What is the recommended oxygen therapy for a patient with desaturating pneumonia?

Oxygen Therapy for Desaturating Pneumonia

For patients with desaturating pneumonia who are not at risk of hypercapnic respiratory failure, initial oxygen therapy should target a saturation of 94-98% using nasal cannulae at 2-6 L/min or simple face mask at 5-10 L/min, with a reservoir mask at 15 L/min for those with initial SpO2 below 85%. 1

Initial Assessment and Oxygen Delivery Method Selection

• For patients with pneumonia presenting with SpO2 below 85%, start treatment with a reservoir mask at 15 L/min to rapidly correct hypoxemia 1
• For patients with pneumonia with SpO2 ≥85%, begin with nasal cannulae at 2-6 L/min (preferred) or simple face mask at 5-10 L/min 1
• Carefully monitor respiratory rate and heart rate, as tachypnea and tachycardia are more common indicators of hypoxemia than visible cyanosis 1

Target Saturation Ranges

• For patients without risk factors for hypercapnic respiratory failure: target SpO2 94-98% 1
• For patients with COPD or other risk factors for hypercapnic respiratory failure: target SpO2 88-92% pending blood gas results 1, 2
• If blood gas results show normal PCO2 in patients with risk factors for hypercapnic failure, target can be adjusted to 94-98% (unless there is a history of previous respiratory failure requiring NIV or IMV) 1

Monitoring and Titration

• After initiating oxygen therapy, monitor oxygen saturation, respiratory rate, heart rate, blood pressure, and mental status at least twice daily 1
• More frequent monitoring is required for patients with severe illness or those requiring regular oxygen therapy 1
• Use an Early Warning Score system for convenient monitoring 1
• Obtain arterial blood gases in critically ill patients, those with unexpected falls in SpO2 below 94%, or those requiring increased FiO2 to maintain constant saturation 1

Titration Algorithm

1. Start with appropriate initial oxygen delivery method based on severity
2. Allow at least 5 minutes at each dose before adjusting further 1
3. If target saturation not maintained with nasal cannulae or simple face mask, change to reservoir mask and seek senior medical advice 1
4. If patient requires reservoir mask, ensure they are assessed by senior medical staff 1
5. Recheck blood gases 30-60 minutes after any significant change in oxygen therapy 1

Special Considerations

• Evidence suggests that oxygen saturations <90% in outpatients with pneumonia are associated with increased morbidity and mortality, supporting hospitalization for patients with saturations <92% 3
• For patients with pneumonia who do not respond to standard oxygen therapy, consider non-invasive ventilation (NIV) which can reduce ICU mortality, need for endotracheal intubation, and complications 4
• Some research suggests a target range of 92-96% may be preferable to 94-98%, though current BTS guidelines still recommend 94-98% 5, 1

Weaning and Discontinuation

• Lower oxygen concentration if the patient is clinically stable and oxygen saturation is above the target range or has been in the upper zone of the target range for 4-8 hours 1
• Most stable convalescent patients will eventually be stepped down to 2 L/min via nasal cannulae prior to cessation of oxygen therapy 1
• Discontinue oxygen therapy once a patient is clinically stable on low-concentration oxygen with saturation within the desired range on two consecutive observations 1
• Monitor oxygen saturation on air for 5 minutes after discontinuation to ensure stability 1

Discharge Considerations

• Patients should be reviewed 24 hours prior to discharge 1
• Consider continued hospitalization if patients have two or more unstable clinical factors: temperature >37.8°C, heart rate >100/min, respiratory rate >24/min, systolic BP <90 mmHg, oxygen saturation <90%, inability to maintain oral intake, or abnormal mental status 1