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Anemia

 

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Background

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  • Periop anemia a/w various complications & ↑ M&M

  • Common periop causes:

    • Nutritional deficiencies (incl Fe deficiency)

    • Inflammation

    • Chronic underlying disorders (ex cancer, CKD, menorrhagia)

    • Surgical blood loss

  • Classification – based on mechanism

    1. ↓ production

    2. ↑ destruction (hemolysis)

    3. Blood loss

  • Classification – based on MCV

    1. Microcytic (ex Fe-deficiency)

    2. Normocytic

      1. Blood loss

      2. Hemolysis

      3. Anemia of chronic dz

      4. Marrow failure

    3. Macrocytic      

      1. Vit B12/folate deficiency, MDS

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Goals & Management

Patient Blood Management

Preop

  • Detection of anemia

    • History (bleeding hx, co-morbid dz)

    • Investigations - CBC, coagulation & iron studies where indicated

  • Management of preexisting anemia

    • If possible, delay surgery to optimize preop

    • Iron - po vs IV (IV if intolerance to po, poor GI uptake, or short timeline preop)

    • Vitamin B12/folate

    • Erythropoietin stimulating agents

    • Referral to hematology prn

Intraop

  • Optimize hemostasis

    • Hold antithrombotic medications preop where appropriate (including herbals that can affect hemostasis)

    • Correct coagulopathy

    • Tranexamic acid (antifibrinolytic)

    • Topical hemostatics

    • Maintain normothermia

  • Minimize blood loss

    • Meticulous hemostasis

    • Minimally invasive techniques

    • Tourniquet prn

  • Maintain blood volume & hemoglobin concentration

    • Replace losses w/ IV crystalloid or colloid until Hb drops below threshold

      • avoid large volume crystalloid infusion

    • Blood transfusion

      • Usual threshold ~70-80 g/L

      • Consider threshold of 90 g/L if:

        • significant ongoing bleeding

        • acute coronary syndrome

        • signs of myocardial/other organ ischemia

      • 1 unit of pRBCs increased Hb by ~10 g/L

  • Use of interdisciplinary blood conservation modalities

    • Cell saver

    • Preop autologous donation (usually discouraged)

    • Acute normovolemic hemodilution

  • Patient-centered decision making

Postop

  • Prevention of new-onset (hospital-acquired) anemia (or exacerbation of existing anemia)

    • Monitor closely for postop bleeding

    • Limit vol & frequency of blood draws

 

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References

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  • Anesthesia for Patients with Anemia. Shander A, et al. Anesthesiol Clin. 2016. PMID: 27816130 Review.

  • Dudley M, Miller RD, Turnbull JH. (2020) Chapter 49: Patient Blood Management: Transfusion Therapy. In Miller’s Anesthesia, 9th Ed. Elsevier. p1546-1578.e5

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