CH14

Chapter 14: Arterial Puncture Procedures

Overview of Arterial Puncture

• Purpose: Arterial puncture is primarily performed to obtain blood for arterial blood gas (ABG) tests, which are crucial for evaluating respiratory function due to the high oxygen content and consistency of arterial blood.

• Disadvantages:

  • Technically difficult procedure

  • Potential for more pain and hazards compared to venipuncture

  • Not typically used for routine blood tests

Objectives of the Chapter

• Demonstrate understanding of arterial blood collection terminology, hazards, and complications.

• Identify and analyze appropriate arterial puncture sites based on established criteria, along with their advantages and disadvantages.

• Describe the ABG collection procedure including patient assessment, equipment necessary, and parameters measured in ABG tests.

• Perform and interpret the modified Allen test.

Personnel Involved in Arterial Puncture

• Who Can Perform:

  • Nurses

  • Medical technologists & technicians

  • Respiratory therapists

  • Emergency medical technicians

  • Level II phlebotomists

• Training Required:

  • Extensive training involving theory, demonstrations, and supervised practice is mandatory.

Site-Selection Criteria for Arterial Punctures

• Factors to Consider:

  • Presence of collateral circulation

  • Accessibility and size of the artery

  • Type of surrounding tissue to minimize injury risks during puncture

  • Absence of inflammation, irritation, or open wounds.

Common Arterial Puncture Sites

1. Radial Artery

• Advantages:

  • Good collateral circulation from radial and ulnar arteries

  • Easy to locate and palpate

  • Less chance of hematoma formation

• Disadvantages:

  • Skill required for successful puncture due to small size

  • Difficult to locate in patients with low blood volume or cardiac output

2. Brachial Artery

• Advantages:

  • Large size makes it easier to palpate and puncture

  • Preferred for collecting large volumes of blood

• Disadvantages:

  • Deeper location makes palpation harder

  • Risks of puncturing median nerve and basilic vein

3. Femoral Artery

• Key Characteristics:

  • Largest artery used for arterial puncture, located in the groin

• Advantages:

  • Large and easy to locate

• Disadvantages:

  • Poor collateral circulation

  • Increased risk of infection and hematoma formation

Other Sites for Arterial Puncture

• Infants: Scalp and umbilical arteries

• Adults: Dorsalis pedis arteries

• Note: Brachial artery is often avoided in infants due to palpation difficulty and poor collateral circulation.

ABG Parameters and Interpretation

• Use Cases:

  • Diagnosis and management of respiratory disorders

  • Information on oxygenation, ventilation, and acid-base balance

• Commonly Measured Analytes:

  • pH: 7.35–7.45

  • PaO2: 80–100 mm Hg

  • PaCO2: 35–45 mm Hg

  • HCO3: 22–26 mEq/L

  • O2 Saturation: 97–100%

  • Base Excess: (−2)–(+ 2) mEq/L

ABG Specimen Collection Procedures

Equipment and Supplies

• Personal protective equipment and sterile supplies such as gloves, antiseptics, and syringes

• Local anesthetic (optional) and gauze for after-care

Patient Preparation

• Proper identification and explanation of the procedure.

• Assessment of patient’s steady state and collateral circulation.

• Conducting the modified Allen test to assess circulation.

Modified Allen Test Procedure

1. Patient makes a fist, compressing both radial and ulnar arteries.

2. Release pressure on the ulnar artery after hand opens.

3. Assess color return:

   • Positive if pink flushes in <15 seconds

   • Negative if no flush occurs.

Radial ABG Collection Steps

1. Receive and verify test requisition.

2. Prepare the patient and ensure consent.

3. Assess and locate the radial artery; optional anesthetic application.

4. Insert needle at 30-45 degree angle toward pulse, stopping when a flash of blood appears.

5. Allow syringe to fill, apply pressure, and activate safety feature of the needle.

6. Label the specimen and dispose of used materials properly.

7. Monitor the site for complications and apply a bandage.

Hazards and Complications of Arterial Puncture

• Common Hazards:

  • Arteriospasm

  • Artery damage

  • Discomfort and infection

  • Hematoma and thrombus formation

• Sampling Errors: Issues such as air bubbles, delay in analysis, and using incorrect anticoagulants can impact results.

Conclusion

• Understanding the procedures, anatomy, and complications of arterial puncture is critical for effective practice in phlebotomy and respiratory care. Regular practice and up-to-date knowledge ensure better patient safety and accurate diagnostic results.