21
CHAPTER 4
Chronic obstructive airways disease Dr Martin Hetzel, MD, FRCP Dr Michael Modell, FRCp FRCGP
SUMMARY 1. Chronic obstructive airways disease is a term which should be reserved for those who have objective evidence of airways obstruction and who do not improve significantly with bronchodilators or steroids. All patients should have a trial of aggressive treatment with these drugs in case they have chronic asthma. 2. All patients should be urged strongly to give up smoking. 3. There is no scientific evidence that slow release aminophylline or theophylline are of benefit in these patients, and they may be hazardous in those with coronary artery disease. 4. Acute infective exacerbations may be due to haemophilus influenzae or pneumococcus; patients with fever should be given co-trimoxazole, ampicillin, co-amoxiclav or erythromycin (co-trimoxazole should generally be avoided in the elderly). 5. Domiciliary oxygen therapy, given for at least 12 and preferably 16 hours a day, will prolong survival in patients with Type II respiratory failure ('blue bloaters'). It may help symptoms in Type I respiratory failure ('pink puffers'). It should only be prescribed after blood gas measurements and the patient must therefore be referred.
Definition and diagnosis The term 'chronic obstructive airways disease' has now come into widespread use, which is unfortunate because patients given this diagnosis do not have a single disease. The term should be reserved for patients who have airways obstruction, demonstrated by pulmonary function tests, peak expiratory flow rate (PEFR), which does not vary like asthma and does not improve significantly with bronchodilator drugs or steroids. Most patients will have reached this situation either because they have asthma which has become refractory to treatment or they have chronic bronchitis and emphysema induced by smoking. A few patients have much rarer causes, for example obliterative bronchiolitis following a virus infection or associated with rheumatoid arthritis. The great danger in this term is that some asthmatics smoke. A previously undiagnosed asthmatic who has smoked may be labelled as having chronic obstructive airways disease and denied the chance of a dramatic improvement after treatment with bronchodilator drugs and steroids. An attempt should therefore be made to determine the underlying cause from a careful history which may reveal, for example, a history of asthma in childhood. It is vital to
establish if patients have previously had a proper trial of aggressive treatment with bronchodilators and steroids. If not, this should be given. If there is a response to treatment the diagnosis should probably be revised to chronic asthma. Some patients with largely irreversible airways ob~truction get some subjective relief from bronchodilators even thqugh this is not reflected in a significant improvement in their PEFR. Some of these patients develop an increasing dependency on salbutamol inhalers.
Physical examination This may give some indication of the severity of chronic airways obstruction but not its cause. Severe cases may have: 1. Low PEFR and FEV, (forced expiratory volume in one
second) 2. Over-inflated chest with reduced cricostemal distance and hyper-resonance on percussion, with diminished breath sounds with or without a wheeze 3. Signs suggesting respiratory failure: either (a) Breathless at rest with accessory muscles active and indrawing of intercostal spaces (good respiratory drive, 'pink puffer') or
(b) Lethargic, cyanosed, peripheral oedema, but less breathless (poor respiratory drive and carbon dioxide retention, 'blue bloater') Assessment and investigations Investigations practicable for the general practitioner are: 1. PEFR 2. Haemoglobin and packed cell volume to exclude polycythaemia in patients with poor respiratory drive. 3. Chest x-ray. As in asthma, this may be of little help, but may indicate emphysema or confirm over-inflation. Moreover, these patients are mostly smokers and an undiagnosed bronchial carcinoma may also be revealed. In some patients whose condition has deteriorated recently, an x-ray reveals a clinically unsuspected area of consolidation. Do not forget pulmonary tuberculosis as a possible diagnosis in the alcoholic 'bronchitic' living in poor social circumstances.
