Patho Chapter 21: Restrictive and Obstructive Pulmonary Disorders

Total lung capacity

the volume of air in the lungs upon the maximum effort of inspiration

Bronchodilation

expansion of the bronchial air passages

Bronchoconstriction

Constriction, or blockage, of the bronchi that lead from the trachea to the lungs.

Plueral membrane

Serous membrane that surrounds the lungs and lines the thoracic cavity

P02

partial pressure of oxygen
measures the effectiveness of the lungs in pulling oxygen into the blood stream from the atmosphere.

In a healthy individual

the brainstem is stimulated to breathe by a rise in C02

The ideal PO2 ranges from

90 mm Hg to 100 mm Hg

Hypercapnia

occurs when the lungs cannot fully
expel carbon dioxide
Can develop due to: bradypnea, asphyxiation, aspiration, asthma, COPD, pneumonia, pulmonary edema, thoracic muscle paralysis

Chronic hypercapnia

Commonly seen with hypoxic lung disease

Over time, the central chemoreceptors become indifferent to an increase in C02 levels -> Peripheral chemoreceptors

Clinical symptoms: Headache, drowsiness, intellectual impairment and disorientation

Hypoxia

occurs when the lungs cannot ventilate or acquire oxygen
Compensation: Increase respiratory rate
Pulmonary artery vasoconstriction: High blood pressure in the pulmonary artery system-\>
Pulmonary hypertension -\> Cor pulmonale
Erythropoietin -\> Erythropoiesis

Chronic hypoxia

Chronic lack of oxygen that occurs with respiratory dysfunction
P02 falls below 60 mm Hg \= CRITICAL
Anaerobic metabolism -\> Lactic acid HgB begins to release oxygen

Severe hypoxia

Behavioral changes, restlessness, uncoordinated movements, impaired judgement, delirium, stupor, coma

Pulmonary disorders can be categorized as

obstructive or restrictive disease

Obstructive disease

characterized by an increase in resistance to airflow from the trachea and larger bronchi to the terminal and respiratory bronchioles.

AIRFLOW BLOCKED, OBSTRUCTED

Types of Obstructive pulmonary disorders

Asthma, COPD (Chronic bronchitis & Emphysema), Obstructive Sleep Apnea

Asthma Background

Chronic inflammatory disorder that causes reversible airway constriction due to bronchial hyperreactivity\> AIRWAY CONSTRICTS \= BLOCKED AIR FLOW
Allergies are the most common stimulus
80-85% of asthma attacks in children are
preceded by viral infection
Exercise- induced asthma

Asthma Pathophysiology

Episodes of spastic reactivity in thenbronchioles
Allergens are a common stimulus
Allergens trigger the immune system
Immune system responses:
Bronchoconstriction (Constriction of airway), Inflammation (Bronchial edema),
Increase in the size and number of Goblet cells( mucus makers) (Increase thick, mucus
Production)

Complications: Status asthmaticus: Persistent bronchoconstriction that endures despite
attempts to treat with medications; medical emergency 911

Asthma

Chronic inflammatory disorder that causes reversible bronchospasm because of bronchial hyperreactivity.

Cause and triggers: pollution, smoking, bacteria and viruses, genetics, pets, household chemicals, or dust

Clinical Presentation: Wheezing, Cough, Dyspnea, Chest tightness

Severe attacks: Accessory muscle use, Distant breath sounds, Diaphoresis(sweating)

Respiratory failure: Inaudible(silent) breath sounds, Repetitive, hacking cough

Rhonchi may be present if the large bronchial airways are involved

Chronic Obstructive Pulmonary Disease (COPD): Background

Characterized by poorly reversible airflow limitation.
3rd leading cause of death in the US
Leading cause of disability
Smoking is the most common cause
Commonly occurs in older individuals
Includes chronic bronchitis and emphysema

Chronic obstructive pulmonary disease (COPD)

is a combination of chronic bronchitis, emphysema, and hyperreactive airway disease
Complications: Peripheral chemoreceptors are dependent
on hypoxia to trigger respirations

COPD Pathophysiology Chronic Bronchitis

Inflammation, edema and excess mucus production
Hypersecretion of mucus in the large and small airways \> Creates obstruction to inspiratory airflow \> Inhibits oxygenation \> Atelectasis (partial or completer collapsed lung)
Diagnostic criteria: Cough for 3 months out of the year for 2 consecutive years
Inflammatory changes cause permanent remodeling of the airway
Severe: Persistent poor ventilation and hypoxia stimulates vasoconstriction

COPD Pathophysiology Emphysema

Overdistention of alveoli with trapped air \>Creates obstruction to expiratory airflow, loss of elastic recoil and retention of C02 in the lungs

BOTH Chronic bronchitis and Emphysema

Airways are hypersensitive

Severe disease leads to chronic hypoxia and chronic hypercapnia

Pulmonary hypertension

Peripheral chemoreceptors

Clinical Presentation: Dyspnea, cough, wheezing Severe disease: Tachypnea, accessory muscle use

Pulmonary hypertension

High blood pressure in the pulmonary arteries.
Primary: Genetic disorder Secondary: Result of another disease process. COPD, chronic hypoxia
As pulmonary hypertension progresses, right ventricular failure worsensleading to diminished cardiac output. Clinical Presentation:Syncope, dyspnea on exertion, fatigue

Peripheral chemoreceptors

found in the aortic arch and bifurcation of the carotid artery (called carotid bodies), respond primarily to a decrease in arterial oxygen.

