What is the goal oxygen saturation range for pulse oximetry (SpO2) in inpatient medicine?

Goal Pulse Oximetry Targets in Inpatient Medicine

For most hospitalized patients, the target oxygen saturation (SpO₂) range should be 94-98%, while patients at risk of hypercapnic respiratory failure should be maintained at 88-92%. 1

Target SpO₂ Ranges Based on Patient Risk Factors

Standard Target (Most Patients):

• Target SpO₂: 94-98% 1
• Applies to most acutely ill patients without risk factors for hypercapnic respiratory failure
• Initial oxygen therapy: nasal cannulae at 2-6 L/min or simple face mask at 5-10 L/min 1
• For severe hypoxemia (SpO₂ <85%): start with reservoir mask at 15 L/min 1

Reduced Target (Patients at Risk of Hypercapnia):

• Target SpO₂: 88-92% 1
• Applies to patients with:
  • Moderate to severe COPD (especially with previous respiratory failure)
  • Severe chest wall or spinal disease (e.g., kyphoscoliosis)
  • Neuromuscular disorders
  • Severe obesity
  • Cystic fibrosis
  • Bronchiectasis
  • Previously unrecognized COPD 1, 2
• Initial oxygen therapy: 24% or 28% Venturi mask or nasal cannulae at 1-2 L/min 1

Implementation and Monitoring

1. Prescription Requirements:

   • Oxygen should be prescribed with a target saturation range 1
   • Record both oxygen saturation and delivery system (including flow rate) on monitoring charts 1

2. Monitoring Protocol:

   • Check arterial blood gases within 30-60 minutes after starting oxygen in patients at risk of hypercapnia 1
   • If PCO₂ is normal in at-risk patients, consider adjusting target to 94-98% (unless history of previous respiratory failure requiring NIV or IMV) 1
   • Any increase in FiO₂ must be followed by repeat blood gases within 1 hour 1

3. Titration Guidelines:

   • Allow at least 5 minutes at each oxygen dose before further adjustment 2
   • Investigate sudden reduction of ≥3% in oxygen saturation even within target range 1
   • Adjust oxygen delivery devices and flow rates to maintain saturation within target range 1

Important Clinical Considerations

• Critical Illness: For critically ill patients, initially use reservoir mask at 15 L/min pending reliable oximetry readings, then titrate to maintain 94-98% 1

• Mortality Risk: Research shows that even modest elevations in oxygen saturations above the recommended range for COPD patients (93-96%) were associated with increased mortality risk compared to the 88-92% range 3

• Practical Challenges: Studies show that patients often spend significant time outside their prescribed target range (average of only 55.6% of time within range), with those having reduced hypercapnic targets spending even less time in range 4

• Racial Considerations: In Black patients, a higher SpO₂ target (95%) may be needed to ensure adequate oxygenation compared to White patients (92%) due to potential oximetry reading discrepancies 5

Common Pitfalls to Avoid

1. Avoid Hyperoxia: Excessive oxygen can be harmful, particularly in COPD, paraquat poisoning, or acid aspiration 1, 2

2. Don't Discontinue Oxygen for Measurement: Never discontinue oxygen therapy just to obtain an oximetry measurement on room air in patients who clearly require oxygen 1

3. Don't Rely on Cyanosis: Tachypnea and tachycardia are more reliable indicators of hypoxemia than visible cyanosis 1

4. Don't Use Different Targets Based on CO₂ Levels: Evidence suggests that the practice of setting different target saturations based on carbon dioxide levels may not be justified; maintaining 88-92% for all COPD patients may be safer 3

5. Don't Forget to Wean: Reduce oxygen in stable patients with satisfactory oxygen saturation, but maintain the prescription for target range in case of deterioration 1