Class 18 review Flashcards
Blood accounts for ____ of total body weight
8%
Whole blood percentage by volume
Plasma 55%
Formed elements 45%
Plasma is majority ______
water 91%
Formed elements are majority ________
Erythrocytes >99%
Platelets <1%
Leukocytes <1%
Hemoglobin (Hg)
This test is a measure of the total amount of Hgb in the blood. It is used as a rapid indirect measurement of the red blood cell (RBC) count
Hematocrit (Hct)
The Hct is a measure of the percentage of the total blood volume that is made up by the RBCs
Reticulocytes
The reticulocyte count is an indication of the ability of the bone marrow to respond to anemia and make RBCs. It is used to classify and monitor therapy of anemias
Serum iron
Amount of iron found in hemoglobin
Total iron binding capacity (TIBC)
TIBC is a measurement of all proteins available for binding mobile iron
Ferritin
The serum ferritin study is a good indicator of available iron stores in the body
Transferrin
Iron is bound to a globulin protein called transferrin and carried to the bone marrow for incorporation into hemoglobin/ Transferrin exists in relationship to the need for iron. When iron stores are low, transferrin levels increase, whereas transferrin is low when there is too much iron
Serum B12
Blood levels of vitamin B12 help to indicate if there is a vitamin deficiency present impacting RBC production
Folate
Blood levels of folate help to indicate if there is a folate deficiency impacting RBC
Mean corpuscular volume
We will use this to determine the size of red blood cells
Bilirubin
When red blood cells are destroyed they release heme into the blood, this results in increased bilirubin in the body and the patient can appear jaundiced
Summary of life cycle of iron
Ferritin: iron stored in mucosal cells (iron plus a protein used to store iron)
Transferrin: iron transport protein for distribution throughout the body (goes either to hemoglobin, liver, or muscle)
Serum iron: the amount of iron found in hemoglobin (70% of most iron in the body)
Three ways that anemia can be classified
- microcytic anemias (small cells - seen in iron deficiency)
- macrocyclic anemias (large cells - seen in vitamin B12 and folic acid deficiencies)
- Normocytic anemias (normal cells - blood loss or kidney failure)
Decreased production of red blood cells is typically due to
Lack of iron, folic acid, or vitamin B12 in the body OR kidney failure
Increased destruction of red blood cells from…
hemolytic anemias
Medications for hematopoiesis and growth factors
Erythropoietin
Epoetin Alfa prototype
Darbepoetin alfa
Medications replacing vitamins or minerals in the body that are responsible for RBC production
Folic acid
Vitamin B12
Ferrous sulfate
Epoetin Alfa (Eprex) MOA
It is a glycoprotein hormone that stimulates the production of RBCs in bone marrow. In response to anemia or hypoxia, circulating levels of erythropoietin rise dramatically, triggering an increase in erythrocyte synthesis. However, because production of erythrocytes requires iron, folic acid, and vitamin B12, the response to erythropoietin is minimal if any of these is deficient
Epoetin Alfa (Eprex) adverse effect
hypertension
Epoetin Alfa (Eprex) nursing considerations
Hemoglobin level should be measured at baseline and twice weekly thereafter until the target level has been reached and a maintenance dose is established. Complete blood counts with a differential should be done routinely. Blood chemistry should be monitored. Iron should be measured periodically
Darbepoetin Alfa (Aranesp) MOA
Is a long-acting analog of epoetin alfa. Both drugs at on erythroid progenitor cells to stimulate production of erythrocytes. It is cleared more slowly than epoetin, that has a longer half-life (49h vs. 18-24h). Administered less frequently. Often for anemia due to CRG and cancer chemotherapy
Darbepoetin Alfa (Aranesp) adverse effect
hypertension
Darbepoetin Alfa (Aranesp) nursing considerations
When initiating darbepoetin or changing dosage, the hemoglobin level should be measured weekly until it stabilizes. Thereafter, hemoglobin should be measured at least once a month
What does low hemoglobin or low RBCs tell us?
