Special Medical Reports

American Thoracic Society Issues Consensus Statement on Dyspnea
Verna L. Rose

The American Thoracic Society (ATS) has issued a consensus statement on the mechanisms, assessment and management of dyspnea. Published in the January 1999 issue of the American Journal of Respiratory and Critical Care Medicine, the 19-page statement, developed by an 18-member expert committee, addresses mechanisms of dyspnea, assessment and treatment.

Decreases in functional status and quality of life, and disabilities are frequently consequences of dyspnea. The ATS believes that a better understanding of all aspects of dyspnea is necessary in order for physicians to appropriately treat patients with shortness of breath.

The ATS states that the underlying causes of dyspnea are chronic obstructive pulmonary disease (COPD), asthma, interstitial lung disease, neuromuscular disorders, lung cancer and coronary disease. The ATS defines dyspnea as a subjective experience of breathing discomfort consisting of qualitatively distinct sensations that vary in intensity. Physiologic, psychologic and environmental factors all may play a role. The severity varies widely among patients. Interventions discussed in the statement include exercise training, oxygen therapy, pharmacologic therapy, nutrition, positioning, continuous positive airway pressure, steroid therapy, cognitive-behavioral approaches and others.

Assessment

The assessment of dyspnea is an important aspect of the evaluation and management of the disorder. Historically, the evaluation of dyspnea has emphasized the search for corresponding pathophysiology. Diagnostic testing should identify the specific nature of the disorder. Standard spirometry and lung volume measurements may be useful in assessment. Standard questionnaires are available to determine the association between levels of activity that are related to dyspnea. Tools are also available to relate the severity of symptoms with observed levels of cardiac and pulmonary responses during performance of tasks. The ATS notes that questionnaires relating dyspnea to quality of life are useful even though they are not yet a routine part of the history and physical examination.

After the physician determines the underlying cause of dyspnea, the focus should be on the symptoms of breathlessness, including trying to determine quality, intensity, duration, frequency, and the amount of distress or discomfort. The statement recommends that physicians distinguish between two broad categories: conditions associated with cardiovascular dyspnea involving inadequate oxygen delivery to the tissues; and pulmonary dyspnea. Sometimes the problem involves a combination of symptoms associated with the two major disorders. Comorbid conditions as well as psychologic status need to be considered in the evaluation of the significance of symptoms, according to the ATS.

Treatment

The statement points out that the physiologic bases for the treatment of dyspnea lie in the discussion of the mechanisms underlying shortness of breath. The ATS categorizes treatments for dyspnea as related to pathophysiologic mechanisms rather than specific diseases. These categories of mechnisms are listed in the table. The ATS acknowledges that questions remain, and research is needed in this area but believes that an approach to treatment that links mechanisms and treatments will help minimize the impact of dyspnea on the patient.

Therapeutic Interventions and Their Tie to Pathophysiologic Mechanism Pathophysiologic mechanism Therapeutic intervention Reduce ventilatory demand Reduce metabolic load Exercise training: improve efficiency of CO2 elimination Supplemental O2 therapy Decrease central drive Supplemental O2 therapy Pharmacologic therapy Opiate therapy Anxiolytic therapy Alter pulmonary afferent information Vibration Ventilator settings Inhaled pharmacologic therapy Fans Improve efficiency of CO2 elimination Altered breathing pattern Reduce ventilatory impedance Reduce/counterbalance lung hyperinflation Surgical volume reduction Continuous positive airway pressure Reduce resistive load Pharmacologic therapy Improve inspiratory muscle function Nutrition Inspiratory muscle training Positioning Partial ventilatory support Minimizing use of steroids Alter central perception Education Cognitive-behavioral approaches Desensitization Pharmacologic therapy Reprinted with permission from the American Thoracic Society. Dyspnea. Mechanisms, assessment, and management: a consensus statement. Am J Respir Crit Care Med 1999;159:321-40.

