Oxygen is considered a medication and requires a practitioner’s order; administer it cautiously and observe the patient closely for adverse reactions. Assess the patient’s need for oxygen and recognize the signs and symptoms of hypoxemia.
Use caution in the presence of oxygen. Oxygen is a fire hazard because it lowers the temperature at which materials catch fire in the presence of an ignition source, such as a spark or heat from a light source.
Respiratory depression can develop in a very small percentage of patients who are chronically hypercapnic when breathing moderate to high oxygen concentrations.undefined#ref1">1
The goal of oxygen therapy is to maintain adequate levels of oxygen to manage suspected or confirmed hypoxemia. Selection of the type of oxygen therapy is based on the patient’s need, the severity of hypoxemia, and the disease process. Signs and symptoms of mild hypoxemia include restlessness, anxiety, disorientation, confusion, listlessness, and headaches (Box 1).
The two types of oxygen delivery devices are high flow and low flow. High-flow devices discourage entraining of room air, which dilutes the fraction of inspired oxygen (FIO2).
The target peripheral oxygen saturation (SpO2) for most acutely ill patients is 94% to 98%.2 Patients with chronic obstructive pulmonary disease should have a target of 88% to 92%.2
Devices that deliver oxygen therapy include a nasal cannula, various types of face masks, and oxygen tents and hoods (Table 1).
A nasal cannula is a simple, effective, comfortable device for delivering low-flow oxygen (Figure 1).1 It consists of two prongs protruding from the center of a disposable tube and inserted into the nostrils. The nasal cannula allows breathing through the mouth or nose, is available for all age groups, and is adequate for short- or long-term use. Compared with other oxygen delivery systems, a nasal cannula decreases a patient’s feeling of claustrophobia, but it may not be suitable for mouth breathers. Cannulas are inexpensive, disposable, and easily accepted by most patients. When cannulas are used at higher flow rates, the airway mucosa may dry. A humidifier should be used to help prevent drying of the nasal and oral mucous membranes if the flow rate is greater than 4 L/min.1 Approximate FIO2 is estimated by the flow rate. The delivered oxygen percentage varies, depending on the rate and depth of the patient’s breathing.1
A simple face mask is for short-term, low-flow oxygen therapy (Figure 2).1 A clear plastic mask is placed on the patient’s face with an elastic strap to secure it. The body of the mask stores oxygen between the patient’s breaths. Side port openings located on either side of the mask allow room air to mix with delivered oxygen and allow exhaled air to escape. The percentage of delivered oxygen varies, depending on the rate and depth of the patient’s breathing.1 Some patients find the face mask uncomfortable, and it must be removed for eating.
A partial rebreathing mask is a face mask with a reservoir bag that delivers moderate to higher concentrations of oxygen (Figure 3A).1 Frequent inspection of the reservoir bag is required to ensure that it remains inflated; if it is deflated, exhaled air collects in it, which results in the patient rebreathing large amounts of exhaled carbon dioxide. Side port openings on either side of the mask vent exhaled air on expiration and allow room air to enter the mask on inspiration. The delivered oxygen percentage varies, depending on the rate and depth of the patient’s breathing.1
A nonrebreathing mask is a face mask with a reservoir bag that delivers high concentrations of oxygen (Figure 3B).1 A one-way inspiratory valve sits on top of the reservoir bag, and a one-way expiratory valve covers one of the side ports on the mask. During inhalation the expiratory valve over the side port closes, preventing air from entering the mask while the inspiratory valve on top of the reservoir bag opens, providing oxygen to the patient. During exhalation, the expiratory valve opens allowing exhaled air to vent out of the mask while the inspiratory valve closes preventing exhaled air from entering the reservoir bag. The open exhalation port is a safety feature designed to allow air to enter the mask if the oxygen source fails. However, this feature can result in dilution of the inspired oxygen. The delivered oxygen percentage varies, depending on the rate and depth of the patient’s breathing.1
A Venturi mask is a cone-shaped device with entrainment ports of various sizes at its base (Figure 4).1 The entrainment ports adjust to deliver various oxygen concentrations. This mask is useful because it delivers a more precise concentration of oxygen to the patient.
A face tent is a shield-like device that fits under the patient’s chin and encircles the face (Figure 5). It is used primarily for humidification and for oxygen only when the patient cannot or will not tolerate a tight-fitting mask. Because it is so close to the patient’s face, there is no way to estimate how much oxygen is delivered to the patient.
High-flow nasal oxygen therapy is a method of providing warmed, humidified oxygen at higher concentrations via specialized nasal cannula (Figure 6). Conventional nasal cannula devices can deliver flows of only 1 to 6 L/min, whereas high-flow nasal oxygen therapy delivers flows from 1 L/min to 60 L/min, depending on the device.1 High-flow oxygen therapy allows for more effective secretion clearance, decreases atelectasis, and prevents dehydration of the airway mucosa.
Verify that the tubing is connected to oxygen, not air or another gas. Connecting the tubing to a gas other than oxygen can have fatal consequences.
Rationale: Humidity prevents drying of nasal and oral mucous membranes and airway secretions. Humidification should be used if the liter flow rate is greater than 4 L/min.
Rationale: The patient is more likely to keep the device in place if it fits comfortably.
Rationale: Ensuring proper positioning of the cannula tips directs oxygen flow into patient’s upper respiratory tract. Looping the cannula around the patient’s ears reduces pressure on the nares.
Rationale: A tight seal reduces carbon dioxide retention.
Rationale: The tent fits loosely, and a mist is always present.
Rationale: Verification ensures patency of the delivery device and accuracy of prescribed oxygen flow rate.
Rationale: Verification ensures patency of the delivery device and accuracy of the prescribed oxygen flow rate. Clinical deterioration of a patient receiving high flow nasal oxygen is a medical emergency given the acuity of the patient and the potentially minimal respiratory reserve.
Rationale: Clinical deterioration of a patient receiving high flow nasal oxygen is a medical emergency given the acuity of the patient and the potentially minimal respiratory reserve.
Rationale: Oxygen therapy may cause drying of the nasal mucosa. The delivery device may cause pressure injuries where it comes in contact with the face, neck, head, and ears.
Ashraf-Kashani, N., Kumar, R. (2017). High-flow nasal oxygen therapy. BJA Education, 17(2), 63-67. doi:10.1093/bjaed/mkw041
Adapted from Perry, A.G., Potter, P.A., Ostendorf, W.R. (Eds.). (2018). Clinical nursing skills & techniques (9th ed.). St. Louis: Elsevier.
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