Hematologic

Adult Concept Review Exam 3: Hematologic Function

Blood Overview

  • Components of Blood:

    • Erythrocytes: Red blood cells (RBCs) responsible for oxygen transport.

    • Erythropoiesis: The formation of red blood cells from erythropoietic stem cells.

    • Erythropoietin: A hormone that stimulates the production of red blood cells.

    • Leukocytes: White blood cells (WBCs) involved in immune response.

    • Thrombocytes: Platelets responsible for blood clotting.

    • Plasma: The fluid portion of blood containing electrolytes, proteins, nutrients, and waste products.

  • Hematopoiesis: The process of blood cell formation, primarily occurring in the bone marrow.

    • Primary Site: Bone marrow (red marrow).

    • Locations: pelvis, ribs, vertebrae, sternum.

Bone Marrow

  • Composition: Cellular components (red marrow) separated by fat (yellow marrow).

  • Stem Cells: Differentiate into Myeloid or Lymphoid stem cells.

    • Myeloid Stem Cells: Produce RBCs, WBCs, and platelets.

    • Lymphoid Stem Cells: Produce lymphocytes (B & T cells).

  • Differentiation: The developmental process that provides cells with functions different from their parent stem cell.

  • Stroma: Tissue in the marrow not directly involved in hematopoiesis; produces colony-stimulating factors needed for hematopoiesis.

Hemostasis & Fibrinolysis

  • Hemostasis: The balance between clot formation and dissolution.

  • Fibrinolysis: The process of breaking down a fibrin clot.

Red Blood Cells (Erythrocytes)

  • Function: Carry hemoglobin (Hgb) to provide oxygen to tissues.

  • Structure: Lack nuclei; contain iron and protein.

  • Reticulocytes: Slightly immature RBCs released into circulation during increased demand (e.g. due to bleeding).

  • Lifespan: Approximately 120 days; old cells are removed by reticuloendothelial cells in liver and spleen.

Erythropoiesis

  • Stimulus: Increased erythropoietin production in response to anemia or oxygen deprivation conditions.

  • Process: Differentiation of myeloid stem cells into erythroblasts, leading to mature RBCs.

White Blood Cells (Leukocytes)

Types of Leukocytes

  1. Granulocytes:

    • Eosinophils: Defend against parasites and mediate allergic reactions; neutralize histamine.

    • Basophils: Produce and store histamine; involved in inflammatory responses.

    • Neutrophils: Mature WBCs that increase during bacterial infections to phagocytize bacteria.

  2. Agranulocytes:

    • Monocytes: Differentiate into macrophages effective against fungi and viruses.

    • Lymphocytes: T cells (immune response) and B cells (produce antibodies); mature in lymph nodes.

Platelets (Thrombocytes)

  • Normal Range: 150,000 to 450,000 platelets/µL of blood.

    • Thrombocytosis: >450,000 platelets/µL.

    • Thrombocytopenia: <150,000 platelets/µL.

  • Production: Regulated by thrombopoietin; lifespan is 7-10 days.

  • Role: Essential in controlling bleeding and maintaining hemostasis.

Plasma and Plasma Proteins

  • Albumin: Maintains fluid balance in the vascular system through osmotic pressure, preventing fluid from leaking out of blood vessels.

Hemostasis Process

  • Function: To minimize blood loss from intact vessels and stop bleeding from severed vessels.

Hematologic Health Assessment

Health History & Physical Assessment

  • **Key Findings: **

    • History of previous bleeding episodes (e.g., epistaxis, menorrhagia).

    • Fatigue and weakness; dyspnea on exertion.

    • Occupational exposures (e.g., chemicals, tobacco).

    • Dietary history and current medications (including alcohol consumption and supplements).

Physical Assessment

  • Evaluating skin color and signs of bleeding (bruises, petechiae).

  • Assessing vital signs; presence of rashes or signs of decreased perfusion.

Diagnostic Evaluation

  • Hematologic Studies:

    • CBC: Total blood cell count, hemoglobin, and hematocrit levels.

    • Peripheral Blood Smear: Observes abnormalities in cell size and shape.

    • PT/INR and aPTT: Coagulation tests.

  • Bone Marrow Aspiration and Biopsy: Evaluates quantity and quality of cells in the marrow.

    • Consent Required: Must be obtained prior to procedure; performed under aseptic conditions.

  • Use of bone marrow aspirate to ascertain the types and counts of cells; biopsy assesses the architecture of the marrow.

Therapeutic Approaches to Hematologic Disorders

  • Splenectomy: Removal of spleen may lead to complications such as hemorrhage or increased infections.

  • Apheresis: Separating specific blood components using a centrifuge.

  • Hematopoietic Stem Cell Transplantation (HSCT): Used for aplastic anemia and leukemia (autologous or allogenic transplants).

