Oxygenation PDF

Oxygenation LEARNING OUTCOMES 1. Outline the structure of the respiratory system. 2. Describe the processes of breathing (ventilation) and gas exchange (respiration). 3. Explain the role and function of the respiratory system in transporting oxygen and carbon dioxide to and from body tissues. 4. Des...

Oxygenation LEARNING OUTCOMES 1. Outline the structure of the respiratory system. 2. Describe the processes of breathing (ventilation) and gas exchange (respiration). 3. Explain the role and function of the respiratory system in transporting oxygen and carbon dioxide to and from body tissues. 4. Describe the mechanisms for respiratory regulation. 5. Identify factors influencing respiratory function. 6. Identify four major types of conditions that can alter respiratory function. INTRODUCTION be bone Oxygen, a clear, odorless gas that constitutes approximately 21% of the air we breathe. is necessary for proper functioning of all living cells. The absence of oxygen can lead to cellular, tissue, and organism death. Cellular metabolism produces carbon dioxide, which must be eliminated from the body to maintain normal acid–base balance. INTRODUCTION Cont. Delivery of oxygen and removal of carbon dioxide require the integration of several systems including: the hematologic, cardiovascular, and respiratory systems. gwastnawa w dardane O2 la regay am 3 system awa dabet INTRODUCTION Cont. The respiratory system provides the essential first process in this integrated system, that is, movement and transfer of gases between the atmosphere and the blood (Patton & Tibodeau, 2010). Impaired function of the system can significantly affect our ability to breathe, transport gases, and participate in everyday activities. Structure of the Respiratory System The respiratory system is divided structurally into: the upper respiratory system the lower respiratory system. The mouth, nose, pharynx, and larynx am partana bo zhmardn gunjawa w agare haya The lower respiratory system includes the trachea and lungs, with the bronchi, bronchioles, alveoli, pulmonary capillary network,and pleural membranes. zmana chkola Structure of the Respiratory System cont. Inhalation Inspired air passes from the nose through the pharynx. The pharynx is a shared pathway for air and food. It includes both the nasopharynx and the oropharynx, which are richly supplied with lymphoid tissue that traps and destroys pathogens entering with the air. Structure of the Respiratory System cont. The larynx is a cartilaginous structure that can be identified externally as the Adam’s apple. bronchi divide repeatedly into smaller and smaller bronchi, ending with the terminal bronchioles. After air passes through the trachea and bronchi, it enters the respiratory bronchioles and alveoli where all gas exchange occurs. Lung lungs is covered by a thin, double layer of tissue known as the pleura. The parietal pleura the visceral pleura Between these pleural layers is a potential space that contains a small amount of pleural fluid, a serous lubricating solution. Prevents friction. regre dakat la lekxshan Processes of respiratory system Respiration is the process of gas exchange between the individual and the environment and involves four components: 1. Ventilation or breathing, the movement of air in and out of the lungs as we inhale and exhale 2. Alveolar-capillary gas exchange, which involves the diffusion of oxygen and carbon dioxide between the alveoli and the pulmonary capillaries Processes of respiratory system Cont. 3. Transport of oxygen and carbon dioxide between the tissues and the lungs. 4. Movement of oxygen and carbon dioxide between the systemic capillaries and the tissues 1. Pulmonary Ventilation The first process of the respiratory system, ventilation of the lungs Adequate ventilation depends on several factors: A. Clear airways. B. An intact central nervous system (CNS) and respiratory center. C. An intact thoracic cavity capable of expanding and contracting. D. Adequate pulmonary compliance and recoil. Clear airways. A number of mechanisms, including ciliary action and the cough reflex, work to keep airways open and clear. The inflammation, edema, and excess mucous production that occur with some types of pneumonia may clog small airways, impairing ventilation of distal alveoli. An intact central nervous system (CNS) and respiratory center The respiratory centers of the medulla and pons in the brain stem control breathing. Severe head injury or drugs that depress the central nervous system (e.g., opiates or barbiturates) can affect the respiratory centers, impairing the drive to breathe. An intact thoracic cavity capable of expanding and contracting. Expansion and recoil of the lungs occur passively in response to changes in pressures within the thoracic cavity and the lungs themselves. The intrapleural pressure surrounding the lungs) (pressure in the pleural cavity The intrapulmonary pressure (pressure within the lungs) Normal elastic recoil of the thorax and lungs is essential to exhalation chronic obstructive pulmonary disease (COPD) The degree of chest expansion during normal breathing is minimal, requiring little energy expenditure. In adults, approximately 500 mL of air is inspired and expired with each breath. This is known as tidal volume. strenuous exercise or some types of heart disease requires greater chest expansion and effort. 