Chapter 31 Disorders Of Ventilation And Gas Exchange

Question 1

Gases of respiration

Answer 1

. Primary function of respiratory system

• Remove CO2
• Addition of O2

. Insufficient exchange of gases

• Hpoxemia
• Hypercarpnia

Question 2

Hypoxemia

Answer 2

. Hypoxemia results from
- An inadequate o2 in the air
- Disease of the respiratory system
- Dysfunction of the neurological system
- Alterations in circulatory function
. Mechanisms 
- hypoventilation 
- impaired diffusion of gases
- Inadequate circulation of blood through the pulmonary capillaries 
- Mismatching of ventilation and perfusion

Question 3

Manifestations of hypoxemia

Answer 3

. Mild hypoxemia

• Metabolic acidosis
• increase in heart rate
• Peripheral vasoconstriction
• Diaphoresis
• increase in blood pressure
• Slight impairment of mental performance

Question 4

Manifestations of hypoxemia

Answer 4

. Chronic hypoxemia
- Manifestations of chronic hypoxia may be insidious in onset and attributed to other causes.
. Compensation masks condition
- Increased ventilation
-Pulmonary vasoconstriction
- Increased production of red blood cells
- Cyanosis

Question 5

Hypercapnia

Answer 5

. Increased arterial PCO2
. Caused by hyperventilation or mismatching of ventilation and perfusion 
. Effects 
- Acid - base balance
- kidney function
- nervous system function
- cardiovascular function

Question 6

Disorders of the pleura

Answer 6

. Pleural effusion: abnormal collection of fluid in the pleural cavity
- Transudate or exudate, purulent, chyle, or sanguineous
. Hemorathorax
. Pleuritis
. Chylothorax
. Atelectasis
. Empyema

Question 7

Types of pneumothorax

Answer 7

. Spontaneous pneumothorax
- Occurs when an air- filled blister on the lung surface ruptured
. Traumatic Pneumothorax
- Caused by penetrating or nonpenetrating injuries
. Tension Pneumothorax
- Occurs when the intrapleural pressure exceeds atmospheric pressure

Question 8

Causes of Disorders of Lung Inflation

Answer 8

. Conditions that produce lung compression or lung collapse

• Compression of the lung by an accumulation of fluid in the intrapleural space
• Complete collapse of an entire lung as in pneumothorax
• Collapse of a segment of the lung ad in atelectasis

Question 9

Characteristics and symptoms of pleural pain

Answer 9

. Abrupt in onset
. Unilateral; localized to lower and lateral part of the chest
. May be referred to the shoulder
. Usually made worse by chest movements
- Tidal volume are kept small
- Breathing becomes more rapid
- Reflex splinting of the chest may occur

Question 10

Pleural Effusion

Answer 10

. Definition
- An abnormal collection of fluid in the pleural cavity

. Types of fluid

• transudate
• Exudate
• Purulent drainage
• Chyle
• Blood

Question 11

Diagnosis and treatment of pleural effusion

Answer 11

. Diagnosis 
- chest radiographs, chest ultrasound 
- computed tomography (CT)
. Treatment 
- Thorencentesis
- Injection of a sclerosis agent into the pleural cavity
- open surgical drainage

Question 12

Atelectasis

Answer 12

. Definition
- the incomplete expansion of a lung or portion of a lung
. Causes
- Airway obstruction
- lung compression such as that occurs in pneumothorax or pleural effusion
- increased recoil of the lung due to loss of pulmonary surfactant

Question 13

Types of Atelectasis

Answer 13

. Primary
- present at birth

. Secondary
- develops in the neonatal period or later in life

Question 14

Physiology of Airway Disease

Answer 14

. Upper respiratory tract 
- trachea and major bronchi
. Lower Respiratory tract
- Bronchi and alveoli 
. Creation of negative pressure
. Effects of CO2/ pH
. Role of inflammatory mediators 
. Increase airway responsiveness by
- producing bronchospasm
- increasing mucus secretion
- producing injury to the mucosal lining of the airways

Question 15

Functions of Bronchial Smooth Muscle

Answer 15

. The tone of the bronchial smooth muscles surrounding the airways determines airway radius
. The presence or absence of airways secretions influences airway patency
. Bronchial smooth muscle is innervated by the autonomic nervous system
- Parasympathetic: Vagal control
. Bronchoconstrictor
- Sympathetic: B2- adrenergic receptors
. Bronchodilator

Question 16

Factors Involved in the pathophysiology of Asthma

Answer 16

. Genetic 
- Atopy
. Early versus late phase
. Environmental 
- Viruses
- Allergens
- Occupational exposure

Question 17

Classification of Asthma Severity

Answer 17

. Mild intermittent
. Mild persistent
. Moderate Persistent
. Severe Persistent

Question 18

Chronic obstructive Airway Disease

Answer 18

. Inflammation and fibrosis of the bronchial wall
. Hypertrophy of the submucosal glands
. Hypersecretion of mucus
. Loss of elastic lung fibers
- Impairs the exploratory flow rate, increase air trapping, and predispose to airway collapse
. Alveolar tissue
- Decrease the surface area for the gas exchange

