(3) front trunk

(4) rear trunk

(5) arm

(6) forearm

(7) hand

(8) thigh

(9) leg

(10) foot

(11) perineum

 

Notice that these regions are not equal in size.

 

Regions	Involvement	Points
regions 1 to 10 (not perineum)	both left and right sides burned	3
	left OR right side burned	2
	neither side burned	1
region 11 (perineum)	burned	2
	not burned	1

 

where:

• The instructions do not distinguish the extent to which a given region is involved. This could result in a burn of a small area in a region being scored the same as the entire region being burned. I would tend to score only a "significant" burn in a region, but this would introduce inter-observer variability.

 

total burn surface index =

= SUM(points for all 11 regions)

 

Interpretation:

• minimum index: 11, which indicates no burn

• minimum index with a burn: 12 (for one side of one region burned)

• maximum index: 32

• The higher the index the greater the burn injury and the lower the survival.

 

To estimate the probability of survival:

 

X =

= (-0.79 * (TBS index)) + 17.41

 

probability of survival =

= 1 / (1 + EXP((-1) * X)

 

Observed survival in study group:

Index	Probability of Survival
12 - 14	100%
15 - 17	97 - 99%
18 - 20	92 - 96%
21	68%
22	56%
23 - 24	22%
25	11%
26 to 32	0%

modified from Table V, page 371

 

Limitations:

• As with all prediction models, the actual survival seen for the individual patient will vary due to many factors such as comorbid illness and experience of the treatment team.

• Modern improvements in therapy can be expected to improve outcomes.