What does bone marrow extraction check?

Bone marrow extraction, commonly known as bone marrow puncture, is a widely used examination method in clinical medicine. Bone marrow puncture can detect various diseases, which is especially of great significance for the diagnosis of patients with blood diseases. Bone marrow puncture has certain steps and methods. Below, we will introduce in detail the indications, operation methods and other related knowledge of bone marrow puncture.

1. Indications

1. Diagnosis, differential diagnosis and treatment follow-up of various blood diseases.

2. Unexplained increase or decrease in the number of red blood cells, white blood cells, and platelets, as well as morphological abnormalities.

3. Diagnosis and differential diagnosis of fever of unknown cause may include bone marrow culture and bone marrow smear to look for parasites.

2. Operation method

1. Selection of puncture site: ① Anterior superior iliac spine: The puncture point is usually 1~2 cm above and behind the anterior superior iliac spine. The bone surface here is relatively flat, easy to fix, and the operation is convenient and safe; ② Posterior superior iliac spine: It is a bony protrusion located on both sides of the sacrum and above the buttocks; ③ Manubrium: It is rich in bone marrow. When puncture at the above sites fails, manubrium puncture can be performed, but the bone here is thin, and there are atria and large blood vessels behind it. It is strictly prevented from penetrating and dangerous, so it is rarely used; ④ Lumbar spinous process: It is located at the protrusion of the lumbar spinous process and is rarely used. 5. For infants and children under 2 years old, choose the anterior and inferior part of the tibial tuberosity.

2. Body position: Lie on your back when puncturing the sternum and anterior superior iliac spine. The posterior superior iliac spine should be punctured in the lateral decubitus position. Lumbar spinous process puncture is performed in a sitting or side-lying position.

3. Routinely disinfect the skin, wear sterile gloves, lay a sterile towel, and use 2% lidocaine for local infiltration anesthesia until the periosteum. Make a "品" shape with more anesthesia. Wait for about 2 minutes to allow the periosteum to be fully infiltrated and anesthetized.

4. Fix the bone marrow puncture needle holder at an appropriate length (about 1.5cm for iliac puncture, it can be appropriately longer for obese people, and about 1.0cm for sternal manubrium puncture), fix the skin of the puncture site with the thumb and index finger of the left hand, hold the needle with the right hand and insert it vertically into the bone surface (if it is sternal manubrium puncture, the puncture needle should be inserted obliquely at an angle of 30~40° to the bone surface). When the puncture needle touches the bone, rotate it left and right and slowly drill into the bone. When you feel the resistance disappear and the puncture needle has been fixed in the bone, it means that it has entered the bone marrow cavity.

5. Use a dry 20ml syringe to withdraw the inner plug by 1cm, pull out the needle core, connect the syringe, and slowly aspirate with appropriate force. A small amount of red bone marrow fluid can be seen entering the syringe. The amount of bone marrow fluid aspirated should be 0.1~0.2ml. Remove the syringe, push the bone marrow fluid onto the glass slide, and have an assistant quickly make 5~6 smears for cell morphology and cytochemistry staining examination.

6. If bone marrow culture is required, connect the syringe again, draw 2-3 ml of bone marrow fluid and inject it into the culture medium.

7. If bone marrow fluid cannot be extracted, it may be that the needle cavity is filled with skin, subcutaneous tissue or bone fragments, or the needle may be inserted too deep or too shallow, and the needle tip is not in the medullary cavity. At this time, the needle core should be reinserted, rotated slightly, or drilled in or out a little bit, and the needle core should be pulled out. If blood is seen on the needle core, bone marrow fluid may be obtained by aspiration again.

8. After aspiration, insert the needle core, slightly turn it to pull out the puncture needle, then cover the needle hole with sterilized gauze, press it slightly, and fix it with pressure tape.

3. Notes

1. After the puncture needle enters the bone, avoid swinging it too much to avoid breaking it.

2. When puncturing the manubrium, the needle should not be inserted vertically and excessive force should not be used to prevent penetration of the medial bone plate.

3. When aspirating bone marrow fluid, gradually increase the negative pressure. When performing cell morphology examination, the aspirated volume should not be too much, otherwise the bone marrow fluid will be diluted, but it should not be too little either.

4. Bone marrow fluid should be smeared immediately after extraction.

5. Bone marrow biopsy should be performed when multiple dry taps are performed.