Obstructive Lung Disease: Patient Assessment and Management

1. OVERVIEW: What Is Obstructive Lung Disease?

• Katzung's Basic and Clinical Pharmacology, 16th Edition

2. PATIENT ASSESSMENT

2a. History and Symptoms

• Chronic cough with sputum production (defining feature of chronic bronchitis: productive cough ≥3 months/year for ≥2 consecutive years)
• Dyspnea - progressive, worsening on exertion
• Wheeze and chest tightness
• Exercise intolerance (hallmark of advanced disease)
• Exacerbation history: number per year, hospitalizations

• Cigarette smoking (primary risk factor - recognized even in smokers with "normal" spirometry)
• Older age
• Environmental/occupational exposures
• Alpha-1 antitrypsin deficiency (genetic)

• mMRC dyspnea scale (0-4)
• CAT score (COPD Assessment Test, 0-40)
• Murray & Nadel's Textbook of Respiratory Medicine

2b. Spirometry (Essential for Diagnosis)

• FEV1/FVC < 0.70 (GOLD fixed-ratio criteria)
• Alternative: < 5th percentile lower limit of normal (ATS/ERS - avoids overdiagnosis in elderly)

• Murray & Nadel's Textbook of Respiratory Medicine, p. 1471

2c. Lung Volumes

• TLC: Increased (especially in emphysema, due to loss of elastic recoil)
• RV: Increased disproportionately (air trapping)
• RV/TLC ratio: Elevated
• FRC: Increased (static hyperinflation)
• Vital capacity: Decreased due to hyperinflation
• Must measure by body plethysmography (not gas dilution) due to heterogeneous airflow and risk of underestimation

2d. Diffusing Capacity (DLCO)

• Reduced in emphysema (loss of alveolar-capillary surface area)
• Near-normal spirometry + severely reduced DLCO + radiographic emphysema = consider combined pulmonary fibrosis and emphysema syndrome

2e. Exercise Testing

• Measures 6-minute walk distance (6MWD)
• Easy to administer, no specialized equipment needed
• Assesses need for supplemental O2 during ambulation
• Component of the BODE index (prognostic tool)
• Better correlates with quality-of-life outcomes than peak VO2

• Murray & Nadel's Textbook of Respiratory Medicine

2f. Cardiopulmonary Exercise Testing (CPET)

• VE/MVV ratio approaches or exceeds 100% (ventilatory limitation)
• Dynamic hyperinflation develops: end-expiratory lung volume (EELV) rises, inspiratory reserve volume (IRV) falls
• PetCO2/PaCO2 may rise with exertion (CO2 accumulation)
• Elevated VE/VCO2 slope and VE intercept (VEint) - reflects increased dead space
• Exercise-related desaturation more common in emphysema than in chronic bronchitis phenotype

2g. Additional Investigations

• Arterial blood gas (ABG): PaCO2 typically does not rise above normal until FEV1 falls to ~20-25% of predicted
• Alpha-1 antitrypsin level: screen in patients <45 years or without clear smoking history
• CBC: polycythemia with chronic hypoxemia; eosinophil count guides ICS use
• CT chest: quantifies emphysema, airway disease; identifies comorbid findings

3. PATHOPHYSIOLOGY REVIEW

• Chronic bronchitis: mucus overproduction from epithelial metaplasia + submucosal gland expansion + ciliary dysfunction; MUC5AC up 10-fold, MUC5B up 3-fold in severe COPD
• Emphysema: increased lung compliance, elevated relaxation volume, "static hyperinflation"
• Dynamic hyperinflation: with exercise or exacerbation, insufficient expiratory time traps air; EELV rises, IRV falls, work of breathing increases
• Diaphragm dysfunction: flattened in hyperinflation, reduced force generation, paradoxical motion in severe disease
• Hypercapnia: develops when FEV1 ~20-25%; due to increased dead space, V/Q mismatch, mechanical disadvantage, blunted chemoreceptor response
• Fishman's Pulmonary Diseases and Disorders

