Transcript Document
Chapter 13 Asthma Figure 13-1. Asthma. DMC, Degranulation of mast cell; SMC, smooth muscle constriction; MA, mucus accumulation; MP, mucus plug; HALV, hyperinflation of alveoli. Slide 1 Copyright © 2006 by Mosby, Inc. Anatomic Alterations of the Lungs Slide 2 Smooth muscle constriction of bronchial airways (bronchospasm) Excessive production of thick, whitish, tenacious bronchial secretions Hyperinflation of alveoli (air-trapping) Mucus plugging and, in severe cases, atelectasis Copyright © 2006 by Mosby, Inc. Etiology Extrinsic asthma Intrinsic asthma Slide 3 Allergic or atopic asthma Nonallergic or nonatopic asthma Copyright © 2006 by Mosby, Inc. Figure 13-2. The immunologic mechanisms in asthma. Slide 4 Copyright © 2006 by Mosby, Inc. Intrinsic Asthma (Nonallergic or Nonatopic Asthma) Slide 5 Infections Exercise and cold air Industrial pollutants or occupational exposure Drugs, food additives, and food preservatives Gastroesophageal reflux Sleep (nocturnal asthma) Emotional stress Premenstrual asthma Copyright © 2006 by Mosby, Inc. Figure 13-3. Factors triggering intrinsic asthma. Slide 6 Copyright © 2006 by Mosby, Inc. Additional Risk Factors Slide 7 Residence in a large urban area, especially the inner city Exposure to secondhand smoke A parent who has asthma Respiratory infections in childhood Low birth weight Obesity Copyright © 2006 by Mosby, Inc. Overview of the Cardiopulmonary Clinical Manifestations Associated with ASTHMA The following clinical manifestations result from the pathophysiologic mechanisms caused (or activated) by Bronchospasm (see Figure 9-10) and Excessive Bronchial Secretions (see Figure 9-11)—the major anatomic alterations of the lungs associated with asthma (see Figure 13-1). Slide 8 Copyright © 2006 by Mosby, Inc. Figure 9-10. Bronchospasm clinical scenario (e.g., asthma). Slide 9 Copyright © 2006 by Mosby, Inc. Figure 9-11. Excessive bronchial secretions clinical scenario. Slide 10 Copyright © 2006 by Mosby, Inc. Clinical Data Obtained at the Patient’s Bedside Vital signs Slide 11 Increased respiratory rate Increased heart rate, cardiac output, blood pressure Copyright © 2006 by Mosby, Inc. Clinical Data Obtained at the Patient’s Bedside Slide 12 Use of accessory muscles of inspiration Use of accessory muscles of expiration Pursed-lip breathing Substernal intercostal retractions Increased anteroposterior chest diameter (barrel chest) Cyanosis Cough and sputum production Copyright © 2006 by Mosby, Inc. Clinical Data Obtained at the Patient’s Bedside Pulsus paradoxus Slide 13 Decreased blood pressure during inspiration Increased blood pressure during expiration Copyright © 2006 by Mosby, Inc. Clinical Data Obtained at the Patient’s Bedside Chest assessment findings Slide 14 Expiratory prolongation Decreased tactile and vocal fremitus Hyperresonant percussion Diminished breath sounds Diminished heart sounds Wheezing and rhonchi Copyright © 2006 by Mosby, Inc. Figure 2-12. Percussion becomes more hyperresonant with alveolar hyperinflation. Slide 15 Copyright © 2006 by Mosby, Inc. Slide 16 Figure 2-17. As air trapping and alveolar hyperinflation develop in obstructive lung diseases, breath sounds progressively diminish. Copyright © 2006 by Mosby, Inc. Clinical Data Obtained from Laboratory Tests and Special Procedures Slide 17 Copyright © 2006 by Mosby, Inc. Pulmonary Function Study: Expiratory Maneuver Findings Slide 18 FVC FEVT FEF25%-75% FEF200-1200 PEFR MVV FEF50% FEV1% Copyright © 2006 by Mosby, Inc. Pulmonary Function Study: Lung Volume and Capacity Findings VT RV FRC N or N or IC N or