6. Pulmonary

Pulmonary Disease Notes

Impact of Lung Disease

• COPD is the 4th leading cause of death in the US.

• Over 50% of Americans with lung disease are undiagnosed.

• Lung disease directly impacts exercise and ADLs, requiring modifications to physical therapy recommendations.

• Smoking statistics:

  • 1960: 55% ♂ / 30% ♀

  • 2008: 22.8% ♂ / 18.5% ♀

  • 2016: 18.6% ♂ / 14.3% ♀

  • 2021: 13% ♂ / 10% ♀

• Patients with chronic respiratory disorders are at risk for acute exacerbations, ER visits, hospitalization, and co-morbidities.

• Chronic lung disorders result in chronic modification of ADLs and therapeutic interventions.

Leading Causes of Death in US (2021)

• 1. Heart disease

• 2. Cancer

• 3. Medical errors (under-documented)

• 4. COPD (Chronic lower respiratory disease)

• 5. Accidents

• 6. Stroke

• 7. Alzheimer’s disease

• 8. Diabetes

• 9. Influenza & pneumonia

• Kidney disease

Pulmonary A&P Review

• Upper airways: above larynx (vocal cords); includes nasopharynx, oropharynx, laryngopharynx.

• Vocal cords division.

• Lower airways: below larynx; includes conducting zone & respiratory zone.

Pulmonary A&P Review (Continued)

• Conducting Zone: Trachea -> Bronchi -> Bronchiole -> Terminal Bronchiole (23-24 bifurcations).

• Respiratory Zone: Respiratory bronchioles -> Alveolar Duct -> Alveolar Sac -> Alveoli.

• Respiratory Zone: Actual interface of alveoli with capillary beds (AC membrane) for exchange of CO2 and O2 with RBCs.

• O2/CO2 exchange (respiration).

• Gases diffuse from high concentration to low concentration.

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Infrastructure of Alveolar-Capillary Interface

• Alveolar Type I cell: compose the actual structure of the cell.

• Alveolar Type II cell: produce surfactant to prevent alveolar collapse.

• Alveolar Type III cell: alveolar macrophage (housekeeping).

• Surface Area of Type I cells (300 million) is 70 m^2 (tennis court).

Ventilation vs. Respiration

• Respiration: O2/CO2 exchange through A/C membrane in the Respiratory Zone.

• Ventilation: mechanical movement of gas in and out of lungs as a function of thorax musculature, lung compliance, and airway resistance.

• Control of ventilation: neuro-chemical through carotid bodies and CSF response through BBB.

• Hypercapnic drive vs. hypoxic drive.

Ventilatory Muscles

• Muscles of resting ventilation:

  • Inspiration: diaphragm.

  • Expiration: none (passive recoil of thorax).

• Muscles of active ventilation (accessory muscles):

  • Inspiration: sternocleidomastoid, external intercostals, scalene, trapezius, pectoralis major/minor.

  • Expiration: internal intercostals, transverse abdominis, external/internal obliques, serratus, latissimus dorsi.

Pulmonary Function Test (PFTs)

• Primary method for Dx/stage lung disease.

• Total Lung Capacity:

  • The Volume of Air in the Lungs After a Maximum Inhalation

• Tidal Volume:

  • The Volume of Air Inhaled or Exhaled During Normal Breathing

• Vital Capacity:

  • The Maximum Amount of Air a Person Can Exhale After a Maximum Inhalation

• Inspiratory Reserve Volume:

  • The Maximum Amount of Extra Air That Can Be Inhaled Above Tidal Volume

• Expiratory Reserve Volume:

  • The Maximum Amount of Extra Air That Can Be Exhaled Beyond Tidal Volume

• Residual Volume:

  • The Volume of Air Remaining in the Lungs After a Maximum Exhalation

Pulmonary Signs and Symptoms

• Sign (objective finding perceived by examiner) vs Symptom (subjective indicator of disease or change as perceived by the patient).

• Cough.

• Dyspnea.

• Abnormal sputum.

• Chest pain/discomfort.

• Hemoptysis.

• Cyanosis.

• Digital clubbing.

• Altered breathing patterns.

Digital Clubbing

• Fingers & toes.

Altered Breathing Patterns & Sounds

• Hyperventilation (hyperpnea vs. tachypnea).

• Hypoventilation (hypopnea vs, bradypnea).

• Stridor (high-pitched inspiratory sound).

• Wheeze (musical expiratory sound).

• Crackles (known as rales, crackling inspiratory sound).

Aging and the Respiratory System

• Normal physiologic changes.

• Senile emphysema (shrinking “tennis court”).

