A 4-year-old boy in respiratory distress is sitting upright in bed and drooling. His mother states that he complained of a sore throat throughout the day, and tonight became severely short of breath and started drooling. He is alert with adequate breathing. His skin is very warm to the touch. Vital signs are pulse, 132; respirations, 28 breaths/min; and SpO2, 90% on room air. Which is your first action in caring for this child?
A. Insert an oral airway and start ventilationsB. Suction the airway of secretionsC. Apply supplemental oxygenD. Use a tongue depressor to inspect for a foreign body obstruction

Supplemental oxygen is the use of oxygen as a medical treatment. This can include for low blood oxygen, carbon monoxide toxicity, cluster headaches,and to maintain enough oxygen while inhaled anesthetics are given. Long-term oxygen is often useful in people with chronically low oxygen, such as from severe COPD or cystic fibrosis. Oxygen can be given in a number of ways including nasal cannula, face mask, and inside a hyperbaric chamber.

Oxygen is widely used in emergency medicine, both in hospital and by emergency medical services or those giving advanced first aid, which is the case here. In the pre-hospital environment, high-flow oxygen is indicated for use in resuscitation, major trauma, anaphylaxis, major bleeding, shock, hypothermia, and active convulsions.