Definition
It refers to assisting for collection of blood sample from an artery by performing an arterial puncture.
Purposes
- For accurate assessment of acid-base status.
- For assessing degree of oxygenation of blood and adequacy of alveolar ventilation.
- For starting continuous arterial blood pressure monitoring in an emergency.
Contraindications
- Local infection.
- Disfigured anatomy.
- Presence of arteriovenous fistulas.
- Peripheral vascular disease of limb to be sampled.
- Thrombolysis or severe coagulopathy.
Articles
- 1 mL or 2 mL disposable syringe.
- Disposable needles size 20 gauge.
- Luer-lock for syringe.
- Heparin (1:1,000).
- Alcohol swab.
- Crushed ice in specimen bag.
- Disposable gloves and disposable probes.
- Arterial catheter for continuous pressure monitoring.
- Waterproof pad.
Preparation of the Patient
Preparing for an arterial puncture, such as for arterial blood gas (ABG) sampling, involves several key steps to ensure safety and accuracy:
- Medical History Review:
- Confirm the patient’s medical history, including any bleeding disorders or vascular conditions.
- Check for contraindications, such as peripheral vascular disease or cellulitis at the puncture site.
- Consent and Communication:
- Explain the procedure to the patient, addressing any concerns or questions.
- Obtain informed consent and reassure the patient to reduce anxiety.
- Positioning:
- Position the patient comfortably, typically with the wrist supported and slightly extended for radial artery access.
- Clothing and Accessories:
- Ensure the area is exposed and free of any obstructions, such as tight clothing or jewelry.
Procedure
| Nursing actions | Rationale | |
| Before procedure | ||
| 1. | Identify the patient by asking name and explain the procedure to the patient. | Helps in obtaining cooperation. |
| 2. | Record patient’s inspired oxygen concentration (FiO₂) set on ventilator. | Degree of hypoxemia cannot be assessed without knowing the inspired oxygen concentration. |
| 3. | Check patient’s temperature. | Hypothermia or hyperthermia influences oxygen release from haemoglobin. |
| 4. | Heparinize the 2 ml syringe: Withdraw heparin into syringe to wet the plunger and fill dead space in the needle. Hold syringe in an upright position and expel excess heparin and air bubbles. | This action coats the interior of the syringe with heparin to prevent clotting. Air remaining in the syringe may affect measurement of PaO2. Heparin in the syringe may affect measurement of pH. |
| During procedure | ||
| 5. | Wash hands and don gloves. | Prevents infection. |
| 6. | Palpate the radial brachial femoral artery. | The radial artery is the preferred site of puncture. Arterial puncture is performed in areas where good pulse is palpable. |
| 7. | If radial artery is selected for puncture, perform the Allen’s test: Obliterate the radial and ulnar pulses simultaneously by pressing on both blood vessels at the wrist. | The Allen’s test is a simple method for assessing collateral circulation in the hand. |
| Ask patient to clench and unclench fist until blanching of skin occurs. | Impedes arterial blood flow in the hand. | |
| Release pressure on ulnar artery (while still compressing radial artery) watch for return of skin color within 15 seconds. Note: If the ulnar artery does not have sufficient blood supply to perfuse entire hand, the radial artery should not be used. | Forces blood from the hand. | |
| Obliterate the radial and ulnar pulses simultaneously at the wrist. Elevate patient’s hand above heart and squeeze or compress hand until blanching occurs. | Identifies that ulnar artery alone is capable of supplying blood to the hand while radial artery is occluded. | |
| Lower patient’s hand while still compressing the ulnar artery and watch for return of skin color. | Identifies that radial artery alone is capable of supplying blood to the hand while ulnar artery is occluded. | |
| 8. | For a radial puncture, place a small towel under the patient’s wrist. | Makes the artery more accessible. |
| 9. | Place waterproof pad under forearms. | Protects the bed linen. |
| 10. | Feel along the course of radial artery and palpate for maximum pulsation with the middle and index fingers. Prepare the skin with germicide. The skin and subcutaneous tissues may be infiltrated with a local anesthetic agent. | The wrist should be stabilized to allow for better control of the needle. Prevents entry of microorganisms. |
