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Sequential blood volume changes in patients undergoing total hip arthroplasty
Anesthesia and Analgesia
|May 1, 1975
Summary
Clinical observation alone is insufficient for guiding blood transfusions after total hip arthroplasty (THA). Serial blood volume (BV) measurements, including plasma volume (PV) and hematocrit (Hv), are recommended for optimal patient management.
Area of Science:
- Anesthesiology
- Transfusion Medicine
- Orthopedic Surgery
Background:
- Total hip arthroplasty (THA) is associated with significant blood loss.
- Transfusion strategies often rely on clinical observations of hemodynamic changes and estimated blood loss.
- The adequacy of these clinical assessments in guiding transfusion therapy requires further investigation.
Purpose of the Study:
- To evaluate the adequacy of transfusion management based solely on clinical observations in patients undergoing THA.
- To compare clinical assessments with serial isotopic measurements of blood volume (BV), red-cell volume (RCV), and plasma volume (PV).
- To determine the utility of peripheral hematocrit (Hv) in guiding transfusion therapy postoperatively.
Main Methods:
- Serial measurements of 51-Cr RCV, 125-I RISA PV, and Hv were performed before and at 2 and 48 hours after THA in 15 adults.
- Blood transfusion and fluid therapy were guided by clinical observations to maintain preoperative BV levels.
- Isotopic data were used to assess actual BV changes and the effectiveness of transfusion interventions.
Main Results:
- Postoperative BV reduction averaged 21.6% at 2 hours, significantly exceeding clinical estimations.
- Patients with BV within 10% of preoperative levels at 2 hours showed continued RCV reduction compensated by PV expansion.
- Hematocrit (Hv) was a reliable guide for transfusion at 48 hours but not at 2 hours postoperatively.
Conclusions:
- Clinical observation alone is inadequate for guiding transfusion therapy in THA patients due to significant and variable postoperative blood volume reductions.
- Measuring derived blood volume (BV) preoperatively and 2 hours postoperatively, using plasma volume (PV) and hematocrit (Hv), is a more sensitive and practical approach.
- Implementing derived BV measurements could improve transfusion adequacy, potentially restoring BV to within 10% of preoperative levels in a higher percentage of patients.