22
Treatment
Non-pharmacological Stopping patients from smoking is of paramount importance though they should be aware that stopping smoking can only slow down the rate of progression of their disease. Unfortunately, except in very young patients, stopping smoking will not improve the present level of symptoms. Unless this is made clear, patients are likely to start smoking again after a little while because they see no apparent benefit. If patients will not stop smoking, attempts at treatment with bronchodilator drugs are likely to be fruitless. Obviously when patients develop life-threatening respiratory failure, they must be treated even if they continue to smoke, but the prognosis for such patients is appallingly bad. Unfortunately, there is no single effective treatment to help people stop smoking but intervention by the general practitioner with written and verbal advice is of proven effectiveness (Russell et al., 1979). Nicotinell patches or Nicorette chewing gum may help in some cases. There are several sources of advice for patients (see next page). It is also important to stop the rest of the family from smoking. Moreover, in the case of a young smoker with emphysema the possibility of alpha 1 anti-trypsin deficiency should be considered as a predisposing cause and advice sought on screening the family. In this way anti-smoking advice can then be targeted intensively at those members discovered to be at increased risk of developing emphysema.
Pharmacological treatment If patients make a reasonable effort to stop smoking a trial of bronchodilator therapy is worthwhile, particularly to exclude late onset asthma. The treatment protocol is much the same as described for maintenance treatment in asthma. Response to treatment is monitored by PEFR. Ipratropium bromide is more useful in chronic obstructive airways disease than in asthma. There is no scientific evidence that slow release aminophylline or theophylline help these patients. These drugs should be avoided, particularly in older patients, because heavy smokers are likely to have coronary artery disease as well as chronic bronchitis and emphysema and are particularly at risk from arrhythmias. Moreover, enzyme induction from smoking renders them less effective. Acute infective exacerbations of chronic bronchitis, emphysema and respiratory failure Infective exacerbations usually follow colds and are mostly due to infection with haemophilus influenzae and pneumococcus. Sputum cultures are usually unhelpful. Patients presenting with fever and purulent sputum should be given co-trimoxazole, ampicillin, co-amoxiclav or erythromycin. Occasionally a resistant haemophilus is encountered and results in failure to respond and is an indication for referral. Because of the risk of serious reactions to co-trimoxazole in the elderly, it should only be prescribed for this group if there is no reasonable alternative. Tetracycline (or doxycycline if there is renal impairment) is sometimes helpful. Most patients with proven chronic bronchitis and emphysema can be given a prescription and told to take the antibiotics at the onset of a respiratory infection. Acute on chronic respiratory failure is an indication for emergency admission. Hypoxia will be more severe in the
'blue bloater' with Type II respiratory failure. These patients have poor responsiveness to a rising pCO2 level in the blood. They have relatively little dyspnoea and make little effort to increase their ventilation. Thus they become very hypoxic and acidotic. Administration of oxygen may suppress their hypoxic drive which is the sole stimulus maintaining their respiration and they may then stop breathing altogether. 'Pink puffers' (with Type I respiratory failure) with good respiratory drive will appear very breathless but their oxygen saturation is less likely to be dangerously low. Oxygen therapy can be safely initiated only if blood gases are measured and patients are under nursing supervision. The general practitioner should therefore seek admission when respiratory failure is suspected clinically and should not give oxygen unless he or she is personally able to stay with the patient all the time that it is being given. Otherwise, it is safest not to give oxygen before arrival in hospital.
