Risk Factors for Postoperative Transfusion in Cardiac Surgery with CPB

The use of blood products is routine in cardiac surgery. Use of blood derivates may vary among institutions and entail high costs and possible complications. This study aims to identify predictors of the need for postoperative blood products transfusion after cardiac surgery with cardiopulmonary bypass (CPB), in order to focus on preventive measures for high-risk populations.

Observational retrospective study carried out in 104 consecutive adults who underwent cardiac surgery using CPB in our hospital. Blood products used were categorized according to the Universal Definition of Perioperative Bleeding (UDPB) in adult cardiac surgery1 (table 1). Clinical, demographic and surgical variables were analyzed. Statistical analysis was performed using SPSSv23. Quantitative variables are expressed as mean ± standard deviation and qualitative variables as proportions (%). Values of p<0.05 were considered statistically significant.

104 patients, 74 males (71,2%), with an average age of 67,2±13,4 years were included. Mean body mass index (BMI) was 26,1±4,2Kg/m2, and 5,8% were ASA II, 92,3 % ASA III and 1,9% ASA IV. Operative procedures included coronary artery bypass in 32 (30,8%) patients, valvar operations in 59 (56,7%), and combined procedures in 7 (6,7%), with 6 omissions. Forty patients (38,5%) received at least one blood product in final postoperative 24h. The distribution of blood products used according to UDPB in adult cardiac surgery is expressed in table 2. There were no significant statistical differences in blood products transfusion between gender, age, BMI, diabetes, Left Ventricular Ejection Fraction (EFLV) and CBP duration. Although there was no significant correlation between hypertension and postoperative use of blood products, there was a strong positive association between the absence of hypertension and UDPB class 0. In our population, there was a significant association between the type of surgery and UDPB score. There seems to be a strong positive association between valvular surgery and UDPB class 0 and between combined procedures and UDPB class1. Reoperation for bleeding within 24h was required in 3,8%.

In our population, the independent predictor of postoperative bleeding was the type of surgery, with a strong positive association between valvular surgery and combined procedures and UDPB class 0 and 1, respectively. The percentage of reoperations due to bleeding after cardiac surgery is in accordance with the literature.