4 Oxygen Therapy and Delivery Devices

Oxygen as a medication

Oxygen is a medication, so use the prescribed device and flow or the applicable emergency protocol. Titrate oxygen to the patient's prescribed saturation target. Device choice depends on the patient's condition and oxygen needs, and the equipment should be set up and used according to its instructions and the clinical plan.

Choosing and using delivery devices

Several devices are used to deliver supplemental oxygen, including nasal cannulas, simple face masks, Venturi masks, reservoir masks, and high-flow nasal cannula systems. Each patient's condition and oxygen needs guide the choice.

For a stable patient who needs low-flow oxygen and can breathe comfortably through the nose, a nasal cannula is a common initial choice. Its oxygen concentration is variable: the concentration actually inspired depends on the patient's breathing pattern and other factors.

A simple face mask should be used at a flow of at least 5 L/min, following the prescription and local protocol. Adequate flow helps clear exhaled carbon dioxide from the mask. Do not cover its exhalation openings, and do not change the oxygen plan during meals without checking the plan.

Controlled and reservoir delivery

A Venturi mask is designed to provide a more controlled oxygen concentration than a standard nasal cannula or simple face mask. Its adapter entrains room air in a set ratio. This depends on correct assembly: use the correct adapter and the flow specified for that device.

For a patient with severe hypoxemia using a non-rebreather mask, check that the reservoir bag remains inflated during inspiration. An empty or collapsing bag can impair oxygen delivery. Set the flow according to device instructions and clinical protocol, and promptly reassess the patient.

Monitoring and responding to deterioration

Monitor oxygen saturation together with breathing effort, respiratory rate, mental status, and response to therapy. A normal pulse-oximeter reading does not rule out respiratory deterioration. Pulse oximetry estimates oxygen saturation; it does not measure carbon dioxide directly, and readings can be inaccurate in some circumstances. Further assessment, such as an arterial blood gas, may be indicated.

If saturation falls or the patient becomes increasingly drowsy or breathless despite oxygen, assess the patient and oxygen equipment promptly. Provide support within the applicable protocol and seek urgent clinical review. Do not delay reassessment, remove oxygen just to obtain a room-air reading, or increase flow without reassessing and seeking help.

Checking pulse-dose suitability

Pulse-dose systems deliver oxygen in response to a detected breath and may not trigger reliably for every user. If a patient is weak or may not reliably trigger the device, have a clinician assess the patient's oxygen needs and the device's suitability. Confirm that the specific device meets the patient's needs, including during activity or sleep when relevant; do not assume that a pulse-dose device delivers oxygen continuously or change its setting without guidance.

Home safety and ongoing reassessment

Oxygen-enriched environments make fires burn more readily. Keep oxygen away from smoking, open flames, and other ignition sources, and follow equipment-specific safety instructions. Removing oxygen tubing before smoking does not make smoking safe near oxygen.

For nasal dryness, use only products recommended by a clinician. Reassess both oxygen saturation and the patient's clinical condition after changes to oxygen therapy, and verify that the equipment is functioning.

• Pulse-dose oxygen device