Massive blood transfusion is defined as transfusion of >= 10 units of bleed during the first 24 hours after trauma center admission.
Parameters:
(1) heart rate in beats per minute
(2) systolic blood pressure in mm Hg
(3) pH of arterial blood
(4) hematocrit in percent
|
Parameter
|
Finding
|
Points
|
|
heart rate
|
<= 105 beats per minute
|
0
|
|
|
> 105 beats per minute
|
1
|
|
systolic blood pressure
|
>= 110 mm Hg
|
0
|
|
|
< 110 mm Hg
|
1
|
|
pH of arterial blood
|
>= 7.25
|
0
|
|
|
< 7.25
|
1
|
|
hematocrit
|
>= 32 percent
|
0
|
|
|
< 32 percent
|
1
|
total number of risk factors for massive blood transfusion =
= SUM(points for the 4 parameters)
X =
= (0.825 * (points for systolic blood pressure)) + (0.826 * (points for heart rate)) + (1.044 * (points for hematocrit)) + (0.462 * (points for pH)) - 1.576
probability of massive blood transfusion =
= 1 / (1 + EXP((-1) * X))
Interpretation:
• minimum number of risk factors: 0
• maximum number of risk factors: 4
• The more risk factors present the more likely that the patient will receive massive blood transfusion.
|
Number of Risk Factors
|
Percent with Massive Transfusion
|
|
0
|
12%
|
|
1
|
22%
|
|
2
|
43%
|
|
3
|
62%
|
|
4
|
82%
|
Performance for probability equation:
• The sensitivity is 59% and specificity 77%.
• The positive predictive value is 66% and negative predictive value 72%.
