Chapter 40: Oxygenation

1. Chapter 40: Oxygenation Bonnie M. Wivell, MS, RN, CNS

2. Structure and Function of the Heart • Right ventricle pumps blood through the pulmonary circulation • Left ventricle pumps blood through the systemic circulation • The circulatory system exchanges respiratory gases, nutrients, and waste products between the blood and tissues

3. Myocardial Pump • Four chambers: 2 atria, 2 ventricles • Fill with blood during diastole, empty during systole • CAD and cardiomyopathy result in decreased pumping action and decreased stroke volume • Frank-Starling’s law: the more stretch on the ventricle muscle, the greater the contraction and the greater the stroke volume • Diseased heart = contractile response resulting in insufficient stroke volume → “back up” in pulmonary → Left heart failure • “back up” in circulation → Right heart failure

4. Myocardial Blood Flow • Blood flow is unidirectional • Diastole = AV valves (mitral and tricuspid) open and blood flows from higher pressure atria to relaxed ventricles • Represents S1 or the first heart sound • Systole = Semilunar (aortic and pulmonic) valves open, and blood flows from the ventricles into the aorta and pulmonary artery • Closer of semilunar valves represents S2 • Murmur caused by regurge from diseased valve

5. Coronary Artery Circulation • Supplies the myocardium with oxygen and nutrients and removes waste • Left and right coronary arteries rise from the aorta just above and behind the aortic valve through the coronary openings • The left coronary artery, the most abundant blood supply, feed the left ventricle, which does most of the heart’s work • Cardiac Function • http://www.youtube.com/watch?v=D3ZDJgFDdk0&feature=related

6. Blood Flow Regulation • Cardiac Output (CO) = amount of blood ejected form the left ventricle each minute • CO changes according to the oxygen and metabolic needs of the body • CO = SV x HR • Stroke Volume (SV) = amount of blood ejected from the left ventricle with each contraction • Preload = amount of blood in the LV at the end of diastole • Afterload = the resistance to LV ejection

7. Conduction System • Heart’s conduction system generates impulses needed to pump blood • Trace the impulse • http://www.youtube.com/watch?v=nK0_28q6WoM&NR=1

8. Normal Sinus Rhythm

9. Respiratory System • Lungs transfer O2 from atmosphere to aveoli • Ventilation • Perfusion • Diffusion • Respirations • http://www.youtube.com/watch?v=hp-gCvW8PRY&feature=related

10. Work of Breathing • Intrapleural pressure is negative or different than the atmosphere • Punctured lung – lung collapses • Inspiration – active process stimulated by chemical receptors in aorta (O2, CO2) • Expiration – passive process that depends on elastic recoil • Surfactant – a chemical produced in the lungs to maintain the surface tension of the alveoli and keep them from collapsing • Decreased surfactant from disease can develop atelectasis • Difficulty breathing – use accessory muscles (elevation of the clavicles) • Seen in COPD, causes fatigue • Compliance – ability of the lungs to distend or to expand in response to increased intraalveolar pressure; decreased compliance increases airway resistance

11. Lung Volumes

12. Pulmonary Circulation

13. Respiratory Gas Exchange • Diffusion – thickness of membrane affects the rate of diffusion • Pulm edema, pulm infiltrates, pulm effusion • Ventilation – amount of O2 entering the lungs • Perfusion – blood flow to lungs and tissues • What influences capacity of blood to carry oxygen? • Venous blood transports the majority of CO2

14. Regulation of Respiration • Neural regulators • Cerebral Cortex • Medulla Oblongata • Chemical regulation • Chemoreceptor

15. Factors Affecting Oxygenation • Decrease in Hgb (O2 carrying capacity) • Anemia – s/s fatigue, decreased activity tolerance, SOB, pallor, tachycardia • Decreased inspired O2 concentration • Hypovolemia • Increase metabolic rate increases O2 demand • Normal in pregnancy, wound healing, and exercise as the body is building tissue • Fever

16. Conditions Affecting Chest Wall Movement • Pregnancy – baby pushes up against diaphragm resulting in dyspnea • Obesity • MSK abnormalities – pectus excavatum, kyphosis, lordosis, or scoliosis • Trauma – multiple rib fractures develop into a flail chest (unstable chest wall); incisions • Neuromuscular diseases – Myasthenia gravis, Guillain Barre syndrome, poliomyelitis • CNS – brain or spinal cord injury, phrenic nerve damage → diaphragm does not descend properl → reduces inspiration • Influence of chronic disease (COPD) influences the body to produce more RBCs (polycythemia vera)

17. Disturbances in Cardiac Functioning • Disturbances in conduction – Dysrhythmias • Altered CO • Left-sided heart failure: decreased CO, pulmonary congestion • Right-sided heart failure: result of pulm disease or long term left-sided failure; increase pulm vascular resistance; congestion in systemic circulation (edema) • Impaired valvular function – stenosis • Myocardial ischemia • Angina • MI – females and elderly present differently

