1 Oxygenation & Gas Exchange
2 Gas Exchange/OxygenationOxygenation can be defined as the mechanisms that facilitate or impair the body’s ability to supply oxygen to all cells of the body. The function of the respiratory system is to obtain oxygen from atmospheric air, to transport this air through the respiratory tract into the alveoli, and ultimately to diffuse oxygen into the body that carries oxygen to all the cells of the body.
3 3-Step Process of OxygenationVentilation The process of moving gases into and out of the lungs Perfusion The ability of the cardiovascular system to pump oxygenated blood to the tissues and return deoxygenated blood to the lungs Diffusion Exchange of respiratory gases in the alveoli and capillaries Three steps are involved in the process of oxygenation: ventilation, perfusion, and diffusion.
4 Pulmonary System Gas ExchangeThe thickness of the alveolar capillary membrane affects the rate of diffusion. Hemoglobin carries O2 and CO2 Carbon dioxide transport Diffusion is the process for exchange of respiratory gases in the alveoli and capillaries of the body tissues. Diffusion of respiratory gases occurs at the alveolar capillary membrane. Increased thickness of the membrane impedes diffusion because gases take longer to transfer across the membrane. Patients with pulmonary edema, pulmonary infiltrates, or pulmonary effusion have a thickened membrane, resulting in slow diffusion, slow exchange of respiratory gases, and decreased delivery of oxygen to tissues. Chronic diseases (e.g., emphysema), acute diseases (e.g., pneumothorax), and surgical processes (e.g., lobectomy) often alter the amount of alveolar capillary membrane surface area. The oxygen transport system consists of the lungs and cardiovascular system. Delivery depends on the amount of oxygen entering the lungs (ventilation), blood flow to the lungs and tissues (perfusion), the rate of diffusion, and the oxygen-carrying capacity. Three things influence the capacity of the blood to carry oxygen: the amount of dissolved oxygen in the plasma, the amount of hemoglobin, and the tendency of hemoglobin to bind with oxygen. Hemoglobin, which is a carrier for oxygen and carbon dioxide, transports most oxygen (approximately 97%). The hemoglobin molecule combines with oxygen to form oxyhemoglobin. The formation of oxyhemoglobin is easily reversible, allowing hemoglobin and oxygen to dissociate (deoxyhemoglobin), which frees oxygen to enter tissues. Decreased hemoglobin levels alter the patient’s ability to transport oxygen. Carbon dioxide, a product of cellular metabolism, diffuses into red blood cells and is rapidly hydrated into carbonic acid (H2CO3). The carbonic acid then dissociates into hydrogen (H) and bicarbonate (HCO3−) ions. Hemoglobin buffers the hydrogen ion, and HCO3− diffuses into the plasma. Reduced hemoglobin (deoxyhemoglobin) combines with carbon dioxide, and venous blood transports most of the carbon dioxide back to the lungs to be exhaled. [Shown is Figure 40-2 from text p. 823.]
5 Pulmonary System Three things influence the capacity of the blood to carry O2: The amount of dissolved O2 in the plasma The amount of hemoglobin The tendency of hemoglobin to bind with O2 The primary function of the lungs is to transfer oxygen from the atmosphere into the alveoli and carbon dioxide out of the body as a waste product. The airways of the lung transfer oxygen from the atmosphere to the alveoli, where the oxygen is exchanged for carbon dioxide. Through the alveolar capillary membrane, oxygen transfers to the blood, and carbon dioxide transfers from the blood to the alveoli. Conditions and diseases that change the structure and function of the pulmonary system alter respiration. The respiratory muscles, pleural space, lungs, and alveoli are essential for ventilation, perfusion, and exchange of respiratory gases. Gases move into and out of the lungs through pressure changes. Intrapleural pressure is negative, or less than atmospheric pressure, which is 760 mm Hg at sea level. For air to flow into the lungs, intrapleural pressure becomes more negative, setting up a pressure gradient between the atmosphere and the alveoli. The diaphragm and external intercostal muscles contract to create a negative pleural pressure and increase the size of the thorax for inspiration. Relaxation of the diaphragm and contraction of the internal intercostal muscles allow air to escape from the lungs. The major inspiratory muscle of respiration is the diaphragm. [Shown is Figure 40-1 on text p. 822.]
