What could be a sign of issues with oxygen therapy?

Cyanosis in extremities is indeed a sign that can indicate issues with oxygen therapy. Cyanosis refers to a bluish discoloration of the skin and mucous membranes, commonly appearing in areas like the lips, fingers, and toes. This condition typically arises when there is a lack of oxygen in the blood, suggesting that the oxygen therapy isn't effectively delivering the necessary oxygen to the body’s tissues.

When effective oxygen therapy is being administered, peripheral tissues should receive adequate oxygenation. The presence of cyanosis signals that this is not occurring, meaning the individual may still be suffering from low levels of oxygen despite receiving therapy. This condition should be evaluated promptly as it could indicate respiratory distress or other underlying medical complications requiring immediate attention.

The other options fall into categories that may not always suggest a direct failure or issue with oxygen therapy. For example, mild headaches or feelings of dizziness could be attributed to several factors unrelated to oxygen levels, such as dehydration, medication side effects, or fatigue. Shortness of breath at rest, while concerning, could also stem from various conditions that may or may not be under the control of oxygen therapy.