Surgical blood loss in abdominal hysterectomy.

Objective: The aim of this study was to evaluate additional error in estimating red cell loss during abdominal hysterectomy.

Methods: Eighty patients admitted consecutively for abdominal hysterectomy were recruited. The surgeries were done after heparinizing the suction tubing system to prevent clotting and reducing the vacuum pressure to reduce red cell lysis. At the end of the surgery, hematocrit was measured and compared with the patient's venous blood and the blood from the suction container. The Mann-Whitney test evaluated statistical significance.

Results: Eight patients were excluded for having a hemolyzed blood sample, receiving a blood transfusion, and having incomplete data. The study cohort consisted of 72 patients: 54 had a simple hysterectomy and 18 had a radical hysterectomy with pelvic and periaortic lymphadenectomy. The hematocrit (mean +/- standard deviation) in the suction container (19.8 +/- 8.8%) was lower than the hematocrit from the venous blood sample (32.4 +/- 6%) (P < 0.001). The hematocrit in the suction container decreased as the duration of the surgeries increased. Although the volume of blood in the suction container was used to estimate blood loss, the concentration of red cells in the container was consistently lower than those in the venous blood sample. The magnitude of dilution increased as the length and radical nature of the surgery increased.

Conclusions: These findings suggest that other fluid, probably lymph, contributes to the dilution of red cells in the container and increases the estimated blood volume loss during surgery. Estimation of red cell surgical blood loss becomes less accurate as the length and radical nature of the surgery increase.