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Table 4 Stepwise procedure for dummy variable selection

From: A simple clinical model for planning transfusion quantities in heart surgery

Step no. Dummy variables Coefficients Estimated
PRBC
1 HctAdmission ≤ 40% 0.928 1
2 CBP time > 130 min 0.951 1
3 Minimum HctCBP ≤ 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
  1. Regression model coefficients are transformed into packs of red blood cells (PRBC) by rounding them to the nearest half integer.
  2. Hct = hematocrit; CBP = cardiopulmonary bypass; CABG = coronary artery bypass graft.