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.