• Chest wall compliance decreases (ribs ossification, joints stiffening).

• Elastic recoil of lungs decreases (loss of muscle fiber).

• Overall decreased ventilatory capacity with reduced VC, increased RV, decreased exercise tolerance (increased DOE and SOB).

Classification of Lung Diseases

• Physiology of Restrictive vs. Obstructive Lung Disease.

• Both classified/diagnosed through patient Hx, chest assessment, CXR, ABGs, and PFTs.

• Restrictive Pulmonary Disease: generally the “inability to take a deep breath

  ” due to restriction (stiffening) of lung tissue or the thorax or neurological disorder.

• Obstructive Pulmonary Disease: generally the “inability to exhale each breath completely

  ” due to a reduced expiratory airflow from obstruction of the airways.

Obstructive Lung Disease

• Acute or Chronic; Reversible or Non-reversible.

• Termed COPD in US and COLD in Europe.

• Prolonged expiratory time required by patient to empty lungs due to thoracic pressure dynamics.

• Following heart disease, 2nd most debilitating disease of adults under 65 and 3rd leading cause of death (Pack-Years > 60).

• Environmental irritants cause exacerbations & increase morbidity/mortality rates.

• Diagnosis/management of COPD recognized world-wide using Global Initiative for Chronic Obstructive Lung Disease (GOLD) standards through NHLBI and WHO.

Acute Obstructive Lung Diseases

• Acute bronchitis: inflammation of trachea and bronchi with a bacterial or viral etiology.

• Asthma: potentially reversible obstructive

  airways disease caused by increased Raw due to hyperactivity in the presence of personal airway triggers; may potentially return to normal lung function.

• Croup and epiglottis: acute obstruction of upper airways.

Chronic Obstructive Lung Diseases

• Chronic bronchitis, emphysema, asthma.

• Term COPD used when CB and emphysema present concurrently.

• Also cystic fibrosis (CF), bronchiectasis, bronchiolitis.

Emphysema

• Anatomic Definition: permanent destruction of alveoli, connective tissue, and capillary beds resulting in hyper-inflation (air trapping) with loss of elastic recoil of lung tissue.

• Centrilobular: cigarette smoking (60 pack-yrs).

• Panlobular: genetic (alpha1-antitrypsin deficiency)

• Loss of elasticity and alveoli -> air trapping -> barrel chest (1:1) -> increased WOB/DOE -> weight loss/difficulty eating -> accessory muscle hypertrophy.

• Progressive anatomic changes:

  • Loss of “tennis court” AC interface -> increased pulmonary vascular resistance -> cor pulmonale -> increased pedal edema, palpable liver, JVD’s in neck.

  • Increased SOB at rest -> increased sedentary lifestyle.

Emphysema PFTs Diagnosis & Staging

• Increased lung volumes.

• Reduced expiratory flow rates.

• Decreased diffusion capacity due to loss of capillary beds.

• Limitation of thoracic cage expansion and diaphragmatic excursion.

• V/Q ratio near normal due to focused work on breathing. Pursed-lip breathing helps keep alveoli from collapsing. Described as “pink puffer.”

• Tx: Disease is progressive with low flow O_2 primary support, possible corticosteroids during exacerbations, inhaled bronchodilators when indicated, when cor pulmonale presents < 6 months survival.

Chronic Bronchitis

• Clinical definition: chronic productive

  cough for 3 months out of year for 2 consecutive years.

• Chronic irritation of airways -> inflammation, edema, excessive mucous production, hyperplastic mucous glands, physical obstruction of large and small airways by mucous, normal mucous clearance impeded due to increased viscosity.

• Initially NORMAL alveoli!

• Cyanosis “Blue Bloater” characteristics with poor ventilation.

• Hypercapnea and hypoxia increase pulmonary vascular pressure resulting in early cor pulmonale.

• Polycythemia, digital clubbing, similar PFT changes as seen with emphysema except normal diffusion rates.

• Treatment: O_2, mucolytic Rx, bronchodilators, corticosteriods, low-carb diet, chest physiotherapy or postural drainage/percussion.

COPD Implications for PT

• Chest physical therapy: postural drainage, breathing techniques (pursed-lip breathing), segmental resistance, breathing exercises to strengthen ventilatory muscles (inspiratory/expiratory trainers), physical training to combat general deconditioning, posture training.

• Instruct in energy conservation.

• Monitor O_2 saturation and HR.

Asthma

• Characterized by airway hyperreactivity to various external/internal stimuli with recurrent episodes of intermittent reversible airway obstruction due to bronchospasm and mucous production.

• Extrinsic (Allergic/Type I): most common in children, due to IgE documented An/Ab rxt.

