Ignativicius Chapter 39: Assessment of the Hematologic System

Bone Marrow Aspiration and Biopsy: Procedure

A local anesthetic agent is injected into the skin around the site. The patient may also receive a mild tranquilizer or a rapid-acting sedative, such as midazolam (Versed), lorazepam (Ativan, Apo-Lorazepam, Novo-Lorazem), or etomidate (Amidate). Some patients do well with guided imagery or autohypnosis. The skin over the site is cleaned with a disinfectant. For an aspiration, the needle is inserted with a twisting motion and the marrow is aspirated by pulling back on the plunger. For a biopsy, a small skin incision is made and the biopsy needle is inserted through the skin opening. Pressure and several twisting motions are needed to ensure coring and loosening of an adequate amount of marrow tissue. Apply external pressure to the site until hemostasis is ensured. A pressure dressing or sandbags may be applied to reduce bleeding.

Tests of Cell Number and Function 1

A peripheral blood smear is made by taking a drop of blood and spreading it over a slide. This rapid test provides information on the sizes, shapes, and proportions of different blood cell types in the peripheral. A complete blood count (CBC) includes a number of studies: red blood cell (RBC) count, white blood cell (WBC) count, hematocrit, and hemoglobin level. The RBC count measures circulating RBCs in 1 mm^3 of blood. The WBC count measures all leukocytes present in 1 mm^3 of blood. WBC count with differential leukocyte count! The hematocrit (Hct) is the percentage of red blood cells in the total blood volume. The hemoglobin (Hgb) level is the total amount of hemoglobin in blood. The mean corpuscular volume (MCV) measures the average volume or size of individual RBCs and is useful for classifying anemias. When the MCV is elevated, the cell is larger than normal (macrocytic), as seen in megaloblastic anemias. When the MCV is decreased, the cell is smaller than normal (microcytic), as seen in iron deficiency anemia. The mean corpuscular hemoglobin (MCH) is the average amount of hemoglobin by weight in a single RBC. The mean corpuscular hemoglobin concentration (MCHC) measures the average amount of hemoglobin by percentage in a single RBC. When the MCHC is decreased, the cell has a hemoglobin deficiency and is hypochromic (a lighter color), as in iron deficiency anemia. Reticulocyte count is helpful in determining bone marrow function. A reticulocyte is an immature RBC. An elevated reticulocyte count indicates that RBCs are being produced and released by the bone marrow before they mature. Normally only about 2% of circulating RBCs are reticulocytes. An elevated reticulocyte count is desirable in an anemic patient or after hemorrhage because this indicates that the bone marrow is responding. An elevated reticulocyte count without a precipitating cause usually indicates health problems, such as polycythemia vera (a malignant condition in which the bone marrow overproduces RBCs).

Tests of Cell Number and Function 2

A platelet count, also known as a thrombocyte count, reflects the number of platelets in circulation. The normal range is 150,000 to 400,000/mm^3. When this value is low (thrombocytopenia), the person is at greater risk for bleeding. Values between 40,000/mm^3 and 80,000/mm^3 may have prolonged bleeding from trauma, dental work, and surgery. Patients who have platelet values below 20,000/mm^3 may have spontaneous bleeding that is very difficult to stop. Hemoglobin electrophoresis detects abnormal forms of hemoglobin, such as hemoglobin S in sickle cell disease. Hgb A is the major adult type. Leukocyte alkaline phosphatase (LAP) is an enzyme produced by normal mature neutrophils. Elevated LAP levels occur during episodes of infection or stress. An elevated neutrophil count without an elevation in LAP level occurs with some types of leukemia. Coombs' tests, both direct and indirect, are used for blood typing. The direct test detects antibodies against RBCs that may be attached to a person's RBCs. Although healthy people can make these antibodies, in certain diseases (e.g., systemic lupus erythematosus, mononucleosis) these antibodies are directed against the patient's own RBCs. This equals hemolytic anemia. The indirect Coombs' test detects the presence of circulating antiglobulins. For pending blood transfusion therapy. Serum ferritin, transferrin, and the total iron-binding capacity (TIBC) tests measure iron levels. Abnormal levels of iron and TIBC occur with problems such as iron deficiency anemia. Serum ferritin test measures the amount of free iron present in the plasma. People with levels 10 g or more lower than the normal range have inadequate iron stores. Transferrin is a protein that transports dietary iron from the intestines to cell storage sites. Measuring the amount of iron that can be bound to serum transferrin indirectly determines whether an adequate amount of transferrin is present. This test is the total iron-binding capacity (TIBC) test. Normally, only about 30% of the transferrin is bound to iron in the blood. TIBC increases when a person is deficient in serum iron and stored iron levels. Such a value indicates that an adequate amount of transferrin is present but less than 30% of it is bound to serum iron.

