oxygen
(O) [ok´sĭ-jen] a chemical element, atomic number 8, atomic weight 15.999. (See Appendix 6.) It is a colorless and odorless gas that makes up about 20 per cent of the atmosphere. In combination with hydrogen, it forms water; by weight, 90 per cent of water is oxygen. It is the third most abundant of all the elements of nature. Large quantities of it are distributed throughout the solid matter of the earth because it combines readily with many other elements. With carbon and hydrogen, oxygen forms the chemical basis of much organic material. Oxygen is essential in sustaining all kinds of life. Among the land animals, it is obtained from the air and drawn into the lungs by the process of
respiration. See also
blood gas analysis.
Oxygen Balance and “
Oxygen Debt.‡‡‡‡‡‡‡‡‡‡‡” The need of every cell for oxygen requires a balance in supply and demand. But this balance need not be exact at all times. In fact, in strenuous exercise the oxygen needs of muscle cells are greater than the amount the body can absorb even by the most intense breathing. Thus, during athletic competition, the participants make use of the capacity of muscles to function even though their needs for oxygen are not fully met. When the competition is over, however, the athletes will continue to breathe heavily until the muscles have been supplied with sufficient oxygen. This temporary deficiency is called oxygen debt.
Severe curtailment of oxygen, as during ascent to high altitudes or in certain illnesses, may bring on a variety of symptoms of
hypoxia, or oxygen lack. A number of poisons, such as
cyanide and
carbon monoxide,, as well as large overdoses of
sedatives, disrupt the oxygen distribution system of the body. Such disruption occurs also in various illnesses, such as
anemia and diseases of lungs, heart, kidneys, and liver.
oxygen 15 an artificial radioactive isotope of oxygen having a half-life of 2.04 minutes and decaying by positron emission. It is used as a
tracer in the measurement of regional blood volume and flow and oxygen metabolism by
positron emission tomography.
oxygen analyzer an instrument that measures the concentration of oxygen in a gas mixture. There are three types of handheld analyzers: physical/paramagnetic, electric, and electrochemical analyzers.
oxygen blender a device used to mix oxygen with other gases to any concentration between 21 per cent and 100 per cent.
oxygen concentrator an electronic device that removes nitrogen from room air, thus increasing the oxygen concentration; commonly used by patients who require long-term oxygen administration at home.
oxygen consumption the amount of oxygen consumed by the tissues of the body, usually measured as the oxygen uptake in the lung. The normal value is 250 ml/min (or 3.5 to 4.0 ml/kg/min), and it increases with increased metabolic rate.
oxygen hood a device that fits over the head of an infant or small child for administration of oxygen or aerosolized medications.
hyperbaric oxygen oxygen under greater than atmospheric pressure.
liquid oxygen oxygen in liquid form, a common storage form of oxygen; one liter of liquid oxygen will produce 860 liters of gas.
oxygen therapy 1. in the
nursing interventions classification, a
nursing intervention defined as administration of oxygen and monitoring of its effectiveness.
2. a form of
respiratory care involving administration of supplemental oxygen for relief of hypoxemia and prevention of damage to the tissue cells as a result of oxygen lack (
hypoxia). Oxygen can be toxic and therefore, as with a drug, its dosage and mode of administration are based on an assessment of the needs of the individual patient. Although many types of hypoxia can be treated successfully by the administration of oxygen, not all cases respond to this therapy. There also is the possibility that the injudicious use of oxygen can produce serious and permanent damage to the body tissues. The administration of oxygen should never be considered a “routine” or harmless procedure.
Adverse Effects of Oxygen. Although it is true that all living organisms require oxygen to maintain life, an environment of 100 per cent oxygen inhibits growth of living tissue cultures, and laboratory experiments have shown that hyperoxygenation of body tissues can cause irreversible damage. It is known that high concentrations of inhaled oxygen can result in collapse of alveoli because of displacement of nitrogen by oxygen.
retinopathy of prematurity in premature infants was found to be caused in part by excessively high levels of oxygen in the blood.