Information on some of the treatments reviewed in the statement follows:

Reduce Ventilatory Demand
Exercise Training. Exertional dyspnea decreases and exercise tolerance improves in response to exercise training in patients with COPD, even in patients with advanced disease. Studies have established that for patients with COPD who remain breathless despite optimal pharmacologic therapy, exercise training can provide significant symptomatic benefits.

Pharmacologic Therapy. Two types of medications have been evaluated as a means of alleviating dyspnea: opiates and anxiolytics. Numerous studies have shown that opiates relieve dyspnea and improve exercise performance in patients with COPD, although evidence is insufficient to recommend their regular use in long-term management. Anxiolytics have the potential to relieve dyspnea by depressing hypoxis or hyercapnic ventilatory responses.

Fans. The movement of cool air with a fan has been noted to reduce dyspnea in pulmonary patients.

Altered Breathing Patterns. Breathing retraining including diaphragmatic breathing and pursed lip breathing has been advocated to relieve dyspnea in COPD patients. The effectiveness of this method is highly variable.

Reduce Ventilatory Impedance
Continuous Positive Airway Pressure. Continuous positive airway pressure has been demonstrated in some studies to relieve dyspnea during asthma attacks, when patients are being weaned from ventilators and during exercise sessions for patients with advanced COPD.

Improve Inspiratory Muscle Function
Nutrition. Some research has shown that respiratory muscle function can be improved in response to nutritional repletion with short-term use of enteral or parenteral nutrition and in outpatient and inpatient controlled trials of oral supplementation. Others have shown the benefits of outpatient programs that provide patient education and distribute nutritional supplements.

Positioning. Body positions that increase abdominal pressure may improve overall inspiratory muscle strength and the function of the respiratory muscles.

Steroids. Use of steroids in pulmonary patients helps reduce inflammation and increases vital lung capacity in interstitial lung disease. The use of steroids for the purpose of reducing dyspnea must be weighed against the adverse effects of steroids on muscles.

Altered Central Perception
Cognitive-Behavioral Approaches. In patients with pain syndromes, distraction, relaxation and education about the symptom have been shown to modify the intensity of the symptom, increase tolerance and decrease distress. Relaxation training may improve symptoms in the short term. Monitoring symptoms helps patients and physicians understand the patterns of symptom intensity.

Other treatments reviewed in the statement include oxygen therapy, supplemental oxygen during exercise, vibration, ventilator settings, surgical volume reduction, desensitization, inspiratory muscle training and education.

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Treatment Guidelines for Heart Failure Stress Multidrug Approach
Sharon Scott Morey

A group of more than 150 cardiologists has issued recommendations for the treatment of chronic heart failure. The recommendations were developed on behalf of a not-for-profit organization called the Advisory Council to Improve Outcomes Nationwide in Heart Failure (ACTION HF). The recommendations are published in the January 21, 1999, issue of the American Journal of Cardiology.

General treatment recommendations advocate the use of a four-drug regimen that includes digitalis, a diuretic, an angiotensin-converting enzyme (ACE) inhibitor and a beta-adrenergic blocker. According to the recommendations, ACE inhibitors and beta blockers are underprescribed for the treatment of chronic heart failure: only about 40 percent of patients receive ACE inhibitors, and only about 5 percent of patients receive beta blockers. Combination therapy is considered to be the optimal approach for most patients with heart failure.

The 38-page report is divided into two parts: part 1 discusses the evaluation of patients with heart failure, and part 2 discusses prevention and management. The following information is excerpted from six tables that provide summaries of recommendations in the report.

General Management Measures

• Measures to decrease the risk of new cardiac injury--cessation of smoking; weight reduction in obese patients; control of hypertension, hyperlipidemia and diabetes; and discontinuation of alcohol use.
• Measures to maintain fluid balance--restriction of daily intake of salt to 3 g or less and daily measurement of weight to detect early occurrence of fluid retention.
• Measures to improve physical conditioning--participation in moderate exercise to prevent or reverse physical deconditioning; do not instruct patients to limit their activity.
• Measures to follow in selected patients--control of the ventricular response in patients with atrial fibrillation or other supraventricular tachycardias; anticoagulation in patients with atrial fibrillation or a previous embolic event (and, possibly, other high-risk patients); and coronary revascularization in patients with angina (and, possibly, in patients with ischemic but viable myocardium).
• Pharmacologic measures to avoid--do not use antiarrhythmic agents to suppress asymptomatic ventricular arrhythmias, most calcium antagonists and nonsteroidal anti-inflammatory drugs.