Patient History

Age and gender are important to consider. Liver function, the presence of known immunologic or hematologic disorders, current drug use, dietary patterns, and socioeconomic status are important to assess. Previous radiation therapy for cancer may impair hematologic function if marrow-forming bones were in the radiation. Ask about the patient's occupation and hobbies and whether the home is located near an industrial setting. Check all drugs that the patient is using or has used in the past 3 weeks. Ask the patient about use of blood "thinners" and NSAIDs. Drugs include anticoagulants, fibrinolytics, and platelet inhibitors. Anticoagulant drugs work by interfering with one or more steps involved in the blood CLOTTING cascade. Anticoagulants do not break down existing clots. Prophylactic! Direct thrombin inhibitors (DTIs) include lepirudin (Refludan), desirudin (Iprivask), bivalirudin (Angiomax), argatroban (ARGATROBAN, Acova), rivaroxaban (Xarelto), and apixaban (Eliquis). The drugs prevent the conversion of prothrombin (factor X) to its active form, thrombin (factor Xa). Indirect thrombin inhibitors include the heparins and heparinoids. These drugs include enoxaparin (Lovenox), dalteparin (Fragmin), tinzaparin (Innohep), and fondaparinux (Arixtra). Cause anticoagulation by binding to and increasing the activity of antithrombin III (AT III). By activating antithrombin III, coagulation factor Xa (thrombin) is indirectly inhibited. Vitamin K antagonists (VKAs) decrease the synthesis of vitamin K in the intestines. Reduces the production of vitamin K-dependent CLOTTING factors II, VII, IX, and X, along with the anticoagulant proteins C and S. Commonly used VKA is warfarin (Coumadin, Jantoven). Fibrinolytic drugs (thrombolytic drugs or "clot busters") selectively break down fibrin threads present in formed blood clots. The mechanism to start fibrin degradation is activation of the inactive tissue protein plasminogen to its active form, plasmin. Plasmin directly attacks and degrades the fibrin molecule. Common fibrinolytic drugs include alteplase (Activase), reteplase (Retavase), tenecteplase (TNKase), and urokinase (Abbokinase, Kinlytic, pulmonary embolism). These drugs are the first-line therapy for problems caused by small, localized formed clots such as myocardial infarction (MI), limited arterial thrombosis, and thrombotic strokes. First 6 hours only, due to 6 hour anoxic tissues poor prognosis. Platelet inhibitors or antiplatelet drugs prevent either platelet activation or aggregation (clumping). The most widely used drug for this effect is aspirin, which inhibits the production of substances that activate platelets, such as thromboxane. Other drugs change the platelet membrane, reducing its "stickiness," or prevent activators from binding to platelet receptors by inhibiting a variety of enzymes important to platelet activation (Karch, 2012). These drugs include cilostazol (Pletal), clopidogrel (Plavix), dipyridamole (Persantine), prasugrel (Effient), ticagrelor (Brilinta), and ticlopidine (Ticlid). Another group of drugs that inhibits platelets by binding to certain membrane proteins include abciximab (ReoPro), eptifibatide (Integrilin), and tirofiban (Aggrastat), which are all administered parenterally. In addition, many complementary therapy agents, such as St. John's wort and Ginkgo biloba, inhibit platelet activity.

