Chapter 83: Chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is described by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) as a ‘common, preventable and treatable disease characterised by non-fully reversible persistent airflow limitation that is usually progressive and associated with an enhanced chronic inflammatory response in the airways and the lung to noxious particles or gases. It is basically a structural disease. Exacerbations and comorbidities contribute to the overall severity in individual patients’.¹

COPD typically affects middle-aged and older people with the usual age of onset in the fifth and sixth decades. It is the fourth leading cause of death and the third leading burden of disease in Australia, affecting 12.4% of Australians between 45 and 70 years. Early diagnosis and treatment is important to outcome and the provisional diagnosis should be based on the clinical features of breathlessness and cough in a smoker or ex-smoker.

Cigarette smoking is undoubtedly the major cause of both chronic bronchitis and emphysema, although only 10–15% of smokers develop the diseases.² Chronic bronchitis is defined as >3 episodes per year for 2 years while emphysema is destruction of alveoli. The clinical differences between asthma and bronchitis are summarised in CHAPTER 49. Patients experiencing overlap of asthma and COPD should be identified and treated differently to patients with either condition alone.

Lifelong passive smoking exposure increases COPD risk by 2.2 to 4.0 times.

FIGURE 83.1 illustrates the influence of smoking on lung function.

• Cigarette smoking (usually 20/day for 20 years or more)⁴

• Natural fuel—wood, twigs, crop residue

• Air pollution (outdoor and indoor)

• Airway infection/chronic bronchitis

• Occupation: related to cadmium, silica, dusts

• Familial factors: genetic predisposition

• Alpha₁-antitrypsin deficiency (emphysema)

• Bronchial hyper-responsiveness

The COPDX Plan guidelines⁵ developed by the Australian Lung Foundation and the Thoracic Society of Australia and New Zealand provide an appropriate framework for diagnosis and management. The key recommendations are: Confirm diagnosis, Optimise function, Prevent deterioration, Develop a self-management plan and manage eXacerbations.

C—Confirm diagnosis and assess severity

Symptoms

Consider the diagnosis of COPD in all smokers and ex-smokers older than 35 years. The diagnosis of COPD rests on the demonstration of airflow obstruction.

The sensitivity of the physical examination for detecting mild to moderate COPD is poor.

Signs

The signs vary according to the nature of the disease and the presence of infection. Signs may be completely absent in the early stages of COPD: chronic bronchitis may present only with wheezing, while dyspnoea is a feature of associated airflow obstruction.

Signs may include:

• tachypnoea

• reduced chest expansion

• hyperinflated lungs

• hyper-resonant percussion

• diminished breath sounds ± wheeze

• ‘pink puffer’—always breathless

• ‘blue bloater’—oedematous and central cyanosis

• signs of respiratory failure

• signs of cor pulmonale

The diagnosis is usually clinical with a history of increasing dyspnoea and sputum production in a lifetime smoker with no features of asthma. It is imprudent to make a diagnosis of chronic bronchitis and emphysema in the absence of cigarette smoking unless there is a family history suggestive of alpha₁-antitrypsin deficiency.⁶

At diagnosis, up to 50% of lung function may have been lost.

Investigations

Pulmonary function tests

Spirometry remains the gold standard for diagnosing, assessing and monitoring COPD. Post-bronchodilator forced expiratory ratio (FER) <0.7 is required for diagnosis.

The Australian stages of severity based on FEV₁% predicted are mild (60–80%), moderate (40–50%) and severe (<40%), while the GOLD¹ staging is 1. mild (≥80%), 2. moderate (50–80%), 3. severe (30–50%), 4. very severe (<30%).

Chest X-ray

This can be normal (even with advanced disease) but characteristic changes occur late in disease. May exclude lung cancer >1 cm.

Blood gases

• May be normal

• PaCO₂ ↑; PaO₂ ↓ (advanced disease)

Gas transfer factor

• A reduced diffusing capacity of the lungs for carbon monoxide (DLCO) is a feature of COPD. DLCO is not reduced in asthma.

ECG

• This may show evidence of cor pulmonale

Sputum culture

• If resistant organism suspected

FBE

• To identify anaemia and polycythaemia

• Haemoglobin and PCV may be raised in COPD

O—Optimise function

The principal goals of therapy are to stop smoking, to optimise function through relief of symptoms with medication and pulmonary rehabilitation, and to prevent or treat aggravating factors and complications.

TABLE 83.1 is a useful consultation checklist mnemonic.⁷

Long-term treatment

Advice to patient

• If you smoke, you must stop (persuading the patient to stop smoking is the key to management). The only treatment proven to slow the progression of COPD is smoking cessation.³ Consider smoking cessation medications.