Close follow-up is advised to detect early evidence of clinical deterioration. In addition, influenza and pneumococcal immunizations are recommended.

Use of Diuretics

The recommendations state that diuretics should be prescribed for all patients with symptoms of heart failure and evidence of a predisposition to fluid retention. Diuretics are the only reliable means of controlling fluid retention associated with heart failure. Diuretics should not be used alone, however; a diuretic generally should be used in combination with an ACE inhibitor and a beta blocker.

The goal of diuretic therapy is to eliminate symptoms and physical signs of fluid retention, as assessed by jugular venous pressure, peripheral edema, or both. If hypotension or azotemia occurs before symptoms and signs are eliminated, the rapidity of diuresis may be slowed, but diuresis should be maintained until fluid retention is eliminated, as long as the changes in blood pressure and renal function are mild or moderate in severity and do not produce symptoms. Measurement of body weight, preferably daily, is the most useful way to select the diuretic dose and monitor the patient's response to diuretic therapy.

Underdosing of diuretics can lead to fluid retention, which may diminish the response to ACE inhibitors and increase the risk of treatment with beta blockers. Overdosing of diuretics can lead to volume depletion, which may increase the likelihood of hypotension with ACE inhibitors and vasodilators and may increase the risk of renal insufficiency with ACE inhibitors and angiotensin II receptor antagonists.

The recommendations state that diuretic resistance can be overcome by intravenous administration of diuretics, by the use of more than two diuretics in combination or by the short-term use of drugs that increase renal blood flow (e.g., dopamine and dobutamine). Diuretic resistance may be caused by concomitant therapy with nonsteroidal anti-inflammatory drugs.

Use of ACE Inhibitors

The recommendations state that all patients with heart failure caused by left ventricular dysfunction should receive an ACE inhibitor unless they are known to be intolerant or to have contraindications to this class of drugs. An ACE inhibitor is generally used with a diuretic in patients who have fluid retention. An ACE inhibitor is also recommended in patients with left ventricular systolic dysfunction but no symptoms of heart failure. Although clinical trials suggest that all ACE inhibitors are likely to exert beneficial effects in heart failure, preference should be given to the target doses of the specific ACE inhibitors evaluated in large-scale studies. ACE inhibitors should generally not be used to stabilize acutely ill patients.

Patients receiving ACE inhibitors should be told that side effects may occur early in therapy but do not generally prevent long-term use, and that symptomatic improvement may not occur for several weeks or months of therapy. Patients should also be informed that ACE inhibitor therapy may reduce the risk of disease progression, even if the symptoms do not respond to treatment.

Use of Beta Blockers

The recommendations state that beta blockers should be used in all patients with stable New York Heart Association class II or class III heart failure caused by left ventricular systolic dysfunction, unless contraindicated. A beta blocker is used in combination with a diuretic and an ACE inhibitor.

As with ACE inhibitor therapy, patients receiving beta blockers should be told that side effects may occur early in therapy but do not generally prevent long-term use. Symptomatic improvement may not occur until after two to three months of therapy. Patients should also be informed that beta blocker therapy may reduce the risk of disease progression even if the symptoms do not respond to treatment.

More data are needed on the effects of beta blockers in patients with unstable disease or class IV symptoms before use of these agents can be recommended for such patients. Beta blockers should not be used as "rescue" therapy in acutely ill patients.

Use of Digitalis

Digoxin is recommended in conjunction with a diuretic, ACE inhibitor and beta blocker in patients with heart failure caused by left ventricular systolic dysfunction. It also is recommended in patients with heart failure and rapid atrial fibrillation, even though beta blockers may be more effective in controlling the ventricular response during exercise.

