Every year, over 5.9 million children die, mostly from preventable or easily treatable diseases, and more than 95% of those deaths occur in developing countries. Pneumonia is the leading cause of death in children under 5 years of age, being responsible for at least 18% of all deaths in this age category (1). In 2010, there were an estimated 120 million episodes of pneumonia in children under 5 years, of which 14 million progressed to severe disease and 1.3 million led to death (2). Hypoxaemia (insufficient oxygen in the blood) is the major fatal complication of pneumonia, increasing the risk for death many times. It is estimated that at least 13.3% of children with pneumonia have hypoxaemia (3), corresponding to 1.86 million cases of hypoxaemic pneumonia each year. A further 23% of the 5.9 million annual child deaths result from neonatal conditions such as birth asphyxia, sepsis and low birth weight, all of which can lead to hypoxaemia. These add to the substantial burden of hypoxaemia, especially in developing countries.