Domiciliary oxygen therapy Domiciliary oxygen therapy given for at least 12 and preferably 16 hours a day will prolong survival in patients with chronic Type II respiratory failure (Stuart-Harris et al., 1981). It does this by improving oxygen saturation, reversing pulmonary hypertension, and therefore preventing right ventricular failure. Oxygen therapy for Type I respiratory failure does not prolong life but may help the symptoms and act as a palliative. It is impossible to decide if domiciliary oxygen therapy is indicated without measurement of blood gases. Referral to the chest physician is therefore essential. Patients are usually admitted for about 24 hours to measure serial blood gases and try different concentrations of oxygen on the ward. This also gives an opportunity to assess whether patients are likely to be compliant with prolonged oxygen therapy at home. Those most likely to benefit will have Type II respiratory failure and particularly: * daytime somnolence * headache * polycythaemia * evidence of right ventricular hypertrophy/failure. If domiciliary oxygen therapy is indicated, this can be ordered by dialing 100 and asking for freephone oxygen concentrator. The concentrator is prescribed on form FPIO. Contact the local chest unit for advice on the flow rate and hours per day required. The company service the equipment at home but the chest unit can arrange for the chest clinic health visitor to follow up patients who are on oxygen concentrators. Oxygen concentrators are much cheaper and safer than oxygen cylinders if oxygen use is to be prolonged. Neither oxygen concentrators nor cylinders available for use at home are suitable for use with nebulizers.
Inappropriate use Over the years many patients have been given oxygen cylinders for use at home for brief periods when they feel breathless. There is no direct correlation between the severity of breathlessness and the presence of hypoxia, though a few patients claim that after 5 or 10 minutes of extra oxygen they find it easier to dress and go upstairs. Oxygen cylinders in the home are a fire hazard (many of these patients or their
23
relatives smoke), they are also heavy and easily cause injury if not properly supported. They are also expensive. Unfortunately, many patients have become psychologically dependent on their oxygen cylinder and it is very difficult to withdraw it.
3. Proportion of patients with domiciliary oxygen therapy who have been appropriately assessed (including blood gases) beforehand. 4. Evidence of persistent advice to give up smoking.
Influenza vaccination Influenza vaccination is worthwhile in patients who have suffered infective exacerbations and is given in October.
Useful addresses Sources of advice for helping patients to give up smoking include: ASH 109 Gloucester Place London WlH 3PH Tel: 071 935 3519 QUIT (National Society of Non-smokers) 102 Gloucester Place London W1H 3DA Tel: 071 487 2858 Tel: QUIT Line 071 487 3000
Information to patient and family Chronic obstructive airways disease is a disease of gradual deterioration punctuated with the recurrent risk of death in respiratory failure during infective exacerbations. If cor pulmonale develops, the patient's survival is unlikely to exceed one year, but oxygen therapy in suitable patients may prolong this for a few years. Nutritional advice may be important. Some 'pink puffers' fall below their ideal weight and weight loss is a bad prognostic sign. Keeping to the ideal weight will increase exercise tolerance and it is particularly important to avoid becoming overweight. Patients should be advised to take as much exercise as they can because physical fitness enables maximum performance from skeletal muscle in the presence of poor oxygenation. Above all, however, the most important advice is a relentless campaign to stop smoking. Long-term use of home nebulizers For advice on the long-term use of home nebulizers, see Chapter 3 (Asthma).
Audit points 1. Proportion of patients who had a trial of treatment with bronchodilators and steroids to exclude chronic asthma. 2. Proportion of patients treated inappropriately with oral aminophylline or theophylline or with a long-term home nebulizer without objective evidence of benefit.
References Russell M A H, Wilson C, Taylor C et al. (1979) Effect of general practitioners' advice against smoking. British Medical Journal 2, 231-5. Stuart-Harris C, Henley D C, Bishop J M et al. (1981) Medical Research Council Working Party: long-term domiciliary oxygen therapy in chronic hypoxic cor pulmonale complicating bronchitis and emphysema. Lancet 1, 681-6.
Further reading Clarke T J H and Godfrey S (Eds) (1983) Asthma. London, Chapman and Hall. Flenley D C (1981) Respiratory Medicine. Concise Medical Textbooks. London, Bailliere Tindall. Johnson N (1989) Pocket Consultant Respiratory Medicine. 2nd ed. London, Blackwells. Medicine International Respiratory Disorders (1986) pt 2, vol. 2, pp 1417-42 and (1987 ) pt 4, vol. 2, pp 1522-40.