The recommendations note that there is no evidence to support monitoring of serum digoxin levels as a guide for the appropriate dose. According to the recommendations, digoxin is well tolerated by most patients with heart failure. It is unknown whether long-term digoxin therapy exerts deleterious cardiovascular effects at the doses that are generally in the therapeutic range.

Role of Antiarrhythmic Agents

Class I antiarrhythmic agents should not be used in patients with heart failure, except in the treatment of life-threatening ventricular arrhythmias that are refractory to treatment. The recommendations state that some class III agents, such as amiodarone, do not appear to increase the risk of death in patients with chronic heart failure, and these drugs are preferred over class I agents when used for the treatment of atrial arrhythmias in patients with left ventricular dysfunction. Given its known toxicity and equivocal evidence for efficacy, amiodarone is not recommended for general use to prevent death, including sudden death, in patients with heart failure already treated with drugs that reduce mortality.

The recommendations also point to the need to monitor and correct potassium and magnesium levels, because low levels can cause atrial and ventricular arrhythmias and can alter the efficacy and toxicity of antiarrhythmic interventions.

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AAP Releases Recommendations on Use of Inactivated and Live Oral Polio Vaccines
Sharon Scott Morey

The American Academy of Pediatrics (AAP) Committee on Infectious Diseases has released the complete AAP recommendations for the use of inactivated poliovirus vaccine (IPV) and live oral poliovirus vaccine (OPV). The recommendations are published in the January 1999 issue of Pediatrics. The recommendations state that AAP anticipates that by the year 2001 only IPV immunization will be recommended for children in the United States.

"Special Medical Reports" in the January 1, 1999, issue of American Family Physician contains the 1999 childhood immunization schedule (see page 203). As reported in AFP, one change in the immunization schedule is the recommendation that IPV be administered for the first two doses, at ages two months and four months. The immunization schedule is the product of a collaboration among the Advisory Committee on Immunization Practices, the American Academy of Family Physicians and the AAP.

The following summarizes the AAP recommendations for use of IPV and OPV:

• For the first two doses of poliovirus vaccine, IPV is recommended under most circumstances for all children at ages two months and four months. OPV immunization is acceptable when the parents refuse IPV or object to the number of injections needed to administer all of the other recommended vaccines.
• Depending on whether a sequential or an IPV-only regimen is used, the next two doses of OPV or IPV should be given at six to 18 months of age and at four to six years of age. If OPV is given for the third and fourth doses, some experts recommend delaying the third dose until the child is 12 months of age.
• An IPV-only regimen is recommended for immunocompromised persons and their household contacts (OPV is contraindicated in these persons). Because of the increased risk of vaccine-associated paralytic poliomyelitis, it is also recommended for infants and children in households with persons older than 17 years of age who are known to be inadequately vaccinated against poliomyelitis.
• An OPV-only regimen is acceptable when the routine immunization schedule was not instituted until after six months of age or if an accelerated schedule is necessary.
• For children who will be traveling to areas where wild-type poliovirus is endemic, selection of the type of vaccine depends on the interval until departure and the number of doses that have already been administered. Two doses of IPV at a minimal interval of one month are recommended for previously unimmunized children who will be traveling in two months or more. If travel will be in less than two months in a previously unimmunized child, a single dose of either OPV or IPV should be given and the immunization schedule should be continued after arrival in the foreign country. If a child has received two doses of IPV, administration of two doses of OPV at an interval of at least one month apart will provide optimal immunity.
• If an outbreak of wild-type poliovirus infection occurs in the United States, OPV is the vaccine of choice to control the spread of infection.

The AAP recommendations note that data from the Centers for Disease Control and Prevention show an increase in the use of IPV. In 1997, IPV accounted for 29 percent of all poliovirus vaccine doses; in 1996, it accounted for 6 percent.

Copyright © 1999 by the American Academy of Family Physicians.
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