Chapter 81 What Blood Conservation Techniques for Total Joint Arthroplasty Work?
In 1997, after the tainted blood issues of the 1980s, the Canadian Commission of Inquiry on the Blood Supply (The Krever Commission; more information is available online at: http://www.hc-sc.gc.ca/ahc-asc/activit/com/krever_e.html) recommended the promotion of the “appropriate use of, and alternatives to, blood components and blood products.” Therefore, it is not a question of whether blood conservation should be considered, but rather which of the available modalities of blood conservation is ef-fective, and moreover cost-effective, in joint arthroplasty.
It should be stressed that blood conservation is not limited to avoiding allogeneic blood utilization but also includes the appropriate utilization of blood and blood products. Simple rules to ordering and administering blood products should be established, published, and reinforced at every institution carrying out joint arthroplasty: (1) A transfusion guideline should be established (Table 81-1); (2) ordering of blood product should include the indication for its administration (e.g., transfuse 1 unit of RBCs for a hemoglobin concentration of 70 g/L), and (3) RBC units should be administered one unit at a time with the patient reassessed before a second unit is administered. Following these simple guidelines will improve the utilization of blood products and reduce unnecessary transfusions.
TABLE 81-1 Guideline for Red Blood Cell Transfusion Based on Hemoglobin Concentration
| HEMOGLOBIN CONCENTRATION (G/L) | TRANSFUSION RECOMMENDATION |
|---|---|
| >100 | Transfusion required only in exceptional circumstances |
| 70-100 | Transfusion required only if there are signs and symptoms of impaired oxygen delivery or if patient is at high risk* |
| <70 | Likely be appropriate |
| <60 | Transfusion highly recommended |
Level III evidence.
* Patients at high risk include those with known coronary artery or valvular hearts disease, previous cerebral vascular event, or poor oxygenation.
OPTIONS
Blood conservation includes preoperative, intraoperative and postoperative modalities. Preoperative modalities focus on the expansion of the RBC mass either ex vivo using preoperative autologous blood donation (PAD) or in vivo using iron supplementation and erythrocyte-stimulating agents (ESA) (e.g., Eprex, Ortho Biotech, Toronto, Ontario, Canada). Intraoperative techniques focus on reducing the loss of RBCs or the reclamation of shed blood. Surgical technique and the strict attention to hemostasis is the single-most important factor for which there is no alternative. Other methods purported to reduce blood loss include controlled hypotension, acute normovolemic hemodilution (ANH), antifibrinolytic agents, and cell salvage. Postoperative blood conservation modalities include cell salvage, continued adherence to a transfusion guideline, and the careful management of hemostasis, keeping in mind the need for postoperative deep vein thrombosis prophylaxis (see Chapter 2).
EVIDENCE
Preoperative Autologous Donation
The efficacy of PAD in reducing patient exposure to allogeneic blood has been demonstrated in numerous randomized clinical trials in several operative settings.1 This evidence is supported by controlled observational trials, but the overall level of evidence remains poor because there are no blinded trials.1
In joint arthroplasty, the evidence in support of PAD is less convincing (Fig. 81-12–4 and 81-25–11). Some authors have concluded that there is no role for PAD in joint arthroplasty, and if the entire surgical population were considered candidates for PAD, then the evidence would support this contention.1 However, for patients who are at increased risk for a blood transfusion (e.g., revision surgery, small body habitus [<70 kg]) and are not anemic (i.e., patient capable of regenerating RBC mass after donation), PAD may be a viable blood conservation modality. It should be the role of a perioperative blood conservation program to identify appropriate patients for PAD using an up-to-date database to evaluate its use.
Preoperative Iron and Erythropoietin Therapy
The incidence of preoperative anemia in patients scheduled for the total arthroplasty is between 20% and 35%.12,13 The causative factor of this anemia is multifactorial, but the two most common causes are iron deficiency anemia and anemia of chronic disease. Importantly, preoperative anemia is the single-most treatable risk factor for a blood transfusion associated with joint arthroplasty surgery.12 Iron supplementation and the use of erythropoietin (Epo) are the primary modes of therapy of preoperative anemia.
The incidence of preoperative iron deficiency anemia is unknown, but elderly patients have a number of risk factors for iron deficiency including use of nonsteroidal anti-inflammatory drugs and poor diet. Iron deficiency anemia is a hypochromic, microcytic anemia, and the RBC mean cell volume (MCV) is a good predictor for response to iron supplementation.14 For anemia (hemoglobin concentration <120 g/L) and MCV less than 80 fL, a 4-week course of supplemental iron results in an 11- to 12-g/L increase in hemoglobin concentration.14 In contrast, anemia with an MCV greater than 90 fL does not respond to iron supplementation alone.14
The routine use of perioperative supplemental iron therapy is controversial in that it has little effect on blood transfusion.15,16 However, in patients in whom erythropoiesis is either stimulated by PAD or recombinant Epo, iron supplementation is recommended. The source of iron is arguably unimportant as long as the goal is to add approximately 100 mg elemental iron to the daily diet. In fact, dietary heme-iron in red meat, poultry, and fish is more readily absorbed than formulated dietary supplements. Other sources of iron include plant food such as lentils and beans. If, however, oral iron absorption is poor and iron supplementation is still required, intravenous iron sucrose is a safe and effective alternative.17,18 Iron sucrose is no more effective than oral iron preparations in increasing the RBC mass.19,20
Epo is a naturally-occurring hormone secreted by the kidneys in response to low partial pressure of oxygen. Epo stimulates effective erythropoiesis only if there are adequate iron stores, and the use of Epo should be combined with supplemental iron. The efficacy of preoperative Epo in total joint arthroplasty (TJA) has been demonstrated in double-blind, randomized, controlled trials, increasing preoperative hemoglobin concentration by 15 g/L whereas reducing the frequency of RBC transfusion by 50%.21 In a systematic review of the literature, Laupacis and colleagues22 found that the overall odds ratio of RBC transfusion in patients who received Epo was 0.36 (95% confidence interval [CI], 0.24–0.56).22
In addition, several studies have evaluated the use of Epo in the clinical setting and confirmed it effectiveness in reducing the exposure of patient to allogeneic blood transfusions.13,23, 24 In a clinical observation trial, Karkouti and colleagues13 demonstrated a reduction in transfusion rates for patients with anemia undergoing TJA from 56.1% to 16.4% when treated before surgery with Epo, and the adjusted odds ratio of RBC transfusion in the Epo group was 0.33 (95% CI, 0.21–0.49).13
Although Epo is undeniably an effective therapy in reducing the risk for an allogeneic blood transfusion, particularly for the patient with anemia, there are two caveats to its routine use that should be considered. First, it remains an expensive therapy ($500 [Canadian currency] per injection), and second, concerns about the safety of Epo have been identified. The first safety concern is that the use of an ESA can increased the risk for thromboembolic events. In a large (N = 681), randomized, control trial, patients with anemia who received Eprex before spinal surgery had a significantly greater rate of thromboembolic events compared with patients given placebo (8.2% vs. 4.1%; more information is available online at: http://download.veritasmedicine.com/PDF/CR004621_CSR.pdf
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