1,500 mL. Accessory muscles of respiration: anterior neck muscles, intercostal muscles, and muscles of the abdomen, Lung compliance the expansibility or stretchability of lung tissue, plays a significant role in the ease of ventilation. At birth, the fluid-filled lungs are stiff and resistant to expansion decrease with aging increasing the risk for atelectasis abnormal collapses of lung lung recoil Collapse of the lungs away from the chest wall lung compliance is necessary for normal inspiration, lung recoil is necessary for normal expiration Surfactant, a lipoprotein produced by specialized alveolar cells, acts like a detergent, reducing the surface tension of alveolar fluid. 2. Alveolar Gas Exchange Diffusion is the movement of gases or other particles from an area of greater pressure or concentration to an area of lower pressure or concentration. The partial pressure (the pressure exerted by each individual gas in a mixture according to its concentration in the mixture) of oxygen Alveolar Gas Exchange Alveoli Arterial Blood Po2 = 100 mmHg Po2 = 60 mmHg Pco2 = 40 mmHg Pco2 = 45 mmHg 3. Transport of Oxygen and Carbon Dioxide The third part of the respiratory process involves the transport of respiratory gases. Oxygen needs to be transported from the lungs to the tissues, and carbon dioxide must be transported from the tissues back to the lungs. (RBCs) and is carried to the tissues as oxyhemoglobin Various factors influence the tendency of oxygen to bind with and release from hemoglobin Decreasing partial pressure changes in blood pH Several factors affect the rate of oxygen transport from the lungs to the tissues: 1. Cardiac output 2. Number of erythrocytes and blood hematocrit 3. Exercise. Any pathologic condition that decreases cardiac output (e.g., damage to the heart muscle, blood loss, or pooling of blood in the peripheral blood vessels) diminishes the amount of oxygen delivered to the tissues. The second factor influencing oxygen transport is the number of erythrocytes or red blood cells (RBCs) and the hematocrit. Hematocrit. Excessive increases in the blood hematocrit raise the blood viscosity, reducing the cardiac output and therefore reducing oxygen transport. Excessive reductions in the blood hematocrit, such as occur in anemia, reduce oxygen transport. Exercise also has a direct influence on oxygen transport. In well trained athletes, oxygen transport can be increased up to 20 times the normal rate, due in part to an increased cardiac output and to increased use of oxygen by the cells. 4. Systemic Diffusion As cells consume oxygen, the partial pressure of oxygen in the tissues decreases, causing the oxygen at the arterial end of the capillary to diffuse into the cells. FACTORS AFFECTING RESPIRATORY FUNCTION Age The lungs gradually expand with each subsequent breath, reaching full inflation by 2 weeks of age. Chest wall and airways become more rigid and less elastic. The amount of exchanged air is decreased. The cough reflex and cilia action are decreased. Mucous membranes become drier and more fragile. Decreases in muscle strength and endurance occur. eska narma If osteoporosis is present, adequate lung expansion may be compromised. Environment Altitude, heat, cold, and air pollution affect oxygenation. The higher the altitude, the lower the PO2 an individual breathes. Healthy people exposed to air pollution Lifestyle Physical exercise or activity increases the rate and depth of respirations and hence the supply of oxygen in the body. Health Status Medications A variety of medications can decrease the rate and depth of respirations. the benzodiazepine sedative-hypnotics and antianxiety drugs (e.g., diazepam [Valium], lorazepam [Ativan], midazolam [Versed]), barbiturates (e.g., phenobarbital), and opioids such as morphine. Stress PO2 --> increase PCO2 --> decrease psychological and physiological arterial PO2 rises and PCO2 falls. The person may experience light-headedness and numbness and tingling of the fingers, toes, and around the mouth as a result. Epinephrine is released during