• Avoid places with polluted air and other irritants, such as smoke, paint fumes and fine dust.

• Go for walks in clean, fresh air.

• A warm, dry climate is preferable to a cold, damp place (if prone to infections).

• Get adequate rest.

• Avoid contact with people who have colds or flu.

• Optimal diet—reduce weight if necessary.

Physiotherapy

Refer to a physiotherapist for chest physiotherapy, breathing exercises and an aerobic physical exercise program.

Drug therapy⁶

In the long-term treatment of COPD, bronchodilators are recommended for the relief of wheezing and shortness of breath. Bronchodilation is important to allow ‘lung emptying’ and reduce gas trapping. These include: short-acting β₂-agonists (SABAs, e.g. salbutamol, terbutaline) and short-acting anticholinergic drugs (ipratropium bromide); long-acting β₂-agonists (LABAs, e.g. eformoterol, salmeterol, indacaterol, vilanterone); long-acting anticholinergic drugs with muscarinic antagonist action (LAMAs, e.g. tiotropium, glycopyrronium, umeclidinium) which block parasympathetic bronchial constriction; and corticosteroids.

The preferred route of administration of bronchodilator is by inhalation, which requires correct device technique.

Inhaled drugs can be administered by MDIs, dry-powder devices or nebulisers. The evidence suggests that an MDI and spacer are as effective as a nebuliser—they are also simpler and cheaper—but the appropriate method depends on patient needs and preference.

The usefulness of a bronchodilator for an individual can only be assessed by a therapeutic trial, accepting either objective improvement in lung function or improvement in symptom control as endpoints.

Short-acting bronchodilator therapy

Most studies suggest that short-acting β₂-agonists and ipratropium bromide are equally efficacious in patients with COPD. If patients do not respond adequately to one of these bronchodilators then it is appropriate to consider a trial of a combination of the two classes of bronchodilator with objective monitoring of response.

Use the following by inhalation:⁶

• salbutamol 100–200 mcg, up to 4 times daily

• or

• terbutaline 500 mcg, up to 4 times daily

• or (with and without)

• ipratropium bromide 40–80 mcg, up to 4 times daily

For patients unable to use an MDI or a spacer, a nebuliser should be used, with the following doses:

• salbutamol or terbutaline 2.5 to 5 mg

• and/or

• ipratropium bromide 250 to 500 mcg by nebuliser, up to 4 times a day

Long-acting bronchodilator therapy

Long-acting β₂-agonists can be used in patients who remain symptomatic despite treatment with combinations of short-acting bronchodilators and those with frequent exacerbations. Used regularly they can be effective and may be more convenient than using short-acting bronchodilators.⁸ Long-acting anticholinergic therapy² with tiotropium bromide (taken by inhalation) has been proven to reduce the frequency of exacerbations with COPD compared with short-acting anticholinergic drugs. The choice of drug can be determined by the patient’s response to a trial of the drug, the drug’s adverse effects and cost including PBS listing.

For treatment with long-acting bronchodilator by inhalation, see TABLE 83.2.

Corticosteroids⁶

Only 10% of patients with stable COPD benefit in the short term from inhaled corticosteroids (ICS). There are no distinguishing clinical features to predict in advance which patients may respond. The aim of treatment is to reduce exacerbation rates and slow the decline of the disease. The effect of ICS on mortality is uncertain, and there is some evidence that ICS use may increase rates of pneumonia. Note that asthma can possibly coexist with COPD. Benefits are not seen in patients who continue to smoke.

If corticosteroids are to be used, usual practice is ICS/LABA combination inhalers (fluticasone/salmeterol, fluticasone/vilanterol or budesonide/eformoterol), which are available on the PBS for use in symptomatic patients with moderate to severe COPD (FEV₁<50% predicted).⁹

In this group, tiotropium combined with an ICS/LABA combination inhaler (triple therapy) is more beneficial than the individual treatments alone.⁹ Combining LAMA and LABA provides a modest additive effect.¹⁰

Inhaled corticosteroids

Guidelines for prescription include:

• documented but limited evidence of responsiveness to inhaled corticosteroids, including functional status

• those with an FEV₁ ≤50% predicted

• two or more exacerbations requiring oral steroids in 12 months

There is no role for ICS monotherapy in the treatment of COPD. Oral corticosteroids are not recommended for maintenance therapy in COPD, although they may be needed in patients with severe COPD where corticosteroids cannot be withdrawn following an acute exacerbation. A stepwise approach to management is outlined in FIGURE 83.2.

P—Prevent deterioration⁵

Reducing risk factors for COPD is a priority, and smoking is the most important and prime target if this continues to be a problem. Stopping is the only measure that slows the progression of COPD. Reinforce patient education programs, and avoid exposure to passive smoke as far as possible.

