Oxygen Titration Orders
Oxygen should be prescribed with a specific target saturation range (not a fixed FiO2) and titrated systematically based on patient risk factors for hypercapnic respiratory failure. 1
Initial Risk Stratification
The first critical decision is determining whether the patient is at risk for hypercapnic respiratory failure (Type 2 respiratory failure): 1
High-risk patients include those with:
- Severe or moderate COPD (especially with previous respiratory failure or on long-term oxygen) 1
- Severe chest wall or spinal disease (e.g., kyphoscoliosis) 1
- Neuromuscular disease 1
- Severe obesity 1
- Cystic fibrosis 1
- Bronchiectasis 1
Target Saturation Ranges
For patients WITHOUT hypercapnic risk: Target SpO2 94-98% 1
For patients WITH hypercapnic risk: Target SpO2 88-92% 1
Initial Oxygen Delivery Device Selection
Critically Ill Patients
- Start with reservoir mask at 15 L/min regardless of hypercapnic risk 1
- This applies to patients with sepsis, trauma, shock, or SpO2 <85% 2, 3
Non-Critical Patients Without Hypercapnic Risk
- Start with nasal cannulae at 2-6 L/min (preferred) 1, 3
- Alternative: Simple face mask at 5-10 L/min 1
Patients With Hypercapnic Risk
- Start with 24% Venturi mask at 2-3 L/min 3
- Alternative: 28% Venturi mask at 4 L/min or nasal cannulae at 1-2 L/min 1, 3
- Obtain arterial blood gases immediately 1
Titration Algorithm
Allow at least 5 minutes between adjustments before escalating therapy 2, 3
Upward Titration for Standard Patients (Target 94-98%)
- Nasal cannulae: 1 → 2 → 4 L/min 3
- Simple face mask: 5-6 L/min 3
- Venturi mask: 35-60% at 8-15 L/min 3
- Reservoir mask: 15 L/min 3
Upward Titration for Hypercapnic Risk Patients (Target 88-92%)
- 24% Venturi at 2-3 L/min 3
- 28% Venturi at 4 L/min 3
- Higher Venturi concentrations only if blood gases show no CO2 retention 1
Monitoring Requirements
Pulse oximetry must be available wherever emergency oxygen is used 1
Monitor the following parameters at least twice daily: 2
- Oxygen saturation (SpO2)
- Respiratory rate
- Heart rate
- Blood pressure
- Mental status
Obtain arterial blood gases when: 2
- Patient is critically ill 2
- Unexpected fall in SpO2 below 94% 2
- Increased FiO2 required to maintain constant saturation 2
- Any increase in FiO2 must be followed by repeat blood gases within 1 hour (or sooner if conscious level deteriorates) 1
Critical Warning Signs
Respiratory rate >30 breaths/min requires immediate intervention even if SpO2 appears adequate, as this indicates respiratory distress 2
If respiratory acidosis develops (pH <7.35 and PaCO2 >6.0 kPa), seek immediate senior review and consider non-invasive ventilation 1
Prescription Documentation
Every oxygen order must specify: 1
- Target saturation range (not fixed FiO2) 1
- Initial delivery device and flow rate 1
- Signed prescription on drug chart or electronic system 1
An oxygen target saturation range should be prescribed for all patients admitted to hospital, even if not currently requiring oxygen, to ensure appropriate therapy if needed 1
Weaning Criteria
Reduce oxygen concentration when: 2, 3
- Patient is clinically stable 2, 3
- Saturation has been in the upper zone of target range for 4-8 hours 2, 3
- Patient is stable on low-concentration oxygen 2, 3
- Saturation remains within target range on two consecutive observations 2, 3
Common Pitfalls to Avoid
Never prescribe a fixed FiO2 without a target saturation range - this prevents appropriate titration by nursing staff 1
Do not assume adequate SpO2 means adequate ventilation - patients with hypercapnic respiratory failure can maintain normal oxygen saturations while accumulating CO2 2
Tachypnea and tachycardia are more reliable indicators of hypoxemia than visible cyanosis, which is difficult to detect clinically 1
For patients with COPD, limiting oxygen to 6 minutes when using oxygen-driven nebulizers helps prevent hypercapnic respiratory failure 1
If target saturation cannot be maintained with nasal cannulae or simple face mask, escalate to reservoir mask and ensure senior medical assessment 1