6 Factors Affecting OxygenationPhysiological factors Decreased oxygen-carrying capacity Anemia Hypovolemia Dehydration and hemorrhage Decreased inspired oxygen concentration High altitudes Increased metabolic rate Fever Any condition that affects cardiopulmonary functioning directly affects the body’s ability to meet oxygen demands. [Ask students if they can remember cardiac anatomy and physiology and to name some condition that would affect oxygenation. Answers may include conduction defects, valvular dysfunction, myocardial ischemia, cardiac myopathy, tissue hypoxemia on the cardiac side and hyperventilation on the respiratory side, hypoventilation, hypoxia, and others.] [Ask students why hypovolemia affects gas exchange. Any condition that reduces chest wall movement will result in decreased ventilation. If the diaphragm is unable to descend fully with breathing, the volume of inspired air decreases, delivering less oxygen to the alveoli and all tissues.] [Ask students if they can name some nervous system diseases that may affect breathing. Answers may include myasthenia gravis, Guillain-Barré, and polio.] When patients take opioids, their respiratory center is depressed.
9 Alterations in Respiratory FunctioningRespiratory Alterations Hyperventilation: ventilation in excess of that required; rate and depth of respirations increase. Hypoventilation: alveolar ventilation inadequate to meet the body’s oxygen demand; respiratory rate and depth is low Hypoxia: Inadequate tissue oxygenation at the cellular level, late sign cyanosis Illnesses or conditions that affect ventilation or oxygen transport cause alterations in respiratory functioning. Impaired chest wall movement reduces the level of tissue oxygenation. Hyperventilation can be caused by anxiety, infection, drugs, acid-base imbalance, fever, aspirin poisoning, or amphetamine use. [Ask students: Why? Answers may include that an increase in respiratory rate causes excessive amounts of carbon dioxide elimination.] Hypoventilation is caused by atelectasis and collapsed alveoli. [Ask students to identify signs and symptoms. Answers may include dizziness, headache upon awakening, lethargy, cardiac dysrhythmias, electrolyte imbalances, convulsions, coma, and cardiac arrest.] Hypoxia is life threatening. Causes may include: anemia, carbon monoxide poisoning, septic shock, cyanide poisoning, pneumonia atelectasis, cardiomyopathy, spinal cord injury, and head trauma. Cyanosis, blue discoloration of the skin and mucous membranes caused by the presence of desaturated hemoglobin in capillaries, is a late sign of hypoxia.
10 Hyperventilation Causes Severe anxiety Infection DrugsAcid-base imbalance Fever Signs and symptoms Rapid respirations Sighing breaths Numbness and tingling of hands/feet Light-headedness Loss of consciousness Ask the students to write causes and signs and symptoms
11 Hypoventilation Causes Signs and Symptoms AtelectasisObesity/Sleep Apnea Signs and Symptoms Mental status changes Dysrhythmias Convulsions Unconscious Death
12 Hypoxia Causes Signs and symptomsA ↓in Hgb and lowered O2-carrying capacity of blood. A diminished inspired O2 A ↓ in diffusion of O2 from the alveoli to the blood Impaired ventilation Signs and symptoms Apprehensive Restlessness, inability to concentrate ↓ LOC Dizziness Behavioral changes Agitated ↑ RR ↑ HR Late signs: ↓ RR, ↓ HR and cyanosis
13 Lifestyle Risk FactorsSmoking Associated with heart disease, COPD, and lung cancer The risk of lung cancer is 10 times greater for a person who smokes than for a nonsmoker. Substance abuse Excessive use of alcohol and other drugs impairs tissue oxygenation. Stress A continuous state of stress or severe anxiety increases the metabolic rate and oxygen demand of the body. •Cigarette smoking and secondhand smoke are associated with a number of diseases, including heart disease, COPD, and lung cancer. Cigarette smoking worsens peripheral vascular and coronary artery diseases. •Women who take birth control pills and smoke cigarettes are at increased risk for thrombophlebitis and pulmonary emboli. •Exposure to secondhand smoke is also dangerous. •The body responds to anxiety and other stresses with an increased rate and depth of respiration. Most people adapt, but some, particularly those with chronic illnesses or acute life-threatening illnesses such as an MI, cannot tolerate the oxygen demands associated with anxiety.
