Nasal Cannula Oxygen During Cardioversion: No Removal Required
You do not need to remove nasal cannula oxygen when performing cardioversion. Standard low-flow nasal cannula (≤5 L/min) can safely remain in place during the procedure, as it does not generate significant aerosols or create a fire hazard at typical flow rates used in clinical practice.
Rationale for Leaving Nasal Cannula in Place
Oxygen Delivery Characteristics
- Low-flow nasal cannula (1-6 L/min) does not create an occlusive seal and delivers oxygen concentrations of approximately 24-50% FiO2, which is well below the threshold for combustion risk during brief electrical procedures 1.
- The British Thoracic Society guidelines emphasize that nasal cannula is preferred for medium-concentration oxygen therapy due to patient comfort and the ability to maintain oxygenation during procedures without interference 1, 2.
Safety Considerations
- Cardioversion is a brief procedure (lasting seconds), and maintaining continuous oxygenation is more important than theoretical fire risk at low flow rates 3.
- Unlike high-flow nasal cannula (30-70 L/min), standard nasal cannula at ≤5 L/min does not generate significant aerosols and poses minimal infection control concerns 3.
- The guidelines for airway management recommend that low-flow nasal oxygen may provide oxygenation during apnea and can delay hypoxemia, with no evidence suggesting it generates problematic aerosols 3.
Clinical Algorithm for Oxygen Management During Cardioversion
Standard Approach (Most Patients)
- Keep nasal cannula in place at current flow rate (typically 2-6 L/min) throughout the cardioversion procedure 1.
- Ensure adequate preoxygenation before sedation if the patient will undergo procedural sedation 3.
- Monitor oxygen saturation continuously with pulse oximetry 2.
High-Flow Nasal Cannula Considerations
- If the patient is on high-flow nasal cannula (HFNC) at 30-60 L/min, consider temporarily reducing flow to standard rates (5-6 L/min) during the actual shock delivery, then immediately resume HFNC afterward 3, 4.
- This precaution is based on the higher oxygen concentrations and flow rates with HFNC, though evidence of fire risk remains theoretical 5.
Face Mask Oxygen
- If the patient is receiving oxygen via face mask (simple mask or reservoir mask), temporarily remove the mask just before shock delivery and replace immediately afterward 2.
- Face masks create higher local oxygen concentrations near the chest wall compared to nasal cannula 2.
Important Caveats and Pitfalls
Fire Safety
- The primary fire risk during cardioversion comes from high oxygen concentrations near ignition sources, but standard nasal cannula at typical flow rates does not create this risk 3.
- Ensure the nasal cannula tubing is not in direct contact with the defibrillator pads 3.
Oxygenation Priorities
- Maintaining adequate oxygenation is more critical than removing oxygen delivery devices for brief procedures like cardioversion 3, 1.
- Patients requiring supplemental oxygen are already at risk for hypoxemia, and interrupting oxygen delivery—even briefly—can lead to rapid desaturation 6.