A simple clinical model for planning transfusion quantities in heart surgery

Table 4 Stepwise procedure for dummy variable selection

Step no.	Dummy variables	Coefficients	Estimated PRBC
1	Hct_Admission ≤ 40%	0.928	1
2	CBP time > 130 min	0.951	1
3	Minimum Hct_CBP ≤ 20%	2.000	2
4	Surgical procedure different from isolated CABG	0.936	1
5	Age > 70 years	0.616	0.5
6	Cardiogenic shock	2.627	2.5
7	Preoperative dialysis	4.246	4
8	Systemic arterial hypertension	0.384	0.5
9	Urgency	0.692	0.5
10	Emergency	1.390	1.5

Regression model coefficients are transformed into packs of red blood cells (PRBC) by rounding them to the nearest half integer.
Hct = hematocrit; CBP = cardiopulmonary bypass; CABG = coronary artery bypass graft.

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