• Intrinsic (Non-Allergic/Type II): adult onset, triggered by cold air, exercise, emotions, drugs.

• Prevalence doubled in US since 1980 and increased by 400% in children.

Asthma Triggers

• Extrinsic stimuli:

  • Pollens (tree, grass).

  • Animal dander.

  • Feathers.

  • Mold spores.

  • Household dust.

  • Foods (nuts, shellfish).

• Intrinsic stimuli:

  • Inhaled irritants (smoke, pollution, sprays).

  • Weather (high humidity, cold, fog).

  • Respiratory infections (common cold, bronchitis).

  • Drugs (ASA, other NSAID- OTC).

  • Emotions (stress).

  • Exercise (super airway cooling).

Asthma Pathogenesis (know general story)

• Mechanism of reaction (Immediate response):

  • Triggers may vary with each incident.

  • Activation of T-cells (TH2) begins leukotriene pathway “domino” reaction.

  • Activation of B-cells and eosinophils.

  • Production of IgE by B cells.

  • Binding of IgE with degranulation of mast cells lining TB tree.

  • Release of histamines, SRSA, cytokines, eosinophils.

  • Results in smooth muscle contraction along TB tree.

• Mechanism of reaction (Delayed response):

  • 4-8 hours after initial acute bronchospasm event, the delayed response brings additional bronchospasm due to release of mast cell components into bloodstream.

  • Results in airway edema (swelling) with copious mucous production.

Asthma Clinical Manifestations

• Recurrent paroxysmal attacks of cough, chest tightness, and difficult breathing, often accompanied by wheezing.

• Thick, tenacious sputum, which may be difficult to expectorate.

• Patient may be symptom-free between attacks or may be in chronic state of mild asthma.

• Hyperinflated lungs with prolonged expiration and diminished breath sounds.

Asthma Treatment

• Bronchodilators (smooth muscle relaxants) (eg, albuterol, theophylline, ipratropium).

• Anti-inflammatory drugs (eg, corticosteroids, cromolyn sodium).

• Leukotriene synthesis or receptor blockers (eg, zileuton, zafirlukast, montelukast).

• Recurrent events = airway remodeling.

• Prevention of triggers.

Cystic Fibrosis

• Etiology: Inherited disease transmitted as autosomal recessive trait.

• 1 genetic defect among Caucasians—simple Mendelian cross (25/50/25 per pg).

• 1 in 38 individuals carried one of the 98 CFTR mutations.

CF (Continued)

• Genetic defect on Chromosome #7 with blockage of Cl- ion transmission across cell membrane in mucus-secreting cells (inability to reabsorb Cl-).

• CFTR (CF transmembrane regulator) protein, which forms chloride channel in some cells, does not function properly.

CF Pathogenesis

• CF results in dysfunction of exocrine system.

  • Mucus-secreting glands→symptoms in lungs, pancreas, bile ducts, intestine.

  • Exocrine glands (most common type of sweat gland).

  • Pancreatic exocrine glands (mucus blocks ducts→fibrosis→↓ secretion of digestive enzymes, possible including ↓ insulin secretion).

• Normal lungs at birth.

• Eventual Pulmonary obstruction occurs due to large quantity of tenacious mucus secreted in bronchi, atelectasis from mucus plugs, respiratory infections, developing COPD changes.

CF Diagnosis

• ↑ NaCl in sweat due to abnormal reabsorption of Cl- in sweat gland duct; Sweat Test used to diagnose.

• 80% of affected children have abnormalities in pancreatic secretion that can→malabsorption of lipids and possibly other nutrients and steatorrhea.

• Bile duct obstruction→liver damage→portal hypertension and splenomegaly.

• Intestinal obstruction in newborn due to thick mucus (Meconium ileus).

• The earlier diagnosed (symptomatically) the more severe the course; DNA testing to determine degree of Chromosome #7 aberration.

CF Prognosis

• CF seen in newborns, children, young adults; prognosis is variable, with median lifespan of about 34 yrs.

• Usually fatal due to respiratory complications.

• There is some success using gene therapy to open Cl- channels in airway epithelial cells.

• PFTs used for staging.

CF Treatment

• Pharmacologic tx:

  • Bronchodilators, mucolytic expectorants to maintain airway patency.

  • Systemic glucocorticoids to limit airway inflammation.

  • Antibiotics to tx respiratory infections.

• Pulmonary hygiene:

  • Postural drainage/airway clearance (Percussion vest).

  • Breathing exercises (PEP, IPPV).

• Lung transplantation.

CF Implications for PT

• Monitor for s/s of pulmonary exacerbation in CF.

• Teach chest PT and breathing exercises.

