Page 119 - Medicine and Surgery

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Chapter 3: Obstructive lung disorders 115

to hypoxia. In emphysema initially hyperventilation 2 Pharmacological
maintains normocapnia. Cyanosis, hypercapnia and cor Bronchodilators:Shortactingbronchodilatorspro-
pulmonale develop only late in the disease after pro- duce significant clinical benefit, helping patients
gressive decline in lung function. Amoxycillin resis- feel less short of breath (although objective im-
tant Haemophilus respiratory infections are common in provement in lung function tests may be slight).
COPD patients as a result of frequent courses of antibi- Salbutamol is usually first line therapy followed by
otic therapy. Acute exacerbations precipitated by viral, ipratropium bromide. Long acting β 2 agonists and
bacterial or mixed infections are common resulting in longactinganticholinergicsimprovelungfunction,
major morbidity and mortality. symptoms, reduce exacerbation frequency and are
recommended for moderate COPD. Long-term
oral theophylline appears to be of some benefit.
Investigations
Inhaled corticosteroids have been shown to pro-
The diagnosis is frequently made clinically but requires
duce small improvements in lung function, to re-
confirmation by demonstration of degree of irreversible
duceexacerbationfrequencyandtoslowthedecline
airway obstruction manifest by a reduced PEF and
in FEV 1 over time. The optimum dose and patient
FEV 1 /FVC after inhaled bronchdilators. In emphysema
group in which they should be used are not yet
the K CO (transfer factor) is also reduced. The lung vol-
clearly defined. They are currently recommended
umes may be normal in chronic bronchitis but are in-
for moderate-severe COPD with two or more ex-
creased in emphysema.
acerbations in the last 12 months.
i Chest X-ray: May be normal or there may be bullae,
An oral course of prednisolone, and antibiotics if
severe over-inflation. There may also be a deficiency
sputum is purulent, should be given promptly in
of bloodvesselsintheperipheralhalfofthelungfields
acute exacerbations in an attempt to minimise lung
in comparison to the proximal vessels.
damage. Amoxycillin resistant Haemophilus respi-
ii CT scan is usually performed to assess the degree of
ratory infections are treated with erythromycin, co-
alveolar destruction due to emphysema. It frequently
amoxiclav or cephalosporins.
shows peribronchial thickening and alveolar coales-
Diuretic therapy for oedema in patients with right
cence.
heart failure.
iii Haemoglobin and packed cell volume may be ele-
3 Persistent hypoxia should be treated with long-term
vated.
domiciliary oxygen therapy to improve prognosis.
iv Blood gases are variable as there may be hypoxia and
4 Non-invasive nasal ventilation is useful in treating
hypercapnia or hypocapnia, depending on the degree
acute exacerbations to avoid the need for intubation
of type I or type II respiratory failure and the degrees
and formal ventilation. It can also be used for noctur-
of respiratory and metabolic compensation.
nal hypoxic episodes and to prolong life, e.g. prior to
v ECG for cor pulmonale (right axis deviation, tall R
planned transplantation.
in V 1 ,peaked P waves) and coexisting cardiac
5 α 1 -antitrypsin infusions are used as replacement for
disease.
patients with serum levels below 11 mmol/L and ab-
vi α1-antitrypsin(normalserumrange20–48mmol/L).
normal lung function, but it is not known if this im-
proves the prognosis.
Management 6 Surgical management
1 Non-pharmacological: By far the most important fac- Patients of young age who are otherwise fit and well
tor that can affect the prognosis and progression of may be considered for lung or heart/lung trans-
chronic obstructive pulmonary disease is stopping plantation. The heart/lung transplant requires car-
smoking. Weight loss is vital in the obese. Physio- diopulmonary bypass and is performed through a
therapy may help clear sputum, and pulmonary re- sternotomy. Bilateral or single lung transplants are
habilitation programmes improve exercise capacity performed through a lateral thoracotomy possibly
and quality of life. Influenza vaccine should be given without bypass. Immunosuppression is achieved
annually. with triple therapy of cyclosporin, azathioprine