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CDHB

Chronic Obstructive Pulmonary Disease (COPD)

Summary

• Smoking is the most important risk factor for COPD, and should be addressed at every possible occasion.
• Consider COPD in patients with other smoking-related diseases.
• Consider COPD in all smokers and ex-smokers older than 35 years.
• The diagnosis of COPD requires spirometry with bronchodilator testing. The diagnosis of COPD rests on the demonstration of airflow limitation which is not fully reversible. The severity assessment of COPD requires spirometry testing.
• If airflow limitation is fully or substantially reversible, the patient should be treated as for asthma.
• Many patients with COPD have comorbid conditions which one should also consider, including higher risk of lung cancer, ischaemic heart disease, diabetes and osteoporosis.
• Currently, the interventions for management of chronic COPD that have good evidence include pulmonary rehabilitation, long term oxygen for those with significant hypoxaemia, tiotropium, and inhaled corticosteroids for those with severe disease and frequent exacerbations.
• An individual plan for the long term management of this most common chronic respiratory condition should be developed in conjunction with the patient and the GP.

Definition

Chronic Obstructive Pulmonary Disease is characterized by airflow limitation that is not fully reversible. The airflow limitation is in most cases both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases. It is a progressive, disabling disease with serious complications and exacerbations that are major burdens for healthcare systems.

Small-airway narrowing (with or without chronic bronchitis) and emphysema caused by smoking are the common conditions resulting in COPD. Chronic bronchitis is daily sputum production for at least three months of two or more consecutive years. Emphysema is a pathological diagnosis, and consists of alveolar dilatation and destruction. Breathlessness with exertion, chest tightness and wheeze are the results of airway narrowing and impaired gas exchange. The loss of lung elastic tissue in emphysema may result in airway wall collapse during expiration, leading to dynamic hyperinflation and consequent increased work of breathing.

The clinical features and pathophysiology of COPD can overlap with asthma, as most COPD patients have some reversibility of airflow limitation with bronchodilators. By contrast, some non-smokers with chronic asthma develop irreversible airway narrowing. However patients with complete reversibility of airflow limitation should be treated as asthma.

Differentiation of COPD from asthma is often difficult, and is best undertaken by a detailed history. COPD often presents later in life, with insidious and gradual onset of breathlessness, with less diurnal variation, associated with a history of exposure to noxious gas (usually cigarette smoking).

Causes of acute deterioration of COPD

• Acute bronchitis (viral or bacterial).
• Pneumonia.
• Pneumothorax.
• Pulmonary embolism.
• Left ventricular failure.
• Sepsis.
• Drugs (beta-blockers, NSAIDs, sedatives).
• Acute abdomen.
• Chest pain (trauma, rib fracture, osteoporosis).
• Post-operative sedation / retention of secretions.

Investigations

• Arterial blood gases (pulse oximetry alone is not adequate).
• CXR.
• Sputum culture and microscopy.
• CBC + diff, Na, K, creatinine.
• ECG.
• Consider BNP to assess contribution of LV dysfunction.

Severity Assessment in COPD

Make an immediate assessment of severity (see table) and initiate treatment accordingly. Confirm the diagnosis, identifying precipitating factor(s) and estimate the degree of usual functional impairment. Referring to old notes for information about previous functional status, spirometry, and blood gas analysis may be helpful. Old notes may also contain previous discussions with patients about ceiling of care, and wishes about resuscitation and ventilation.

Severity Assessment in COPD

Topic Code: 1630