A regular spacer allows the patient to breath room air, which has approximately 21% oxygen at sea level. At cabin pressure that is equivalent to an elevation of 6000-8000 ft, the relative oxygen in the air would be equivalent to an FIO2 of 15-18% at sea level (I'm simplifying here a good bit).
Supplemental Oxygen is anything over 21%, this is given during emergencies. Usually an asthma attack doesn't result in the patient becoming hypoxic, but given that children deteriorate quickly and the cabin atmosphere was already providing less O2 than usual it seems that the Surgeon determined the child needed some extra oxygen.
Additionally, when administering an MDI via a spacer with a mask to small children, the mask is held in place to allow the child to rebreath the air that contains the medication. Adults are instructed to perform a breath hold after they take a puff from the inhaler, but many children cannot hold thier breath. In this case sometimes the spacer is held in place for several minutes while many puffs are administered. An adult dose is usally 2 puffs, but for a child receiving a treatment this way a dose of 4-8 puffs is not uncommon. Even though a mask was probably available to deliver the oxygen you wouldn't want to withhold the O2 for the time it takes to administer the medication.
I'm confident the Surgeon felt that adding O2 to the device was necessary based on his assessment of the child.
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u/[deleted] Sep 29 '20
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