What is the best course of action for a patient with a history of lung cancer who experiences hypoxemia after sneezing?

Immediate Management of Acute Hypoxemia in Lung Cancer Patient

Start a reservoir mask at 15 L/min immediately, as this patient's oxygen saturation of 83% is below 85% and requires high-flow oxygen therapy targeting a saturation of 94-98%. 1

Initial Oxygen Therapy

• Initiate reservoir mask at 15 L/min without delay for any patient with SpO₂ below 85%, regardless of the underlying cause. 1
• Target oxygen saturation of 94-98% for this patient, assuming no history of COPD or other risk factors for hypercapnic respiratory failure. 1, 2
• If the patient has coexisting COPD or risk factors for hypercapnia (severe kyphoscoliosis, neuromuscular disorders, morbid obesity), target 88-92% instead and obtain arterial blood gases urgently. 1

Critical Assessment Within First Hour

• Obtain arterial blood gases within 60 minutes to assess for hypercapnia and guide ongoing management. 2
• Measure respiratory rate and heart rate carefully, as tachypnea and tachycardia are more sensitive indicators of physiologic distress than cyanosis. 1
• Assess for the underlying cause of acute desaturation:
  • Pneumothorax (especially post-sneeze): This requires immediate aspiration or drainage if the patient is hypoxemic. 1
  • Pulmonary embolism: Consider this diagnosis even though most minor PEs do not cause hypoxemia. 1
  • Pleural effusion: If present and causing hypoxemia, drainage is required in addition to oxygen therapy. 1
  • Pneumonia or disease progression: Common in lung cancer patients. 1

Monitoring and Adjustment

• Once oxygen therapy is initiated, recheck blood gases after 30-60 minutes to ensure adequate oxygenation without hypercapnia. 1
• If the target saturation range cannot be maintained with the reservoir mask, ensure immediate assessment by senior medical staff. 1
• Record oxygen saturation, delivery system, and flow rate on monitoring charts. 2
• Once the patient stabilizes and SpO₂ improves above 85%, you may transition to nasal cannulae at 2-6 L/min or simple face mask at 5-10 L/min while maintaining the target range. 1

Critical Pitfalls to Avoid

• Do not delay oxygen therapy to investigate the cause—start high-flow oxygen immediately for SpO₂ <85%. 1
• Do not assume the sneeze is incidental—it may have precipitated a pneumothorax, which is a medical emergency requiring drainage. 1
• Do not use lower flow oxygen initially when SpO₂ is below 85%, even if concerned about hypercapnia—correct the life-threatening hypoxemia first, then adjust based on blood gas results. 1, 2
• Avoid assuming this is simply disease progression without ruling out reversible causes like pneumothorax, PE, or pleural effusion. 1