COPD is a preventable and treatable disease with some extra- pulmonary effects that may contribute to the severity in individual patients Its pulmonary component is characterized by airflow limitation that is progressive and not fully reversible. There is an abnormal inflammatory response of the lung to noxious gases and particles, most commonly cigarette smoke 3. Airflow obstruction is defined as post-bronchodilator FEV1/FVC ratio (where FEV1 is the forced expiratory volume in one second and FVC is the forced vital capacity) of less than 0.7 If FEV1 is ≥ 80% predicted, a diagnosis of COPD should only be made in the presence of respiratory symptoms 4.
Chronic obstructive pulmonary disease (COPD) is a debilitating condition resulting in significant morbidity and mortality. It is the fifth leading cause of death in the UK 1, estimated to be the third by 2020 2.
COPD is a preventable and treatable disease with some extra- pulmonary effects that may contribute to the severity in individual patients Its pulmonary component is characterised by airflow limitation that is progressive and not fully reversible. There is an abnormal inflammatory response of the lung to noxious gases and particles, most commonly cigarette smoke 3.
Airflow obstruction is defined as post-bronchodilator FEV1/FVC ratio (where FEV1 is the forced expiratory volume in one second and FVC is the forced vital capacity) of less than 0.7 If FEV1 is ≥ 80% predicted, a diagnosis of COPD should only be made in the presence of respiratory symptoms 4.
Within the UK it is estimated that 3 million people are affected with COPD 4. However, only 900,000 are diagnosed -4An estimated two million people who have COPD remain undiagnosed 4.
90% of cases are smoking related 4, particularly those with >20 pack year smoking histories 5. Environmental and occupational factors can also play a role, including exposure to biomass fuels such as: coal, straw, animal dung, wood and crop residue which are used to cook in some countries and heat poorly ventilated homes COPD occurs in 10-20% of smokers, suggesting there is an element of genetic susceptibility 2-3, 5.
To make a diagnosis of COPD an obstructive deficit must be demonstrated on spirometry in patients over the age of 35 years with risk factors (mainly smoking) and signs and symptoms of the disease 4.
Signs and Symptoms:
Table 1. Severity of airflow obstruction 4
Stage |
Severity post- bronchodilator |
FEV1 (%) Predicted |
Comments |
1 |
Mild |
≥ 80% |
Only diagnosed in the presence of symptoms |
2 |
Moderate |
50- 79% |
Managed within the community |
3 |
Severe |
30-49% |
TLCO usually Low Hospitalization may be needed only with exacerbations |
4 |
Very Severe |
<30% |
Or FEV1 <50% with respiratory failure |
Table 2. BODE Index 3, 5-8
|
1 |
2 |
3 |
|
FEV1 Predicted (%) |
≥ 65 |
50- 64 |
36- 49 |
≤ 35 |
Distance walked in 6 minutes (meters) |
≥ 350 |
250- 349 |
150- 249 |
≤ 149 |
MRC dyspnoea scale |
0-1 |
2 |
3 |
4 |
BMI |
≥ 21 |
≤ 21 |
|
|
Table 3. Medical research council (MRC) Dyspnoea scale 5, 8
1 |
Dyspnoeic only on strenuous activity |
2 |
Dyspnoeic on walking up a slight incline or when hurrying |
3 |
Walks slower than contemporaries on the flat, or has to stop for breath, or has to stop for breath when walking at own pace |
4 |
Stops for breath on walking 100m or after a few minutes on walking on the flat |
5 |
Breathless on minimal exertion e.g. dressing/ undressing. To breathless to leave the house |
Goals of management include:
Non-pharmacological management:
Inhaled therapy should offer sufficient bronchodilator response. A spacer can be used for those with poor technique. Nebulisers are reserved for patients who demonstrate respiratory distress despite maximal inhaled therapy, and for those that show an improvement in symptoms or exertional capacity 4.
Diagram 1: Summary of step-by-step management 4
Patients with stable COPD who are receiving maximum medical therapy are assessed by measuring arterial blood gases taken on two separate occasions at least 3 weeks apart. To meet the criteria patients must have 4:
LTOT should be used for a minimum of 15L per day, including during sleep 3-4.
Patients who continue to smoke should be made aware of the serious risk of facial injuries due to the highly flammable nature of oxygen.
Referrals for specialist advice or specialist investigations may be appropriate at any stage of the disease.
Other possible reasons for referral 4
* Diagnostic uncertainty |
* Suspected severe COPD |
* Onset of Cor pulmonale |
* Rapid decline in FEV1 |
* Assessment for LTOT, home nebulisers or oral corticosteroid therapy |
* Symptoms that do not correlate to lung function deficit |
* Pulmonary rehabilitation assessment |
* Frequent infective exacerbations |
* Family history of alpha-1- antitrypsin deficiency |
* Haemoptysis |
* Onset of symptoms < 40 years |
* Bullous lung disease |
* Assessment for lung volume reduction surgery/ lung transplantation |
* Dysfunctional breathing |
Patients with stable mild-moderate COPD should be reviewed by their general practitioner at least once a year and those with severe COPD twice yearly.
At each visit 4:
For those patients with very severe airflow obstruction (FEV1 < 30%), the above still remains, in addition to the assessment of 4:
Those patients requiring long term non-invasive ventilation will be reviewed by a specialist on a regular basis.
Competing Interests: None Declared