Another serious complication of high-oxygen concentration therapy is the development of a
hyaline membrane because of a deficiency of pulmonary
surfactant; surfactant is vitally important to normal expansion and deflation of the alveoli. Prolonged exposure to inspired oxygen concentrations in excess of 50 per cent can impair the production of this surfactant in a patient of any age. The result is a loss of lung compliance and reduction of the transport of oxygen across the alveolar membrane.
The danger of oxygen toxicity can be minimized by careful assessment of each patient's need for oxygen therapy and systematic
blood gas analysis to determine patient response and effectiveness of treatment. Symptoms of oxygen toxicity are substernal distress, nausea and vomiting, malaise, fatigue, and numbness and tingling of the extremities.
Indications for Oxygen Therapy. In general, the clinical situations in which the administration of supplemental oxygen is indicated are: (1) Profound but potentially reversible hypoxia that appears amenable to the short-term administration of high concentrations of oxygen. Examples would include the patient who is apneic, is suffering from cardiovascular collapse, or is a victim of carbon monoxide poisoning. (2) Conditions in which there is a need to reduce the work load of the cardiovascular and pulmonary systems and at the same time assure an adequate supply of oxygen to the tissues. Congestive heart failure, myocardial infarction, and such acute pulmonary diseases as pulmonary embolism and pneumonia are examples of the types of clinical situations that are best treated by the administration of moderate levels of oxygen concentration. (3) Evidence of hypoventilation, whether from anesthesia and sedation,
chronic obstructive pulmonary disease, or other conditions. The patient who is hypoventilating is in danger of suffering from an adverse effect of oxygen therapy because increased oxygenation can lead to decreased respiratory effort. In other words, the oxygen acts as a respiratory depressant and may produce an increase in partial pressure of carbon dioxide in the arterial blood, thus contributing to rather than overcoming the problem of hypoxia. If there is evidence that the patient is hypoventilating, it may be necessary to administer the oxygen by assisted or controlled ventilation.
The delivery of appropriate and effective oxygen therapy requires frequent monitoring of arterial blood gases. An initial blood gas analysis at the time the therapy is started provides baseline data with which to evaluate changes in the patient's status.
In addition to monitoring blood gases to assess the patient's need for and response to supplemental oxygen, it is helpful to observe the patient closely for signs of hypoxemia. However, these signs are not as reliable as blood gas analysis because the clinical manifestations of hypoxemia vary widely in individual patients. The typical clinical manifestations of hypoxemia are confusion, impaired judgment, restlessness, tachycardia, central cyanosis, and loss of consciousness.
Dosage and Method of Administration. It must be kept in mind that oxygen is considered a drug and should be prescribed and administered as such; thus it is apparent that vague orders about its administration are never acceptable. There must be specific written orders for flow rate and mode of administration. Decisions about the initial dosage, as well as any changes in mode of administration and dosage, including the discontinuance of oxygen therapy, should be based on evaluation of the P
O2, the P
CO2, and the blood pH. (See also
transcutaneous oxygen monitoring and
pulse oximeter.)
The clinical signs and symptoms of hypoxemia may vary from patient to patient, and they should not be depended upon as valid indications of oxygen insufficiency. This is especially true of cyanosis, a symptom that depends on local circulation to the area, the red cell count, and hemoglobin level. In addition to the data obtained from blood gas analyses, an oxygen analyzer should be used occasionally to check inspired oxygen concentration.
In general, the dosage and mode of administration fall into the following categories.
High concentrations above 50 per cent usually are prescribed when there is a need for the delivery of high levels of oxygen for a short period of time to overcome acute hypoxemia, as in cardiovascular failure and pulmonary edema. The flow rate may be as high as 12 liters per minute, administered through a close-fitting face mask with or without a rebreathing bag, or via an endotracheal tube.
