What therapy should be started when the child's SpO2 falls to 81%?

When a child's SpO2 (oxygen saturation) falls to 81%, this indicates a critical level of oxygenation that requires immediate intervention to ensure the child receives adequate oxygen. Administering oxygen through a non-rebreather mask is the appropriate choice in this scenario because it allows for the delivery of high concentrations of oxygen directly to the child, which is essential for rapidly improving oxygen saturation levels.

A non-rebreather mask is designed to deliver 10-15 liters of oxygen per minute, providing a reservoir of oxygen that can help restore adequate oxygen levels in emergency situations. This is particularly important in children, as they can decompensate quickly when faced with low oxygen levels.

In contrast, oral medications would not provide immediate relief or address the acute need for increased oxygenation. IV bronchodilator therapy is often used for conditions like asthma exacerbations but may not be the first line of treatment when a child is experiencing significant hypoxemia. Similarly, high-flow nasal cannula can be effective for oxygen support but may not deliver oxygen as quickly or efficiently as a non-rebreather mask in cases of severe hypoxia. Thus, starting oxygen therapy with a non-rebreather mask is the best and most effective immediate action for a child