anemia or bleeding
What does high hemoglobin or low RBCs tell us?
polycythemia
What does pancytopenia tell us?
aplastic anemia or leukemia - something is happening with bone marrow production of RBC/ WBC
What does increased WBC tell us?
typically infection or stress
What do deceased platelets tell us?
adverse event of drug therapy, disease, inflammation
Anemia critical values
<135 in men
<120 in women
Hct >30-35%
no symptoms
Hct 25-30%
fatigue, malaise
Hct 20-25%
SOBOE, dyspnea
Hct 15-20%
light-headed, confusion
Hct <15%
death, MI, etc
Absolute anemia
destruction or loss of RBC
Relative anemia
fluctuations in plasma volume
4 primary reasons why anemia occurs in the body
- decreased production of red blood cells in the body
- destruction of red blood cells in the body
- blood loss (acute or chronic)
- dilution anemia (relative anemia)
Iron-deficiency anemia
Microcytic, pale cell
Common
Low iron impedes synthesis of Hgb therefore less O2 transported
Etiology of Iron-deficiency anemia
1) inadequate dietary intake of iron
2) chronic blood loss from body
3) impaired absorption of iron resulting from gastritis, chronic inflammatory bowel disease, or diarrhea
4) severe liver disease (storage and management)
Ferrous sulfate
Oral - tablets or liquid formation
- iron is best absorbed as ferrous sulphate (Fe2+) in an acidic environment
- take 1 hour before meals
- vitamin C helps to increase absorption of iron
- undiluted liquid iron may stain teeth - give diluted through a straw
- GI side effects: heartburn, constipation and diarrhea
- stools will become black because GI tract excretes excess iron
Kinds of megaloblastic (macrocytic) anemias
Vitamin B12 (cobalamin, Cbl) deficiency anemia Folic acid (FA, B vitamin) deficiency anemia
Megaloblastic (macrocytic) anemia description
- deficiency causes impaired DNA - results in a larger than normal cell
- abnormalities target the cell for early destruction
- neuropathy occurs only with B12 deficiency, indicating that additional mechanisms are involved in the CNS
B12 deficiency treatment
- if chronic due to malabsorption, then administer intramuscular B12
- best treated before significant neural symptoms - may not reverse
Anemia of chronic disease description
Many causes, often chronic inflammation or malignancy
-typically normochromic, normocytic, hypo proliferative, and mild in degree
Factors that contribute to hypo proliferative state
- reduced iron absorption, trapping in macrophages
- shorter RBC survival
- a decreased response to circulating erythropoietin (elevated with little response)
Anemia is common in patients with….
Chronic kidney disease where erythropoietin production may be reduced
Adverse effects related to RBC colony stimulating drugs
- hypertension
- cardiovascular events (stroke, myocardial infarction)
- autoimmune pure red-cell aplasia (severe anemia and a complete absence of erythrocyte precursor cells in bone marrow)
Anemias related to RBC destruction
Intrinsic hemolytic anemias
Extrinsic hemolytic anemias
Hemolytic anemia
Caused by premature destruction of RBCs (ie hemolysis)
Mild to life threatening
Labs for hemolytic anemia
- low Hct, Hgb, high in reticulocyte count
- high bilirubin
- high enzyme lactate dehydrogenase (LDH)
Thalassemia
Microcytic, pale cell
Inadequate production of normal Hb therefore low RBC production
Absent or reduced globulin protein
Genetic links: mediterranean, south East Asian, Middle East, Africa, China
Gene varieties of thalassemia
It is autosomal recessive
Thalassemia minor - mild form (1 gene of pair)
Thalassemia major - severe form (both genes in pair)
Acute causes of blood loss anemia
Trauma
Blood vessel rupture
Chronic causes of blood loss anemia
Gastritis
Menstrual flow
Hemorrhoids
What is first to be noticed with an internal bleed?
Low bp, high hr. Delay for dilution of Hgb and Hct
Signs of bleeding
Bruising, petechiae Hematuria Vomiting blood Fatigue Decreased LOC, confusion