18. Alterations in Respiratory Function • Goal: PaCO2 between 35-45 mm Hg and PaO2 95-100 mm Hg • Hyperventilation: state of ventilation in excess of that required to eliminate the CO2 produced by cellular metabolism; sometimes chemically induced (salicylate poisoning, amphetamines) • Hypoventilation: alveolar ventilation is inadequate to meet the body’s O2 demand or to eliminate sufficient CO2; atelectasis • Hypoxia: inadequate tissue oxygenation at the cellular level; cyanosis (central vs peripheral)

19. COPD vs Asthma • Physiology, emphysema • http://www.youtube.com/watch?v=aktIMBQSXMo • http://www.youtube.com/watch?v=82gn_rDRpHk

20. Developmental Factors • Infants and toddlers: at risk for URIs which are usually not dangerous • School-age children and adolescents: second hand smoke exposure, may start smoking • Young and middle-age adults: multiple risk factors such as unhealthy diet, lack of exercise, stress, OTC and RX meds not used as intended, illegal substances, and smoking • Older adults: calcification of heart valves, SA node and costal cartilages; osteoporosis changes size and shape of thorax

21. Lifestyle • Modify risk factors • Weight reduction • Smoking cessation • Low-cholesterol, low-Na+ diet • Management of HTN • Moderate exercise • Substance abuse • Stress • Environmental factors

22. Nutrition • Cardio-protective nutrition • Fiber • Whole grains • Fresh fruit • Vegetables • Nuts • Antioxidants • Lean meats, fish, chicken • Omega-3 fatty acids

23. Assessment • Nursing History • Pain • Fatigue • Smoking • Dyspnea/Orthopnea • Cough/hemoptysis • Wheezing • Environmental or geographical exposures • Respiratory infections • Allergies • Health risks • Medications

24. Physical Exam • Inspection – symmetry, breathing patterns, chest movement, barrel shape in COPD • Pink puffers/Blue bloaters • Palpation • Thoracic excursion • Tenderness • Tactile fremitus, thrills, heaves, PMI • CMS, edema • Percussion • Auscultation

25. CBC Cardiac Enzymes Myoglobin Serum Electrolytes Cholesterol Sputum (AFB, C/S, Cytology) ECG Stress test (Exercise vs Thallium) Cardiac cath PFTs Bronchoscopy Lung Scan Thoracentesis Diagnostic Tests

26. Activity intolerance Anxiety Decreased cardiac input Fatigue Impaired gas exchange Ineffective airway clearance Risk for infection Impaired spontaneous ventilation Impaired verbal communication Ineffective breathing pattern Ineffective health maintenance Risk for imbalanced fluid volume Nursing Diagnosis

27. Planning • Goals and outcomes • Pt. will have clear lungs to auscultation • Pt. will achieve bilateral lung expansion • Pt. will have a productive cough • Pt. will have maintain/improve pulse ox • Setting priorities • Collaborative care • Family members • Colleagues • Other specialists • Pulmonary rehab

28. Implementation • Health Promotion • Vaccinations • Healthy Lifestyle Behavior • Low-fat, high-fiber diet • Reduce stress • Exercise • Maintain a good BMI • Monitor cholesterol, triglycerides, HDL, LDL • Eliminate smoking • Avoid pollutants/second hand smoke • Adequate hydration and sodium intake (especially if on diuretics

29. Acute Care • Dyspnea management • Airway maintenance • Mobilization of pulmonary secretions • Hudification • Nebulization • Chest physiotherapy (CPT) • Postural drainage (see pages 932-933) • Suctioning • Oropharyngeal, nasopharyngeal, orothracheal, nasotracheal

30. Acute Care Continued • Artificial airways (for decreased LOC) • Oral airway (displaces tongue) • Endotracheal and tracheal airway (high risk for infection) • Maintenance and promotion of lung expansion • Positioning (turn, cough, deep breath) • Incentive Spirometry (IS)

33. Procedures • Thoracentesis • http://www.youtube.com/watch?v=6-9W-Y2dbpc&feature=related • Chest tube insertion • http://www.youtube.com/watch?v=B0wGmWn8Ubs&feature=related • Pleur-Evac • http://www.youtube.com/watch?v=-I4bj0qwhM0

34. Chest Tubes • Pneumothorax – a collection of air in the pleural space; loss of negative pressure in the intrapleural space • Spontaneous, or trauma • Often caused by the rupture of an air-filled sac in the lung, called a bleb or bulla • From procedure such as insertion of central line • Hemothorax – accumulation of blood and fluid in the pleural cavity usually as a result of trauma • Tension pneumo – air pressure builds in the pleural space, collapsing the lung and creating a life-threatening event

36. Oxygen Therapy • Goal • Purpose • Safety

37. Methods of Delivery • Nasal cannula • Simple face mask • Venturi mask • Home O2 • Compressed • Liquid • Concentrator

38. Restorative and Continuing Care Hydration Coughing techniques Respiratory muscle training Breathing exercises Pursed-lip breathing to blow off CO2 Diaphragmatic breathing

39. Evaluation