Oxygen Therapy Health Article

Definition

Oxygen may be classified as an element, a gas, and a drug. Oxygen therapy is the administration of oxygen at concentrations greater than that in room air to treat or prevent hypoxemia (not enough oxygen in the blood). Oxygen delivery systems are classified as stationary, portable, or ambulatory. Oxygen can be administered by nasal cannula, mask, and tent. Hyperbaric oxygen therapy involves placing the patient in an airtight chamber with oxygen under pressure.

Purpose

The body is constantly taking in oxygen and releasing carbon dioxide. If this process is inadequate, oxygen levels in the blood decrease, and the patient may need supplemental oxygen. Oxygen therapy is a key treatment in respiratory care. The purpose is to increase oxygen saturation in tissues where the saturation levels are too low due to illness or injury. Breathing prescribed oxygen increases the amount of oxygen in the blood, reduces the extra work of the heart, and decreases shortness of breath. Oxygen therapy is frequently ordered in the home care setting, as well as in acute (urgent) care facilities.

Some of the conditions oxygen therapy is used to treat include:

• documented hypoxemia
• severe respiratory distress (e.g., acute asthma or pneumonia)
• severe trauma
• chronic obstructive pulmonary disease (COPD, including chronic bronchitis, emphysema, and chronic asthma)
• pulmonary hypertension
• cor pulmonale
• acute myocardial infarction (heart attack)
• short-term therapy, such as post-anesthesia recovery

Oxygen may also be used to treat chronic lung disease patients during exercise.

Hyperbaric oxygen therapy is used to treat the following conditions:

• gas gangrene
• decompression sickness
• air embolism
• smoke inhalation
• carbon monoxide poisoning
• cerebral hypoxic event

Helium-oxygen therapy is a treatment that may be used for patients with severe airway obstruction. The combination of helium and oxygen, known as heliox, reduces the density of the delivered gas, and has been shown to reduce the effort of breathing and improve ventilation when an airway obstruction is present. This type of treatment may be used in an emergency room for patients with acute, severe asthma.

Oxygen delivery (other than mechanical ventilators and hyperbaric chambers)

In the hospital, oxygen is supplied to each patient room via an outlet in the wall. Oxygen is delivered from a central source through a pipeline in the facility. A flow meter attached to the wall outlet accesses the oxygen. A valve regulates the oxygen flow, and attachments may be connected to provide moisture. In the home, the oxygen source is usually a canister or air compressor. Whether in home or hospital, plastic tubing connects the oxygen source to the patient.

Oxygen is most commonly delivered to the patient via a nasal cannula or mask attached to the tubing. The nasal cannula is usually the delivery device of choice since it is well tolerated and doesn't interfere with the patient's ability to communicate, eat, or drink. The concentration of oxygen inhaled depends upon the prescribed flow rate and the ventilatory minute volume (MV).

Another delivery option is transtracheal oxygen therapy, which involves a small flexible catheter inserted in the trachea or windpipe through a tracheostomy tube. In this method, the oxygen bypasses the mouth, nose, and throat, and a humidifier is required at flow rates of 1 liter (2.1 pt) per minute and above. Other oxygen delivery methods include tents and specialized infant oxygen delivery systems.

TYPES OF OXYGEN DELIVERY SYSTEMS. The types of oxygen delivery systems include:

• Compressed oxygen—oxygen that is stored as a gas in a tank. A flow meter and regulator are attached to the oxygen tank to adjust oxygen flow. Tanks vary in size from very large to smaller, portable tanks. This system is generally prescribed when oxygen is not needed constantly (e.g., when it is only needed when performing physical activity).
• Liquid oxygen—oxygen that is stored in a large stationary tank that stays in the home. A portable tank is available that can be filled from the stationary tank for trips outside the home. Oxygen is liquid at very cold temperatures. When warmed, liquid oxygen changes to a gas for delivery to the patient.
• Oxygen concentrator—electric oxygen delivery system approximately the size of a large suitcase. The concentrator extracts some of the air from the room, separates the oxygen, and delivers it to the patient via a nasal cannula. A cylinder of oxygen is provided as a backup in the event of a power failure, and a portable tank is available for trips outside the home. This system is generally prescribed for patients who require constant supplemental oxygen or who must use it when sleeping.
• Oxygen conserving device, such as a demand inspiratory flow system or pulsed-dose oxygen delivery system—uses a sensor to detect when inspiration (inhalation) begins. Oxygen is delivered only upon inspiration, thereby conserving oxygen during exhalation. These systems can be used with either compressed or liquid oxygen systems, but are not appropriate for all patients.