Chapter 31: Disorders of Ventilation and Gas - PowerPoint Presentation

Slide1

Chapter 31:

Disorders of Ventilation and Gas

Exchange

Slide2

Gases of Respiration

Primary function of respiratory system

Remove CO

2

Addition of O

2

Insufficient exchange of gasses

Hypoxemia

Hypercapnia

Slide3

Hypoxemia

Hypoxemia results from

An inadequate O

2

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

Slide4

Manifestations of Hypoxemia #1

Mild hypoxemia

Metabolic acidosis

Increase in heart rate

Peripheral vasoconstriction

Diaphoresis

Increase in blood pressure

Slight impairment of mental performance

Slide5

Manifestations of Hypoxemia #2

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

Slide6

Hypercapnia

Increased arterial PCO

2

Caused by

hypoventilation or mismatching of ventilation and perfusion

Effects

Acid–base balance (decreased pH, respiratory acidosis)

Kidney function

Nervous system function

Cardiovascular function

Slide7

Disorders of the Pleura

Pleural effusion:

abnormal collection of fluid in the pleural cavity

Transudate or exudate, purulent (containing pus), chyle, or sanguineous (bloody)

Hemothorax

Pleuritis

Chylothorax

Atelectasis

Empyema

Slide8

Types of Pneumothoraxes

Spontaneous Pneumothorax

Occurs when an air-filled blister on the lung surface ruptures

Traumatic Pneumothorax

Caused by penetrating or nonpenetrating injuries

Tension Pneumothorax

Occurs when the intrapleural pressure exceeds atmospheric pressure

Slide9

Causes of Disorders of Lung Inflation

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 as in atelectasis

Slide10

Characteristics and Symptoms of Pleural Pain

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 volumes are kept small.

Breathing becomes more rapid.

Reflex splinting of the chest may occur.

Slide11

Pleural Effusion

Definition

An abnormal collection of fluid in the pleural cavity

Types of fluid

Transudate

Exudate

Purulent drainage (empyema)

Chyle

Blood

Slide12

Diagnosis and Treatment of Pleural Effusion

Diagnosis

Chest radiographs, chest ultrasound

Computed tomography (CT)

Treatment:

directed at the cause of the disorder

Thoracentesis

Injection of a sclerosing agent into the pleural cavity

Open surgical drainage

Slide13

Atelectasis

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

Slide14

Types of Atelectasis

Primary

Present at birth

Secondary

Develops in the neonatal period or later in life

Slide15

Question #1

Which of the following is a disorder caused by abnormal accumulation of fluid in the pleural space?

Pneumothorax

Pleural effusion

Atelectasis

Hypercapnia

Slide16

Answer to Question #1

B. Pleural effusion

Rationale: Pleural effusion can be caused by transudate, exudate, chyle, or other fluid.

Slide17

Physiology of Airway Disease

Upper respiratory tractTrachea and major bronchiLower respiratory tractBronchi and alveoliCreation of negative pressureEffects 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

Slide18

Functions of Bronchial Smooth Muscle

The tone of the bronchial smooth muscles surrounding the airways determines airway radius.

The presence or absence of airway secretions influences airway patency.

Bronchial smooth muscle is innervated by the autonomic nervous system.

Parasympathetic: vagal control

Bronchoconstrictor

Sympathetic:

β

2

-

adrenergic

receptors

Bronchodilator

Slide19

Factors Contributing to the Development of an Asthmatic Attack

Allergens

Respiratory tract infections

Exercise

Drugs and chemicals

Hormonal changes and emotional upsets

Airborne pollutants

Gastroesophageal reflux

Slide20

Factors Involved in the Pathophysiology of Asthma

Genetic

Atopy

Early versus late phase

Environmental

Viruses

Allergens

Occupational exposure

Slide21

Classifications of Asthma Severity

Mild intermittent

Mild persistent

Moderate persistent

Severe persistent

Slide22

Question #2

Which of the following has not been implicated in the development of asthma?

Allergens

Respiratory tract infections

Diet

Drugs and chemicals

Hormonal changes and emotional upsets

Airborne pollutants

Gastroesophageal reflux

Slide23

Answer to Question #2

C.

Diet

Rationale: Diet does not affect the respiratory tract other than via allergic reactions.