ERV N or RV/TLC ratio VC Slide 19 TLC Copyright © 2006 by Mosby, Inc. Arterial Blood Gases Mild to Moderate Asthma Episode pH Slide 20 Acute alveolar hyperventilation with hypoxemia PaCO2 HCO3 (Slightly) PaO2 Copyright © 2006 by Mosby, Inc. Time and Progression of Disease Disease Onset Alveolar Hyperventilation 100 90 PaO2 or PaCO2 80 Point at which PaO2 declines enough to stimulate peripheral oxygen receptors 70 60 PaO2 50 40 30 20 10 0 Figure 4-2. PaO2 and PaCO2 trends during acute alveolar hyperventilation. Slide 21 Copyright © 2006 by Mosby, Inc. Arterial Blood Gases Severe Asthmatic Episode (Status Asthmaticus) Acute ventilatory failure with hypoxemia pH Slide 22 PaCO2 HCO3PaO2 (Significantly) Copyright © 2006 by Mosby, Inc. Time and Progression of Disease Disease Onset Alveolar Hyperventilation Acute Ventilatory Failure 100 90 Pa02 or PaC02 80 70 Point at which PaO2 declines enough to stimulate peripheral oxygen receptors Point at which disease becomes severe and patient begins to become fatigued 60 50 40 30 20 10 0 Figure 4-7. PaO2 and PaCO2 trends during acute ventilatory failure. Slide 23 Copyright © 2006 by Mosby, Inc. Oxygenation Indices QS/QT DO2 VO2 Normal O2ER Slide 24 C(a-v)O2 Normal SvO2 Copyright © 2006 by Mosby, Inc. Abnormal Laboratory Tests and Procedures Abnormal laboratory tests and procedures Sputum examination • Eosinophils • Charcot-Leyden crystals (see next slide) • Casts of mucus from small airways called Kirschman spirals • IgE level (elevated in extrinsic asthma) Slide 25 Copyright © 2006 by Mosby, Inc. Charcot-Leyden Crystals Needle shaped crystals - Represents breakdown products of eosinophils Slide 26 Copyright © 2006 by Mosby, Inc. Radiologic Findings Chest radiograph Slide 27 Increased anteroposterior diameter Translucent (dark) lung fields Depressed or flattened diaphragm Copyright © 2006 by Mosby, Inc. Figure 13-4. Chest X-ray of a 2-year-old patient during an acute asthma attack. Slide 28 Copyright © 2006 by Mosby, Inc. Table 13-1. Asthma Classification Based on Severity—Excerpts Disease Symptoms Step 4: Continual symptoms Step 3: Daily symptoms Step 2: Symptoms > than twice weekly Step 1: Symptoms < than twice weekly From McCance KL, Huether SE: Pathophysiology: The biologic basis for disease in adults and children, ed 4, St. Louis, 2002, Mosby. Slide 29 Copyright © 2006 by Mosby, Inc. Table 13-2. Asthma Zone Management System—Excerpts Green zone Yellow zone 50% to 80% of personal best PEFR Red zone Slide 30 80% to 100% of personal best PEFR <50% of personal best PEFR Copyright © 2006 by Mosby, Inc. General Management of Asthma Environmental control Respiratory care treatment protocols Slide 31 Oxygen therapy protocol Bronchial hygiene therapy protocol Aerosolized medication protocol Mechanical ventilation protocol Medications commonly prescribed Xanthines Corticosteroids Anti-inflammatory agents Leukotriene inhibitors Copyright © 2006 by Mosby, Inc. General Management of Asthma Slide 32 Monitoring Arterial blood gas measurements Pulse oximetry Serial PFTs • PEFR • FEV1 Vital signs Chest radiographs Copyright © 2006 by Mosby, Inc. General Management of Asthma Slide 33 Patient compliance Asthma-symptom/medication-use diaries Serum theophylline levels Carboxyhemoglobin determinations Total (circulating) eosinophil counts No-show rates at physician offices Rate of medication use Frequency of emergency department visits and hospitalizations Number of red zone days per months (see Table 13-2) Copyright © 2006 by Mosby, Inc. Classroom Discussion Case Study: Asthma Slide 34 Copyright © 2006 by Mosby, Inc.