Chapter 24 Chronic Pulmonary Disease
Obstructive pulmonary disease
1. What are some examples of obstructive pulmonary disease?
2. What is obstructive pulmonary disease?
3. Why does arterial hypoxemia occur in patients with obstructive pulmonary disease?
4. Why does carbon dioxide retention occur in patients with obstructive pulmonary disease?
5. What are common physical, radiographic, and functional findings in patients with obstructive pulmonary disease?
Asthma
7. How is the diagnosis of asthma made?
8. What are some of the physical examination findings noted in patients with asthma during periods of normal pulmonary function? What are some of the physical examination findings noted in patients with bronchial asthma during periods of exacerbation of their asthma?
9. What are some findings found in the pulmonary function studies and flow-volume loops during asthma exacerbations?
10. What agents are commonly used for the chronic treatment of asthma?
11. How can an acute asthmatic attack be treated?
12. How should the patient with asthma be assessed preoperatively?
13. How should a patient with asthma be assessed before a thoracic or abdominal procedure?
14. Is regional anesthesia the preferred anesthetic choice in patients with bronchial asthma scheduled to undergo surgery on the extremities?
15. What is the goal of the anesthetic management of patients with asthma?
16. What agents may be used for the induction of general anesthesia in patients with asthma? What is an advantage and a disadvantage of ketamine for these patients?
17. Which neuromuscular blocking drugs are associated with histamine release? What is the concern regarding the use of these neuromuscular blocking drugs in patients with asthma?
18. What is the benefit of using a slow respiratory rate when mechanically ventilating the lungs of a patient with asthma?
19. What is a benefit of maintaining adequate hydration intraoperatively in patients with asthma and chronic obstructive pulmonary disease (COPD)?
20. What are the options for extubation of the trachea that will minimize the degree of airway hyperreactivity in response to manipulation of the endotracheal tube?
21. How can the reversal of neuromuscular blocking drugs with anticholinesterases cause bronchospasm?
22. Name five potential causes of intraoperative bronchospasm.
Chronic obstructive pulmonary disease
24. What characterizes pulmonary emphysema physiologically?
25. What characterizes chronic bronchitis physiologically?
26. How do emphysema and chronic bronchitis differ clinically?
27. Why is the work of breathing increased in patients with pulmonary emphysema?
28. For patients with COPD scheduled to undergo a surgical procedure, what should the preoperative evaluation include? When might preoperative pulmonary function tests be necessary?
29. What are some pulmonary function test and arterial blood gas measurement results that indicate that the patient is at an increased risk of postoperative respiratory failure? What are some treatment interventions that may be warranted by the preoperative evaluation of the patient’s pulmonary function?
30. What are the main considerations for the anesthetic management of patients with COPD?
31. What are some potential disadvantages of using nitrous oxide as part of a general anesthetic in patients with COPD?
32. What are two methods by which anesthesiologists may minimize the drying of secretions in the airways of patients with COPD in the intraoperative period?
33. What ventilatory settings are appropriate for intraoperative mechanical ventilation of the lungs of patients with COPD?
34. What characterizes chronic bronchitis physiologically? What is the major predisposing factor to the development of chronic bronchitis?
35. What is the impact of COPD on the postoperative course?
36. What is the clinical significance of an exacerbation of COPD, and what is its implication on an upcoming surgical procedure?
Pulmonary hypertension
37. How is pulmonary hypertension defined? What is the most common form of pulmonary hypertension?
38. What are the physiologic effects of pulmonary hypertension?
39. How can pulmonary hypertension affect the performance of the left ventricle?
40. What are the main anesthetic considerations for patients with pulmonary hypertension?
Anesthesia for lung resection
Preoperative Evaluation and Preparation
44. What are some preoperative considerations for the patient scheduled to undergo thoracic surgery?
45. What are some specific preoperative history and physical examination findings that are indicative of an increased risk of postoperative pulmonary complications after thoracic surgery?
46. What are some preoperative prophylactic measures that may be taken in an attempt to minimize postoperative pulmonary complications?
47. How does cigarette smoking affect the lungs physiologically?
48. What is the benefit of the preoperative cessation of cigarette smoking? After what duration of time after the cessation of smoking are these benefits noted to occur?
49. For which patients are preoperative pulmonary function tests indicated?
50. What values derived from pulmonary function tests are indicative of an increased risk of postoperative pulmonary morbidity after a pneumonectomy?
51. What are PPO − FEV1 (predicted postoperative FEV1) and PPO – DLCO (predicted postoperative DLCO)?
Management of Anesthesia
52. What are some benefits of the administration of volatile anesthetics for patients undergoing thoracic surgery?
53. What is a disadvantage of the administration of nitrous oxide for patients undergoing thoracic surgery?
54. What is a benefit of the administration of nondepolarizing neuromuscular blocking drugs for patients undergoing thoracic surgery?
Isolation of the lungs
55. What are some absolute indications for one-lung ventilation during surgery and anesthesia? What are some relative indications for one-lung ventilation during surgery and anesthesia?
56. What is the most frequently used double-lumen endotracheal tube used for the isolation of the right or left lung or for one-lung ventilation during thoracic surgery?
57. What is the potential problem with an endobronchial tube placed in the right bronchus for isolation of the right lung? How can this problem be avoided?
58. What size double-lumen endotracheal tube is usually appropriate for adult patients? What depth in centimeters typically places the endobronchial tube in approximately the correct position in most adult patients of average height?
59. What is the technique for placement of a left-sided double-lumen endotracheal tube? How is the proper placement of a double-lumen endotracheal tube best confirmed?