Slide24

Chronic Obstructive Airway Disease

Inflammation and fibrosis of the bronchial wall

Hypertrophy of the submucosal glands

Hypersecretion of mucus

Loss of elastic lung fibers

Impairs the expiratory flow rate, increases air trapping, and predisposes to airway collapse

Alveolar tissue

Decreases the surface area for gas exchange

Slide25

Causes of Chronic Obstructive Airway Disease

Chronic bronchitis

Emphysema

Bronchiectasis

Cystic fibrosis

Slide26

Types of Chronic Obstructive Pulmonary Disease

Emphysema

Enlargement of air spaces and destruction of lung tissue

Types:

centriacinar

and

panacinar

Chronic Obstructive Bronchitis

Obstruction of small airways

Slide27

Characteristics of Type A Pulmonary Emphysema

Smoking history

Age of onset: 40 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

Slide28

Characteristics of Type B Chronic Bronchitis #1

Smoking history

Age of onset 30 to 40 years

Barrel chest may be present

Shortness of breath, a predominant early symptom

Rhonchi often present

Sputum frequent, an early manifestation

Slide29

Characteristics of Type B Chronic Bronchitis #2

Often dramatic cyanosis

Hypercapnia and hypoxemia may be present.

Frequent cor pulmonale and polycythemia

Numerous life-threatening episodes due to acute exacerbations

Slide30

Bronchiectasis

Permanent dilation of the bronchi and bronchioles

Secondary to persisting infection or obstruction

Manifestations

Atelectasis

Obstruction of the smaller airways

Diffuse bronchitis

Recurrent bronchopulmonary infection

Coughing; production of copious amounts of foul-smelling, purulent sputum; and hemoptysis

Weight loss and anemia are common.

Slide31

Cystic Fibrosis

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 (Cl

−

) channel in epithelial cell

Slide32

Manifestations of Cystic Fibrosis

Pancreatic exocrine deficiency

Pancreatitis

Elevation of sodium chloride in the sweat

Excessive loss of sodium in the sweat

Nasal polyps

Sinus infections

Cholelithiasis

Slide33

Diffuse Interstitial Lung Diseases

Definition

A diverse group of lung disorders that produce similar inflammatory and fibrotic changes in the interstitium or interalveolar septa of the lung

Types

Sarcoidosis

The occupational lung diseases

Hypersensitivity pneumonitis

Lung diseases caused by exposure to toxic drugs

Slide34

Occupational Lung Diseases

Pneumoconioses

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

Slide35

Pulmonary Embolism

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

Slide36

Pulmonary Hypertension

Signs and Symptoms of Secondary Pulmonary Hypertension

Dyspnea and fatigue

Peripheral edema

Ascites

Signs of right heart failure (cor pulmonale)

A disorder characterized by an elevation of pressure within the pulmonary circulation

Pulmonary arterial hypertension

Slide37

Cor Pulmonale

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 right-sided heart failure.

Slide38

Acute Respiratory Distress Syndrome

A number of conditions may lead to ALI/ARDS.

They all produce similar pathologic lung changes that include diffuse epithelial cell injury with increased permeability of the alveolar–capillary membrane.

Slide39

Causes of ARDS

Aspiration of gastric contents

Major trauma (with or without fat emboli)

Sepsis secondary to pulmonary or nonpulmonary infections

Acute pancreatitis

Hematologic disorders

Metabolic events

Reactions to drugs and toxins

Slide40

Causes of Respiratory Failure

Impaired ventilation

Upper airway obstruction

Weakness of paralysis of respiratory muscles

Chest wall injury

Impaired matching of ventilation and perfusion

Impaired diffusion

Pulmonary edema

Respiratory distress syndrome

Slide41

Treatment of Respiratory Failure

Respiratory supportive care directed toward maintenance of adequate gas exchange

Establishment of an airway

Use of bronchodilating drugs

Antibiotics for respiratory infections

Ensure adequate oxygenation

Slide42

Question #3

Which of the following has been implicated as a causative factor in right ventricular failure?

Cor pulmonale

Pneumothorax

Cystic fibrosis

ARDS

Slide43

Answer to Question #3

A. Cor pulmonale

Rationale: Cor pulmonale will result in RV failure due to the increase in workload that will result.