Supplemental Oxygen Therapy

• Oxygen constitutes 21% of normal air and is tasteless, odorless, and colorless

Providing Supplemental Oxygen

• Oxygen therapy provides a higher concentration of oxygen than ambient air
• Oxygen therapy increases the diffusion of gas across the alveolar membrane and increases hemoglobin saturation
• Oxygen therapy is indicated with suspected hypoxemia; target saturation is usually 94-98%
• Patients with COPD or hypercapnia risk factors may have a target saturation of 88-92%
• Supplemental oxygen is supportive, requiring the cause of hypoxemia to be addressed
• Oxygen is a medication, requiring a prescription, except in emergencies
• Provide clear explanations to patients about oxygen therapy to reduce anxiety
• Oxygen supports combustion, so precautions are necessary
• Check the electrical equipment in the room to ensure it is in good working order
• Avoid synthetic fabrics and oils to prevent static electricity and spontaneous ignition
• Avoid contamination of medical devices and gas cylinders
• Ensure hands are clean, and hand gel has dried completely before handling oxygen equipment

Sources of Oxygen

• Therapeutic oxygen is supplied from a wall outlet or a portable tank
• A flow meter attached to the wall outlet regulates oxygen flow
• A regulator is used to release oxygen safely and at the desired rate from a cylinder or tank
• Oxygen concentrators concentrate room air for oxygen delivery and are often used at home
• Oxygen-conserving devices reduce oxygen consumption

Oxygen Flow Rate

• The flow rate, measured in liters per minute, determines the amount of oxygen delivered
• The rate varies based on the patient's condition and route of administration
• The flow rate does not necessarily reflect the inspired oxygen concentration, as there may be leaking and mixing with atmospheric air
• If precise doses are needed, they are prescribed in terms of percentage of inspired oxygen
• The inspired air mixture may be analyzed every 4 hours to regulate the oxygen percentage accurately

Humidification

• Use is unnecessary with low-flow oxygen (4 L/min or less) via nasal cannula in adults, or for less than 24 hours
• Recommended for patients experiencing discomfort from dry mucosa, those receiving oxygen at higher flow rates (greater than 35%), patients with a tracheostomy or artificial airway, and those having difficulty expectorating sputum
• Use distilled or sterile water and ensure that water does not enter the tubing

Transporting a Patient with a Portable Oxygen Cylinder

• Check for an oxygen source at the destination
• Check the oxygen amount in the cylinder (use if more than 500 psi)
• Connect oxygen tubing to the flow meter and adjust it to the prescribed setting
• Ensure the cylinder is secured in a holder
• After transfer, attach the patient's oxygen cannula to wall oxygen and turn off the cylinder
• Remove excess oxygen in the pressure gauge and turn the flow-control dial off

Supplemental Oxygen Delivery Systems

• Oxygen can be administered by many different delivery systems
• Low-flow systems are based on the patient's inspiratory flow, reducing the concentration accuracy
• Examples of low-flow devices include nasal cannulas, simple masks, partial rebreather masks, nonrebreather masks, and transtracheal oxygen catheters
• High-flow devices produce constant oxygen/air mixes, unaffected by the patient's breathing
• Examples of high-flow devices: Venturi masks and high-flow nasal cannulas
• Oxygen enclosures (tents and incubators) are primarily for infant and pediatric applications

Nasal Cannula

• A low-flow device commonly used for adults and children in hospitals and the community
• Can deliver 1-6 L/min and an increased flow of 10 to 15 Lpm for short-term
• Does not impede eating or speaking
• Can be dislodged easily, and low-flow rates can cause dryness
• Mouth breathing does not reduce the efficiency of oxygen delivery
• High-flow nasal cannula (HFNC) delivers oxygen flow greater than 30Lpm and up to 100% humidified oxygen
• It maintains continuous positive pressure, improving oxygenation, reducing dyspnea, and re-expanding alveoli
• High-flow nasal cannula oxygen therapy reduces patient discomfort and upper airway dryness, improves extubation outcomes and weaning, reduces the risk of intubation, and improves the management of respiratory secretions

Face Masks

• Fit the mask carefully to the patient's face to avoid leakage of oxygen
• The mask includes the simple face mask, the partial rebreather, the nonrebreather mask, and the Venturi mask
• Silicone borders or hydrocolloid dressings prevent injuries to the cheeks, chin, or bridge of the nose
• Simple face mask is a low-flow device used when higher oxygen levels are needed than nasal cannulas can provide
• This mask has vents on the sides to allow room air to leak in, diluting the source oxygen, and exhaled carbon dioxide to escape
• The simple face mask is used when an increased delivery of oxygen is needed for short periods, like 12 hours or less
• Can be difficult because that mask should fit closely to the face, and can make skin breakdown a possiblity
• The partial rebreather mask is a low-flow device with a reservoir bag to mix exhaled air with 100% oxygen
• This mask delivers relatively high oxygen concentrations when set at 10-15 L/min
• The oxygen flow rate must be set high to prevent reservoir bag deflation
• The nonrebreather mask is similar to the partial rebreather mask, delivering the highest concentration of oxygen using valves to prevent re-inhalation of exhaled air
• A malfunction of the bag or oxygen flow could cause carbon dioxide buildup and suffocation

Venturi Mask

• The Venturi mask is a high-flow device
• This mask delivers the most precise concentrations of oxygen by using a Venturi barrel to control the oxygen concentration
• The barrel is changed based on the prescription for oxygen concentration
• The ports on the barrel must be open, or the oxygen delivered might be unsafe

Monitoring Patients Receiving Supplemental Oxygen Therapy

• The health history and prescribed intervention with method and rate should be considered
• Monitor flow rate, patient color, respiratory rate and depth, work of breathing, pulse oximetry, and ABG results closely
• Titrate the oxygen flow and change the delivery system as prescribed or indicated
• Assess comfort with the device as well as moisture-related injuries

Oxygen Therapy in the Home

• Liquid oxygen and oxygen concentrators are used more commonly in the home setting
• An oxygen concentrator removes nitrogen from the room air and concentrates the oxygen
• Patients with chronic hypoxemia may be treated with transtracheal oxygen delivery

Teaching points for using oxygen at home

• No smoking, secure oxygen, and notify the fire department
• 30m tubing lengths do not show important changes in flow, and too much and too little can be detrimental
• Know reasons and contacts for vendors, physicians, and emergencies
• It is essential to educate patients and families about the precautions/equipment required for long-term oxygen use.
• Reservoir cannulas store O2 during exhalation and deliver a bolus with inhalation so that a lower continuous flow is needed
• Intermittent flow conserves oxygen by delivering only the needed portion and turning off when not needed