Newport Beach, California ... physical examination and also on the ability to record both nocturnal ... niques can be used to record respiratory effort, electrocar-.
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increase the likelihood of successful weaning, but the effects of nutritional therapy on stable patients with COPD are less clear and are under investigation. A recent preliminary report, however, showed that three months of supplemental oral nutrition in poorly nourished COPD patients resulted in decreased breathlessness and increased muscle strength, walking distance, and general well-being. Other studies in malnourished patients with emphysema have shown an improvement in respiratory muscle function after nutritional intervention. Considering the chronic nature of this disease, it is not surprising that nutritional therapy may have only a limited impact. Regardless, malnutrition can be an additive factor to morbidity and perhaps to mortality in this disease, and thus prompts our concern and attention. The care of patients with COPD should include a careful nutritional assessment and intervention where necessary, particularly in patients with chronic bronchitis and emphysema in whom malnutrition is more prevalent. Patients with severe lung impairment who are underweight may need a higher caloric intake than expected. Standard formulas for predicting energy expenditure often underestimate their needs. Recent work indicates that the Quebbeman-Ausman predictive equation correlates well with indirect calorimetry in patients with COPD (for men, daily caloric requirement = weight x 12.3 + 754; women, weight x 6.9 + 874; weight in kg). This may require using liquid dietary supplements, including tube feedings for inpatients whose dietary intake may be inadequate. Overfeeding must likewise be avoided because of its obvious consequences. If a patient with severe pulmonary impairment has hypercapnia, care should be taken to avoid a high-carbohydrate nutritional intake that can increase carbon dioxide production and worsen the hypercapnia in these patients. A special liquid formula is available for this use. PAUL A. SELECKY, MD Newport Beach, California
REFERENCES Askanazi J (Ed): Nutrition and respiratory disease. Clin Chest Med 1986;
7: 1-151 Efthimiou J, Fleming J, Gomes C, et al: Effect of supplementary oral nutrition in poorly nourished patients with chronic obstructive pulmonary disease (Abstr). Am Rev RespirDis 1987; 135:A149 Wilson DO, Rogers RM, Hoffman RM: Nutrition and chronic lung disease. Am Rev Respir Dis 1985; 132:1347-1365
Newer Methods in
Sleep Disorders Medicine SLEEP DISORDERS MEDICINE is a new clinical area dealing with disorders such as the sleep apnea syndrome, periodic leg movements of sleep, narcolepsy, insomnias, and the assessment of impotence. A diagnosis relies on a history and physical examination and also on the ability to record both nocturnal sleep and daytime sleep tendencies. Polysomnography, the laboratory-based recording of sleep, typically includes monitoring an electroencephalogram (EEG), electro-oculogram, and electromyogram to score sleep stages. Additional variables recorded for diagnostic purposes may include respiratory effort and airflow, oxyhemoglobin levels (oximetry), an electrocardiogram, or penile tumescence. Laboratory-based polysomnography also involves simultaneous monitoring by a technician of patient activities and equipment, videotaping for later review, and direct correlation with patient expectations and experiences. Understandably, this is labor-intensive and expensive.
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Recent technical advances have allowed for easier and more accurate characterization of certain sleep-related variables. The use of microprocessors has greatly aided the ability to store and analyze data. Computerized programs are available to analyze continuous oximetric data. The programs provide graphic results and an immediate analysis of the number, length, and severity ofdesaturation events. This technology can be used to screen for sleep apnea and has been particularly useful in the inpatient setting. Computerized analysis of RR-interval variation can also screen for sleep apnea, indicating the severity of cardiac consequences of obstructive apnea. Computer-assisted EEG analysis and sleep stage scoring systems have become commercially available. In theory, these systems provide for efficient storage of information and use of technicians' time. Their costeffectiveness and usefulness in clinics with various staffing and case-load requirements is not yet certain, however. Using this technology can aid traditional polysomnography and, coupled with daytime alertness testing, allow for an accurate diagnosis, estimation of the severity of a disorder, the impact of abnormal physiologic variables on cardiovascular and neuropsychologic function, and the determination of treatment. Ambulatory monitoring is becoming more sophisticated, reflecting a need for accurate and inexpensive diagnostic methods. Sleep disorders are common, and large populations that may be undiagnosed, such as hypertensive men who snore, can benefit from widespread screening. Portable systems can be used to diagnose sleep apnea or the periodic leg movements of sleep, but patients whose results show abnormalities often require polysomnography to determine a specific treatment, thus increasing the cost in certain cases. As microprocessing techniques improve, more physiologic variables can be recorded in the home. For example, several channels of an EEG can be recorded on a cassette tape to detect seizure foci. The wrist movement monitor is a simple method of differentiating wakefulness from sleep and has been validated in clinical studies. Analog or digital techniques can be used to record respiratory effort, electrocardiograms, and movements of the wrist or legs. Although available, home monitoring of oximetry is not widely used but in combination with respiratory measures can add diag-
