Biology Reference
In-Depth Information
that lymphocyte function is impaired and that the immunosuppression may
increase the risk of deep prosthesis infection.
While the Kendall et al. study documents the immunosuppression that
occurs with allogeneic transfusions, Murphy et al. [17] demonstrated increased
risk of post-operative infection in patients receiving total hip arthroplasty.
Higher infection rates were noted if the patients received allogeneic blood
transfusions. Aside from the infection risks, other authors have demonstrated
a benefit of higher blood parameters (i.e., hematocrit and hemoglobin concen-
trations) during the peri-operative period.
Quality of life and other parameters
Another benefit of higher blood values is post-operative vigor. Keating et al.
[18] described the assessment of patient vigor and defined a concise patient-
based and caregiver-based instrument. Among the objective measurements
studied, a statistically significant correlation was noted between vigor and
hematocrit value. The question remains whether this increased vigor translates
into shorter hospital stays and/or facilitates the ability of the patient to partic-
ipate in the rehabilitation process.
Disease transmission is only part of the fear with blood management in the
surgical setting. With growing evidence of possible negative consequences of
immunosuppression as well as the benefits of increased vigor and fewer med-
ical complications, the goal of the surgeon should be to not only minimize
allogeneic transfusions but also to maximize the blood parameters with an
aggressive peri-operative management program.
Risk factors for transfusion
The need for and the rate of transfusion have been historically correlated with
the level of anemia in patients before surgery and the amount of blood lost dur-
ing surgery [19-21]. One of the best ways to predict which patients will
require allogeneic transfusion is to assess the pre-operative blood values, e.g.,
hematocrit and hemoglobin concentration. In our original study evaluating
transfusion risks in patients receiving orthopedic surgery [22], we found that
the pre-operative hemoglobin and hematocrit values were the best predictors
of transfusion requirements in patients. Patients who received a transfusion
lost the same amount of blood as patients who did not receive a transfusion.
The important factor was pre-operative blood values: Patients who began with
higher pre-operative hemoglobin concentrations were better able to tolerate the
10% hematocrit decrease because of surgery.
The relationship between pre-operative hemoglobin values and transfusion
requirements was not only noted in total knee arthroplasty but was also seen
in total hip arthroplasty. Nuttall et al. [23] evaluated 299 patients who had
