Exchange Gases of Respiration Primary function of respiratory system Remove CO 2 Addition of O 2 Insufficient exchange of gasses Hypoxemia Hypercapnia Hypoxemia Hypoxemia results from An inadequate O ID: 774828
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Slide1
Chapter 31:
Disorders of Ventilation and Gas
Exchange
Slide2Gases of Respiration
Primary function of respiratory system
Remove CO
2
Addition of O
2
Insufficient exchange of gasses
Hypoxemia
Hypercapnia
Slide3Hypoxemia
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
Slide4Manifestations of Hypoxemia #1
Mild hypoxemia
Metabolic acidosis
Increase in heart rate
Peripheral vasoconstriction
Diaphoresis
Increase in blood pressure
Slight impairment of mental performance
Slide5Manifestations 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
Slide6Hypercapnia
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
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
Slide8Types 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
Slide9Causes 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
Slide10Characteristics 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.
Slide11Pleural Effusion
Definition
An abnormal collection of fluid in the pleural cavity
Types of fluid
Transudate
Exudate
Purulent drainage (empyema)
Chyle
Blood
Slide12Diagnosis 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
Slide13Atelectasis
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
Slide14Types of Atelectasis
Primary
Present at birth
Secondary
Develops in the neonatal period or later in life
Slide15Question #1
Which of the following is a disorder caused by abnormal accumulation of fluid in the pleural space?
Pneumothorax
Pleural effusion
Atelectasis
Hypercapnia
Slide16Answer to Question #1
B. Pleural effusion
Rationale: Pleural effusion can be caused by transudate, exudate, chyle, or other fluid.
Slide17Physiology 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
Slide18Functions 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
Slide19Factors 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
Slide20Factors Involved in the Pathophysiology of Asthma
Genetic
Atopy
Early versus late phase
Environmental
Viruses
Allergens
Occupational exposure
Slide21Classifications of Asthma Severity
Mild intermittent
Mild persistent
Moderate persistent
Severe persistent
Slide22Question #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
Slide23Answer to Question #2
C.
Diet
Rationale: Diet does not affect the respiratory tract other than via allergic reactions.
Slide24Chronic 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
Causes of Chronic Obstructive Airway Disease
Chronic bronchitis
Emphysema
Bronchiectasis
Cystic fibrosis
Slide26Types 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
Slide27Characteristics 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
Slide28Characteristics 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
Slide29Characteristics 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
Slide30Bronchiectasis
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.
Slide31Cystic 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
Slide32Manifestations 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
Slide33Diffuse 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
Slide34Occupational 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
Slide35Pulmonary 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
Slide36Pulmonary 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
Slide37Cor 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.
Slide38Acute 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.
Slide39Causes 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
Slide40Causes 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
Slide41Treatment 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
Slide42Question #3
Which of the following has been implicated as a causative factor in right ventricular failure?
Cor pulmonale
Pneumothorax
Cystic fibrosis
ARDS
Slide43Answer to Question #3
A. Cor pulmonale
Rationale: Cor pulmonale will result in RV failure due to the increase in workload that will result.