A simple mathematical approach to calculate blood loss in radical prostatectomy

Introduction: The aim of this study was to apply a simple mathematical approach to calculate blood loss in 126 patients undergoing radical retropubic prostatectomy (RRP).

Materials and methods: Perioperative red blood cell loss (RBCL) was estimated by adding the difference in circulating red blood cells from before to after surgery to the allogeneic red blood cells transfused in the same period.

Results: Mean preoperative hematocrit was 45 +/- 4% and mean perioperative RBCL was 574 +/- 297 ml, corresponding to a mean equivalent whole blood loss (WBL) of 1,479 +/- 831 ml. Twenty of 126 patients (15.9%) received 42 units of allogeneic packed red blood cells (PRBC), for a mean of 2.1 +/- 1.2 U/patient. The transfusion rate was higher in patients with a preoperative hematocrit of 40% or less (45 vs. 13%, p = 0.014).

Conclusions: Anatomical RRP is still associated with appreciable operative blood loss. Owing to the high preoperative hematocrit values, the allogeneic blood transfusion rate is low and the transfusion requirement of the majority of patients is limited to about 2 units of PRBC. Preoperative autologous blood augmentation strategies may not be routinely needed for patients with a basal hematocrit of >40%.