Arterial Blood Gas Sampling (Internal Medicine)

• Determination of pH and partial pressure of respiratory gases
• Determination of other serum blood levels (e.g., lactate)
• Assessment of response to therapeutic interventions and disease state
• Sampling of blood in emergencies when venous blood cannot be obtained

• Coagulopathy, anticoagulant medications, and thrombolysis
• Abnormalities of the overlying skin
• Prior vascular surgery at or proximal to the entry site
• Inadequate local circulation

• Gloves and antiseptic **UNIVERSAL PRECAUTIONS** **STERILE TECHNIQUE**
• Syringe, 25- to 27-gauge needle and 1% lidocaine without epinephrine for anesthetic (optional) See Local Anesthesia for further details.
• Syringe for aspiration (heparinized). Prepackaged ABG kits are available, or a standard syringe may be prepared with heparin.
• 1.5-inch 22- to 23-gauge needle and syringe cap
• Specimen bag and ice
• Bandage

• Radial artery
  • The radial artery is the preferred site for arterial puncture.
  • Collateral circulation is from the palmar branches of the ulnar artery. The artery is medial and proximal to the radial styloid on the volar side of the wrist.
• Brachial artery
  • The brachial artery may be chosen if the radial arteries are not accessible. The brachial artery lies deep in the antecubital fossa and may be difficult to enter. It is medial in the antecubital fossa, lateral to the medial epicondyle, and medial to the biceps brachii tendon.
• Femoral artery
  • The femoral artery is the least desirable site.
  • It is located midway between the symphysis pubis and anterior superior iliac spine, coursing under the inguinal ligament, lateral to the femoral vein, and medial to the femoral nerve.

Figure 1 :  Arterial blood gas sampling

View Larger Image

Figure 3 :  Equipment

View Larger Image

Figure 5 :  Radial artery anatomy

View Larger Image

The full content of this section includes:

• Step-by-step text instructions for performing the procedure
  
• Clinical pearls providing practical clinical tips from medical experts
• Patient safety guidelines consistent with Joint Commission and OHSA standards
• Links to medical evidence and related procedures

Figure 13 :  Arterial entry approaches

View Larger Image

Figure 14 :  Blood fills the syringe spontaneously

View Larger Image

• Immediately apply direct pressure to the puncture site, for up to 10-15 minutes for patients taking anticoagulant medications or who have coagulopathy.
• Check site frequently and instruct the patient to not disturb the site and to report any abnormalities immediately.
• Analyze results.

• Hematoma formation with possible transfusion, infection, and compression neuropathy
• Distal ischemia
• Pseudoaneurysm and arteriovenous fistula formation
• Localized trauma
• Infection (soft-tissue and bone)

Figure 15 :  Apply pressure for 5 minutes

View Larger Image