Chapter 39- Assessment of the Hematology System

Reticulocyte Count

0.5-2% of RBC's Increased levels may indicate chronic blood loss. Decreased levels indicate possible inadequate RBC production.

INR

0.8-1.1 times the control value Increased values indicate longer clotting times. This is desirable for anticoagulation therapy with warfarin. Decreased values indicate hypercoagulation and increased risk for venous thromboembolic events.

CBC

1. RBC count 2. WBC count 3. Hematocrit 4. Hemoglobin levels

Prothrombin time (PT)

11-12.5 sec 85%-100% Increased time indicates possible deficiency of clotting factors V and VII. Decreased time may indicate vitamin K excess.

Platelet Count

150,000-400,000/ mm3 Increased levels may indicate polycythemia vera or malignancy. Decreased levels may indicate bone marrow suppression, autoimmune disease, hypersplenism.

Key Points: Check the needle insertion site at least ____ hours after a bone marrow aspiration or biopsy. If the patient is going home, teach the patient and family on how to assess the site for bleeding and when to seek help.

2

Total Iron Binding Capacity (TBC)

250-460 mcg/dL Increased levels indicate iron deficiency. Decreased levels may indicate anemia, hemorrhage, hemolysis.

WBC Count:

5,000-10,000/ mm^3 Increased levels are associated with infection, inflammation, autoimmune disorders, and leukemia. Decreased levels may indicate prolonged infection or bone marrow suppression.

What priority assessment question should the nurse ask when taking a history for a 79-year-old female patient who reports progressive fatigue, shortness of breath, and headaches? a. "Could you tell me about your dietary habits?" b. "Are you experiencing any type of depression?" c. "What medications do you routinely take?" d. "Do you have a history of cardiovascular disease?"

A All are possible questions to ask a patient regarding symptoms of fatigue, shortness of breath, and headaches. However, older patients are more likely to experience signs and symptoms of anemia (fatigue, shortness of breath, headaches) related to diet and chronically bleeding GI lesions (peptic ulcer disease).

Plasma Proteins:

Albumin: maintains osmotic pressure of the blood. Preventing the plasma from leaking into the tissues Globulins: have many functions, such as transporting other substances, and as antibodies, protecting the body against infection Fibrinogen: activated to form fibrin, which is critical to the blood clotting process

Reticulocyte count

Assessment of bone marrow function Elevated means RBCs are being released before they mature. An elevated count without a cause means polycythemia vera. (body produces too much RBCs)

Anti-clotting forces

Because clotting occurs through a rapid cascade process, in theory it keeps forming fibrin clots whenever the cascade is set into motion until all blood throughout the entire body has coagulated and perfusion stops. Therefore, whenever the clotting cascade is started, anti-clotting forces are also started to limit clot formation only to damaged areas so normal perfusion is maintained everywhere else. The anti-clotting forces both ensure that activated clotting factors are present only in limited amounts and also cause fibrinolysis to prevent overenlargement of the fibrin clot. (Rebar 799)

A patient is transitioning from IV heparin therapy to oral warfarin. Which laboratory finding does the nurse identify that confirms warfarin treatment efficacy? a. Bleeding time of 5 minutes b. Prothrombin time (PT) of 18 seconds c. International normalized ratio (INR) of 2.5 d. Partial thromboplastin time (PTT) of 24.3 seconds

C INR is a more accurate measure of anticoagulation therapy because of variations in PT values across different laboratories. The goal of warfarin therapy is usually to maintain the patient's INR between 2.0 and 3.0 regardless of the actual PT in seconds.

Clotting

Complex, multi step process by which blood forms a protein-based structure (clot)

Hemoglobin (Hgb) Count:

Females: 12-16 g/dL Males: 14-18g/dL Decreased & Increased: Same as for RBC

Hematocrit (Hct) Count:

Females: 37-47% Males: 42-52% Decreased & Increased: Same as for RBC

Red Blood Cell Count

Females: 4.2-5.4 million/uL Males: 4.7-6.1 million/ uL Decreased Levels: indicate possible anemia or hemorrhage Increased Levels: indicate possible chronic hypoxia or polycythemia vera

Iron (Fe) Count:

Females: 60-160mcg/dL Males: 80-180mcg/dL Increased levels indicate iron excess, liver disorders, hemochromatosis, megaloblastic anemia. Decreased levels indicate possible iron deficiency anemia, hemorrhage. (Rebar 803)

Fibrin Clot Formation

Fibrin clot formation is the last phase of blood CLOTTING. Fibrinogen is an inactive protein made in the liver. The activated enzyme thrombin removes the end portions of fibrinogen, converting it to active fibrin that can link together to form fibrin threads. Fibrin threads make a meshlike base to form a blood clot.

Hemoglobin electrophoresis

Hgb A1: 95%-98% Hgb A2: 2%-3% Hgb F: 0.8%-2% Hgb S: 0% Hgb C: 0% Hgb E: 0% Variations indicate hemoglobinopathies

key points: Instruct patients about the importance of eating a diet with adequate amounts of foods that are good sources of ______,______, and _____.