nostic certainty. Using microprocessors to evaluate nocturnal penile tumescence holds a future promise for home diagnosis, but this technology is not fully validated. These devices may be best used in combination with laboratory observation to show the association of erections with rapideye-movement sleep, to involve the patient in an objective assessment, and to rule out sleep disorders that can themselves cause impotence. Sleep disorders medicine is a rapidly changing discipline that requires prolonged monitoring of many physiologic variables. In addition to technical advances, clinical decision analyses are evolving to help physicians manage and advise patients who are too sleepy to safely perform activities such as driving a car or working in industry. J. STEVEN POCETA, MD MILTON K. ERMAN, MD MERRILL M. MITLER, MD La Jolla, California REFERENCES
Ancoli-Israel S, Kripke DF, Mason W, et al: Comparisons of home sleep recordings and polysomnograms in older adults with sleep disorders. Sleep 1981; 4:283-291
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Bridgers SL, Ebersole JS: The clinical utility of ambulatory cassette EEG. Neurology 1985; 35:166-173 Guilleminault C, Connolly S, Winkle R, et al: Cyclical variation of the heart rate in sleep apnoea syndrome-Mechanisms and usefulness of24 h electrocardiography asa screening technique. Lancet 1984; 1:126-131 Gyulay S, Gould D, Sawyer B, et al: Evaluation of a microprocessor-based portable home monitoring system to measure breathing during sleep. Sleep 1987; 10:130-142 Timms RM, Dawson A, Taft R, et al: Oxygen saturation by oxymetry: Analysis by microcomputer. J Polysomnographic Technol 1988, in press
Pulmonary Complications of the Acquired Immunodeficiency Syndrome PULMONARY COMPLICATIONS are a major source of morbidity and mortality in patients with the acquired immunodeficiency syndrome (AIDS). Indeed, a sudden increase in the prevalence of Pneumocystis carinii pneumonia in otherwise healthy young homosexual men first alerted the medical community to this disease. The T-cell defect produced by the human immunodeficiency virus leaves these patients prey to numerous opportunistic pathogens and neoplasms that produce pulmonary disease. Pneumocystis carinii is the major pulmonary pathogen occurring in 60% to 85% of patients with AIDS. The presenting symptoms include fever, cough, and dyspnea (85%), with chills (26%) and pleuritic chest pain (23%) occurring less frequently. A chest x-ray film is usually normal or shows diffuse interstitial infiltrates. Unilateral infiltrates and cavitary disease have been reported in patients with P carinii pneumonia. The alveolar-arterial oxygen difference is typically widened- > 15 torr, 92%-and portends a poor prognosis if greater than 25 torr. Although gallium lung scanning, the diffusing capacity for carbon monoxide, and exercise testing may be used for noninvasive assessments, a diagnosis rests on detecting organisms. Tests of induced sputum specimens may be positive 50% of the time, and transbronchial
lung biopsy combined with bronchoalveolar lavage has a 95 % to 100% sensitivity. Pentamidine isethionate or trimethoprim-sulfamethoxazole, administered intravenously for two to three weeks, remains the mainstay of therapy. Prophylactic studies using nebulized pentamidine aerosol delivered into the bronchial tree are very encouraging. A 15% to 30% mortality is expected with each episode of P carinii pneumonia, however. Other pulmonary infections associated with AIDS include Cytomegalovirus (15% to 34%), Mycobacterium avium-intracellulare (16% to 21 %), Mycobacterium tuberculosis (4%), fungal infections (4%), and, most particularly, cryptococcal pneumonia, Legionella pneumophila (4%), and Nocardia. Because of a B-cell defect, AIDS patients also have a higher incidence of bacterial pneumonias (10%), chiefly caused by Staphylococcus aureus, primarily in association with pulmonary Kaposi's sarcoma. There are also noninfectious causes of pulmonary infiltrates in this patient population. Kaposi's sarcoma is clinically and radiologically indistinguishable from P carinii pneumonia and accounts for about 10% of infiltrates. Pulmonary Kaposi's sarcoma is associated with a high mortality rate-88 %. Nonspecific pneumonitis, on the other hand, generally carries a good prognosis and may be responsible for as high as 12 % ofthe complications of AIDS. JAMES TUCHSCHMIDT, MD BISHER AKIL, MD
Los Angeles
REFERENCES
Murray JF, Felton CP, Garay S, et al: Pulmonary complications of the acquired immunodeficiency syndrome-Report of a National Heart, Lung and Blood Institute workshop. N Engl J Med 1984; 310:1682-1688 Polsky B, Gold JWM, Whimbey E, et al: Bacterial pneumonia in patients with the acquired immunodeficiency syndrome. Ann Intern Med 1986; 104:38-41 Solal-Celigny P, Couderc LJ, Herman D, et al: Lymphoid interstitial pneumonitis in acquired immunodeficiency syndrome-related complex. Am Rev Respir Dis 1985; 131:956-960
ADVISORY PANEL TO THE SECTION ON CHEST DISEASES LOWELL E. RENZ, MD Advisory Panel Chair Section Editor CMA Scientific Board Representative MICHAEL STULBARG, MD
GERALD L. MEYERS, MD
THOMAS A. RAFFIN, MD
CMA Section Chair Berkeley
Stanford University
University of California, San Francisco
GLEN LILLINGTON, MD
OM P. SHARMA, MD
University of California, Davis
University of Southern California
CMA Section Secretary Los Angeles
ARCHIE WILSON, MD
IRA J. STRUMPF, MD
University of California, Irvine
Woodland Hills
MITCHELL P. TARKOFF, MD
DONALD TIERNEY, MD
JOHN E. HODGKIN, MD
University of California, Los Angeles
Deer Park PHILIP HOPEWELL, MD San Francisco SPENCER K. KOERNER, MD Los Angeles
EDWARD A. OPPENHEIMER, MD
CMA Section Assistant Secretary Oakland PHILIP M. GOLD, MD Loma Linda University
*Deceased
GENNARO M. TnSI, MD*
University of California, San Diego