Annual influenza vaccination

Influenza vaccination reduces the risk of exacerbations, hospitalisation and death. It should be given in early autumn to all patients with COPD.

Pneumococcal vaccination

Vaccination (23vPPV) to prevent invasive bacteraemic pneumococcal pneumonia is recommended, with a booster at 5 years.¹¹

Long-term oxygen therapy

Long-term oxygen therapy (LTOT) reduces mortality in COPD. Long-term continuous therapy given for at least 15 hours a day (as close as possible to 24 hours a day) prolongs life in hypoxaemic patients—those who have PaO₂ consistently <55 mm Hg (7.3 KPa; SpO₂ 88%) when breathing air. At assessment for ongoing therapy, the patient’s condition must be stable and the patient must have stopped smoking at least 1 month previously. Flow should be set at the lowest rate needed to maintain a resting PaO₂ of 60 mm Hg. A flow rate of 0.5–2.0 L/min is usually sufficient. Best used for at least 18 hours a day.⁶ There is no clear-cut evidence about the effectiveness of intermittent ambulatory domiciliary oxygen therapy, but patients with hypoxaemia during sleep may require nocturnal oxygen therapy.

Check current smoking status

Smoking cessation clearly reduces the rate of decline of lung function. GPs and pharmacists can help smokers quit. Brief counselling is effective and every smoker should be offered at least this intervention at every visit.

Refer to strategies in CHAPTER 21, including effectiveness of treatment for nicotine dependence.

Antibiotics

Current evidence does not support long-term antibiotic use to prevent exacerbations, but they should be used in exacerbations with an increase in cough, dyspnoea, sputum volume or purulence.

Corticosteroids

No medication has yet been shown to prevent the long-term decline in lung function. Inhaled corticosteroids (ICS) are indicated for patients with a documented response or those who have moderate to severe COPD with frequent exacerbations. ICS use has been observed to be associated with increased rates of pneumonia.

Note: fixed-dose combinations of LABA and ICS (see CHAPTER 82) are used for patient convenience.⁶

Mucolytic agents

Mucolytic agents may reduce the frequency and duration of exacerbations (evidence level I). Mucolytic therapy should be considered for patients with a chronic cough productive of sputum. Oral mucolytics include potassium iodide, bromhexine, N-acetylcysteine, ambroxol and glyceryl guaiacolate. Compounds containing codeine should be avoided.

Antitussive agents

Regular use of antitussives in stable COPD is contraindicated.

Regular review

Regular review with objective measures of function is recommended in anticipation of reducing complications, frequency and severity of exacerbations and admissions to hospital. Regular schedules for follow-up visits are appropriate. Medication review should involve consideration of deprescribing as well as prescribing.

Lung surgery¹²

The options are bullectomy, lung volume reduction surgery and transplantation. Patients should be referred for consideration for bullectomy if they have a single large bulla on CT scan associated with breathlessness and an FEV₁ <50% predicted. Other lung surgery should be considered in patients with severe COPD who remain breathless with marked restriction of their activities of daily living, despite maximal therapy. Emphysema mainly involving the upper lobes with PaCO₂ <55 mm Hg and FEV >20% predicted are some factors required for lung volume reduction surgery.

D—Develop support network and self-management plan⁵

COPD imposes a considerable handicap on patients and carers, with heavy psychosocial issues including fears about the outcome of the disease.

Respiratory physician referral

Early referral to a respiratory physician is appropriate in order to clarify the diagnosis, consider other therapies, consider long-term home oxygen and facilitate organisation of pulmonary rehabilitation.

Pulmonary rehabilitation

One highly effective strategy is pulmonary rehabilitation, which aims to increase patient and carer knowledge and understanding, reduce carer strain and develop positive attitudes toward self-management and exercise. Integrated programs include education, exercise, behaviour modification and support, which are more effective than any separate component.

The support team and multidisciplinary care plans

As the patient’s primary health care provider, the GP is uniquely placed to identify smokers and help them quit, facilitate early diagnosis and coordinate the support team. The support team can enhance the quality of life and reduce morbidity for the COPD patient. The support team can include a nurse/respiratory educator, physiotherapist, occupational therapist, social worker, clinical psychologist, speech pathologist, pharmacist and dietitian.

Government and community support services such as Home Care, home maintenance, exercise programs, Meals on Wheels and support groups can be galvanised to provide support.

Self-management plans

Patients should be encouraged to take appropriate responsibility for their own management. The primary care team, supported by Extended Primary Care item numbers, should develop systems to identify those with more severe COPD who might benefit from more focused education and training in self-management skills.