CHAPTER 4
Chronic obstructive airways disease Dr Martin Hetzel, MD, FRCP Dr Michael Modell, FRCp FRCGP
SUMMARY 1. Chronic obstructive airways disease is a term which should be reserved for those who have objective evidence of airways obstruction and who do not improve significantly with bronchodilators or steroids. All patients should have a trial of aggressive treatment with these drugs in case they have chronic asthma. 2. All patients should be urged strongly to give up smoking. 3. There is no scientific evidence that slow release aminophylline or theophylline are of benefit in these patients, and they may be hazardous in those with coronary artery disease. 4. Acute infective exacerbations may be due to haemophilus influenzae or pneumococcus; patients with fever should be given co-trimoxazole, ampicillin, co-amoxiclav or erythromycin (co-trimoxazole should generally be avoided in the elderly). 5. Domiciliary oxygen therapy, given for at least 12 and preferably 16 hours a day, will prolong survival in patients with Type II respiratory failure ('blue bloaters'). It may help symptoms in Type I respiratory failure ('pink puffers'). It should only be prescribed after blood gas measurements and the patient must therefore be referred.
Definition and diagnosis The term 'chronic obstructive airways disease' has now come into widespread use, which is unfortunate because patients given this diagnosis do not have a single disease. The term should be reserved for patients who have airways obstruction, demonstrated by pulmonary function tests, peak expiratory flow rate (PEFR), which does not vary like asthma and does not improve significantly with bronchodilator drugs or steroids. Most patients will have reached this situation either because they have asthma which has become refractory to treatment or they have chronic bronchitis and emphysema induced by smoking. A few patients have much rarer causes, for example obliterative bronchiolitis following a virus infection or associated with rheumatoid arthritis. The great danger in this term is that some asthmatics smoke. A previously undiagnosed asthmatic who has smoked may be labelled as having chronic obstructive airways disease and denied the chance of a dramatic improvement after treatment with bronchodilator drugs and steroids. An attempt should therefore be made to determine the underlying cause from a careful history which may reveal, for example, a history of asthma in childhood. It is vital to
establish if patients have previously had a proper trial of aggressive treatment with bronchodilators and steroids. If not, this should be given. If there is a response to treatment the diagnosis should probably be revised to chronic asthma. Some patients with largely irreversible airways ob~truction get some subjective relief from bronchodilators even thqugh this is not reflected in a significant improvement in their PEFR. Some of these patients develop an increasing dependency on salbutamol inhalers.
Physical examination This may give some indication of the severity of chronic airways obstruction but not its cause. Severe cases may have: 1. Low PEFR and FEV, (forced expiratory volume in one
second) 2. Over-inflated chest with reduced cricostemal distance and hyper-resonance on percussion, with diminished breath sounds with or without a wheeze 3. Signs suggesting respiratory failure: either (a) Breathless at rest with accessory muscles active and indrawing of intercostal spaces (good respiratory drive, 'pink puffer') or
(b) Lethargic, cyanosed, peripheral oedema, but less breathless (poor respiratory drive and carbon dioxide retention, 'blue bloater') Assessment and investigations Investigations practicable for the general practitioner are: 1. PEFR 2. Haemoglobin and packed cell volume to exclude polycythaemia in patients with poor respiratory drive. 3. Chest x-ray. As in asthma, this may be of little help, but may indicate emphysema or confirm over-inflation. Moreover, these patients are mostly smokers and an undiagnosed bronchial carcinoma may also be revealed. In some patients whose condition has deteriorated recently, an x-ray reveals a clinically unsuspected area of consolidation. Do not forget pulmonary tuberculosis as a possible diagnosis in the alcoholic 'bronchitic' living in poor social circumstances.