14 Environmental FactorsThe incidence of pulmonary disease is higher in smoggy, urban areas than in rural areas. A patient’s workplace sometimes increases the risk for pulmonary disease. Coccidioidomycosis (Fungal disease) Farmers Asbestosis Occupational pollutants include asbestos, talcum powder, dust, and airborne fibers. For example, farm workers in dry regions of the southwestern United States are at risk for coccidioidomycosis, a fungal disease caused by inhalation of spores of the airborne bacterium Coccidioides immitis. Asbestosis is an occupational lung disease that develops after exposure to asbestos. The lung with asbestosis often has diffuse interstitial fibrosis, creating a restrictive lung disease. Patients exposed to asbestos are at risk for developing lung cancer, and this risk increases with exposure to tobacco smoke.
15 Pneumonia Pneumonia is an acute inflammation of the lung that is most frequently caused by a microorganism. Fluid and exudate in the alveoli. Culture Sputum Stareptococcus pneumoniae
16 Nursing InterventionsPositioning: HOB up semi Fowlers Helps to drain secretions from specific segments of the lungs and bronchi into the trachea ALWAYS – the first intervention for difficulty breathing
17 Intervention Order: 10 times/hr while awake Slowly, steady inhale
18 Interventions Diaphragmatic breathing/belly breathing Cascade coughDeep breathing and coughing Diaphragmatic breathing/belly breathing Cascade cough Huff Cough Hydration Humidification Nebulization Oral and IV
21 Methods of Oxygen DeliveryNon-Rebreather – Higher oxygen concentration 60-95% Oxygen; Reservoir and Mask Valve to prevent air from flowing back into bag Partial Rebreather 40-60% Oxygen; Reservoir and Mask; No Valve Non-Rebreather Mask Oxygen 60% to 95%, flows into reservoir bag and mask. Valve prevents expired air from flowing back into bag. Partial Rebreather Mask Reservoir bag conserves oxygen concentrations of 40-60%, only difference is valve between mask and bag is removed
22 Oxygenation Safety Oxygen must be prescribed and adjusted only with a HCP’s order. Determine that all electrical equipment in the room is functioning correctly and properly grounded. An electrical spark in the presence of oxygen can result in a serious fire. Check the oxygen level of portable tanks before transporting a patient to ensure there is enough oxygen in the tank.
23 Oxygenation Safety Secure oxygen cylinders so they do not fall over. Store them upright and either chained or secured in appropriate holders.
25 Tracheostomy equipment
26 Suctioning (Skill 40-1) Signs and symptoms of Hypoxia ApprehensiveKey points: Use sterile procedure Suction set on continuous suction of mm Hg Insert catheter, suction intermittently seconds and slowly rotate and withdraw Monitor patient: Risk for hypoxia Hypotension Arrhythmias Trauma Irritation Nursing Diagnosis: Ineffective airway clearance r/t retention of secretions and poor cough effort. DO NOT SUCTION LONGER THAN 15 SECONDS Vagal stimulation: potentially hazardous complication from suctioning, can lead to bradycardia vagus nerve is the pneumogastric (10th cranial nerve) with motor and sensory functions, wide distribution Signs and symptoms of Hypoxia Apprehensive Restlessness, inability to concentrate ↓ LOC Dizziness Behavioral changes Agitated ↑ RR ↑ HR Late signs: ↓ RR, ↓ HR and cynosis
27 Suctioning Suctioning is necessary when patients are unable to clear respiratory secretions from the airways by coughing or other less invasive procedures.
28 Chest Tubes Chest tubesA catheter placed through the thorax to remove air and fluids from the pleural space Purpose To remove air and fluids from the pleural space To prevent air or fluid from reentering the pleural space To re-establish normal intra-pleural and intra- pulmonary pressures
29 Pneumothorax Pneumothorax occurs when air accumulates in the pleural space and causes complete or partial collapse of a lung.