Iron, Folic Acid, and Vitamin B12

Erythropoeitin

KIDNEY -> BONE MARROW: increases RBC synthesis • Same rate as RBC destruction or loss occurs to maintain a constant normal level of circulating RBCs

Diagnostic Assessment

Laboratory tests of cell number and function: • Peripheral blood smear • CBC • Reticulocyte count • Platelet count • Hemoglobin electrophoresis • Coombs' tests (direct and indirect) • Serum ferritin, transferrin, and TIBC Laboratory tests measuring bleeding and coagulation: Prothrombin time (PT) International normalized ratio (INR) Partial prothromboplastin time (PTT) Anti-factor Xa test Platelet aggregation Imaging assessment: Radioisotopic imaging Standard x-rays

Serum Ferritin Transferrin, and Total-iron-binding Capacity (TIBC) tests

Measure iron levels. Serum ferritin measures amount of free iron in plasma, which represents 1% of total body stores. Transferrin is a protein that transports dietary iron from the intestines to cell storage sites. 10ng/100mL=normal

Erythrocyte Growth Pathway

Pluripotent Stem Cell--> Committed Myeloid Stem Cell--> Proerythroblast-->Basophilic Erythroblast--> Polychromatic Erythroblast--> Orthochromatic Erythroblast-->Reticulocyte-->Erythrocyte

Eythropoeisis

RBC production • must be balanced with RBC destruction or loss • When balanced, process helps tissue perfusion by ensuring adequate delivery of O2

Bone Marrow

Responsible for blood formation by producing RBC's, WBC's, and platelets. Bone marrow first produces blood stem cells, which are immature, unspecialized (undifferentiated ) cells that are capable of becoming any type of blood cell, depending on the body's needs. Everyday: Bone marrow releases 2.5 billion RBCs/ kg of body weight, 2.5 billion platelet/kg of body weight s, and 1 billion WBC's per kg of body weight. With age, fatty tissue replaces active bone marrow and only a small portion of the remaining marrow continues to produce in older adults.

Accessory organs of blood formation

Spleen and Liver

Platelets

Third type of blood cells, smallest blood cells formed in bone marrow from megakaryocyte precursor cells. When activated, platelets stick to injured blood vessel walls and form platelet plugs that can stop the flow of blood at the injured site. •Production of platelets is controlled by the growth factor thrombopoietin. • After platelets leave the bone marrow, they are stored in the spleen and then released slowly to meet the body's needs. Normally 80% of platelets circulate and 20% are stored in the spleen. (Rebar 797)

Perfusion

Total arterial blood flow through the tissues (peripheral perfusion) and blood that is pumped by the heart (Central perfusion)

Partial Thromboplastin Time. (PTT)

assesses the intrinsic clotting cascade. (2,5,8,9,11,12) Monitored during heparin therapy. Prolonged whenever these factors are deficient, like in hemophilia. Also in liver disease b/c the factors 2, 9, and 10 are produced in the liver.

Mean Corpuscular Hemoglobin (MCH)

average amt. of Hgb by weight in a single RBC MCH decreased= cell has hemoglobin deficiency; hypochromic (lighter color); as in iron deficiency anemia

Key points: handle patients with suspected hematologic problems gently to avoid _____________ or _____________.

bleeding or bruising

Key Points: Both ___________ forces, and anti-_____________ forces are needed to maintain adequate perfusion.

clotting forces, and anti clotting forces.

Upon assessment, the nurse notices that a patient has bleeding gums. The patient reports increased fatigue, malaise, and "chills." What is the priority nursing intervention? a. Document assessment findings. b. Notify the health care provider of the patient's symptoms. c. Obtain vital signs and administer antipyretic medications. d. Review laboratory analysis for signs and symptoms of bone marrow suppression.

d. The nurse should initially review the patient's laboratory analysis for collective signs of pancytopenia related to the patient's report and assessment findings of fatigue (anemia), bleeding gums (thrombocytopenia), and chills (neutropenia). Laboratory data are needed before informing the heath care provider and deciding whether to administer an antibiotic. Obtaining blood cultures prior to antibiotic administration is an important intervention. Antipyretic medications may be prescribed to treat the patient's symptoms ("chills").

Key points: The most common symptom of a hematologic problem is ____________.

fatigue

Serum Ferritin

females: 10-150ng/mL Males: 12-300 ng/mL Increased/Decreased same as iron

Key Points: A platelet clot and ________ clot are not the same

fibrin clot.

Key points: Apply an ___________ to the needle site after a bone marrow aspiration or biopsy.

ice-pack

key points: Verify that a patient having a bone marrow aspiration or biopsy has signed an _______________________

informed consent statement

Key points: Rely on ____________ tests rather than skin color changes in older adults to assess anemia or jaundice.

laboratory tests.