Psychological issues

The issues facing the COPD patient include fear, stress, sleep disturbance, anxiety, panic and depression. Proactive management, including optimal care of these problems as they arise, will facilitate coping. Management also focuses on symptom control and maximising the quality of life. These patients have to face palliative care at the end stage and ethical issues have to be handled sensitively.

Referral to in-patient care

The management plan should include the identification of clinical markers indicating more intensive hospital treatment.

Indications for hospitalisation include:⁵

• rapid rate of onset of acute exacerbation with increased dyspnoea, cough or sputum

• inability to cope at home

• inability to walk between rooms when previously mobile

• severe breathlessness leading to inability to eat or sleep

• inadequate response to ambulatory treatment

• altered mental status suggestive of hypercapnia

• significant comorbidity (e.g. cardiac disease)

• new arrhythmia

• cyanosis

X—manage eXacerbations⁵

Diagnosis of an exacerbation is symptomatically the acute onset over minutes to hours of:

• increasing dyspnoea including use of accessory muscles at rest

• increased sputum

• more purulent sputum

Fever may be present, but fever and chest pain are uncommon symptoms. One-third have no identifiable cause, but infections and heavy pollutants can cause the exacerbation. Consider investigating with pulse oximetry, chest X-ray and sputum culture.

Patients should be treated with a bronchodilator, preferably with a large-volume spacer. If nebulisers are used they should be driven by compressed air (to avoid the problem of potentially adverse oxygenation). Systemic glucocorticoids reduce the severity and shorten recovery.

Ventilatory support may be used if hypercapnia develops or worsens despite optimal drug therapy. Non-invasive ventilatory support may avoid the need for intubation.

Treatment in summary^6,14

Bronchodilators

Initial therapy by SABA inhalation:

• salbutamol 100 mcg MDI, up to 8 to 10 inhalations, repeat as required

• or

• terbutaline 500 mcg DPI, 1 to 2 inhalations, repeat as required

• or

• ipratropium bromide 20 mcg MDI, up to 4–6 inhalations, repeat as required

If control is inadequate, combine salbutamol or terbutaline with ipratropium bromide.

If a nebuliser is used (which is usually the case upon hospitalisation), use salbutamol 2.5–5 mg, terbutaline 2.5–5 mg or ipratropium bromide 250–500 mcg, as required.

Oxygen therapy⁶

Controlled oxygen delivery—28% via Venturi mask or 2 L/min via nasal prongs should be commenced if the patient is hypoxaemic (oxygen saturation >92% with pulse oximetry). Maintain the arterial oxyhaemoglobin saturation at 90%. It is important to obtain a direct measurement of arterial blood gases to confirm the degree of hypoxaemia and if hypercapnia or acidosis is present.

Note that patients with severe COPD are prone to hypercapnia if they breathe high oxygen concentrations. Supplemental oxygen should be kept to a minimum. If hypercapnia develops assisted ventilation may be required.

Corticosteroids

Corticosteroids should be used routinely for severe exacerbations. Use:

• prednisolone or prednisone 30–50 mg (o), daily

If oral medication cannot be tolerated, use:

• hydrocortisone 100 mg IV 6 hourly (or equivalent dose of alternative corticosteroid)

Conversion from IV to oral corticosteroid should occur as soon as practicable.

The duration of oral corticosteroid therapy for exacerbations of COPD is not well established; however, courses of 7 to 14 days are commonly used.

A tapering dose schedule is not required for short courses.

Antibiotics⁶

The use of antibiotics for exacerbations is not routinely indicated as many episodes are due to viral infections. Some patients have repeated exacerbations due to bacterial infection (usually Haemophilus influenzae, S. pneumoniae or Moraxella catarrhalis) where antibiotics have been proven to be beneficial, reducing the risk of mortality by 77%.¹³

The indication for antibiotic treatment is:

• increased cough and dyspnoea, together with

• increased sputum volume and/or purulence

When indicated, use:

• amoxycillin 500 mg (o), 8 hourly for 5 days

• or

• doxycycline 200 mg (o) as 1 dose on day 1, then 100 mg (o) daily for a further 5 days

• or

• azithromycin 500 mg (o) daily for 5 days

A stepwise approach is summarised in FIGURE 83.3.

Evidence update^15,16

Evidence indicates that regular treatment with long-acting β₂-agonists is more effective than treatment with short-acting agents (evidence level I) and is associated with improved quality of life (evidence level II), although they are more costly and do not significantly improve lung function. Current recommended guidelines based on the severity of disease are summarised in TABLE 83.3.

Hand-out sheets from Murtagh’s Patient Education 7th edition:

• Chronic obstructive pulmonary disease

• Bronchitis: chronic bronchitis