Moderate concentrations of oxygen are indicated when the patient is suffering from impaired circulation of oxygen, as in congestive heart failure and pulmonary embolism, or from increased need for oxygen, as in thyrotoxicosis, in which the increased metabolic rate creates a need for more oxygen. The rate of flow should be 4 to 8 liters per minute, administered through an air entrainment mask that delivers concentrations above 23 per cent, or in a dosage of 3 to 5 liters per minute through a nasal cannula.
Low concentrations of oxygen are indicated when the patient is receiving oxygen therapy over an extended period of time, as in chronic obstructive pulmonary disease, and there is the possibility of hypoventilation and the danger of increased CO
2 retention. The rate of flow should be 1 to 2 liters per minute, administered through a nasal cannula, or via an air entrainment mask that delivers 24 to 35 per cent oxygen.
Other methods of oxygen administration include the nasal catheter and the oxygen tent. The nasal catheter can cause some discomfort to the patient, and since it is no more and no less effective than the cannula, most therapists and patients prefer not to use it. The oxygen tent is considered by many to be obsolete, its use being limited to the administration of oxygen to children who cannot or will not tolerate other modes of delivery, and to children in whom the objective is to provide oxygen and humidity or humidity alone.
Patient Care. No matter what mode of administration is used, it is essential that the inspired air be moisturized. This is necessary to prevent drying of the respiratory mucosa and thickening of secretions that can further inhibit the flow of air through the air passages. Humidity may be provided by humidifying the oxygen with water, or by aerosoling the water into fine particles and adding it to the oxygen. Most patients need 60 to 65 per cent relative humidity at room temperature. Patients with endotracheal tubes require as close to 100 per cent humidity as possible.
Oxygen is not an explosive gas, but it does support combustion and presents a serious fire hazard. All electrical equipment should be checked for defects that could produce sparks. All appliances that transmit house current must be kept outside an oxygen tent, and all equipment with exposed switches and meters must be considered potential sources of fire. Static electricity is a minimal risk which can be further reduced by maintaining a relatively high humidity in the oxygen tent. Smoking in the immediate area of oxygen administration is prohibited and there should be signs informing visitors and others of this restriction.
When the patient is wearing a mask for an extended period of time, discomfort can be minimized by removing the mask and washing and drying the face at least every eight hours. To be effective the mask must fit snugly and follow the contour of the face. This means that reddened areas will appear where the mask has pressed against the skin. These areas should be gently massaged and the skin lightly powdered to reduce friction.
A program of infection control is especially important in the prevention of cross-infection from the equipment that is used to administer oxygen. Humidifiers and nebulizers may serve as sources of infection because they provide a medium for the growth of bacteria and molds. There is less danger of this happening when disposable equipment is used, but this does not preclude the need for a systematic development of policies and procedures to prevent and control the spread of infection. Every person involved in the care of the patient must be aware of this program and cooperate in its implementation.
transcutaneous oxygen monitoring a method for obtaining data about oxygen levels through electrodes attached to the skin. This method is preferred for ill neonates who cannot tolerate frequent drawing of blood samples for blood gas analysis. The PO2 levels obtained by cutaneous monitoring correlate with those obtained from samples of arterial blood and spare the neonate blood loss and interruption of rest.
The transcutaneous electrodes are heated to encourage an adequate supply of blood to the area of skin to which they are attached and remain in place to permit continuous monitoring of arterial oxygen levels. To avoid burns, the electrode site can be changed every two hours. An ongoing record provides information about the neonate's oxygen level at any given moment. It allows caregivers to observe the neonate's response to handling and other procedures that may require modification to avoid severe anoxia. Placing the electrodes at specific sites can also aid the diagnosis of patent ductus arteriosus.
therapy
[ther´ah-pe] activity therapy in the
nursing interventions classification, a
nursing intervention defined as the prescription of and assistance with specific physical, cognitive, social, and spiritual activities to increase the range, frequency, or duration of an individual's (or group's) activity.
