Abstract
Blood conservation is an essential aspect of total hip arthroplasty (THA). As recently as 10 years ago, it was standard practice across North America for patients to undergo pre-operative autologous blood donation (PAD) prior to an elective TJA. Though the cost of PAD is about the same as allogenic blood transfusion, it has fallen out of favor due to mixed results.
Instead, most surgeons have implemented a practice of obtaining pre-operative hemoglobin levels. If anemia is diagnosed, the patient should be worked up for the underlying cause. In cases of pre-operative anemia where a specific deficiency cannot be elucidated, consideration can be given to the use of erythropoietin (EPO).
The routine use of tranexamic acid (TXA) has become the standard of care at most institutions since it is safe, inexpensive, easy to administer, and very effective at minimizing peri-operative blood transfusion. Intravenous TXA can be administered effectively in a variety of different ways and a number of different protocols are described. The popularised Mayo Clinic protocol is to administer TXA once prior to incision (1g IV in 50mL of normal saline) and once during wound closure.
Acute normovolemic hemodilution is a technique utilised just before or after the induction of anesthesia in which whole blood is removed while keeping the patient normovolemic with acellular fluids (i.e. crystalloids or colloids). This technique is rarely used.
Hypotensive anesthesia is a technique utilised to keep mean arterial pressures (MAP) at a level around 50mm Hg. It appears to be most effective with the use of epidural anesthesia. Certain patients may not be good candidates for hypotensive anesthesia (high cardiac risk factors), but it can be an effective corollary to other intra-operative measures.
Historically, many surgeons practiced reflexive transfusion protocols rather than treating patients on an individual basis. Current practice has adopted a more pragmatic approach to transfusion. Specifically, patients are assessed for signs of anemia and are often allowed to drift well below 8g/dL as long as they remain asymptomatic and have a suitable cardiac risk.
