What is the treatment for a patient with severe hypoxemia (SpO2 less than 85) and breathlessness?

Treatment of Severe Hypoxemia (SpO2 <85%) with Breathlessness

For acutely breathless patients with SpO2 below 85%, treatment should be started with a reservoir mask at 15 L/min to rapidly correct hypoxemia, then adjusted downward once the patient stabilizes to maintain a target saturation of 94-98%. 1

Initial Assessment and Management

• All patients with severe hypoxemia (SpO2 <85%) require immediate oxygen therapy and urgent clinical assessment to identify and treat the underlying cause 1
• Check arterial blood gases (ABGs) within 1 hour of initiating oxygen therapy to assess for hypercapnia and guide further management 1
• For critically ill patients or those with shock/hypotension, obtain arterial blood samples rather than capillary samples 1

Oxygen Delivery Based on Patient Risk Profile

For patients WITHOUT risk of hypercapnic respiratory failure:

• Initial treatment: Reservoir mask at 15 L/min oxygen flow 1
• Once stabilized (SpO2 improving), titrate down to maintain target saturation of 94-98% using:
  • Nasal cannulae at 1-6 L/min, or
  • Simple face mask at 5-10 L/min 1
• If medium-concentration therapy fails to achieve target saturation, return to reservoir mask and seek senior or specialist advice 1

For patients WITH risk of hypercapnic respiratory failure:

• Initial treatment: 24% Venturi mask at 2-3 L/min or 28% Venturi mask at 4 L/min or nasal cannulae at 1-2 L/min 1
• Target saturation range: 88-92% 1, 2
• Check ABGs within 30-60 minutes of starting oxygen therapy 1
• If PCO2 is normal, adjust target range to 94-98% (unless previous history of NIV or IMV) 1
• Increase Venturi mask flow by up to 50% if respiratory rate exceeds 30 breaths/min 1

Risk Factors for Hypercapnic Respiratory Failure

• COPD and other conditions causing fixed airflow obstruction (e.g., bronchiectasis) 1
• Cystic fibrosis 1
• Neuromuscular disease or neurological conditions affecting respiratory muscles 1
• Chest wall deformities or morbid obesity 1

Special Considerations

• Patients with paraquat poisoning or bleomycin lung injury may be harmed by supplemental oxygen; target saturation should be 85-88% 1
• Patients with high respiratory rates (common in cystic fibrosis and interstitial lung disease) should receive oxygen via a Venturi mask at a flow rate exceeding their peak tidal and exertional inspiratory flow 1
• For patients with intractable breathlessness in palliative care settings who are not hypoxemic (SpO2 ≥92%), oxygen therapy is not recommended; consider opiates or non-pharmacological treatments instead 1

Monitoring and Follow-up

• Record oxygen saturation, delivery system, and flow rate on the patient's monitoring chart 1
• Adjust oxygen delivery device and flow rate to maintain target saturation range 1
• If oxygen requirements increase, this indicates need for urgent clinical reassessment 1
• Consider non-invasive ventilation for patients with persistent hypoxemia despite oxygen therapy, especially those with COPD exacerbations 2

Pitfalls to Avoid

• Do not rely solely on pulse oximetry in severely hypoxemic patients (SpO2 <80%) as accuracy decreases; confirm with ABGs 3
• Oxygen is a treatment for hypoxemia, not breathlessness alone; non-hypoxemic patients with breathlessness may not benefit from oxygen therapy 1, 4
• Do not delay obtaining ABGs in patients with severe hypoxemia, as this will guide appropriate management 1
• Remember that a normal SpO2 does not rule out abnormal blood pH or PCO2; blood gases are still required 1