animal-assisted therapy in the
nursing interventions classification, a
nursing intervention defined as the purposeful use of animals to provide affection, attention, diversion, and relaxation.
art therapy in the
nursing interventions classification, a
nursing intervention defined as facilitation of communication through drawings or other art forms.
aversion therapy (
aversive therapy) a form of
behavior therapy that uses aversive conditioning, pairing undesirable behavior or symptoms with unpleasant stimulation in order to reduce or eliminate the behavior of symptoms. The term is sometimes used synonymously with
aversive conditioning.
client-centered therapy a form of psychotherapy in which the emphasis is on the patient's self-discovery, interpretation, conflict resolution, and reorganization of values and life approach, which are enabled by the warm, nondirective, unconditionally accepting support of the therapist, who reflects and clarifies the patient's discoveries.
cognitive therapy (cognitive-behavioral therapy) a directive form of psychotherapy based on the theory that emotional problems result from distorted attitudes and ways of thinking that can be corrected. Using techniques drawn in part from behavior therapy, the therapist actively seeks to guide the patient in altering or revising negative or erroneous perceptions and attitudes.
collapse therapy a formerly common treatment for pulmonary
tuberculosis in which the diseased lung was collapsed in order to immobilize it and allow it to rest.
pneumonolysis and
thoracoplasty are methods still sometimes used to collapse a lung and allow access during thoracic surgery.
continuous renal replacement therapy hemodialysis or
hemofiltration done 24 hours a day for an extended period, usually in a critically ill patient.
convulsive therapy treatment of mental disorders, primarily depression, by induction of
convulsions. The type almost universally used now is
electroconvulsive therapy (ECT), in which the convulsions are induced by electric current. In the past, drugs were sometimes used.
diet therapy treatment of disease by regulation of the
diet.
estrogen replacement therapy administration of an
estrogen to treat estrogen deficiency, such as that occurring after menopause; there are a number of indications, including the prevention of postmenopausal osteoporosis and coronary artery disease, and the prevention and treatment of vasomotor symptoms such as hot flashes and of thinning of the skin and vaginal epithelium, atrophic vaginitis, and vulvar atrophy. In women with a uterus, a progestational agent is usually included to prevent endometrial hyperplasia. Called also
hormone replacement therapy.
exercise therapy: ambulation in the
nursing interventions classification, a
nursing intervention defined as promotion of and assistance with walking to maintain or restore autonomic and voluntary body functions during treatment and recovery from illness or injury.
exercise therapy: balance in the
nursing interventions classification, a
nursing intervention defined as use of specific activities, postures, and movements to maintain, enhance, or restore
balance.
exercise therapy: joint mobility in the
nursing interventions classification, a
nursing intervention defined as the use of active or passive body movement to maintain or restore joint flexibility.
exercise therapy: muscle control in the
nursing interventions classification, a
nursing intervention defined as the use of specific activity or exercise protocols to enhance or restore controlled body movement.
family therapy 1. group therapy of the members of a family, exploring and improving family relationships and processes, understanding and modifying home influences that contribute to mental disorder in one or more family members, and improving communication and collective, constructive methods of problem-solving.
2. in the
nursing interventions classification, a
nursing intervention defined as assisting family members to move their family toward a more productive way of living.
hemofiltration therapy in the
nursing interventions classification, a
nursing intervention defined as cleansing of acutely ill patient's blood via a hemofilter controlled by the patient's hydrostatic pressure. See also
hemofiltration.
hormone replacement therapy the administration of hormones to correct a deficiency; usually used to denote
estrogen replacement therapy occurring after menopause.
host modulating therapy efforts to control
periodontal disease by directly targeting the host response; an example is the use of drugs that do this, such as sub-antimicrobial doses of
doxycycline,
nonsteroidal antiinflammatory drugs, or
bisphosphonates.
humidification therapy (
humidity therapy) the therapeutic use of air supersaturated with water to prevent or correct a moisture deficit in the respiratory tract; see also
humidity therapy.
