subject: Emphysema and its management [print this page] Management Management
Restoration of normal function is not possible in chronicbronchitis and emphysema. The aim of therapy must therefore be to reduce disability by tackling the interrelatedproblems of airways obstruction, recurrent infections,breathlessness, hypoxia and poor exercise tolerance.Factors aggravating chronic bronchitis, particularly cigarettesmoking, must be withdrawn.
Airways obstructionConventionally the airways obstruction of chronic bronchitisand emphysema is regarded as being irreversible.However, the majority of patients show some improvementin lung function with therapy directed at relaxingbronchial smooth muscle and, although small, this improvementcan have an important impact on the disabilityof these patients. Prognosis in patients who respond wellto bronchodilators is considerably better than for thosewith completely fixed obstruction.
The most importantbronchodilator agents are the selective pYadrenergicagonists (e.g. salbutamol and terbutaline), which are bestadministered by inhalation. For some patients maximalbronchodilatation requires a large drug dose and may bebest administered by nebulizer (e.g. salbutamol 2.5-5 mg).Inhaled atropine analogues (ipratropium and oxitropium)can be helpful but, provided optimum doses of(32 agonists are administered, confer little additionalbenefit.
Oral theophyllines available in slow-release formulationare of marginal use in chronic bronchitis and emphysema.It had been claimed that theophylline improved respiratorymuscle contractility, but subsequent studies did notconfirm this effect.Patients with severe airways obstruction should havea therapeutic trial of steroids - for example oral prednisolone(30 mg daily) for a period of 2-3 weeks - providedthere are no contraindications. For patients in whom oralsteroids pose problems (e.g. diabetes) a period of highdoseinhaled steroid is appropriate.
Long-term oralsteroids will not be indicated in most patients but, whenprescribed, require regular assessment; dosage shouldseldom exceed 7.5-10 mg daily, thereby minimizing drugcomplications. Steroid-responsive patients should betreated with inhaled steroid. Although inhaled corticosteroidsare extensively prescribed for COPD, there are nodata to suggest they affect the long term decline in lungfunction. When given systemically, they are valuable inacute exacerbations. There is some recent evidence to suggest that mucolytic agents such as acetyl cysteine maybe beneficial in reducing the numbers of exacerbations ofchronic bronchitis. Early studies of leukotriene receptorantagonists and specific phosphodiesterase inhibitors areencouraging.
Infection
In acute exacerbations of chronic bronchitis an infectiveviral or bacterial pathogen is isolated in less than 50% ofcases. However, viral infections are frequently complicatedby bacterial overgrowth and the majority of patientsdevelop purulent sputum. Severe exacerbations have amortality of up to 25%, and prompt antibacterial therapyis of the greatest importance. Common infective organismsare Strep, pneumoniae and H. influenzae, and suitableantibiotics are amoxycillin, erythromycin, clarithromycin,azithromycin, macrolide antibiotics, ciprofloxacin and thecephalosporins. For most patients long-term chemoprophylaxisis not helpful, but if intermittent treatment fails atrial of continuous rotating antibiotic therapy is appropriate.Regular immunization against influenza is sensible,and pneumococcal vaccine should be administered every 3years.
Oxygen therapy
During an acute exacerbation of chronic bronchitis andemphysema, oxygen therapy is necessary to avoid deathfrom hypoxia. In patients with hypercapnia oxygen mustbe given at low and controlled concentrations (usually24% or 28% O2). A more contentious question is the valueof long-term domiciliary oxygen therapy. Studies suggestthat long-term controlled oxygen therapy can benefitpatients with airways obstruction who have severe hypoxiaand who refrain from smoking cigarettes.
It is necessary to administer oxygen virtually continuously, including duringsleep. Long-term follow-up of domiciliary oxygen therapyin severe COPD demonstrates that the treatment canprolong mean survival by 5 years.The administration of continuous oxygen presents considerablepractical and financial difficulties. Oxygen maybe supplied in cylinders, as a liquid, or, preferably, generatedby an oxygen concentrator. This therapy should bereserved for patients with severe disease who are wellmotivated.
Oxygen therapy requires careful pretreatmentassessment and long-term supervision.In practice, much oxygen used by patients in their homesis for a few minutes only and the main purpose is to relievebreathlessness. Oxygen is also available in small portablecylinders, and some patients find this helpful in reducingbreathlessness on exercise, improving exercise capacity,and permitting excursions from the home. Many differenttechniques of delivering oxygen, including transtrachealcatheters, are available.
Drug therapy for breathlessnessIn patients with airways obstruction it is the 'pink puffers'with normal CO2 values and mild or moderate hypoxiawho are most breathless. In some patients reducing ventilationwith diazepam, promethazine and dihydrocodeinecan reduce breathlessness, and in patients without carbondioxide retention a careful trial of such therapy is justifiedwhen symptoms are severe. For the devastating dyspnoeawhich is frequently a feature of terminal respiratoryfailure, diamorphine is helpful whatever the cause.