4. MANAGEMENT

COPD Management Overview

4a. Non-Pharmacological (All Patients)

1. Smoking cessation - single most effective intervention; slows progression
2. Vaccination: influenza (annual), pneumococcal, COVID-19, pertussis
3. Pulmonary rehabilitation: exercise training, self-management education, written action plans
4. Supplemental oxygen: indicated if PaO2 ≤55 mmHg or SaO2 ≤88% at rest; prolongs survival
5. Active lifestyle and exercise

4b. Pharmacological Management

• Short-acting beta-2 agonist (SABA): albuterol (salbutamol) - drug of choice for acute bronchospasm; inhaled, lasts several hours
• Short-acting anticholinergic (SAMA): ipratropium bromide
• Combination SABA + SAMA: more effective than either alone for acute relief

• Long-acting beta-2 agonist (LABA): salmeterol, formoterol, vilanterol - preventive, 12-24 hour duration; NOT for acute exacerbations
• Long-acting anticholinergic/muscarinic antagonist (LAMA): tiotropium, umeclidinium
• LABA + LAMA combination: recommended for patients with persistent symptoms; superior to monotherapy

• Severe airflow obstruction (GOLD 3-4)
• History of two or more exacerbations/year OR one hospitalized exacerbation
• Elevated blood eosinophil count (suggests T2-high phenotype - more likely to respond)
• Clear coexisting asthma history
• Caution: ICS use is associated with increased risk of bacterial pneumonia

• Roflumilast (PDE4 inhibitor): improves lung function and reduces exacerbation frequency; approved for severe COPD with chronic bronchitis phenotype
• Azithromycin (daily): significantly reduces exacerbation frequency in patients with ≥2 exacerbations/year; used as add-on
• Theophylline: no longer routinely recommended - recent large RCT failed to show benefit on exacerbation frequency
• Katzung's Basic and Clinical Pharmacology, 16th Edition

4c. COPD Exacerbation Management

• Katzung's Basic and Clinical Pharmacology, 16th Edition

4d. Managing Chronic Hypercapnia

• NIPPV (non-invasive positive pressure ventilation) is a cornerstone of management for chronic hypercapnic COPD patients
• Persistent hypercapnia carries poor prognosis
• During REM sleep, diaphragmatic dysfunction is most pronounced - SaO2 drops, PtCCO2 rises

4e. Advanced/Surgical Options

• Lung volume reduction surgery (LVRS): in selected patients with upper-lobe predominant emphysema and low exercise tolerance post-rehabilitation
• Lung transplantation: end-stage disease; 6MWD used during transplant evaluation
• Bronchoscopic lung volume reduction (endobronchial valves)

5. ONGOING REVIEW

• Symptoms (CAT, mMRC)
• Exacerbation frequency
• Smoking status
• Inhaler technique and adherence (critical - poor technique negates benefit)
• Physical activity level
• Need for pulmonary rehabilitation
• Need for O2, NIV, or palliative approaches
• Management of comorbidities (cardiovascular disease is common and major contributor to mortality)
• Spirometry at least annually

Summary: Key Points for Assessment

1. Spirometry is mandatory for diagnosis - post-bronchodilator FEV1/FVC <0.70 confirms obstruction
2. Severity = GOLD 1-4 by FEV1 + GOLD ABE by symptoms and exacerbation history
3. 6MWT and BODE index guide prognosis and transplant evaluation
4. DLCO distinguishes emphysema from other causes; measure lung volumes by plethysmography
5. Blood eosinophil count guides ICS prescribing
6. PaCO2 rises late (when FEV1 ~20-25%) - its presence marks severe disease

Physiotherapy Management of Obstructive Lung Disease

1. PULMONARY REHABILITATION: Overview

• Dyspnea and breathlessness
• Hospital admissions and emergency visits
• Psychological symptoms (anxiety, depression, fear)
• Medical resource utilization

• Exercise tolerance (endurance, maximal activity, strength)
• Health-related quality of life (HRQoL)
• Physical activity levels
• Patient independence and self-efficacy
• Knowledge and self-management skills
• Possible prolonged survival

Key point: Lung function (FEV1) does NOT typically improve with rehabilitation - but patients function far better within their existing limits.