Question 19

Causes of Chronic Obstructive Airway Disease

Answer 19

. Chronic Bronchitis
. Emphysema
. Bronchiectasis
. Cystic fibrosis

Question 20

Types of Chronic Obstructive Pulmonary Disease

Answer 20

. Emphysema 
- Enlargement of air spaces and destruction of lung tissue
- Types : Centriacinar and panacinar
. Chronic Obstructive Bronchitis 
- obstruction of small airways

Question 21

Characteristics of Type A pulmonary Emphysema

Answer 21

. Smoking history
. Age of onset: 40 years to 50 years 
. Often dramatic barrel chest
. Weight loss 
. Decreased breath sounds
. Normal blood gases until late in disease process
. Cor pulmonale only in advanced cases
. Slowly debilitating disease

Question 22

Characteristics of type B chronic Bronchitis # 1

Answer 22

. Smoking history
. Age of onset 30 to 40 years
. Barrel chest May be present
. Shortness of breath, a predominant early symptoms
. Rhonchi often present
. Sputum frequent, an early manifestations

Question 23

Characteristics of type B chronic bronchitis # 2

Answer 23

. Often dramatic cyanosis
. Hypercapnia and hypoxemia May be present
. Frequent cor pulmonale and polycythemia
. Numerous life- threatening episodes due to acute exacerbation

Question 24

Bronchiectasis

Answer 24

. Permanent dilation of the bronchial and bronchioles
. Secondary to persisting infection or obstruction
. Manifestations
- Atelectasis
- Obstruction of the smaller airways
- Diffuse bronchitis
- Recurrent bronchopulmomary infection
- Coughing: production of copious amounts of foul- smelling, purulent sputum, and hemoptysis
- Weight loss and anemia are common

Question 25

Cystic Fibrosis

Answer 25

. Definition - An autosomal recessive disorder involving fluid secretion in the exocrine glands and the epithelial lining of the respiratory, gastrointestinal, and reproductive tracts . Cause - Mutations in a single gene on the long arm of chromosome 7 that encodes for the cystic fibrosis transmembrane regulator ( CFTR) , which functions as a chloride ( CI-) channel in epithelial cell

Question 26

Manifestations of Cystic Fibrosis

Answer 26

``` . Pancreatic exocrine deficiency . Pancreatitis . Elevation of sodium chloride in the sweat . Excessive loss of sodium in the sweat . Nasal polyps . Sinus infections . Cholethiasis ```

Question 27

Diffuse Interstitial Lung Diseasee

Answer 27

. Definition - A diverse group of lung disorders that produce similar inflammatory and fibrotic changes in the interstitum or interalveolar septa of the lung .Types - Sarcoidosis - The occupational lung diseases - Hypersensitivity pneumonitis - Lung disease caused by exposure to toxic drugs

Question 28

Occupational Lung Disease

Answer 28

. Pneumoconionoses - The inhalation of inorganic dusts and particulate matter . Hypersensitivity diseases - The inhalation of organic dusts and related occupational antigens . Byssinosis: Cotton workers; has characteristics of the pneumoconioses and hypersensitivity lung disease

Question 29

Pulmonary Embolism

Answer 29

. Development - A blood - borne substance lodges in a branch of the pulmonary artery and obstructs the flow . Types - Thrombus : arising from DVT - Fat: mobilized from the bone marrow after a fracture or from a traumatized fat depot . Amniotic Fluid: enters the maternal circulation after rupture of the membranes at the time of delivery

Question 30

Pulmonary Hypertension

Answer 30

. Signs and symptoms of secondary pulmonary hypertension - Dyspnea and fatigue - peripheral edema - ascites - signs of right heart failure . A disorder characterized by an elevation of pressure within the pulmonary circulation . Pulmonary arterial hypertension

Question 31

Cor Pulmonale

Answer 31

. Right heart failure resulting from primary lung disease and long- standing primary or secondary pulmonary hypertension . Involves hypertrophy and the eventual failure of the right ventricle . Manifestations include the signs and symptoms of the primary lung disease and the signs of the right- sided heart failure

Question 32

Acute Respiratory Distress Syndrome

Answer 32

. A number of conditions may lead to ALI/ ARDS. . They all produce similar pathological lung changes that include diffuse epithelial cell injury with increased permeability of the alveolar- capillary membrane

Question 33

Causes of ARDS

Answer 33

``` . Aspiration of gastric contents . Major trauma . Sepsis secondary to pulmonary or non pulmonary infections . Acute pancreatitis . Hematologist disorders . Metabolic events . Reactions to drugs and toxins ```

Question 34

Causes of respiratory failure

Answer 34

``` . Impaired ventilation - upper airways obstruction - Weakness of paralysis of respiratory muscles - Chest wall injury . Impaired matching of ventilation and perfusion . Impaired diffusion - pulmonary edema - Respiratory distress syndrome ```

Question 35

Treatment of respiratory failure

Answer 35

. Respiratory supportive care directed toward maintenance of adequate gas exchange . Establishment of an airway . Use of bronchodilator drugs . Antibiotics for respiratory infections . Ensure adequate oxygenation