Chronic bronchitis Clinical Presentation

Problem: Cannot get 02 in

BLUE BLOATERS: chronic Hypoxia, cyanosis

Clubbing of the fingers

Edema due to heart failure

Severe: Signs of right-sided heart failure (cor pulmonale) due to pulmonary Hypertension.

JVD, ascites, hepatosplenomegaly, ankle edema

Emphysema Clinical Presentation

Problem: Cannot get C02 out
PINK PUFFERS: Well-oxygenated until late Stage. Pursed-lip breathing
Well oxygenated until the disease becomes severe
Barrel-shaped chest: Width and depth are \= Prolonged exhalation using pursed lip breathing

Apnea

Reduction in airflow by 90% for at least 10 seconds

Obstructive Sleep Apnea (OSA)

Upper airway obstruction caused by intermittent collapse of the upper airway tissues.
Patients experience sleep disturbances, daytime sleepiness, and hypoxemia
Risk Factor: Obesity is the most common risk factor

Obstructive Sleep Apnea (OSA) Clinical Presentation

Symptoms include snoring, choking or gasping in sleep, and unrestful sleep Diagnosis requires a sleep study
Treatment: Use of continuous positive airway pressure (CPAP) while sleeping. This forces air through the nasal passages to keep airways from closing.

Restrictive disease

is characterized by reduced expansion of lung tissue with decreased total lung capacity.
REDUCED EXPANSION
Types of pulmonary restrictive disorders-Pneumothorax, Pleural effusion

Pleural cavity (AKA pleural space)

Space between the outer layer of the
pleural membrane and the inner layer of the pleural membrane.
Vacuum: Only thing in this space is surfactant. There should not be any other air or fluid. Negative intrathoracic pressure
The pleural space

Pneumothorax

most common restrictive disease

Pathophysiology: The presence of air in the pleural cavity that causes collapse of a large section or whole lobe of lung tissue.
Can be either spontaneous or
caused by trauma.

Pneumothorax Complication- Tension pneumothorax
Air continues to build up in the pleural cavity and causes compression of not only the lungs but also the trachea, cardiac structures and vena cava.
Air can enter the pleural space but not exit.

Clinical Presentation: Hypoxemia, tracheal deviation
Medical emergency!!

Pneumothorax Clinical presentation

Chest pain, dyspnea, tachypnea, accessory muscle use
May be an obvious asymmetry of the chest
Auscultation: Diminished or absent breath sounds on the affected side

Pleural Effusion Pathophysiology

Abnormal collection of fluid within the pleural cavity that compresses lung tissue and inhibits lung inflation.
Commonly edematous fluid that accumulates because of heart failure, severe pulmonary infection or cancer.
Fluid can be: Exudate (Thin, watery), Purulent: (Pus), Lymph, Sanguineous (Blood)

Pleural Effusion Clinical Presentation

Dyspnea, tachypnea, sharp pleuritic chest pain
Auscultation: Diminished breath sounds on the affected side

Pulmonary Edema: Pathophysiology

Accumulation of fluid around the alveoli
Fluid inhibits oxygen transfer
Causes: Left- sided heart failure: Weakened left ventricle cannot eject all of the blood within the chamber causing blood to accumulate in the left ventricle.
The pressure builds all the way back to the pulmonary capillaries causing fluid from the blood to diffuse into the interstitial tissues.

Pulmonary Edema Clinical Presentation

SEVERE respiratory distress: Pink, frothy sputum, Hypoxia, Auscultation: Coarse, loud crackles, Extreme shortness of breath

suffocation in own fluid

Medical emergency!!

Pulmonary Embolism (PE)

A blood clot that has traveled to the pulmonary arterial circulation > obstruction of blood flow in the lungs Clot commonly originates from a deep vein thrombosis (DVT) in an extremity Pulmonary Embolism (PE)

Clinical Presentation- Sudden shortness of breath, chestpain, tachycardia, death

leading cause of death

Medical emergency!!

Adult (Acute) Respiratory Distress Syndrome (ARDS)

Pulmonary dysfunction characterized by: Alveolar injury, Pulmonary capillary damage, Bilateral pulmonary infiltrates, Sudden, progressive pulmonary edema, Severe hypoxemia
Sepsis is the most common risk factor

Adult (Acute) Respiratory Distress Syndrome (ARDS) Clinical Presentation

Acute onset of respiratory distress
Severe hypoxemia: Decreased level of consciousness, tachycardia, diminished circulation, sweating, restlessness and anxiety.
Auscultation: Crackles