Chart Talk: Anesthesia Coding Conversations

Hypothermic circulatory arrest (HCA) is one of the most complex and high-risk techniques used in cardiac and major vascular surgery. Because of its complexity—and its frequent confusion with hypothermia alone—it is also an area where anesthesia coding errors commonly occur.
This post breaks down what HCA is, how it differs from hypothermia without arrest, and when ASA code 00563 is appropriate.

What Is Hypothermic Circulatory Arrest?

Hypothermic circulatory arrest is a planned, intentional cessation of systemic blood circulation, achieved after cooling the patient to a deep hypothermic state (typically ≤20°C / 68°F).

Key elements of HCA:

• Complete stoppage of circulation
• Deep hypothermia induced via cardiopulmonary bypass
• Neuroprotection achieved by reducing cerebral metabolic demand
• Time-limited arrest period, followed by controlled reperfusion and rewarming

This technique is most often used when bloodless surgical fields are required—such as in complex aortic arch repairs—where clamping alone is not sufficient.

Hypothermia vs. Hypothermic Circulatory Arrest

(Why this distinction matters for coding)

Important: Hypothermia alone—even deep hypothermia—does not qualify for ASA 00563 unless circulatory arrest is clearly documented.

What Is ASA 00563?

ASA 00563 represents anesthesia services involving hypothermic circulatory arrest.
It is not an add-on for hypothermia, and it should not be reported unless the case meets strict clinical and documentation criteria.

Typical procedures where HCA may apply:

• Aortic arch reconstruction or replacement
• Complex thoracic aortic aneurysm repair
• Certain congenital cardiac surgeries requiring bloodless fields

Documentation Requirements to Support ASA 00563

Clear, explicit documentation is critical. The anesthesia record should support all of the following:

1. Intentional Circulatory Arrest

• Explicit wording such as:
  • “Circulatory arrest initiated”
  • “Systemic circulation stopped”
• Vague statements like “deep hypothermia achieved” are not sufficient

2. Arrest Start and Stop Times

• Precise start and end times of circulatory arrest
• Duration documented in minutes

3. Core Temperature

• Documentation of deep hypothermia (often ≤20°C)
• Recorded via reliable monitoring (e.g., nasopharyngeal, bladder, or esophageal probe)

4. Reperfusion and Rewarming

• Documentation that circulation was restarted
• Controlled rewarming process noted

Common Coding Pitfalls

🚫 Do not report ASA 00563 when:

• Hypothermia is used without stopping circulation
• Only cardiopulmonary bypass is documented
• Arrest time is implied but not clearly stated
• Surgeon documentation is vague and anesthesia record lacks confirmation

✅ Do report ASA 00563 when:

• Circulatory arrest is clearly intentional and documented
• Arrest duration is specified
• Deep hypothermia is confirmed
• The anesthesia record independently supports the service

Audit Tip: Defending ASA 00563

When preparing for an audit:

• Ensure anesthesia documentation stands alone
• Do not rely solely on operative reports
• Verify arrest times match perfusion and anesthesia records
• Use consistent terminology across the case record

A simple checklist approach can dramatically reduce denials and post-payment recoupments for this high-risk code.

Final Takeaway

ASA 00563 is reserved for true hypothermic circulatory arrest—not hypothermia alone.
The distinction hinges on complete cessation of circulation, supported by clear, time-based anesthesia documentation.

Accurate coding protects both compliance and reimbursement—and ensures that the complexity of these high-risk anesthesia services is properly recognized.

Educational use only. Always follow current ASA guidelines, CPT instructions, payer policies, and internal compliance standards.