What should be done in case of an Arterial Blood Gas (ABG) interruption?

Management of Arterial Blood Gas (ABG) Interruption

In case of an arterial blood gas (ABG) interruption, direct pressure should be applied to the puncture site for at least 5 minutes to ensure hemostasis and prevent complications such as hematoma formation or arterial occlusion. 1

Proper ABG Procedure and Interruption Management

Before the Procedure

• Perform Allen's test to ensure dual blood supply to the hand from both radial and ulnar arteries before radial artery puncture 1
• Obtain informed consent with discussion of potential risks 1
• Use local anesthesia for all ABG specimens except in true emergencies 1

During Interruption

• Apply immediate direct pressure to the puncture site 1, 2
• Maintain pressure for at least 5 minutes, longer in patients on anticoagulants 2
• Monitor the site for signs of bleeding, hematoma formation, or distal ischemia 2
• If using a safety syringe, ensure proper activation of safety mechanism before removing the needle 2

After Managing the Interruption

• Assess whether a repeat attempt is necessary based on clinical urgency 1
• If repeat attempt is needed, consider an alternative site 2
• Document the interruption and any complications 3

Alternative Approaches When ABG Cannot Be Completed

For Initial Assessment

• Consider capillary blood gases (CBGs) as an alternative when arterial sampling is not feasible 1
• Note that PO₂ is less accurate in earlobe blood gas samples (underestimates by 0.5-1 kPa) 1
• Monitor oximetry carefully if earlobe blood gas specimens are used 1

For Oxygen Titration

• CBGs can be used in place of ABG sampling for re-measuring PaCO₂ and pH at different oxygen flow rates 1
• Cutaneous capnography can be used for re-measuring PaCO₂ alone (but not pH) 1
• A combination of CBGs and oximetry (not capnography) could be used as an alternative tool for assessment 1

Special Considerations

For Patients on Anticoagulants

• For patients on antiplatelet therapy or anticoagulants, apply pressure for a longer period (at least 10 minutes) 2
• Consider checking clotting status before attempting ABG if on anticoagulation 1

For Critically Ill Patients

• In critically ill patients or those with shock/hypotension (systolic BP <90 mmHg), arterial samples are preferred over capillary samples 1
• Consider arterial line placement if frequent ABG measurements are anticipated 3, 4

For Patients with Respiratory Failure

• Patients with baseline hypercapnia should be monitored for the development of respiratory acidosis and worsening hypercapnia 1
• If a patient develops respiratory acidosis and/or a rise in PaCO₂ of >1 kPa (7.5 mm Hg) during assessment, they may have clinically unstable disease 1

Common Pitfalls and How to Avoid Them

• Air bubbles in sample: Expel all air bubbles immediately as they can affect PO₂ measurements 3, 5
• Delayed analysis: Process samples within 10-15 minutes or place on ice if delay is unavoidable 3
• Inadequate heparinization: Ensure proper heparinization of syringe to prevent clotting 2
• Venous blood contamination: Confirm bright red blood and pulsatile flow to ensure arterial sample 5, 6
• Incorrect patient positioning: Position the wrist in slight hyperextension for optimal radial artery access 2