Monday, 20 September 2010

BONE MARROW ASPIRATION AND BIOPSY

A specimen of bone marrow—the major site of blood cell formation—may be obtained by aspiration or needle biopsy. The procedure allows evaluation of overall blood composition by studying blood elements and precursor cells as well as abnormal or malignant cells. Aspiration removes cells through a needle inserted into the marrow cavity of the bone; a biopsy removes a small, solid core of marrow tissue through the needle. Both procedures are usually performed by a physician, but some facilities authorize specially trained chemotherapy nurses or nurse clinicians to perform them with an assistant.
Aspirates aid in diagnosing various disorders and cancers, such as oat cell carcinoma, leukemia, and such lymphomas as Hodgkin's disease. Biopsies are often performed simultaneously to stage the disease and monitor response to treatment.
Equipment
For aspiration:
Prepackaged bone marrow set, which includes povidone-iodine pads • two sterile drapes (one fenestrated, one plain) • ten 4″ × 4″ gauze pads • ten 2″ × 2″ gauze pads • two 12-ml syringes • 22G 1″ or 2″ needle • scalpel • sedative • specimen containers • bone marrow needle • 70% isopropyl alcohol • 1% lidocaine (unopened bottle) • 26G or 27G ½″ to 5/8″ needle • adhesive tape • sterile gloves • glass slides and coverglass • labels and laboratory biohazard transport bags.
For biopsy:
All equipment listed above • Biopsy needle, such as Vim-Silverman, Jamshidi, Illinois sternal, or Westerman-Jensen needle • Zenker's fixative.
Implementation
  • Tell the patient that the physician will collect a bone marrow specimen, and explain the procedure to ease his anxiety and ensure cooperation. Make sure the patient or a responsible family member understands the procedure and signs a consent form obtained by the physician.
  • Inform the patient that the procedure normally takes 5 to 10 minutes, that test results usually are available in 1 day, and that more than one marrow specimen may be required.
  • Check the patient's history for hypersensitivity to the local anesthetic. Tell him which bone—sternum or posterior superior or anterior iliac crest—will be sampled. Inform him that he will receive a local anesthetic and will feel heavy pressure from insertion of the biopsy or aspiration needle as well as a brief, pulling sensation. Tell him that the physician may make a small incision to avoid tearing the skin.
  • If the patient has osteoporosis, tell him that the needle pressure may be minimal; if he has osteopetrosis, inform him that a drill may be needed.
  • Provide a sedative, as ordered, before the test.
  • Position the patient according to the selected puncture site. (See Common sites for bone marrow aspiration and biopsy, page 160.)
  • Using sterile technique, the puncture site is cleaned with povidone-iodine pads and allowed to dry; then the area is draped.
    P.160

  • To anesthetize the site, the physician infiltrates it with 1% lidocaine, using a 26G or 27G ½″ to 5/8″ needle to inject a small amount intradermally and then a larger 22G 1″ to 2″ needle to anesthetize the tissue down to the bone.
  • When the needle tip reaches the bone, the physician anesthetizes the periosteum by injecting a small amount of lidocaine in a circular area about ¾″ (2 cm) in diameter. The needle should be withdrawn from the periosteum after each injection.
  • After allowing about 1 minute for the lidocaine to take effect, a scalpel may be used to make a small stab incision in the patient's skin to accommodate the bone marrow needle. This technique avoids pushing skin into the bone marrow and also helps avoid unnecessary skin tearing to help reduce the risk of infection.
Bone marrow aspiration
  • The physician inserts the bone marrow needle and lodges it firmly in the bone cortex. If the patient feels sharp pain instead of pressure when the needle first touches bone, the needle was probably inserted outside the anesthetized area. If this happens, the needle should be withdrawn slightly and moved to the anesthetized area.
  • The needle is advanced by applying an even, downward force with the heel of the hand or the palm, while twisting it back and forth slightly. A crackling sensation means that the needle has entered the marrow cavity.
  • Next, the physician removes the inner cannula, attaches the syringe to the needle, aspirates the required specimen, and withdraws the needle.
  • The nurse puts on gloves and applies pressure to the aspiration site with a gauze pad for 5 minutes to control bleeding while an assistant prepares the marrow slides. The area is then cleaned with alcohol to remove the povidone-iodine, the skin is dried thoroughly with a 4″ × 4″ gauze pad, and a sterile pressure dressing is applied. Specimens are labeled appropriately, placed in laboratory biohazard transport bags, and sent to the laboratory.
Bone marrow biopsy
  • The physician inserts the biopsy needle into the periosteum and advances it steadily until the outer needle passes into the marrow cavity.
    P.161

  • The biopsy needle is directed into the marrow cavity by alternately rotating the inner needle clockwise and counterclockwise. Then a plug of tissue is removed, the needle assembly is withdrawn, and the marrow specimen is expelled into a properly labeled specimen bottle containing Zenker's fixative or formaldehyde. It's then placed in the laboratory biohazard transport bag and sent to the laboratory.
  • The nurse puts on gloves, cleans the area around the biopsy site with alcohol to remove the povidone-iodine solution, firmly presses a sterile 2″ × 2″ gauze pad against the incision to control bleeding, and applies a sterile pressure dressing.
Special considerations
  • Faulty needle placement may yield too little aspirate. If no specimen is produced, the needle must be withdrawn from the bone (but not from the overlying soft tissue), the stylet replaced, and the needle inserted into a second site within the anesthetized field.
  • Bone marrow specimens shouldn't be collected from irradiated areas because radiation may have altered or destroyed the marrow.
Complications
Bleeding and infection are potentially life-threatening complications of aspiration or biopsy at any site. Complications of sternal needle puncture are uncommon but include puncture of the heart and major vessels, causing severe hemorrhage; puncture of the mediastinum, causing mediastinitis or pneumomediastinum; and puncture of the lung, causing pneumothorax.
If a hematoma occurs around the puncture site, apply warm soaks. Give analgesics for site pain or tenderness.
Documentation
Chart the time, date, location, and patient's tolerance of the procedure and the specimen obtained.