22
Treatment
Non-pharmacological Stopping patients from smoking is of paramount importance though they should be aware that stopping smoking can only slow down the rate of progression of their disease. Unfortunately, except in very young patients, stopping smoking will not improve the present level of symptoms. Unless this is made clear, patients are likely to start smoking again after a little while because they see no apparent benefit. If patients will not stop smoking, attempts at treatment with bronchodilator drugs are likely to be fruitless. Obviously when patients develop life-threatening respiratory failure, they must be treated even if they continue to smoke, but the prognosis for such patients is appallingly bad. Unfortunately, there is no single effective treatment to help people stop smoking but intervention by the general practitioner with written and verbal advice is of proven effectiveness (Russell et al., 1979). Nicotinell patches or Nicorette chewing gum may help in some cases. There are several sources of advice for patients (see next page). It is also important to stop the rest of the family from smoking. Moreover, in the case of a young smoker with emphysema the possibility of alpha 1 anti-trypsin deficiency should be considered as a predisposing cause and advice sought on screening the family. In this way anti-smoking advice can then be targeted intensively at those members discovered to be at increased risk of developing emphysema.
Pharmacological treatment If patients make a reasonable effort to stop smoking a trial of bronchodilator therapy is worthwhile, particularly to exclude late onset asthma. The treatment protocol is much the same as described for maintenance treatment in asthma. Response to treatment is monitored by PEFR. Ipratropium bromide is more useful in chronic obstructive airways disease than in asthma. There is no scientific evidence that slow release aminophylline or theophylline help these patients. These drugs should be avoided, particularly in older patients, because heavy smokers are likely to have coronary artery disease as well as chronic bronchitis and emphysema and are particularly at risk from arrhythmias. Moreover, enzyme induction from smoking renders them less effective. Acute infective exacerbations of chronic bronchitis, emphysema and respiratory failure Infective exacerbations usually follow colds and are mostly due to infection with haemophilus influenzae and pneumococcus. Sputum cultures are usually unhelpful. Patients presenting with fever and purulent sputum should be given co-trimoxazole, ampicillin, co-amoxiclav or erythromycin. Occasionally a resistant haemophilus is encountered and results in failure to respond and is an indication for referral. Because of the risk of serious reactions to co-trimoxazole in the elderly, it should only be prescribed for this group if there is no reasonable alternative. Tetracycline (or doxycycline if there is renal impairment) is sometimes helpful. Most patients with proven chronic bronchitis and emphysema can be given a prescription and told to take the antibiotics at the onset of a respiratory infection. Acute on chronic respiratory failure is an indication for emergency admission. Hypoxia will be more severe in the
'blue bloater' with Type II respiratory failure. These patients have poor responsiveness to a rising pCO2 level in the blood. They have relatively little dyspnoea and make little effort to increase their ventilation. Thus they become very hypoxic and acidotic. Administration of oxygen may suppress their hypoxic drive which is the sole stimulus maintaining their respiration and they may then stop breathing altogether. 'Pink puffers' (with Type I respiratory failure) with good respiratory drive will appear very breathless but their oxygen saturation is less likely to be dangerously low. Oxygen therapy can be safely initiated only if blood gases are measured and patients are under nursing supervision. The general practitioner should therefore seek admission when respiratory failure is suspected clinically and should not give oxygen unless he or she is personally able to stay with the patient all the time that it is being given. Otherwise, it is safest not to give oxygen before arrival in hospital.
