Effect of normovolemic hemodilution on fatal postoperative pulmonary embolism in major elective orthopedic surgery. A retrospective analysis on 4653 patients

It has been suggested that the benefits of transfusion are currently greatly overrated, with physicians reflexively administering blood in the nearly unchallenged view that failure to transfuse would have dire consequences. As a matter of fact, the tolerability and safety of normovolemic anemia have been well documented for many years in several anesthesiologic settings. Objective: To assess the impact of normovolemic hemodilution on blood bank resources and in-hospital mortality in major elective orthopedic surgery. Methods: The authors therefore retrospectively analyzed in-hospital mortality of patients submitted to elective surgery for total hip replacement in the Rizzoli Institute since 1979. From 1979 to 1983, 1488 patients underwent a standard treatment (without normovolemic hemodilution), whereas 4653 patients submitted to surgery from 1984 to 1993 underwent normovolemic hemodilution-up to extreme accepted values of hemoglobin > 6 g/dL. Results: Homologous blood transfusion was required in 1220/1488 patients of Group I and in 977/4653 patients of Group II (82% vs 21%, P < .001). The number of blood units required for each transfused patient was 2.8 in the 1220 transfused patients of Group I, and 2.1 in the 977 transfused patients of Group II (P < .001). There were 6 deaths in Group I and 7 deaths in Group II (0.4% vs 0.15%, P < .05). The overall incidence of fatal pulmonary thromboembolism was 4/1488 in Group I and 1/4653 in Group II (0.27% vs 0.02%, P < .001). Conclusions: Normovolemic hemodilution was extremely well tolerated in patients undergoing major elective orthopedic surgery and allowed substantial sparing of blood bank resources. It had no detectable unfavorable effect on surgical outcome, but rather it was associated with a dramatic decrease in perioperative mortality of patients undergoing total hip replacement, owing to a thirteen-fold reduction in fatal pulmonary thromboembolism.