Current Health Problems

Ask about lymph nodes swelling, excessive bruising or bleeding, and whether the bleeding was spontaneous or induced. Ask about the amount and duration of bleeding after routine dental. Ask women to estimate the number of pads or tampons used. Ask whether clots are present in menstrual blood. If menstrual clots occur, ask her to estimate clot size using coins or fruit. Assess for shortness of breath on exertion, palpitations, frequent infections, fevers, recent weight loss, headaches, or paresthesias. The most common manifestation of anemia is fatigue as a result of decreased oxygen delivery to cells. Cells use oxygen to produce the high-energy chemical adenosine triphosphate (ATP). Ask patients about feeling tired, needing more rest, or losing endurance during normal activities. Determine whether other manifestations of anemia, such as vertigo, tinnitus, and a sore tongue, are present.

Family History and Genetic Risk

Ask whether anyone in the family has had hemophilia, frequent nosebleeds, postpartum hemorrhages, excessive bleeding after tooth extractions, or heavy bruising after mild trauma. Ask whether any family member has sickle cell disease or sickle cell trait.

Action Alert

Aspiration or biopsy procedures are invasive, and sterile technique must be observed.

Nutrition Status

Assess possible iron, protein, mineral, or vitamin deficiencies. Diets high in fat and carbohydrates and low in protein, iron, and vitamins can cause many types of anemia and decrease the functions of all blood cells. Diets high in vitamin K, found in leafy green vegetables, may increase the rate of blood clotting. Assess the amount of salads and other raw vegetables that the patient eats and whether supplemental vitamins and calcium are used. Ask about alcohol consumption because chronic alcoholism causes nutrition deficiencies and impairs the liver.

Gender Health Considerations

At all ages, women have lower blood cell counts than do men. This difference is greater during menstrual years because menstrual blood loss may occur faster than blood cell production. This difference also may be related to blood dilution caused by fluid retention from female hormones. Always assess for RBC adequacy in a female patient.

Kidney and Urinary Assessment

Bleeding problems may cause gross or occult hematuria (blood in the urine). Inspect urine for color. Hematuria may appear as grossly bloody red or dark brownish gold urine. Test the urine for proteins with a urine test dipstick because blood contains protein and blood in the urine increases its protein content. Keep in mind that the person with chronic kidney disease (CKD) produces less natural erythropoietin and often is anemic.

Blood Components

Blood is composed of plasma and cells. The three major types of plasma proteins are albumin, globulins, and fibrinogen. Albumin maintains the 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 is activated to form fibrin, which is critical in the blood CLOTTING process. Red blood cells (erythrocytes) are the largest proportion of blood cells. The normal range is from 4,200,000 to 6,100,000/mm3. Healthy, mature, circulating RBCs have a life span of about 120 days. Old cells are trapped and destroyed in the tissues, spleen, and liver. Some parts of destroyed RBCs (e.g., iron, hemoglobin) are recycled. Each hemoglobin molecule needs iron to be able to transport up to four molecules of oxygen. Hemoglobin also carries carbon dioxide. RBCs also help maintain acid-base balance. RBC production or erythropoiesis (selective growth of stem cells into mature erythrocytes) must be properly balanced with RBC destruction or loss. Trigger for RBC production is an increase in the tissue need for oxygen. The kidney produces the RBC growth factor erythropoietin at the same rate as RBC destruction or loss. Synthetic erythrocyte stimulating agents (ESAs) such as Procrit, Epogen, and EPO have the same effect on bone marrow. Substances are needed to form hemoglobin and RBCs, including iron, vitamin B12, folic acid, copper, pyridoxine, cobalt, and nickel. White blood cells (WBCs, leukocytes) also are formed in the bone marrow. Platelets are the smallest blood cells, formed in the bone marrow from megakaryocyte precursor cells. When activated, platelets stick to injured blood vessel walls and form platelet plugs. They also produce substances important to blood CLOTTING and aggregate (clump together) to perform most of their functions. Platelets help keep small blood vessels intact by initiating repair. Production of platelets is controlled by the growth factor thrombopoietin.

Bone Marrow

Bone marrow is responsible for blood formation. It produces red blood cells (RBCs, erythrocytes), white blood cells (WBCs, leukocytes), and platelets. Bone marrow normally releases about 2.5 billion RBCs, 2.5 billion platelets, and 1 billion WBCs per kilogram of body weight per day. Adults, cell-producing marrow is present only in flat bones (sternum, skull, pelvic and shoulder girdles) and the ends of long bones. With aging, fatty tissue replaces active bone marrow. The bone marrow first produces blood stem cells, which are immature, unspecialized (undifferentiated) cells that are capable of becoming any type of blood cell. Next stage in blood cell production is the committed stem cell (or precursor cell). Require the presence of a specific growth factor for specialization. For example, erythropoietin is a growth factor specific for the RBC.

