ICU Anemia

Aka: ICU Anemia, Anemia in the Intensive Care Unit, Anemia of Critical Illness, Anemia Following ICU Admission

1. See Also
   1. Intensive Care
   2. Post-ICU Ambulatory Care
   3. Anemia of Chronic Disease (Anemia of Inflammation)
2. Epidemiology
   1. Hemoglobin drops on average 1.5 g/dl in non-bleeding ICU patients within first 3 days of care
      1. Supine position alone results in hemodilution (interstitial fluid enters vasculature)
      2. Supine position drops Hematocrit 4.1% (Hemoglobin 1.4 g/dl)
      3. Jacob (2005) Mayo Clin Proc 80:611-4 [PubMed]
   2. In septic patients, Hemoglobin continues a downward trend (whereas it stabilizes in non-septic patients)
      1. Nguyen (2003) Crit Care Med 31:406-10 +PMID:12576944 [PubMed]
3. Risk Factors
   1. Malignancy
   2. Sepsis
   3. Female Gender
   4. Advanced Age
4. Causes: Acute Anemia with Markedly Decreasing Hemoglobin
   1. Active bleeding
   2. Hemolysis
5. Causes: Gradually Decreasing of Chronic Anemia
   1. See Medication Causes of Marrow Toxicity
   2. Hematopoiesis suppressed
      1. Anemia of Inflammation (Anemia of Chronic Disease)
      2. Poor nutritional intake in the Intensive Care unit
      3. Sepsis
   3. Stress Ulcer
   4. Frequent blood draws in Critical Illness (40-70 ml/day in Critical Illness)
      1. In one week, blood draw related losses approach one unit of pRBC (500 ml)
6. Symptoms
   1. See Anemia
   2. Fatigue
   3. Dyspnea
7. Labs: Acute Anemia with Markedly Decreasing Hemoglobin
   1. Complete Blood Count
   2. Lactate Dehydrogenase (Hemolysis)
   3. Type and Screen (ABO and Rh)
8. Labs: Gradually Decreasing of Chronic Anemia
   1. Complete Blood Count
   2. Serum Iron, Ferritin, and Total Iron Binding Capacity
   3. Reticulocyte Count
   4. Serum Vitamin B12
9. Evaluation: Acute Anemia with Markedly Decreasing Hemoglobin
   1. Identify source of bleeding
      1. Bedside Ultrasound (e.g. FAST Exam) for Hemothorax or intraabdominal Hemorrhage signs
      2. Evaluate stool for Gastrointestinal Bleeding (e.g. Stress Ulcer)
10. Management
    1. Treat underlying cause if found
    2. Treat Hemorrhagic Shock if present
    3. Conservative transfusion strategy (if hemodynamically stable)
       1. Approximately 12% of post-ICU patients require transfusion (in other studies, up to 50% received transfusions)
          1. Marque (2006) Crit Care 10(5):R129 [PubMed]
       2. Avoid Blood Transfusion if hemodynamically stable and above Hemoglobin target
          1. See Transfusion Complications
       3. Blood Transfusion Indications (Hemoglobin targets)
          1. Hemoglobin <7 mg/dl: Most patients
          2. Hemoglobin <8 mg/dl: Active Myocardial Ischemia or post-CABG
       4. Transfusion protocol
          1. Transfuse one unit at a time and reassess (avoids volume overload and over-correction)
11. Prevention
    1. Reduce blood lost through laboratory blood draws
       1. Avoid unnecessary blood draws
       2. Reinject the 5 ml of blood typically discarded with each venous catheter blood draw
    2. Gastric Ulcer Prophylaxis
       1. See Gastric Ulcer Prevention in Patients with Critically Illness
12. References
    1. Internet Book of Critical Care (Farkas, EM-Crit)
       1. https://emcrit.org/ibcc/guide/
    2. Marino (2014) The ICU Book, p. 349-68
    3. Vincent (2002) JAMA 288(12):1499-507 [PubMed]