Mean Corpuscular Volume (MCV)

measures average size of RBCs, used for classifying anemias MCV elevated= macrocytic; seen in megaloblastic anemias MCV decreaed= microcytic; deficiency anemia

Prothrombin Time Test

measures how long blood takes to clot, tests clotting factors: II, V, VII, and X

anti-factor Xa test

measures the amount of anti-activated factor X (anti-Xa) in blood, which is affected by heparin.

INRi

measures the same process as PT, establishing a normal mean or standard for PT. • When using INR for warfarin therapy, the desired is 2.0-3.0 regardless of the actual PT in seconds. • But for any other patient it is individualized for specific patient factors and medical conditions.

Hemostasis

multi-stepped process of controlling blood clotting 1. Platelet Aggregation (with platelet plug formation) 2. Blood Clotting Cascade 3. Formation of a complete fibrin clot.

The nursing priority after a bone marrow aspiration or biopsy is:

prevention of excessive bleeding. Cover the site with a dressing after bleeding is controlled, and closely observe for 24 hrs for bleeding/infection. Mild analgesic (aspirin free) may be given for pain, and ice packs can be placed over the site to limit bruising.

Peripheral Blood Smear

provides info on the sizes, shapes and proportions of different blood cell types within peripheral blood

Do not palpate the ____________ area of any patient suspected of having a hematologic problem

splenic

Fibrinolysis

the process that dissolves fibrin clot edges with special enzymes.

Hemoglobin electrophoresis

used to identify abnormal hemoglobin ex: Hemoglobin S in sickle cell disease Hemoglobin A is the major type in an adult.

Maintain pressure over a ______________ site for at least 5 minutes to prevent excessive bleeding.

venipuncture site

Assessment

• Age, gender • Liver function • Drug use (prescribed, OTC, illicit) • Dietary patterns • Socioeconomic status • Previous radiation therapy • Occupation, hobbies • Location of home Use of "blood thinners," NSAIDs • Nutrition status • Family history and genetic risk • Current health problems

Hematologic changes associated with aging

• Aging changes the blood components. • The older adult has a decreased blood volume with lower levels of plasma proteins. The lower plasma protein level may be related to a low dietary intake of proteins and to reduced protein production by the older liver. • Decrease in blood volume with lower levels of plasma proteins • Bone marrow produces fewer blood cells RBC, WBC counts lower • Lymphocytes less reaction to antigens, lose immune function • Hemoglobin levels fall after middle-age

Blood Components

• Plasma proteins (albumin, globulins, fibrinogen) • RBC's • WBC's • Platelets

Liver

• Produces prothrombin and other blood clotting factors. • Proper liver function is important in forming vitamin K in the intestinal tract. ( Vit K is needed to produce clotting factors, VII, IX, and X and prothrombin) • Large amounts of whole blood and blood cells can be stored in the liver, also stores extra iron with the protein ferritin.

Physical Assessment

• Skin • Head and neck • Respiratory • Cardiovascular • Kidney and urinary • Musculoskeletal • Abdominal • Central nervous system • Psychosocial

Red Blood Cells (erythrocytes)

• The largest proportion of blood cells • Produce Hemoglobin (Hgb) • Hgb carry CO2, so RBCs maintain acid-base balance. • Most importantly, Hgb combines loosely with O2, only a small drop in tissue oxygen levels increase the transfer of O2 from Hgb to tissues. • Mature RBC's have a biconcave disk shape, and no nucleus. Allows RBC's to change their shape without breaking as they pass through the narrow, winding capillaries. • Normal range is usually: 4,200,000-6,100,000/mm^3 (Rebar 796) • Start off as stem cells, enter myeloid pathway and progress to mature RBCs • Healthy, mature RBC's have a lifespan of about 120 days. • As RBCs age, their membranes become more fragile. These old cells are trapped and destroyed in the tissues, spleen, and liver. Some parts of destroyed RBCs (e.g., iron, hemoglobin) are recycled and used to make new RBCs. (Rebar 796)

Platelet Aggregation

• begins forming a platelet plug by having platelets clump together • Platelets normally circulate as individual small cells that do not clump together until activated. • Activation causes platelet membranes to become sticky, allowing them to clump together. • When platelets clump, they form large, semi-solid plugs in blood vessels, disrupting local blood flow. These platelet plugs are not clots and last only a few hours. Thus they cannot provide complete hemostasis but only start the hemostatic process. (Rebar 798)

Spleen

• contains three type of tissue: 1. white pulp (WBC's- antibody production) 2. red pulp (RBC storage + platelets 3. marginal pulp (contains the ends of many blood vessels) • These tissues help balance blood cell production with blood cell destruction and assist with immunity. • The spleen destroys old or imperfect RBCs, breaks down the hemoglobin released from these destroyed cells, stores platelets, and filters antigens. Anyone who has had a splenectomy has reduced immune functions and an increased risk for infection and sepsis. (Rebar 797)

Blood Clotting Cascade

• triggered by the formation of a platelet plug, which then rapidly amplifies the cascade.