Laboratory Tests

Chart 39-2 lists laboratory data used to assess hematologic function. When a venipuncture is necessary, apply pressure to the site for at least 5 minutes on a patient suspected of having a hematologic problem to prevent bleeding and hematoma formation.

Head and Neck Assessment

Check for pallor or ulceration of the oral mucosa. The tongue is smooth in pernicious anemia and iron deficiency anemia or smooth and beefy red in other nutrition deficiencies. These manifestations may occur with fissures at the corners of the mouth. Assess for scleral jaundice. Inspect and palpate all lymph node areas. Document any lymph node enlargement, including whether palpation of the enlarged node causes pain and whether the enlarged node moves or remains fixed.

Action Alert

Do not palpate the splenic area of the abdomen for any patient with a suspected hematologic problem. An enlarged spleen ruptures easily and can lead to hemorrhage and death.

Bone Marrow Aspiration and Biopsy

Evaluate the patient's hematologic status when other tests show abnormal findings that indicate a possible problem in blood cell production or maturation. Results provide information about bone marrow function, including the production of all blood cells and platelets. In a bone marrow aspiration, cells and fluids are suctioned from the bone marrow. In a bone marrow biopsy, solid tissue and cells are obtained by coring out an area of bone marrow with a large-bore needle.

Bone Marrow Aspiration and Biopsy: Patient Preparation

Explain the procedure, and reassure the patient that you will stay during the entire procedure. Occasionally a friend or family member is permitted to be present. The local anesthetic injection will feel like a stinging or burning sensation. Tell him or her to expect a heavy sensation of pressure and pushing while the needle is being inserted. Sometimes a crunching sound can be heard or scraping sensation felt. A brief sensation of painful pulling will be experienced as the marrow is being aspirated. If a biopsy is performed, the patient may feel more discomfort as the needle is rotated into the bone. The site (usually the iliac crest). If this site is not available or if more marrow is needed, the sternum may be used. If the iliac crest is the site, place the patient in the prone or side-lying position.

Hemostasis and Blood Clotting 1

Hemostasis is the multi-stepped process of controlled blood CLOTTING. Three sequential processes result in blood clotting: platelet aggregation with platelet plug formation; the blood clotting cascade; and the formation of a complete fibrin clot. Platelet aggregation begins forming a platelet plug by having platelets 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. Substances that activate platelets and cause clumping include adenosine diphosphate (ADP), calcium, thromboxane A2, and collagen. Platelets secrete some of these substances. Blood clotting is a cascade triggered by the formation of a platelet plug, which then rapidly amplifies the cascade. The cascade works like a landslide—a few small pebbles rolling down a steep hill can dislodge large rocks, trees, and soil, causing an enormous movement of earth. Cascade reactions are hard to stop once set into motion.

Vitamin K dependent clotting factors!

II, VII, IX, and X, along with the anticoagulant proteins C and S

Imaging Assessment

Include radioisotopic imaging. Isotopes are used to evaluate the bone marrow for sites of active blood cell formation and sites of iron storage. Radioactive colloids are used to determine organ size and liver and spleen function. The patient is given a radioactive isotope by IV. He or she must lie still for about an hour during the scan. No special patient preparation or follow-up care is needed. Standard x-rays may be used to diagnose some hematologic problems. For example, multiple myeloma causes classic bone destruction, with a "Swiss cheese" appearance.

Skin Assessment

Inspect the skin and mucous membranes for pallor or jaundice. Assess nail beds for pallor or cyanosis. Pallor of the gums, conjunctivae, and palmar creases (when the palm is stretched) indicates decreased hemoglobin levels and poor tissue oxygenation. Assess the gums for active bleeding in response to light pressure or brushing the teeth with a soft-bristled brush, and assess any lesions or draining. Inspect for petechiae and large bruises (ecchymoses). Petechiae are pinpoint hemorrhagic lesions in the skin. Bleeding around nasogastric tubes, endotracheal tubes, central lines, peripheral IV sites, or Foley catheters. Check the skin turgor, and ask about itching because dry skin from poor perfusion itches. Assess body hair. Areas with poor circulation, especially the lower legs and toes, may have sparse or absent hair.