  • Therapeutic Phlebotomy: Removing blood for patients with polycythemia or hemochromatosis.

  • Blood Transfusions: Must be cross-matched and adequately prepared to prevent reactions.

Blood Transfusions

Patient History Considerations

  • Assess for previous transfusion reactions.

  • Number of pregnancies may elevate reaction risks.

Physical Assessment Prior to Transfusion

  • Vital signs; respiratory and cardiovascular assessments.

  • Look for signs of fluid overload (edema) and evaluate skin color for jaundice.

Transfusion Protocol

  1. Obtain packed red blood cells (PRBCs).

  2. Double-check all blood product labels and patient identification.

  3. Observe for signs of contamination (e.g., gas bubbles, unusual color).

  4. Initiate PRBC transfusion within 30 minutes after removal from the refrigerator.

  5. Monitor closely during the first 15 minutes for potential transfusion reactions; increase the flow rate gradually after.

  6. Important: administration must not exceed 4 hours to prevent bacterial contamination.

  7. Document and monitor for adverse reactions.

Complications of Blood Transfusion

  1. Febrile Non-Hemolytic Reaction: Most common; S/S include fever, chills, muscle stiffness.

  2. Acute Hemolytic Reaction: Life-threatening; occurs due to ABO mismatching. Symptoms include fever, chills, low back pain, nausea, hypotension.

  3. Delayed Hemolytic Reaction: Occurs 14 days post-transfusion; symptoms include elevated bilirubin, jaundice.

  4. Allergic Reaction: Development of hives or itching.

  5. Disease Acquisition: Risk of transmission of viruses (e.g., Hepatitis B, C, HIV) through transfusions.

Management of Transfusion Reactions

  1. Stop transfusion immediately and maintain IV with normal saline.

  2. Assess vital signs and compare to baseline data.

  3. Notify healthcare provider and follow institutional protocol for adverse reactions.

  4. Document appropriately in patient’s medical record.

Transfusion Alternatives

  • Pharmacologic alternatives: Use of growth factors, erythropoietin, granulocyte-colony-stimulating factors, etc.

Chapter 29 – Anemia & Bleeding Disorders

Anemia Overview

  • Definition: Lower than normal hemoglobin concentration and fewer circulating erythrocytes.

  • Types:

    • Hypoproliferative: Caused by iron, B12, or folate deficiency; chronic disease; bone marrow dysfunction.

    • Bleeding: Results in red blood cell loss due to hemorrhage or other bleeding causes.

    • Hemolytic: Increased destruction of erythrocytes due to various factors.

Classification of Anemias (Table 29-1)

  • Hypoproliferative Anemia Types:

    • Iron Deficiency (microcytic)

    • Causes: Inadequate intake, blood loss.

    • Vitamin B12 & Folate Deficiency (megaloblastic):

    • Causes: Malabsorption, increased requirements.

  • CBC Findings: MCV, reticulocyte counts, and nutritional markers.

Management of Anemia

  • Dietary Management: Iron, B12, and Folate supplementation.

  • Blood Transfusions for symptomatic patients.

  • Pharmacotherapy: Erythropoiesis-stimulating agents for chronic disease.

Other Hematological Disorders

Sickle Cell Disease

  • Description: Inherited disorder characterized by the presence of abnormal hemoglobin (HbS) causing distorted RBC shape under low oxygen conditions. This leads to various complications including vaso-occlusive crises.

  • Clinical Manifestations: Anemia, episodes of pain, increased risk of infection, and delayed growth.

Neutropenia

  • Decreased number of neutrophils (<2,000/mm3) leads to increased risk of infections. Management includes monitoring and prophylactic antibiotics.

Thrombocytopenia

  • Low platelet count (<150,000/mm3) leading to bleeding tendencies. Management involves treating the underlying cause and may include platelet transfusions.

Inherited Bleeding Disorders

  • Hemophilia (A and B) characteristics:

    • Autosomal recessive, factor deficiencies. Manifestations include excessive bleeding from minimal trauma. Management includes factor replacement therapy.

  • Von Willebrand Disease (vWD): Deficiency of vWF leading to mucosal bleeding and heavier menstrual flows.

Collaborative Care & Nursing Interventions for Hematologic Disorders

  • Assessment: Health history, physical examination, and laboratory tests.

  • Diagnosis: Document potential complications like anemia, infection, fatigue, and nutritional status.

  • Intervention Goals: Control bleeding, prevent infection, provide emotional support.

  • Patient Education: About disease processes, signs of complications, and importance of medication adherence.

Conclusion

This study guide covers critical aspects of hematologic function, blood components, and relevant disorders, emphasizing the significance of timely assessment and management of various conditions for optimal patient care.