What are the indications for supplemental oxygen therapy?

• Hypoxemia is frequently defined as an arterial partial pressure of oxygen (PaO2) < 60 mmHg. 
• Clinicians frequently use pulse oximeter oxygen saturation measurements (SpO2) of <90-94% to diagnose and initiate therapy for hypoxemia
• There is variability in recommendations for SpO2 goals (ranging from >88 to >94%) in the management of respiratory failure patients. There are multiple trials ongoing to elucidate the optimal strategy. SpO2 goals may have significant implications on oxygen consumption. 

See chapter 6 of the WHO Severe Acute Respiratory Infection Toolkit for oxygen therapy initiation algorithms; see WFSA ANZCA Wall Chart