leech therapy in the
nursing interventions classification, a
nursing intervention defined as the application of medicinal
leeches to help drain replanted or transplanted tissue engorged with venous blood.
marital therapy a type of
family therapy aimed at understanding and treating one or both members of a couple in the context of a distressed relationship, but not necessarily addressing the discordant relationship itself. In the past, the term has also been used in a narrower sense to mean what is defined as
marriage therapy, but that is increasingly considered a subset of marital therapy. Called also
couples therapy.
marriage therapy a subset of
marital therapy that focuses specifically on the bond of marriage between two people, enhancing and preserving it.
milieu therapy 1. treatment, usually in a psychiatric treatment center, that emphasizes the provision of an environment and activities appropriate to the patient's emotional and interpersonal needs.
2. in the
nursing interventions classification, a
nursing intervention defined as the use of people, resources, and events in the patient's immediate environment to promote optimal psychosocial functioning.
music therapy 1. the use of music to effect positive changes in the psychological, physical, cognitive, or social functioning of individuals with health or educational problems. Music therapy is used for a wide variety of conditions, including mental disorders, developmental and learning disabilities, Alzheimer's disease and other conditions related to aging, brain injury, substance abuse, and physical disability. It is also used for the management of acute and chronic pain and for the reduction of stress.
2. in the
nursing interventions classification, a
nursing intervention defined as using music to help achieve a specific change in behavior or feeling.
nutrition therapy in the
nursing interventions classification, a
nursing intervention defined as administration of food and fluids to support metabolic processes of a patient who is malnourished or at high risk for becoming malnourished. See also
nutrition.
optometric vision therapy a treatment plan prescribed to correct or improve specific dysfunctions of the vision system; it includes, but is not limited to, the treatment of
strabismus (turned eye), other dysfunctions of
binocularity (eye teaming),
amblyopia (lazy eye),
accommodation (eye focusing), ocular motor function (general eye movement ability), and visual-motor and visual-perceptual abilities.
oral rehydration therapy (ORT) oral administration of a solution of electrolytes and carbohydrates in the treatment of
dehydration.
peritoneal dialysis therapy in the
nursing interventions classification, a
nursing intervention defined as administration and monitoring of dialysis solution into and out of the peritoneal cavity. See also
peritoneal dialysis.
recreation therapy in the
nursing interventions classification, a
nursing intervention defined as the purposeful use of recreation to promote relaxation and enhancement of social skills.
reminiscence therapy in the
nursing interventions classification, a
nursing intervention defined as using the recall of past events, feelings, and thoughts to facilitate pleasure, quality of life, or adaptation to present circumstances.
replacement therapy treatment to replace deficient formation or loss of body products by administration of the natural body products or synthetic substitutes. See also
replacement. Called also
substitution therapy.
root canal therapy that aspect of
endodontics dealing with the treatment of diseases of the dental pulp, consisting of partial (
pulpotomy) or complete (
pulpectomy) extirpation of the diseased pulp, cleaning and sterilization of the empty
root canal, enlarging and shaping the canal to receive sealing material, and obturation of the canal with a nonirritating hermetic sealing agent. Called also
pulp canal therapy. simple relaxation therapy in the
nursing interventions classification, a
nursing intervention defined as the use of techniques to encourage and elicit relaxation for the purpose of decreasing undesirable signs and symptoms such as pain, muscle tension, or anxiety.
speech therapy the use of special techniques for correction of
speech disorders.
swallowing therapy in the
nursing interventions classification, a
nursing intervention defined as facilitating
swallowing and preventing complications of impaired swallowing.
thrombolytic therapy the administration of drugs for
thrombolysis (dissolution of a thrombus in an artery), to reduce the size of occlusion and thereby reduce damage to muscular tissue; the coronary artery is a commonly used site. Agents commonly used are
streptokinase and
tissue plasminogen activator (t-PA).
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.