31 Chest Tube Nursing Care (interventions)Maintain secure, airtight dressing Maintain underwater seal Monitor and secure all connections Observe for bubbling Monitor tubing for patency Record output (quantity, characteristics) Monitor patient Dressing changes per agency
32 Chest Tube Simply put, if you take the air that someone is breathing and find out how much of it (percentage-wise) is oxygen, you get the FiO2. The air around us is made up of 78.1% nitrogen, 20.9% oxygen, 0.9% argon and 0.1% carbon dioxide and other gases. Therefore, your FiO2 is 0.21 (21%). If someone in the hospital is on a breathing machine that is delivering pure 100% oxygen, then his/her FiO2 would be 1.00 (100%). They named it such because, as you point out, it stands for "fraction of inspired oxygen". In other words, it is the "fraction" of the "inspired" air (inspire means to breathe in) that is made up of "oxygen", O2.
33 Chest Tube Chest Tube Functioning
34 Case Study: Mr. Will SmithMr. Smith is a 65-year-old man who developed shortness of breath while on a family vacation in the mountains. When he returned home from vacation he presented to the emergency department alert and feeling ill with an elevated temperature of F and chills. Mr. Smith has a 1-pack per week history of smoking and no history of alcohol or illicit drug abuse. Recent history includes dry hacking cough, low-grade fever, fatigue, loss of appetite, and feeling terrible.
35 Case Study: Mr. William SmithBen Adams is the nursing student assigned to his first hospital-based clinical experience. He has some experience in health assessment and patient teaching related to health promotion activities from a recent rotation at a clinic. In the previous experience, patients were encouraged to adjust their at-risk health behaviors, such as smoking or poor diet. Ben feels confident when he arrives in the clinical area this morning because Mr. Smith has similar health needs to the clinical experiences he has had.
36 Case Study: Mr. William SmithWhat questions Ben would have asked Mr. Smith if he had been at the hospital when Mr. Smith was being admitted. Environmental or Geographical Exposures Smoking Respiratory infections Allergies Health Risks Medications
37 Case Study: Mr. William SmithWhile Ben is completing his morning physical assessment, what observations would he focus on to determine if Mr. Smith’s oxygen needs were being met? Inspection Palpation Percussion Auscultation Presences of:
38 Case Study: Mr. William SmithPresences of: Pain Fatigue Dyspnea Cough Breath sounds Respiratory rate Inspection Color of skin and mucous membranes, LOC, breathing patterns, chest wall movement, cap refill, Palpation Chest, feet, legs, Pulses Percussion Abnormal fluid or air in lungs Auscultation Breath sounds and lung sounds The physical examination includes assessment of the cardiopulmonary system. When assessing an older adult patient, give special consideration to changes that occur with the aging process. These changes affect the patient’s activity tolerance and level of fatigue or cause transient changes in vital signs and are not always associated with a specific cardiopulmonary disease. Inspection: skin and mucous membranes for color, appearance, level of consciousness, circulation, breathing patterns, and chest wall movement. In some conditions, such as metabolic acidosis, acidic pH stimulates an increase in both rate and depth of respirations (Kussmaul’s respirations) to compensate by decreasing carbon dioxide levels. Apnea is the absence of respirations for a period of time. Cheyne-Stokes respiration occurs when blood flow is decreased or injury to the brainstem occurs. Palpation: assess thoracic excursion, tenderness, identification of thrills, heaves, tactile fremitus, and the cardiac point of maximum impulse (PMI). Palpation of the feet and extremities identifies edema, which is rated from 1 to 4, and arterial blood flow. Palpate the pulses in the neck and extremities to assess arterial blood flow (see Chapter 30). Use a scale of 0 (absent pulse) to +4 (full, bounding pulse) to describe what you feel. The normal pulse is +2, and a weak, thready pulse is +1. Percussion: detects the presence of abnormal fluid or air in the lungs. It also determines diaphragmatic excursion. Auscultation: identification of normal and abnormal heart and lung sounds. Auscultation of lung sounds involves listening for movement of air throughout all lung fields: anterior, posterior, and lateral. [See also Table 40-1 on text p. 833 Assessment Findings in the Aging Cardiopulmonary System and Table 40-2 on text p. 834 Inspection of Cardiopulmonary Status.]