• Duration: typically 6-12 weeks, 2-3 supervised sessions per week
• Each session: several hours of supervised exercise + individual/group education and psychosocial support
• Benefits demonstrated in specialist centers AND community-based settings
• Fishman's Pulmonary Diseases and Disorders

2. PRE-REHABILITATION ASSESSMENT

Pulmonary Function

• Spirometry and lung volumes - characterize disease and quantify impairment
• FEV1 is most useful for estimating maximal ventilatory capacity during exercise
• Diffusing capacity and maximal respiratory pressures (to assess muscle strength) added as needed

Exercise Testing

• Determines exercise tolerance and physiologic limitations
• Reveals coexisting conditions (e.g., cardiac disease)
• Used to establish a safe training prescription
• Type of test should match planned training modality (e.g., treadmill if walking training is planned)
• Incremental test to symptom-limited maximum → establishes peak capacity
• Steady-state test → preferred for determining training prescription

Blood Gas and Oxygenation Status

• ABG at rest AND during exercise - mandatory, since exercise-induced hypoxemia is common but cannot be reliably predicted from resting values
• In mild COPD: PaO2 may not change or may even improve with exercise
• In moderate-to-severe COPD: PaO2 may increase, decrease, or stay the same - unpredictable
• Pulse oximetry (SpO2) is useful for continuous monitoring but has ±4-5% accuracy limits
• Hypoxemia is not a contraindication to exercise training - portable O2 systems allow safe training

Psychosocial Evaluation

• Screen for depression, anxiety, social isolation, fear of dyspnea, and poor coping

Goal Setting

• After evaluation, set realistic, individualized goals
• Include family members and significant others
• Use standardized outcome measures:
  • 6-minute walk distance (6MWD) - exercise tolerance
  • mMRC or Borg dyspnea scale - symptoms
  • SGRQ or CAT - health-related quality of life
• Fishman's Pulmonary Diseases and Disorders

3. CORE PHYSIOTHERAPY COMPONENTS

3a. Breathing Retraining Techniques

• Technique first observed by Laennec in 1830; many patients adopt it naturally
• Patient tenses lips and narrows mouth opening during expiration
• Slows expiration, maintains positive airway pressure, prevents dynamic airway collapse
• Reduces dynamic hyperinflation
• Reduces respiratory rate, prolongs expiratory time
• Most consistently improves dyspnea symptoms

• Patient consciously coordinates abdominal wall expansion with inspiration
• Slows expiration through pursed lips simultaneously
• Primary effect: slows respiratory rate, increases tidal volume
• Improves respiratory synchrony between abdominal and thoracic musculature
• Symptom improvement (dyspnea) is a more consistent finding than measurable physiologic change

3b. Bronchial Hygiene (Airway Clearance)

• Chronic sputum production
• Excess mucus during exacerbations
• Chronic bronchitis phenotype

• Fishman's Pulmonary Diseases and Disorders

3c. Exercise Training

• Many patients report disabling dyspnea at very low levels of upper limb work (lifting, grooming, overhead activities)
• Upper limb exercise creates a higher ventilatory demand per unit of work than lower limb exercise
• Training is largely muscle-specific - upper limb training improves upper limb function in ways lower limb training cannot

Exercise Prescription

• Start at a level the patient can sustain comfortably for several minutes
• Progress by increasing duration first, then intensity, guided by symptom tolerance (Borg dyspnea/breathlessness rating) rather than heart rate
• Target: 15-30 minutes of continuous sustained activity
• In severe disease with ventilatory limitation: interval training (alternating bouts of high and low intensity) may allow higher total work volumes than continuous training
• Resistive training added for strength gains relevant to ADLs
• Encourage patients to incorporate exercise into enjoyable daily activities (gardening, golf, social walking)
• Fishman's Pulmonary Diseases and Disorders