Hemostasis and Blood Clotting 2

Intrinsic factors are conditions, such as circulating debris or venous stasis, within the blood itself that can activate platelets and trigger the blood CLOTTING cascade. Extrinsic factors outside of the blood can also activate platelets. The most common extrinsic event is trauma that damages blood vessels and exposes collagen. Collagen then activates platelets to form a platelet plug. Other blood vessel changes that can activate platelets include inflammation, bacterial toxins, or foreign proteins. End result of the cascade is: formation of a fibrin clot and local blood CLOTTING (coagulation). The cascade, from the formation of a platelet plug to the formation of a fibrin clot, depends on the presence of specific clotting factors, calcium, and more platelets at every step. Clotting factors (see Table 39-2) are inactive enzymes that become activated in a sequence. The last two steps in the cascade are the activation of thrombin from prothrombin and the conversion (by thrombin) of fibrinogen into fibrin. Only fibrin molecules can begin the formation of a true clot. 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. After the fibrin mesh is formed, clotting factor XIII tightens up the mesh, making it more dense and stable. More platelets stick to the threads of the mesh and attract other blood cells and proteins to form an actual blood clot. As this clot tightens (retracts), the serum is squeezed out and clot formation is complete.

Chart 39-1 Nursing Focus on the Older Adult Hematologic Assessment

PG 788 IGGY

Cultural Considerations

Pallor and cyanosis are more easily detected in people with darker skin by examining the oral mucous membranes and the conjunctiva of the eye. Jaundice can be seen more easily on the roof of the mouth. Petechiae may be visible only on the palms of the hands or the soles of the feet. Bruises can be seen as darker areas of skin and palpated as slight swellings or irregular skin surfaces. Ask the patient about pain when skin surfaces are touched lightly or palpated.

Tests Measuring Bleeding and Coagulation

Prothrombin time (PT) measures how long blood takes to clot, reflecting the level of clotting factors II, V, VII, and X and how well they are functioning. A normal PT shows blood CLOTTING between 11 and 12.5 seconds or within 85% to 100% of the time needed for a control sample of blood to clot. PT is prolonged when one or more of these clotting factors are deficient. International normalized ratio (INR) measures the same process as the PT by establishing a normal mean or standard for PT. The INR is calculated by dividing the patient's PT by the established standard PT. A normal INR ranges between 0.7 and 1.8. When using the INR to monitor warfarin therapy, the desired outcome is usually to maintain the patient's INR between 2.0 and 3.0 regardless of the actual PT in seconds. The partial thromboplastin time (PTT) assesses the intrinsic CLOTTING cascade and the action of factors II, V, VIII, IX, XI, and XII. PTT is prolonged whenever any of these factors is deficient, such as in hemophilia or disseminated intravascular coagulation (DIC). Liver disease can prolong the PTT. Therapeutic ranges for anticoagulation are usually between 1.5 and 2.0 times normal values but can be greater depending on the reason the person is receiving anticoagulation therapy. The anti-factor Xa test measures the amount of anti-activated factor X (anti-Xa) in blood, which is affected by heparin. It is used mainly to monitor heparin levels. For people not receiving heparin in any form, the reference range is less than 0.1 IU/mL. The usual therapeutic range for patients receiving standard heparin is 0.5 to 1.0 IU/mL, and the usual therapeutic range for patients receiving low-molecular-weight heparin is 0.3 to 0.7 IU/mL. Platelet aggregation, or the ability to clump, is tested by mixing the patient's plasma with an agonist substance that should cause clumping. The degree of clumping is noted. Aggregation can be impaired in von Willebrand's disease and during the use of drugs such as aspirin, anti-inflammatory agents, psychotropic agents, and platelet inhibitors.

