Parameters:
(1) percent of total body area with full thickness burns (0 to 100)
(2) percent of total body area with partial thickness burns (0 to 100)
(3) age of the patient in years
burn index = BI =
= (full thickness percent BSA) + (0.5 (partial thickness percent BSA))
prognostic burn index = PBI =
= (burn index) + (age in years)
= (full thickness percent BSA) + (0.5 (partial thickness percent BSA)) + (age)
Interpretation:
• minimum BI: 0
• maximum BI: 100
• minimum PBI < 1
• maximum PBI: over 200 (in theory)
• Tagami et al found that a PBI >= 85 was associated with increased hospital mortality.
|
PBI
|
Mortality (Tagami et al)
|
|
<= 59
|
0.4%
|
|
60 to 69
|
1.5%
|
|
70 to 79
|
2.6%
|
|
80 to 89
|
6%
|
|
90 to 99
|
14%
|
|
100 to 109
|
40%
|
|
110 to 119
|
68%
|
|
120 to 129
|
76%
|
|
>= 130
|
88-89%
|
Additional major risk factors for mortality:
(1) inhalation injury with need for mechanical ventilation (odds ratio 13)
Additional minor risk factors for mortality:
(1) comorbidity (Charlson comorbidity index >= 2, odds ratio 1.8)
(2) male gender (odds ratio 1.5)
