Why was the patient not intubated with a SpO2 (oxygen saturation) of 67% indicating severe hypoxemia?

Critical Hypoxemia at SpO2 67% Demands Immediate Intubation

A patient with SpO2 of 67% represents life-threatening hypoxemia and should have been intubated immediately—this level of oxygen saturation is associated with severe risk of cardiac arrest, brain injury, and death. 1

Why This SpO2 Level is a Medical Emergency

SpO2 below 90% is universally recognized as severe hypoxemia requiring urgent intervention, and 67% represents catastrophic oxygen deprivation. 1, 2, 3

• SpO2 <90% is defined as a clinical emergency requiring immediate action 4
• SpO2 <80% represents severe hypoxemia that typically mandates endotracheal intubation and mechanical ventilation 2
• At 67%, the patient is experiencing profound tissue hypoxia with imminent risk of:
  • Cardiac arrest
  • Irreversible brain injury
  • Multi-organ failure
  • Death 1

Standard Thresholds for Intubation

Guidelines clearly establish that supplemental oxygen should be started when SpO2 falls below 92%, and intubation should be strongly considered when SpO2 remains below 90% despite maximal oxygen therapy. 1, 2

Oxygen Therapy Escalation Algorithm:

• SpO2 <92%: Start supplemental oxygen 1, 2
• SpO2 <90%: Clinical emergency—administer high-flow oxygen via reservoir mask at 15 L/min 2, 3
• SpO2 <85%: Severe hypoxemia—consider high-flow nasal cannula (HFNC) or non-invasive ventilation (NIV) 1, 2
• SpO2 remains <90% despite maximal oxygen/NIV: Proceed to intubation 1

At 67%, the patient has already failed all non-invasive measures and requires definitive airway management.

When Intubation Should Occur

The British Journal of Anaesthesia guidelines for critically ill adults recommend early intubation in a controlled setting when worsening respiratory failure occurs, particularly when SpO2 cannot be maintained above 90%. 1

Key indicators for intubation include:

• Persistent SpO2 <90% despite high-flow oxygen or NIV 1
• Severe respiratory distress with increased work of breathing 2, 3
• Altered mental status indicating hypoxemic encephalopathy 2
• Hemodynamic instability 2

All of these criteria are likely met or exceeded at SpO2 67%.

Critical Pitfalls in This Case

Possible Reasons for Non-Intubation (All Inappropriate):

1. Measurement artifact: If the reading was inaccurate due to poor perfusion, motion, or probe malfunction 4, 5

   • However, clinical assessment should confirm hypoxemia (cyanosis, altered mental status, respiratory distress) 2, 3
   • Arterial blood gas should be obtained immediately to verify, but treatment should not be delayed 2, 3

2. Misguided concern about intubation risks: While intubation carries risks in critically ill patients, the mortality risk of untreated severe hypoxemia far exceeds intubation risks 1

3. Delayed recognition: The anaesthesia guidelines emphasize that inability to adequately control airways is frequently associated with arterial oxygen desaturation and represents a major cause of anaesthetic mortality 1

4. Palliative care context: The only scenario where SpO2 67% might not trigger intubation is in comfort-focused end-of-life care where the patient has declined life-sustaining interventions 1

   • Even then, this should be an explicit documented decision 1

Immediate Management That Should Have Occurred

The correct approach at SpO2 67%:

1. Call for immediate airway assistance (anesthesia, critical care) 1
2. Administer 100% oxygen via reservoir mask at 15 L/min while preparing for intubation 2, 3
3. Position patient with head elevated 20-30° to optimize pre-oxygenation 1
4. Prepare for rapid sequence intubation with appropriate medications and equipment 1
5. Have rescue airway devices ready (second-generation supraglottic airway) in case of difficult intubation 1
6. Obtain arterial blood gas to assess pH and PaCO2, but do not delay intubation 2, 3

Pre-oxygenation before intubation is critical to prevent further desaturation during the procedure, as even healthy patients can desaturate to SpO2 <90% within 1-2 minutes of apnea without pre-oxygenation. 1

Bottom Line

There is no acceptable clinical scenario (outside of documented comfort care) where a patient with SpO2 67% should not be intubated. This represents a critical deviation from standard care that places the patient at immediate risk of death. 1, 2