Oxygen therapy

Definition: Oxygen therapy is the administration of oxygen at a concentration of pressure greater than that found in the environmental atmosphere. Purpose: -To overcome clinical signs of tissue hypoxemia. - To decrease the work of breathing. - To decrease the stress on myocardium.

Sources of oxygen: 1- Cylinder. 2- Wall outlets. Oxygen is moistened by passing it through a humidification system to prevent the mucous membranes of the respiratory tree from becoming dry.

1- Using oxygen cylinders: The oxygen cylinder is delivered with a protective cap to prevent accidental force against the cylinder outlet. To release oxygen safety and at a desirable rate, a regulator is used. It consists of two parts.

a- a reduction gauge that reduces the pressure to a working level and shows the amount of oxygen in the tank. b- a flow meter that regulates the control of oxygen in liters per minutes.

2- Wall – outlet oxygen: The oxygen is supplied from a central source through a pipeline. Only a flow meter and a humidifier are required.

Methods of oxygen administration: Oxygen may be administered by a variety of means: 1- Nasal cannula (prongs): It is a disposable, plastic devise with two protruding prongs for insertion into the nostrils, connected to an oxygen source. It is used when the patient requires a low- to – medium concentration of oxygen (24-44%).

*This method is relatively simple to use and allows the patient to move about in bed, cough and eat without interruption of oxygen flow. Disadvantage: may cause irritation to the nasal and pharyngeal mucosa if oxygen flow rates are above 6 liters/minute.

2- Face mask: Most masks are made of clear, flexible plastic or rubber that can be molded to fit the face. They are held to the head with elastic bands. Some have a metal clip that can be bent over the bridge of the nose for a comfortable fit.

*The most commonly used types of masks include: The simple Oxygen mask: The mask delivers 35% to 60% oxygen at a flow rate of 6 to 10 liters per minute. It has vents on its sides which allow room air to leak in at many places, thereby diluting the source oxygen. Often it is used when an increased delivery of oxygen is needed for short periods (i.e., less than 12 hours).

The partial rebreather mask: The mask is equipped with a reservoir bag for collection of the first parts of the patients' exhaled air. It is used to deliver oxygen concentrations up to 80%. The oxygen flow rate must be maintained at a minimum of 6 L/min to ensure that the patient does not rebreathe large amounts of exhaled air. The remaining exhaled air exits through vents.

The non rebreather mask: This mask provides the highest concentration of oxygen (95-100%) at a flow rate6-15 L/min. It is similar to the partial rebreather mask except two one-way valves prevent conservation of exhaled air. The bag is an oxygen reservoir. When the patient exhales air, the one-way valve closes and all of the expired air is deposited into the atmosphere, not the reservoir bag. In this way, the patient is not rebreathing any of the expired gas.

The venturi mask: It is high –flow system that delivers exact concentration of oxygen. Oxygen concentrations vary from 24-40% or 50% at liters flow of 4 to 15 L/min. -The mask is so constructed that there is a constant flow of room air blended with a fixed concentration of oxygen.

*The venturi mask is designed with wide- bore tubing and various color - coded jet adapters. Each color code corresponds to a precise oxygen concentration and a specific liter flow. *The venturi system, room air dilutes the oxygen entering the tubing to a certain concentration (the percentage specified for the particular jet adapter). The amount of air drawn in is determined by the size of the orifice (jet adapter).

*The narrower the jet adapter, the greater the air dilution, and the lower the concentration of oxygen. *It is used primarily for patients with chronic obstructive pulmonary disease.

The disadvantages of a face mask: are the mechanical restrictions it imposes on eating, drinking, and talking. There is also certain amount of discomfort associated with the use of a mask for any length of time.

Oxygen toxicity: *It is a condition in which ventilatory failure occurs due to inspiration of a high concentration of oxygen for a prolonged period of time. *Oxygen concentration greater than 60% over 24 to 48 hours can cause pathological changes in the lungs.

Signs and symptoms of oxygen toxicity: Non-productive cough. Nausea and vomiting. Substernal chest pain. Fatigue. Nasal stuffiness. Headache. Sore throat. Hypoventilation.. Nasal congestion.. Dyspnea.. Inspiration pain.

RationalSteps *It is your responsibility to ascertain the accuracy of the physician ’ s order prior to initiating O2 therapy. *Provides data with which to compare future respiratory results. * Assessment: 1. Check the physician order. 2. Assess the laboratory results, especially the ABG analyses. 3. Identify the type of oxygen equipment and oxygen source in your facility. Technique of oxygen administration A-Administering oxygen by nasal cannula:

RationalSteps To prevent infection. To ensure the patient safety. *Planning: 4. Wash hands. 5.Plan for any assistance needed. 6.Prepare equipment.

RationalSteps To be sure you are performing the procedure for the correct patient. To gain his cooperation. This position permits easier chest expansion and hence easier breathing. To prevent dehydration of mucous membrane. To facilitate oxygen administration and comfort the patient. To reduce irritation and pressure and protect the skin. To provide optimal delivery of oxygen to patient. Oxygen dries the mucous membrane and cause irritation. Lubricant counteracts the drying effect of oxygen. *Implementation: 7.Identify the patient. 8. Explain procedure to the patient. 9. Assist the patient to a semi-fowler's position if possible. 10. Attach the oxygen supply tube with humidification to the cannula. a- Allow 3-5 L oxygen to flow through the tubing. b- Place the prongs in the patient's nostrils and adjust it comfortably. c- Use gauze pads both behind the head or the ears and under the chin and tighten to comfort. d- Adjust the flow rate to the ordered level. e- Encourage patient to breath through his nose with his mouth closed. f- Assess the patient nose and mouth and provide oronasal care at least every 8 hours. g- Check nose for evidence of irritation or bleeding. 11. Wash your hands.

*Evaluation: 12- Evaluate using the following desired outcome criteria: a- breathing pattern regular and at normal rate. b- pink color in nail beds, lips, conjunctiva of eyes. c- no confusion, disorientation, difficulty with cognition. d- arterial oxygen concentration or hemoglobin oxygen saturation within normal limits.

*Documentation: 13- Document the following: a- date and time oxygen started. b- method of delivery. c- oxygen concentration and flow rate. d- patient observation. e- add oronasal care to the nursing care plan.

RationalSteps To prevent leakage. To ensure a tight fit. To reduce irritation and pressure and protect the skin. There is danger of inhaling powder if it is placed on the mask. To overcome dryness of mucous membrane produced by oxygen. For patient's comfort& safety against infection. *Implementation: 10. Attach the oxygen supply tube to the mask, proceed flow: a- Regulate the oxygen flow. b- Position the mask over the patient's nose and mouth. And fit it securely, shaping the metal band on the mask to the bridge of the nose. c- Adjust the elastic band around the patient's head and tighten. d- Use gauze pads both behind the head or the ears. e- Adjust the flow rate to the ordered level. f- Remove the mask and dry the skin every2-3 hours if the oxygen is running continuously. Don't powder around the mask. 11. Wash patient's mouth. 12. Wash patient's face. 13. Clean the equipment& keep oxygen device sterile. A-Administering oxygen by mask: