[Evolution of blood loss in total knee prosthesis with blood recovery system vs conventional drainage].

Introduction: knee prosthetic surgery can be associated with significant blood loss that can account for up to 20% of blood volume. The objective of our study is to analyze blood loss (BL) after total knee replacement (TKR), with the use of a blood recovery system vs a normal drain.

Material and methods: prospective, comparative, and observational study of two groups of 30 patients who underwent TKR, one control (CG) and another study group with a recovery system (RG). We analyzed PS, hemoglobin (Hb), hematocrit (Htc), systolic blood pressure (SBP) and diastolic blood pressure (DBP) and heart rate (HR) at 3-, 24-, 48-, 72- and 96-hours post-surgery, the need for transfusion, and the percentage of discharges in 72 hours and complications.

Results: the highest percentage of change in Htc and Hb occurred in the first 3 hours post-surgery and recovery began at 72 hours in the RG (p = 0.02) and at 96 hours in the CG (p = 0.04). The decrease in Hb and Htc began his recovery at 72 hours in the RG and at 96 hours in the CG. The TAS, TAD and FC began their recovery at 72 hours in both groups. The decrease in SBP was greater in the CG at 3 hours (p = 0.02), 24 hours (p = 0.02) and 48 hours (p = 0.01) post-surgery. Six patients were transfused in RG and 10 in CG (p = 0.22). 20% and 74% of the patients were discharged at 72 hours in the CG and RG, respectively.

Conclusion: the greatest BL occurs in the first 3 hours post-surgery and recovery begins at 72-96 hours. Recovery blood system decreases BL during the first 3 hours, enhance the recuperation of Hb and SBP, decreases the need for transfusion and favors early discharge.