stress. Epinephrine causes the bronchioles to dilate, increasing blood flow and oxygen delivery to active muscles. ALTERATIONS IN RESPIRATORY FUNCTION Respiratory function can be altered by conditions that affect: Patency (open airway) Patency = clean airway The movement of air into or out of the lungs The diffusion of oxygen and carbon dioxide between the alveoli and the pulmonary capillaries The transport of oxygen and carbon dioxide via the blood to and from the tissue cells. Diffusion: is a process that exchanging O2 & Co2 from large area pressure to lower area of pressure Conditions Affecting the Airway An upper airway obstruction—that is, in the nose, pharynx, or larynx—can occur when a foreign object such as food is present, when the tongue falls back into the oropharynx when a person is unconscious, or when secretions collect in the passageways. In the latter instance, the respirations will sound gurgly or bubbly as the air attempts to pass through the secretions. Lower airway obstruction involves partial or complete occlusion of the passageways in the bronchi and lungs most often due to increased accumulation of mucus or inflammatory exudate. Partial obstruction of the upper airway passages is indicated by a low-pitches snoring sound during inhalation. Complete obstruction is indicated by extreme inspiratory effort that produces no chest movement and an inability to cough or speak. Such a client, in an effort to obtain air, may also exhibit marked sternal and intercostal retractions. Lower airway obstruction is not always as easy to observe. Stridor , a harsh, high-pitched sound, may be heard during inspiration. The client may have altered arterial blood gas levels, restlessness, dyspnea, and adventitious breath sounds. Conditions Affecting Movement of Air The term breathing patterns refers to the rate, volume, rhythm, and relative ease or effort of respiration. Normal respiration (eupnea ) is quiet, rhythmic, and effortless. Tachypnea (rapid respirations) is seen with fevers, metabolic acidosis, pain, and hypoxemia. Bradypnea is an abnormally slow respiratory rate, which may be seen in clients who have taken drugs such as morphine or sedatives, who have metabolic alkalosis, or who have increased intracranial pressure (e.g., from brain injuries) Apnea is the absence of any breathing. Hypoventilation, that is, inadequate alveolar ventilation, may be caused by either slow or shallow breathing, or both. Hypoventilation may occur because of diseases of the respiratory muscles, drugs, or anesthesia. Hypoventilation may lead to increased levels of carbon dioxide (hypercarbia or hypercapnia ) or low levels of oxygen (hypoxemia). Hyperventilation is the increased movement of air into and out of the lungs. During hyperventilation, the rate and depth of respirations increase and more CO2 is eliminated than is produced. Kussmaul’s breathing, by which the body attempts to compensate for increased metabolic acids by blowing off acid in the form of CO2. Hyperventilation can also occur in response to stress or anxiety. Orthopnea is the inability to breathe easily unless sitting upright or standing. dyspnea is shortness of breath (SOB). The client with dyspnea will generally have observable (objective) signs such as flaring of the nostrils, laboredappearing breathing, increased heart rate, cyanosis, and diaphoresis. Cardiac or respiratory disorders are the main causes of dyspnea. Nurse have a important role in conducting a thorough history of the onset, duration, and precipitating and relieving factors of the client’s dyspnea plus a comprehensive physical examination. Conditions Affecting Diffusion Impaired diffusion may affect levels of gases in the blood, particularly oxygen. Hypoxemia may be caused conditions that impair diffusion at the alveolar-capillary level such as pulmonary edema or atelectasis (collapsed alveoli) or by low hemoglobin levels. low level in the blood = hypoxemia low level in the tissue = hypoxia jegrawa The cardiovascular system compensates for hypoxemia by increasing the heart rate and cardiac output, to attempt to transport adequate oxygen to the tissues. If the cardiovascular system is unable to compensate or hypoxemia is severe, tissue hypoxia (insufficient oxygen anywhere in the body) results, potentially causing cellular injury or death. Cyanosis (bluish discoloration of the skin, nail beds, and mucous membranes due to reduced hemoglobin-oxygen saturation) may be present with hypoxemia or hypoxia. The face of the acutely hypoxic person usually appears anxious, tired, and drawn. The person usually assumes a sitting position, often leaning forward slightly to permit greater expansion of the thoracic cavity. With chronic hypoxemia, the