• Encourage proper nutrition (low fat diet).

• Design and teach exercise programs.

• Manage osteoporosis in late-stage CF.

• We want the coughing

Restrictive Lung Disease

• Any lung condition that prevents the patient from breathing deeply.

• Diagnosed via PFTs showing characteristic ↓ in TLC and VC with normal flowrates (insp/expir).

• Also called restrictive lung dysfunction, restrictive alterations in pulmonary function.

RLD Etiology

• Respiratory center depression

• Neuromuscular problem

• Thoracic deformity

• Trauma

• Obesity

• Pregnancy

• Pleural disorders

• Pleural effusion

• Pneumothorax

• Pulmonary fibrosis

• TB

• Atelectasis

• ARDS

• Pulmonary edema

• Aspiration pneumonia

Atelectasis

• “airless state of the lung” involving collapse of alveoli or incomplete expansion at birth.

• Causes of collapse:

  • Compression (eg, tumor, hematoma).

  • Airway obstruction (eg, by secretions that collect after surgery if patient does not cough or breathe deeply).

  • Lack of surfactant (eg, hyaline membrane disease, ARDS).

Pulmonary Edema

• Excess fluid accumulation in interstitial tissues, alveoli or both.

• Most common cause left ventricular failure (CHF), but may include many non-cardiac issues like drug overdose, high altitude, diving/submerging, sepsis, medications, smoke inhalation, noxic gas, blood transfusion rxt, shock, IV fluid overload, or DIC.

• Fluid outside the alveoli compress it, fluid inside alveoli prevent O2/CO2 exchange, hypoxia results with ñWOB.

• Tx: diuretics, O_2$$, Beta 1 & 2 Rx.

• Prognosis: potentially reversible, but may lead to respiratory failure.

RLD – Tuberculosis (TB)

• Was once leading cause of death in U.S.

• Still one of top causes of death in world.

• 15,000 new cases annually in US (250-300 in Alabama).

• Caused by infection with Mycobacterium tuberculosis.

• Characterized by granulomas, caseous necrosis, and cavity formation.

• Transmission: airborne.

• Primary versus secondary infection.

• Multi-drug resistant TB.

TB (Continued)

• At-risk groups:

  • Immunocompromised

  • Crowded living conditions

TB Transmission

• Primary TB: inhalation of Mycobacterium tuberculosis from infected (Secondary TB).

• + TB skin test denotes exposure.

• Body forms Ghon foci calcification around MTB.

• Time bomb? May choose to tx with INH x 1 year.

• Secondary (post-Primary or Reactivation):

  • Not due to exogenous infection, rather reinfection of endogenous TB.

• TB treatable but difficult to recognize.

• Symptoms subtle, easy to ignore, nonspecific (eg, cough, phlegm production, weight loss, dyspnea, night sweats, fever, malaise, anorexia).

• Diagnosis: H&P, TB skin test, chest radiograph, microscopic examination and culture of sputum.

• During Secondary Infection, person is extremely contagious and should be placed in respiratory isolation until after 10-14 days of anti-TB Rx.

• Pharmacologic tx:

  • Agents that inhibit bacterial protein synthesis on DNR/RNA (INH, rifampin, pyrazinamide).

  • Agents that inhibit bacterial DNA/RNA synthesis and function (eg, ethambutol, rifampin).

• Recommended duration: 6-9 months.

• Rx side effects may include liver damage, hepatitis, temporary blindness (optic nerve toxicity), temporary loss of hearing.

• RESPIRATORY ISOLATION (mask only).

RLD: Aspiration Pneumonia

• Aspiration: inhalation of foreign material, usually food, drink, or vomit; common sequelae of stroke, seizure.

• Aspiration pneumonia: inflammation of lungs that results from aspiration.

• Introduction of aerobic and anaerobic bacteria into lungs, difficult to treat/resolve.

RLD: Acute Respiratory Distress Syndrome (ARDS)

• Acute respiratory failure due to systemic or pulmonary insult (eg, sepsis, trauma, major surgery).

• Also called adult respiratory distress syndrome, shock lung, hyaline membrane disease (adult or newborn), diffuse alveolar damage.

• Often fatal (80% mortality rate for patients >35 yrs and 20% fatal for patients <35 yrs).

• Pathogenesis: damage to alveolar epithelium and capillary endothelium→ pulmonary edema → “drowning” at cellular level.

• Onset: within 12-48 hrs, w/ initial presentation of ↑ RR (shallow, rapid).

• Characterized by dropping SaO2 while increasing FIO2

• Neonates benefit from surfactant replacement Rx

• Adults do not benefit from surfactant Rx