Musculoskeletal Assessment

Rib or sternal tenderness may occur with leukemia (blood cancer) when the bone marrow overproduces cells, increasing the pressure in the bones. Examine the skin over superficial bones, including the ribs and sternum, by applying firm pressure with the fingertips. Assess the range of joint motion, and any swelling or joint pain.

Abdominal Assessment

Spleen is usually not palpable, but an enlarged spleen occurs with many hematologic problems. Palpating the edge of the liver in the right upper quadrant of the abdomen can detect enlargement. The normal liver may be palpable as much as 4 to 5 cm below the right costal margin. Cause of anemia among older adults is a chronically bleeding GI ulcer or intestinal polyp. If the ulcer is located in the stomach or the small intestine, obvious blood may not be visible in the stool. Occult blood testing!

Cardiovascular Assessment

The heart works harder to make adjustments to maintain tissue PERFUSION. Pulses may become weak and thready. Observe for distended neck veins, edema, or indications of phlebitis. Use a stethoscope to listen for abnormal heart sounds and irregular rhythms. Assess blood pressure (BP). Systolic BP tends to be lower than normal in patients with anemia and higher than normal when the patient has excessive red blood cells.

Respiratory Assessment

The lungs work harder to make adjustments that can maintain tissue PERFUSION. Assess the rate and depth of respiration while the patient is at rest and during and after mild physical activity. Can the patient complete a 10-word sentence without stopping for a breath? Assess whether the patient is fatigued easily, has shortness of breath at rest or on exertion, or needs extra pillows to breathe well at night.

Bone Marrow Aspiration and Biopsy: Follow-Up Care

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 it for 24 hours for manifestations of bleeding and infection. A mild analgesic (aspirin-free) may be given. Ice packs can be placed over the site to limit bruising. Instruct the patient to inspect the site every 2 hours for the first 24 hours and to note the presence of active bleeding or bruising. Advise him or her to avoid contact sports or any activity that might result in trauma.

Hematologic Changes Associated with Aging

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, as well as to reduced protein production by the older liver. As bone marrow ages, it produces fewer blood cells. Total red blood cell (RBC) and white blood cell (WBC) counts are lower. Platelet counts do not change. Lymphocytes become less reactive to antigens and lose immune function. Antibody levels and responses are lower and slower. The WBC count does not rise as high in response to infection in older people. Hemoglobin levels in men and women fall after middle age.

Accessory Organs of Blood Formation

The spleen and liver are important accessory organs for blood production. The spleen contains three types of tissue: white pulp, red pulp, and marginal pulp. White pulp is filled with white blood cells (WBCs) and is a major site of antibody production. As whole blood filters through the white pulp, bacteria and old RBCs are removed. Red pulp is the storage site for RBCs and platelets. Marginal pulp contains the ends of many blood vessels. Splenectomy equals reduced immune functions and has an increased risk for infection. The liver produces prothrombin and other blood CLOTTING factors. Also, proper liver function is important in forming vitamin K in the intestinal tract. (Vitamin 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. The liver also stores extra iron within the protein ferritin.

What might you NOTICE in a patient with adequate tissue PERFUSION related to normal hematologic function?

Vital signs: • Heart rate and respiratory rate within normal range • Blood pressure within normal range Physical assessment: • Able to speak a sentence of 12 words without stopping for breath • Able to walk and talk without stopping for breath • Skin color normal (no cyanosis, pallor, or jaundice) • Oral mucous membrane and nail beds pink with rapid capillary refill • Gums pink, no petechiae or bleeding • Appropriate distribution of body hair, especially on legs and feet • Warm hands and feet, no dependent edema • Skin clear with no large bruises or petechiae • Lower eyelid conjunctivae red • Urine output just about equal to fluid intake • Urine clear and yellow Psychological assessment: • Oriented and not confused • Energy level good; able to engage in desired work, recreational, and personal activities Laboratory assessment: • Red blood cell, hemoglobin, hematocrit, white blood cell, and platelet levels within normal limits for age and gender • Reticulocyte count less than 2%

Central Nervous System Assessment

Vitamin B12 deficiency impairs nerve function, and severe chronic deficiency may cause permanent neurologic degeneration. Many neurologic problems can develop in patients who have leukemia, because leukemia can cause bleeding, infection, or tumor spread within the brain. When the patient with a suspected bleeding disorder has any head trauma, expand the assessment to include frequent neurologic checks

