The purpose of this protocol is to provide treatment with HBOC-201 to patients with life-threatening anemia for whom allogeneic blood transfusion is not an option. HBOC 201 [hemoglobin glutamer - 250 (bovine)] has been previously studied as an alternative to blood transfusions in severely anemic patients needing a way to enhance tissue oxygenation. HBOC-201 is purified, cross-linked and polymerized acellular bovine hemoglobin in a modified lactated Ringer's solution, and does not require blood compatibility.

Inclusion Criteria:

1. Patients ≥ 18 years of age

2. Critically ill patients with hemoglobin ≤ 6 g/dL (or 7-8 g/dL with significant active bleeding), and physiologic evidence of critical ischemia, for example: elevated troponins, altered mental status, acute renal failure, lactic acidosis or evidence of central nervous system acute deficits

3. Patients or their Legally Authorized Representative who are able and willing to provide informed consent

4. Blood is not an option due to:

   • refusal of transfusion
   • lack of compatible red blood cells

Exclusion Criteria:

1. Patients with known hypersensitivity or allergy to beef products

2. Patients with pre-existing uncontrolled hypertension, heart failure, renal failure, circulatory hypervolemia or systemic mastocytosis*

3. Patients who are eligible for blood transfusions

4. Patients who are > 80 years old*

   • on a case by case and quality of life determination