client often appears fatigued and is lethargic. The client’s fingers and toes may be clubbed as a result of long-term lack of oxygen in the arterial blood supply Conditions Affecting Transport Conditions that decrease cardiac output, such as congestive heart failure or hypovolemia, affect tissue oxygenation and also the body’s ability to compensate for hypoxemia. Nursing management Interview for taking history of present illness Physical examination Diagnostic studies Nursing process Physical Examination Physical examination techniques : Inspection Palpation Percussion Auscultation. Inspection The nurse first observes the rate, depth, rhythm, and quality of respirations, noting the position the client assumes for breathing. The nurse also inspects for variations in the shape of the thorax that may indicate adaptation to chronic respiratory conditions. For example, clients with emphysema frequently develop a barrel chest. Palpation and auscultation The nurse palpates the thorax for bulges, tenderness, or abnormal movements. Palpation is also used to detect vocal (tactile) fremitus. The nurse frequently auscultates the chest to assess if the client’s breath sounds are normal or abnormal. Diagnostic Studies sputum specimens, throat cultures, venous and arterial blood specimens, and pulmonary function tests. Flow-oriented spirometry volume-oriented spirometry Nursing Diagnosing NANDA International (Herdman & Kamitsuru, 2014) includes the following diagnostic labels for clients with oxygenation problems: Ineffective Airway Clearance: inability to clear secretions or obstructions from the respiratory tract to maintain a clear airway. Ineffective Breathing Pattern: inspiration and/or expiration that does not provide adequate ventilation. Impaired Gas Exchange: excess or deficit in oxygenation and/or carbon dioxide elimination at the alveolar-capillary membrane. Activity Intolerance: insufficient physiological or psychological energy to endure or complete required or desired daily activities. Anxiety related to ineffective airway clearance and feeling of Suffocation. Fatigue related to ineffective breathing pattern Fear related to chronic disabling respiratory illness Powerlessness related to inability to maintain independence in self-care activities because of ineffective breathing pattern Insomnia related to orthopnea and required O2 therapy Social Isolation related to activity intolerance and inability to travel to usual social activities. Planning The overall outcomes/goals for a client with oxygenation problems are to: Maintain a patent airway. Improve comfort and ease of breathing. Maintain or improve pulmonary ventilation and oxygenation. Improve the ability to participate in physical activities. Prevent risks associated with oxygenation problems such as skin and tissue breakdown, syncope, acid–base imbalances, and feelings of hopelessness and social isolation. Implementing Examples of nursing interventions to facilitate pulmonary ventilation are: Ensuring a patent airway, positioning, encouraging deep breathing and coughing, adequate hydration. suctioning, lung inflation techniques, administration of analgesics before deep breathing and coughing, postural drainage, and percussion and vibration, oxygen therapy, maintenance of a chest tube. tracheostomy care, and Promoting Oxygenation Interventions by the nurse to maintain the normal respirations of clients include: Positioning the client to allow for maximum chest expansion Encouraging or providing frequent changes in position Encouraging deep breathing and coughing Encouraging ambulation Implementing measures that promote comfort, such as giving pain medications. The semi-Fowler’s or high-Fowler’s position Deep Breathing and Coughing Medications Bronchodilators, anti-inflammatory drugs, expectorants, and cough suppressants Other medications can be used to improve oxygenation by improving cardiovascular function. The digitalis glycosides act directly on the heart to improve the strength of contraction and slow the heart rate. Beta-adrenergic stimulating agents such as dobutamine similarly increase cardiac output, thus improving O2 transport. Beta-adrenergic blocking agents such as propranolol affect the sympathetic nervous system to reduce the workload of the heart. These drugs, however, can negatively affect people with asthma or COPD because they may constrict airways by blocking beta-2 adrenergic receptors. Percussion, Vibration, and Postural Drainage Postural drainage Percussion Vibration Oxygen Delivery Systems Cannula Face Mask Face Tent Transtracheal Catheter Noninvasive Positive Pressure Ventilation (NPPV) Oropharyngeal and Nasopharyngeal Airways Endotracheal Tubes Tracheostomy tube Suctioning