How can I tell if oxygen therapy is actually delivering oxygen?

Oxygen therapy is commonly used for patients with hypoxia. To determine whether oxygen is being effectively delivered during therapy, clinicians may assess the patient’s subjective sensation, changes in peripheral capillary oxygen saturation (SpO₂), and airflow at the delivery site. Specific assessment methods are as follows:

1. Patient’s subjective sensation: The patient perceives airflow passing through the nasal cavity and entering the posterior nasal aperture.

2. Change in oxygen saturation: A pulse oximeter probe is placed on the patient’s finger to measure SpO₂ via pulsatile blood flow. An increase in SpO₂ following oxygen administration indicates successful oxygen delivery.

3. Airflow inspection: Remove the nasal cannula or nasal prongs and place your hand near the open end of the tubing to feel for airflow. The presence of airflow confirms that the tubing is patent and functioning properly.

If tubing obstruction occurs—particularly with nasal prongs—nasal secretions may block the nasal cannula, leading the patient to perceive no oxygen flow and resulting in no significant rise in SpO₂. In such cases, it is essential to rule out nasal prong occlusion or nasal cannula blockage by nasal secretions.