3d. Ventilatory (Inspiratory) Muscle Training (IMT)

• Techniques: isocapnic hyperventilation, inspiratory resistive loading, inspiratory threshold loading
• Can improve respiratory muscle function in isolation
• However, improvement in general exercise performance from IMT alone has not been demonstrated consistently in COPD
• Role as a routine component of PR is not clearly established
• May be tried in patients with demonstrable respiratory muscle weakness alongside nutritional support
• Evidence for IMT efficacy remains limited
• Fishman's Pulmonary Diseases and Disorders; Murray & Nadel's Textbook of Respiratory Medicine

3e. Supplemental Oxygen During Rehabilitation

• Long-term continuous oxygen therapy (LTOT): clearly improves survival and reduces morbidity in patients with severe resting hypoxemia (PaO2 ≤55 mmHg or SaO2 ≤88%)
• Benefits for non-hypoxemic patients or those with intermittent hypoxemia (exercise- or sleep-induced) are less clearly defined
• Each patient's oxygen needs should be individually assessed
• Portable liquid oxygen systems are preferred for ambulatory patients - more gas, less weight than compressed tanks
• Oxygen-conserving devices extend the life of portable gas sources
• Transtracheal oxygen delivery: improves compliance in selected patients; requires careful catheter care instruction
• Hypoxemia during exercise is NOT a contraindication - portable O2 allows safe training

3f. Education and Self-Management

• Normal lung anatomy and physiology
• Understanding their specific lung disease
• Inhaler technique and medication use (nebulizers, MDIs, DPIs)
• Supplemental oxygen use and equipment management
• Written action plan - recognizing exacerbation signs and when to seek help
• Energy-conservation techniques for ADLs
• Nutrition
• Travel with lung disease
• Stress reduction and relaxation techniques
• Smoking cessation support
• Breathlessness management strategies

3g. Psychosocial Support

• Combat progressive hopelessness and inability to cope with chronic progressive disease
• Depression, anxiety (especially around dyspnea), denial, anger, and isolation are all common
• Sexual dysfunction and fear of physical activity are frequent
• Group sessions provide peer support and reduce isolation
• Desensitization to dyspnea: through exercise training, patients still experience dyspnea but develop less anxiety and fear about it and can persist in activity longer - a key mechanism of rehabilitation benefit

4. REHABILITATION IN SPECIAL SITUATIONS

After Acute Exacerbation

• Landmark evidence: PR initiated within 10 days of hospital discharge for COPD exacerbation leads to large, clinically meaningful improvements in exercise capacity and HRQoL vs. usual care
• Reduces hospital readmission rates (supported by Cochrane meta-analysis)
• May reduce mortality
• Early post-exacerbation rehabilitation is strongly indicated
• Fishman's Pulmonary Diseases and Disorders

Pre- and Post-Lung Transplantation

• Pre-transplant: maintain function during waiting period (which may last months to years); monitor disease progression; prevent complications; provide education about transplant procedure and expectations; psychosocial support for patients and families
• Post-transplant: different goals - rebuilding from baseline; managing new medications; functional independence

Pre- and Post-Lung Volume Reduction Surgery (LVRS)

• Rehabilitation improves surgical candidacy and post-operative recovery
• Post-LVRS: reduced hyperinflation means respiratory muscles operate more favorably on their length-tension curve → improved diaphragmatic function → better exercise response to training

5. NON-INVASIVE VENTILATION (NIV) AND PHYSIOTHERAPY

• BiPAP/NIPPV provides inspiratory muscle support, offloads the burden on the respiratory muscles, and reduces work of breathing
• Used acutely in emergency department and ICU for acute hypercapnic exacerbation
• Increasingly used in the outpatient setting for chronic hypercapnic COPD
• Can be combined with exercise training in very severe disease to allow higher training intensities
• Physiotherapists play a key role in NIV setup, mask fitting, and patient education

6. OUTCOMES AND MONITORING

Summary Table: Physiotherapy Interventions