60. What is the single-lumen Univent tube? What is its potential advantage for ventilation?
61. What is a Arndt endobronchial blocker?
62. What is a Cohen tip deflecting endobronchial blocker?
63. How does a bronchial blocker compare to a double-lumen endotracheal tube?
Gas exchange during one lung ventilation
64. How does the lateral decubitus position during mechanical ventilation of the lungs affect the ventilation-to-perfusion ratio in the lungs?
65. What are four factors that influence the amount of perfusion that goes to the nondependent, unventilated lung during ventilation of a patient in the lateral decubitus position with a double-lumen endotracheal tube?
66. What are the interventions that can be made when arterial hypoxemia is noted in a patient during ventilation for thoracic surgery?
Answers*
Obstructive pulmonary disease
1. Examples of obstructive pulmonary disease include asthma, emphysema, chronic bronchitis, and cystic fibrosis. Emphysema and chronic bronchitis are overlapping clinical manifestations of the same disease – COPD. Obstructive pulmonary disease is characterized by the progressive, persistent obstruction to air flow, particularly expiratory flow. Asthma is an acute form of obstructive disease, which is treatable and at least partially reversible even when established. If asthma persists over time, either because it is untreated or because it is particularly severe, it may develop irreversible air flow obstruction and become a chronic disease not significantly different from emphysema and chronic bronchitis. (431)
2. Obstructive pulmonary disease is chiefly characterized by expiratory flow limitation due to increased airway resistance coupled with the loss of elastic lung recoil. These factors lead to lung hyperinflation, increased work of breathing, and impaired gas exchange. Obstructive pulmonary disease is the most frequent cause of chronic pulmonary disease. (431)
3. Arterial hypoxemia occurs in patients with obstructive pulmonary disease because of ventilation-perfusion mismatch. Decreased ventilation (which preferentially leads to hypoxemia) occurs because of the progressive destruction of functional alveoli. (433)
4. Carbon dioxide retention occurs in patients with obstructive pulmonary disease because of ventilation-perfusion mismatch. Both decreased ventilation and decreased perfusion (dead space) lead to hypercarbia. Initially, this is compensated by hyperventilation. As patients become older and weaker, such compensation fails, leading to chronic carbon dioxide retention. (433)
5. Patients with obstructive pulmonary disease often appear dyspneic, with a hyperinflated, “barreled” chest. Upon careful examination, you will notice a prolonged expiratory phase often terminated by obvious expiratory muscle activity – an attempt to exhale the whole tidal volume. On chest auscultation, lung sounds are distant (because of the hyperinflation), sometimes with associated wheezing. On the chest radiogram the lungs appear very “tall” and the diaphragm flattened. The lung fields may appear hyperlucent, and the vasculature may be difficult to discern. Pulmonary function studies in patients with obstructive pulmonary disease will reveal a decreased volume of the gas that can be forcefully exhaled in 1 second (FEV1). The vital capacity may also be decreased, but not to as great an extent as the FEV1, resulting in a decreased FEV1/FVC ratio. (431)
Asthma
6. Asthma is characterized by reversible expiratory flow obstruction, airway hyperreactivity, and chronic inflammation leading to airway edema, secretions, and progressive thickening. (431)
7. The diagnosis of asthma is made primarily on the clinical history of increasing coughing and wheezing spells with or without the identification of a supposed trigger. Common triggers include pollens, medications, cold air temperature, and exercise. Spirometry shows an obstructive defect (low FEV1) that is partially reversible (12% to 15%) with inhaled bronchodilators. The sputum taken from patients with asthma often contains eosinophils, in contrast to the neutrophils most commonly found in the sputum of patients with bronchitis. (341, Figure 27-1)
8. Patients with asthma during periods of normal pulmonary function are typically devoid of any signs of pulmonary disease, although scattered expiratory wheezing can still be heard. During periods of exacerbation, typical signs and symptoms include breathlessness, coughing fits, and chest tightness, associated with the objective finding of a prolonged expiratory phase and wheezing, sometimes audible without the aid of a stethoscope.
9. Pulmonary function studies during asthma exacerbations reveal a decrease in the FEV1 and FEV1/FVC. The FEV1 may be used as a measure of the degree of obstruction and the effectiveness of interventions. A flow-volume loop during an asthma exacerbation reveals a downward scooping of the expiratory phase, with a normal shape of the inspiratory phase. A significant response to a bronchodilator may normalize the aspect of the loop that is characteristic of bronchial asthma and increase the FEV1. An increase of 12% is judged clinically significant, and is used to separate asthma from COPD by functional criteria. (431-433, Figure 27-1; Table 27-1)
10. Chronic treatment of asthma includes antiinflammatory agents and bronchodilators. Inhaled corticosteroids (beclometasone and fluticasone) have potent antiinflammatory effects and are considered a mainstay of chronic asthma treatment. Long-acting β2-adrenergic agonists (salmeterol and formoterol) and anticholinergics (tiotropium) are effective bronchodilators used to treat moderate to severe asthma. Their advantage in respect to the traditional counterparts (see later discussion) is their longer duration of action that allows single daily administration. With that, they are also not indicated in the treatment of an acute exacerbation. Other antiinflammatory agents effective in the chronic (and not in the acute) setting are the leukotriene antagonists and synthesis inhibitors (montelukast, zafirlukast, and zileuton). Methylxanthines (aminophylline, theophylline) are no longer recommended in the treatment of asthma. (431-432)
11. An acute asthmatic attack should be treated with the administration of oxygen, nebulized β2
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