Children’s Oxygen Administration Strategies Trial (COAST): a randomised controlled trial of high flow versus oxygen versus control in African children with severe pneumonia


Pneumonia is swelling, or inflammation, of the tissue in the lungs and is usually caused by a bacterial infection. It is a life-threatening condition and is one of the leading causes of childhood death in sub-Saharan Africa. Alongside antibiotics, the World Health Organization recommends delivering oxygen to children who have severe pneumonia or hypoxia – when there is a low level of oxygen in the tissues. Although giving oxygen is a basic element of hospital care, this treatment is costly and supplies are inadequate and inconsistent in African hospitals. The aim of this study is to identify what would be the best oxygen delivery method in children admitted to African hospitals with hypoxia and signs of severe pneumonia.


COAST was a randomised clinical trial and aimed to include 4200 African children, aged between 28 days and 12 years, with respiratory illness, hypoxia (lack of adequate oxygen identified by oxygen levels below 92%) and signs of severe pneumonia (lung inflammation). The COAST trial evaluated two related interventions looking at how much oxygen should be given and how it should be given. Treatment followed one of two routes based on the level of oxygen in the child’s blood (known as oxygen saturation), or how severe hypoxia they have:

  1. For children with less severe hypoxia (oxygen levels between 80% and 91%), they will be randomly allocated to either receive oxygen, either at a higher flow or lower flow (usual care), or not receive oxygen.
  2. For children with more severe hypoxia (oxygen levels less than 80%), they will be randomly allocated to receive oxygen either at a higher flow or lower flow (usual care).


The trial was stopped early after enrolling 1852 children. This included 388 children in the severe hypoxia group who randomised to receive oxygen at a higher flow (n = 194) or lower flow (n = 194) and 1454 children in the less severe hypoxia group who were randomised to higher flow oxygen (n = 363) vs lower flow oxygen (n = 364) vs not receiving oxygen (n = 727). In the less severe hypoxia group, 15% of patients in the permissive hypoxaemia group received oxygen (when SpO2 < 80%). In the severe hypoxaemia group, death at 48-hours was 9.3% for children receiving high flow oxygen vs. 13.4% for children receiving low flow oxygen. In the less sever hypoxia group, death at 48 hours was 1.1% for high flow oxygen vs. 2.5% for low flow oxygen and 1.4% for those not receiving oxygen.

Conclusion In Africa, in children hospitalised with severe pneumonia and less severe hypoxia (with oxygen saturations between 80 and 91%) who did not receive oxygen, mortality assessed at 48 hours was comparable to the usual method of oxygen delivery (low-flow oxygen) and in those receiving high-flow oxygen. The potential impact of high flow oxygen on patient-centred outcomes and on critical care resources, particularly oxygen supplies, should be investigate further, particularly in children with severe pneumonia managed in low resource settings.

Who funded the study?

Joint Global Health Trials scheme (UK Medical Research Council, UK Department for International Development and the Wellcome Trust)


Maitland K, Kiguli S, Olupot-Olupot P, Hamaluba M, Thomas K, Alaroker F, Opoka RO, Tagoola A, Bandika V, Mpoya A, Mnjella H, Nabawanuka E, Okiror W, Nakuya M, Aromut D, Engoru C, Oguda E, Williams TN, Fraser JF, Harrison DA, Rowan K. Randomised controlled trial of oxygen therapy and high-flow nasal therapy in African children with pneumonia. Intensive Care Med 2021; 47(5):566-76.

Kiguli S, Olopot-Olupot P, Alaroker F, Engoru C, Opoka RO, Tagoola A, Hamaluba M, Mnjalla H, Mpoya A, Mogaka C, Nalwanga D, Nabawanuka E, Nokes J, Nyaigoti C, Briend A, van Woensel JBM, Grieve R, Sadique Z, Williams TN, Thomas K, Harrison DA, Rowan K, Maitland K. Children's Oxygen Administration Strategies And Nutrition Trial (COAST-Nutrition): a protocol for a phase II randomised controlled trial. Wellcome Open Res 2021; 6:221.

Maitland K, Kiguli S, Opoka RO, Olupot-Olupot P, Engoru C, Njuguna P, Bandika V, Mpoya A, Bush A, Williams TN, Grieve R, Sadique Z, Harrison D, Rowan K. Children’s Oxygen Administration Strategies Trial (COAST): A randomised controlled trial of high flow versus oxygen versus control in African children with severe pneumonia. Wellcome Open Res 2017; 100(2).