Domiciliary oxygen therapy Domiciliary oxygen therapy given for at least 12 and preferably 16 hours a day will prolong survival in patients with chronic Type II respiratory failure (Stuart-Harris et al., 1981). It does this by improving oxygen saturation, reversing pulmonary hypertension, and therefore preventing right ventricular failure. Oxygen therapy for Type I respiratory failure does not prolong life but may help the symptoms and act as a palliative. It is impossible to decide if domiciliary oxygen therapy is indicated without measurement of blood gases. Referral to the chest physician is therefore essential. Patients are usually admitted for about 24 hours to measure serial blood gases and try different concentrations of oxygen on the ward. This also gives an opportunity to assess whether patients are likely to be compliant with prolonged oxygen therapy at home. Those most likely to benefit will have Type II respiratory failure and particularly: * daytime somnolence * headache * polycythaemia * evidence of right ventricular hypertrophy/failure. If domiciliary oxygen therapy is indicated, this can be ordered by dialing 100 and asking for freephone oxygen concentrator. The concentrator is prescribed on form FPIO. Contact the local chest unit for advice on the flow rate and hours per day required. The company service the equipment at home but the chest unit can arrange for the chest clinic health visitor to follow up patients who are on oxygen concentrators. Oxygen concentrators are much cheaper and safer than oxygen cylinders if oxygen use is to be prolonged. Neither oxygen concentrators nor cylinders available for use at home are suitable for use with nebulizers.
Inappropriate use Over the years many patients have been given oxygen cylinders for use at home for brief periods when they feel breathless. There is no direct correlation between the severity of breathlessness and the presence of hypoxia, though a few patients claim that after 5 or 10 minutes of extra oxygen they find it easier to dress and go upstairs. Oxygen cylinders in the home are a fire hazard (many of these patients or their
23
relatives smoke), they are also heavy and easily cause injury if not properly supported. They are also expensive. Unfortunately, many patients have become psychologically dependent on their oxygen cylinder and it is very difficult to withdraw it.
3. Proportion of patients with domiciliary oxygen therapy who have been appropriately assessed (including blood gases) beforehand. 4. Evidence of persistent advice to give up smoking.
Influenza vaccination Influenza vaccination is worthwhile in patients who have suffered infective exacerbations and is given in October.
Useful addresses Sources of advice for helping patients to give up smoking include: ASH 109 Gloucester Place London WlH 3PH Tel: 071 935 3519 QUIT (National Society of Non-smokers) 102 Gloucester Place London W1H 3DA Tel: 071 487 2858 Tel: QUIT Line 071 487 3000
Information to patient and family Chronic obstructive airways disease is a disease of gradual deterioration punctuated with the recurrent risk of death in respiratory failure during infective exacerbations. If cor pulmonale develops, the patient's survival is unlikely to exceed one year, but oxygen therapy in suitable patients may prolong this for a few years. Nutritional advice may be important. Some 'pink puffers' fall below their ideal weight and weight loss is a bad prognostic sign. Keeping to the ideal weight will increase exercise tolerance and it is particularly important to avoid becoming overweight. Patients should be advised to take as much exercise as they can because physical fitness enables maximum performance from skeletal muscle in the presence of poor oxygenation. Above all, however, the most important advice is a relentless campaign to stop smoking. Long-term use of home nebulizers For advice on the long-term use of home nebulizers, see Chapter 3 (Asthma).
Audit points 1. Proportion of patients who had a trial of treatment with bronchodilators and steroids to exclude chronic asthma. 2. Proportion of patients treated inappropriately with oral aminophylline or theophylline or with a long-term home nebulizer without objective evidence of benefit.
References Russell M A H, Wilson C, Taylor C et al. (1979) Effect of general practitioners' advice against smoking. British Medical Journal 2, 231-5. Stuart-Harris C, Henley D C, Bishop J M et al. (1981) Medical Research Council Working Party: long-term domiciliary oxygen therapy in chronic hypoxic cor pulmonale complicating bronchitis and emphysema. Lancet 1, 681-6.
Further reading Clarke T J H and Godfrey S (Eds) (1983) Asthma. London, Chapman and Hall. Flenley D C (1981) Respiratory Medicine. Concise Medical Textbooks. London, Bailliere Tindall. Johnson N (1989) Pocket Consultant Respiratory Medicine. 2nd ed. London, Blackwells. Medicine International Respiratory Disorders (1986) pt 2, vol. 2, pp 1417-42 and (1987 ) pt 4, vol. 2, pp 1522-40.
