Red blood Cell Changes and Circulatory problems Hematology-Oncology Course

Erythrocytes - Characteristics Red cells 40 - 50% of blood volume, 5 x 106 cells /mL “bag” of hemoglobin: non-nucleated, no proliferation, cell membrane in excess so that deformation does not rupture Shape Biconcave disc, 8 mm in diameter, 2.7 mm thick, volume ~ 90 mm3, area ~ 160 mm2 Men - ery 5,0  0,8 x 1012/l, Hb 135 - 175 g/l, hematocrit 0,45  0,06. Women - ery 4,4  0,8 x 1012/l, Hb 115 - 160 g/l, hematocrit 0,40  0,06. MCV80 - 100 fl, MCH 28 - 36 pg, Reticulocytes 0,5-2%.

RBC MORPHOLOGY ON A PERIPHERAL SMEAR

DEFINITION OF ANEMIA Anemia is usually associated with decreased levels of hemoglobin and/or a decreased RBC count, and/or a decreased packed cell volume (hematocrit). Anemia is a functional inability of the blood to supply the tissue with adequate O2 for proper metabolic function. Occasionally there is an abnormal hemoglobin with an increased O2 affinity resulting in an anemia with normal or raised hemoglobin levels, hematocrit, or RBC count. In summary, anemia may develop: When RBC loss or destruction exceeds the maximal capacity of bone marrow RBC production or When bone marrow production is impaired Various diseases and disorders are associated with decreased hemoglobin levels.

Symptoms and Signs of Anemia Decreased oxygenation Exertional dyspnea, Dyspnea at rest Fatigue, Lethargy, confusion Bounding pulses Trophic changes Decreased volume Fatigue Muscle cramps Postural dizziness Syncope

COMPENSATORY MECHANISMS Cardiovascular Respiratory Tissue Adjustation CNS

CLASSIFICATION OF ANEMIAS Anemias may be classified morphologically based on the average size of the cells and the hemoglobin concentration into: Macrocytic Normochromic, normocytic Hypochromic, microcytic Anemias may also be classified functionally into: Hypoproliferative (when there is a proliferation defect) Ineffective (when there is a maturation defect) Hemolytic (when there is a survival defect) Anemias may also be classified due to life span into: Decreased production Increase loss - hemolytic Chronic posthemorrhagic Acute posthemorrhagic - mostly loss of volume Anemias may also be classified biochemically due to: Genetic, enzyme, AA, protein defects

Anemia in General General Effects of Anemia  O2 carrying capacity Tissue hypoxia Compensatory mechanisms to restore tissue oxygenation Compensation for Anemia General Compensatory Mechanisms to Anemia  Pulmonary and Cardiac function  O2 supply  O2 Extraction at the tissue level Specific Compensatory Mechanisms to  Oxygenated Blood Flow  in Heart rate (HR)  Cardiac output (CO)  Circulatory rate Preferential  in blood flow to vital organs Specific Compensatory Mechanisms to  O2 Utilization by Tissues  in 2,3-DPG in erythrocytes Enhances O2 release at the cell  O2 Affinity in the cells Extent of Compensation Determined by: Severity of the anemia Competency of cardiovascular-pulmonary systems O2 Requirements of the individual Duration of the anemia Underlying disease process Presence or absence of co-existing disease

Polycythemia Increased number of RBCs causing increased blood volume & viscosity Relative causes normal amount of RBCs but decrease in plasma volume, seen in: dehydration, increased fluid losses (diuretics, vomiting, burns, fever) decreased fluid intake, crushing injuries, stress Absolute cause increased number of RBCs Primary (polycythemia vera) Secondary polycythemia