CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)

COPD is primarily a respiratory disorder characterised by slowly progressive airflow obstruction that is not fully reversible; there is additional systemic illness. The person with COPD becomes increasingly breathless, even at rest, ultimately requiring palliative care. COPD is the fifth most common cause of death in the UK. Smoking is the predominant cause of COPD, although not all smokers are affected. An occupational cause warrants secondary referral. Stopping smoking is the most important way to improve outcomes.

Practice nurses should be alert to patients who may be at risk of COPD, e.g. at new patient medicals or when patients consult for other reasons, and offer advice and assessment of respiratory function. See also Smoking cessation

Diagnosis

Diagnosis of COPD is a clinical judgement, based on the history and physical examination, supported by the results of spirometry or post-bronchodilator spirometry showing respiratory obstruction that is not completely reversible. Consider a diagnosis of COPD in a person aged over 35 years who has:

• a risk factor (usually smoking)
• one or more symptoms:

Spirometry is an essential investigation for COPD diagnosis. It allows more sensitive measurement of lung function than peak-flow measurement. Demonstrating reversibility in COPD is not necessary except where the history is not clear. The main objective of reversibility testing is to demonstrate the substantial increase (400 ml or more) in FEV1 (forced expiratory volume in 1 second) that occurs in patients with asthma in response to bronchodilator treatment.

Determining disease severity

Airflow obstruction in COPD is measured with spirometry. Measure annually to assess disease progression.

 

FEV1 alone does not determine quality of life in COPD. NICE recommends use of the MRC dyspnoea scale to measure COPD’s effect on daily activities. Frequency of exacerbations (see below) is another factor.

 

Treatment

Inhaled medication, short- and long-acting, is added stepwise, in line with NICE guidance, as COPD progresses and symptoms worsen. Long-term oxygen therapy (LTOT) may be necessary in severe disease. Pulmonary rehabilitation can improve exercise tolerance, confidence and quality of life in moderate/severe COPD and should be available to all appropriate patients. End-of-life support should be offered to patients and families as necessary.

Exacerbations

An exacerbation of COPD is:

• a worsening of symptoms beyond normal daily variation
• acute in onset
• often associated with increased breathlessness and sputum, and cough
• frightening for the patient.

Additional medication is often necessary (often patient has a supply ready at home, and a self-management plan), and sometimes admission to hospital. It is important to minimise the frequency and impact of exacerbations by:

• ensuring use of effective inhaled medication
• offering pneumococcal and influenza vaccination
• giving advice on self-management and prompt response to symptoms
• use of non-invasive ventilation when indicated
• using hospital-at-home or assisted discharge schemes. 

Outcomes Strategy for COPD

Among the aims of the Outcomes Strategy for COPD are to:

• Improve the respiratory health and well being of all communities and minimise inequalities
• Reduce the number of people who develop COPD by increasing awareness of risk factors
• Reduce the number of people with COPD who die prematurely through a proactive approach to early identification, diagnosis and intervention (an estimated 2 million patients are undiagnosed).
• Ensure that people with COPD receive safe and effective care
• Provide high quality care and support, and improve end-of-life care.

The Quality and Outcomes Framework (QOF) requires all patients with COPD to have at least an annual review, carried out by a suitably qualified individual. Be aware of QOF indicators, and ensure correct application of Read codes.

NICE guidance (NG115)

Assess (at least annually at stages 1-3, at least twice a year at stage 4):

• smoking status and desire to quit
• symptom control (breathlessness, ability to perform daily chores, exacerbation frequency)
• presence of complications
• effects/side-effects of each drug treatment and OTC medications
• inhaler technique
• need for referral to specialist and therapy services
• need for pulmonary rehabilitation

and additionally at Stage 4

• presence of cor pulmonale
• need for LTOT
• nutritional status
• need for social services and occupational therapy input
• presence of depression

• FEV1 and FVC
• BMI
• MRC dyspnoea score

and, additionally at Stage 4

• oxygen saturation of arterial blood (SaO2)

The review is also an opportunity to:

• give smoking cessation advice
• discuss avoidance and treatment of exacerbations
• give and discuss management plan, if appropriate
• discuss problems and worries, e.g. sexual activity and breathlessness
• make plans for end-stage COPD if necessary.

SPIROMETRY: measuring lung function

Diagnosis of COPD is confirmed by spirometry. Spirometry is carried out using a spirometer, a machine that measures:

• FVC (forced vital capacity), volume of air patient can forcibly expel from the lungs in one breath after maximal inhalation.
• FEV1 (forced expiratory volume in 1 second), volume of air patient can exhale in the first second of forced expiration after maximal inhalation.

The machine records the results of the patient’s efforts. FVC is a measure of lung volume. FEV1 is a measure of the speed of exhalation, i.e. how quickly full lungs can be emptied. Normal lungs will achieve 80% in 1 second, obstructed lungs will achieve <80% in 1 second.

• FEV1/FVC ratio is less than 0.7 (<70%) and
• FEV1 is <80% (NICE) or <70% (QOF) of the predicted value.

Many spirometers carry out the necessary calculations.

To calculate % predicted (Actual measurement/predicted value) x 100 eg, if actual FEV1 = 3.5 litres, and predicted FEV1 = 4.0 litres, (3.5/4.0) x 100 = 87.5% = % predicted

To calculate FEV1/FVC ratio (Actual FEV1/actual FVC) x 100 eg, if FEV1 = 3.0 litres, and FVC = 4.0 litres Ratio = (3/4) x 100 = 75%

Flow-volume curves Some spirometers produce a graph of lung function. The volume of air breathed out (in litres) is plotted against time (in seconds), to give a flow–volume curve. This spirometry trace may be: a) normal – when lungs are healthy, the trace rises rapidly at the start and then slows steadily, with no irregularities b) obstructive – a flattened curve indicates slow exhalation of a normal lung volume c) restrictive – a small curve of normal shape indicates a normal expiratory rate but reduced lung volume d) combined – a flattened curve with low volumes indicates that both obstruction and restriction are present.