| 11. | The needle is at a 45-60° angle to the skin surface and is advanced into the artery. Once the artery is punctured, arterial pressure will push up the piston of the syringe and a pulsating flow of blood will fill the syringe. | The arterial pressure will cause the syringe to be filled within few seconds. |
| 12. | After blood is obtained, withdraw needle and apply firm pressure over the puncture site with a dry sponge for 5 minutes. | Significant bleeding can occur because of the pressure in the artery. |
| 13. | Remove air bubbles from syringe and needle. Insert needle into the rubber stopper placed on the flat surface. Do not hold the rubber stopper. | Immediate capping of needle prevents room air from mixing with blood specimen. Holding rubber stopper in one hand may lead to needle stick injury. |
| 14. | Place the capped syringe in the container of ice. | Icing the syringe will prevent false results. |
| 15. | Maintain firm pressure on the puncture site for 5 minutes. If the patient is on anticoagulant therapy, apply direct pressure over puncture site for 10-15 minutes and then apply a firm pressure dressing. | Firm pressure on the puncture site prevents further bleeding and hematoma formation. |
| After procedure | ||
| 16. | For patients requiring serial monitoring of arterial blood, an arterial catheter is placed into the radial or femoral artery. | All connections must be tight to avoid disconnection and rapid blood loss. The arterial line also allows for direct blood pressure monitoring in critically ill patients. |
| 17. | Send labeled, iced specimen to the laboratory immediately with duly filled request. | Blood gas analysis should be done as soon as possible because PaO2 and pH can change rapidly. |
| 18. | Palpate the pulse (distal to the puncture site), inspect the puncture site, and assess for reduced temperature, cold, numbness, tingling, or discoloration. | Hematoma and arterial thrombosis are complications. |
| 19. | Change ventilator settings, inspired oxygen concentration or type and setting of respiratory therapy equipment as indicated by the results. | The PaO2 results will determine whether to maintain, increase, or decrease the FiO2. The Pao2, and pH results will dictate if any changes are needed in tidal volume or rate of patient’s ventilator. |
Special Consideration
- Confirm the patient’s medical history, including any bleeding disorders or vascular conditions.
- Perform a modified Allen test to ensure adequate collateral circulation before puncturing the radial artery.
- Verify if the patient is on blood-thinning medications, as these may increase the risk of bleeding.
- Adjust medications as per the healthcare provider’s instructions.
- Explain the procedure to the patient, addressing any concerns or questions.
- Obtain informed consent and reassure the patient to reduce anxiety.
- Maintain strict sterile conditions to minimize the risk of infection.
- Use sterile gloves, syringes, and antiseptic solutions.
- Observe the patient for signs of discomfort, vasospasm, or complications during the procedure.
- Ensure the patient remains still to prevent accidental injury.
- Use the correct angle and technique for arterial puncture (e.g., 45-degree angle for radial artery).
- Avoid excessive probing to minimize tissue damage.
- Apply firm pressure to the puncture site for at least 5 minutes or until bleeding stops.
- Monitor for the formation of a hematoma and take appropriate action if it occurs.
- Monitor the patient for delayed complications, such as bleeding, infection, or arterial occlusion.
- Provide clear instructions for follow-up care and signs to watch for, such as numbness or discoloration.
REFERENCES
- Annamma Jacob, Rekha, Jhadav Sonali Tarachand: Clinical Nursing Procedures: The Art of Nursing Practice, 5th Edition, March 2023, Jaypee Publishers, ISBN-13: 978-9356961845 ISBN-10: 9356961840
- Omayalachi CON, Manual of Nursing Procedures and Practice, Vol 1, 3 Edition 2023, Published by Wolters Kluwer’s, ISBN: 978-9393553294
- Sandra Nettina, Lippincott Manual of Nursing Practice, 11th Edition, January 2019, Published by Wolters Kluwers, ISBN-13:978-9388313285
- Adrianne Dill Linton, Medical-Surgical Nursing, 8th Edition, 2023, Elsevier Publications, ISBN: 978-0323826716
- Donna Ignatavicius, Medical-Surgical Nursing: Concepts for Clinical Judgment and Collaborative Care, 11th Edition ,2024, Elsevier Publications, ISBN: 978-0323878265
- Lewis’s Medical-Surgical Nursing, 12th Edition,2024, Elsevier Publications, ISBN: 978-0323789615
- AACN Essentials of Critical Care Nursing, 5th Ed. Sarah. Delgado, 2023, Published by American Association of Critical-Care Nurses ISBN: 978-1264269884
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