39 Case Study: Mr. William SmithDiagnostic Tests CBC WBC: 5-10, 000 RBC: Male: 4-6,000,000 Female 4-5,000,000 Hgb: Male: g/dL Female g/dL Hct: Male 42%-52% Female 37%- 47% Chest x-ray Sputum specimens for C & S Pulse oximetry
40 Case Study: Mr. William SmithBen’s morning assessment included the following findings: BP 110/70 mm Hg HR 102 beats/min Temp 101.5 RR 36 breaths/min Breath sounds: Expiratory wheezing, crackles and diminished breath sounds over the right lower lobe are audible. O2 Sats at 89% with O2 per NC at 2L/NC Sputum is thick and discolored (yellow-green). Wt 190 lbs
41 Nursing Diagnosis – Impaired Gas ExchangeImpaired gas exchange r/t fluid and exudate accumulation in the alveoli AEB wheezing. Outcome Patient will have a O2 sat of % Clear breath sounds and temperature between
42 Nursing Diagnosis – Impaired Gas ExchangeAssessment – S & S of altered resp. function Rapid, shallow, or irregular respirations Dyspnea, orthopnea Use of accessory muscles when breathing Diminished or absent breath sounds Restlessness, irritability Confusion, somnolence Dusky or cyanotic skin color Group work: design a plan of care for Mr. Smith. After a period of time, ask a member of each group to come up and type a different nursing intervention onto the slide. (Remember, to do this, you can not be in full view) Assessments Monitor for s/s of pneumonia Monitor VS q 4 hrs Temp Respiratory rate, rhythm, depth and effort of respirations Monitor BS q 4 hrs Monitor for increased restlessness, anxiety, and air hunger Monitor O2 sats Monitor WBC Nursing interventions Maintain bed rest HOB up semi Fowlers Administer O2 2L/NC Encourage deep breathing and coughing Assist with incentive spirometer Encourage ambulation on second day Encourage fluids Consult with physician for RT consult Administer Meds: Teach The importance in hand washing The importance in staying away from crowds until antibiotics are completed The s/s to report to the physician The importance in finishing all antibiotics on discharge The side effects of the antibiotics to be taken on discharge
43 Nursing Diagnosis – Impaired Gas ExchangeAssessment/Monitoring – S & S of altered resp. function Monitor oximetry results and report abnormal Monitor characteristics of sputum: amount, color Monitor VS Monitor chest x-ray results and Lab results (WBCs) Group work: design a plan of care for Mr. Smith. After a period of time, ask a member of each group to come up and type a different nursing intervention onto the slide. (Remember, to do this, you can not be in full view) Assessments Monitor for s/s of pneumonia Monitor VS q 4 hrs Temp Respiratory rate, rhythm, depth and effort of respirations Monitor BS q 4 hrs Monitor for increased restlessness, anxiety, and air hunger Monitor O2 sats Monitor WBC Nursing interventions Maintain bed rest HOB up semi Fowlers Administer O2 2L/NC Encourage deep breathing and coughing Assist with incentive spirometer Encourage ambulation on second day Encourage fluids Consult with physician for RT consult Administer Meds: Teach The importance in hand washing The importance in staying away from crowds until antibiotics are completed The s/s to report to the physician The importance in finishing all antibiotics on discharge The side effects of the antibiotics to be taken on discharge
44 Nursing Diagnosis – Impaired Gas ExchangeInterventions Maintain bed-rest for 24 hours Maintain HOB at semi- to high Fowler’s position Teach and assist to turn, cough, and deep breathe or use IS 10 times/hr while awake Maintain IV at 100 ml/hr Encourage fluid intake of at least 2800 ml/day: 500 ml/oral route
45 Nursing Diagnosis – Impaired Gas ExchangeInterventions Maintain oxygen therapy at 3L/NC Encourage and assist to BR Encourage ambulation as tolerated after 24 hrs of rest (10-15 minutes 3 times a day) Administer Cefepime 1 g every 8 hours over 30 min Consult with HCP for RT consult Teach Importance in stopping smoking How to use the IS