Introduction: In patients undergoing cardiopulmonary bypass-guided cardiac surgery, knowledge of the preoperative effects of platelet distribution width (PDW), red cell distribution width – standard deviation (RDW-SD), and platelet large cell ratio (P-LCR) factors strongly suggests that they may predict unfavourable outcomes.

Objectives: This retrospective study aimed to evaluate the effects of cardiopulmonary bypass (CPB) on PDW, RDW-SD, P-LCR and their relationship with early clinical outcomes.

Methods: This retrospective study included patients who underwent CPB-guided cardiac surgery after fulfilment of the exclusion criteria. Preoperative and postoperative routine PDW, RDW-SD, and P-LCR parameters were compared. In addition, the relationships between PDW, RDW-SD, and P- LCR parameters and pre- and postoperative variables of the patients were evaluated.

Results: Data from 240 patients were included in the study. The mean age of the patients was 64.15 years; 143 were male and 97 were female. 12 patients underwent a single coronary artery bypass graft (CABGx1), 35 underwent CABGx2, 50 underwent CABGx3, 54 underwent CABGx4, 46 underwent CABGX5, 22 underwent mitral valve replacement (MVR), and 21 underwent aortic valve replacement (AVR). RDW-SD and P-LCR levels of the patients were significantly increased in the postoperative period compared to the preoperative period (p =0.000 and p = 0.009, respectively). However, there was no significant difference between preoperative and postoperative PDW values (p = 0.251). Correlation analysis showed that there was a correlation between PDW level and intraoperative bleeding rate, ICU length of stay, and hospital stay. There was also a correlation between P-LCR level and intraoperative bleeding rate, and a correlation between RDW-SD level and intubation time, ICU length of stay, and hospital stay.

Conclusion: We postulate that CPB affects RDW-SD and P-LCR levels, and that there is a significant relationship between PDW, RDW-SD, and P-LCR levels and early post- CPB clinical data. We also postulate that PDW, RDW-SD, and P-LCR have important prognostic values in predicting adverse events.