Anti-Clotting Forces

Whenever the blood clotting cascade is started, anti-clotting forces are also started to limit clot formation only to damaged areas so that normal perfusion is maintained. Anti-clotting forces both ensure that activated clotting factors are present only in limited amounts and also cause fibrinolysis to prevent over-enlargement of the fibrin clot. Fibrinolysis is the process that dissolves fibrin clot edges with special enzymes (Fig. 39-5). The process starts by activating plasminogen to plasmin. Plasmin, an active enzyme, then digests fibrin, fibrinogen, and prothrombin. Blood clotting cascade is activated, certain anti-clotting substances are also activated, such as protein C, protein S, and antithrombin III. Protein C and protein S increase the breakdown of clotting factors V and VIII. Antithrombin III inactivates thrombin and clotting factors IX and X. Deficiency of any anti-clotting factor increases the risk for pulmonary embolism, myocardial infarction, and strokes.

Drugs Causing Hemolysis

• Acetohydroxamic acid • Amoxicillin • Chlorpropamide • Doxapram • Glyburide • Mefenamic acid • Menadiol diphosphate • Methyldopa • Nitrofurantoin • Penicillin G benzathine • Penicillin V • Primaquine • Procainamide hydrochloride • Quinidine polygalacturonate • Quinine • Sulfonamides • Tolbutamide • Vitamin K

Drugs Causing Bone Marrow Suppression

• Altretamine • Amphotericin B • Azathioprine • Chemotherapeutic agents • Chloramphenicol • Chromic phosphate • Colchicine • Didanosine • Eflornithine • Foscarnet sodium • Ganciclovir • Interferon alfa • Pentamidine • Sodium iodide • Zalcitabine • Zidovudine

Drugs Disrupting Platelet Action

• Aspirin • Carbenicillin • Carindacillin • Dipyridamole • Ibuprofen • Meloxicam • Naproxen • Oxaprozin • Pentoxifylline • Sulfinpyrazone • Ticarcillin • Ticlopidine • Valproic acid

Key Points: Physiological Integrity

• Interpret blood cell counts and CLOTTING tests to assess hematologic status. • Be aware of these facts for hematologic function: 1. Tissue oxygenation and perfusion rely on normal hematologic function for oxygen delivery. 2. The most common manifestation of a hematologic problem is fatigue. 3. A platelet plug and a fibrin clot are not the same. 4. Both CLOTTING forces and anti-CLOTTING forces are needed to maintain adequate PERFUSION. 5. Women have reduced red blood cell, hematocrit, and hemoglobin levels at all ages compared with men. • Use the lip rather than nail beds to assess capillary refill on older adults. • Rely on laboratory tests rather than skin color changes in older adults to assess anemia or jaundice. • Assess the patient's endurance in performing ADLs. • Apply an ice pack to the needle site after a bone marrow aspiration or biopsy. • Check the needle insertion site at least every 2 hours after a bone marrow aspiration or biopsy. If the patient is going home, teach the patient and family how to assess the site for bleeding and when to seek help. • Instruct patients to avoid activities that may traumatize the site after a bone marrow aspiration or biopsy.

Key Points: Psychosocial Integrity

• Teach patients and family members about what to expect during procedures to assess hematologic function, including restrictions, drugs, and follow-up care. • Ask patients about their activity level and whether they are satisfied with the energy they have for activities. • Support the patient during a bone marrow aspiration or biopsy.

Key Points: Health Promotion and Maintenance

• Teach people to avoid unnecessary contact with environmental chemicals or toxins. If contact cannot be avoided, teach people to use safety precautions. • Instruct patients about the importance of eating a diet with adequate amounts of foods that are good sources of iron, folic acid, and vitamin B12.

Key Points: Safe and Effective Care Environment

• Verify that a patient having a bone marrow aspiration or biopsy has signed an informed consent statement. • Handle patients with suspected hematologic problems gently to avoid bleeding or bruising. • Do not palpate the splenic area of any patient suspected of having a hematologic problem. • Maintain pressure over a venipuncture site for at least 5 minutes to prevent excessive bleeding.