leg movements, for example, get dramatically better with treatment and only ... mares, anxiety attacks, chronic obstructive pulmonary dis- ease, asthma, memory ...
editorial * editorial
Polysomnography: addressing the need for standards William A. Whitelaw, BSc, PhD, MD; W. Ward Flemons, BMSc, MD
The field of sleep disorders medicine is facing enormous challenges as it strives to gain recognition from the medical profession, the public and government. One of these challenges is to ensure that limited resources for diagnosis are used wisely. The authors argue that the standards for polysomnography developed by the Canadian Sleep Society and the Canadian Thoracic Society (see pages 1673 to 1678 of this issue) will go a long way toward ensuring that this expensive resource is used prudently. In the meantime, more research is needed to determine valid measures of the impact of sleep disorders and to establish the reliability of different diagnostic methods.
S leep disorders medicine is an emerging and rapidly evolving discipline that faces enormous challenges as it strives to gain recognition from the medical profession, the public and government. In 1992 the US National Commission on Sleep Disorders Research reported that chronic disorders of sleep and wakefulness affected approximately 40 million Americans, most of whom went undiagnosed and untreated.' The direct cost of three of these disorders - insomnia, sleep apnea and narcolepsy - was estimated at US$15.7 billion. Indirect and related costs resulting from lost work days, disability, property damage, accidents and so forth are nearly impossible to measure but are likely many times this amount. In general, the medical profession lacks understanding of most sleep disorders; this is hardly surprising given that most undergraduate curricula devote less than 2 hours of lectures to the subject. Public and professional interest in sleep disorders is increasing rapidly in response to the growth of scientific knowledge about sleep physiology, the discovery of obstructive sleep apnea (and the subsequent development
Le domaine de la medecine des troubles du sommeil a d'enormes defis a relever au moment oju il essaie de se faire reconnaitre par la profession medicale, le public et les gouvernements. Un de ces defis consiste a assurer que les ressources limitees affectees au diagnostic sont utilisees a bon escient. Les auteurs soutiennent que les normes de polysomnographie mises au point par la Soci&6 canadienne du sommeil et la Societe canadienne de thoracologie (voir pages 1673 'a 1678 dans le present numero) aideront enormement a assurer que cette ressource couteuse est
utilisee judicieusement. Entre-temps, il faut pousser les recherches pour trouver des mesures valides de l'impact des troubles du sommeil et etablir la fiabilite de diff6rentes methodes de diagnostic.
of an effective treatment) and the proliferation of medications for altering sleep. The vast numbers of patients eager to get help for such common complaints as snoring, insomnia, somnolence and fatigue place immense pressure on resources for diagnosis and treatment. Polysomnography, the standard investigation for many sleep disorders, is expensive, costing approximately $1000 per patient. Waiting lists of many months and sometimes over a year are, unacceptably, the norm in many cities across Canada. Governments are puzzled as to how much of their health care budgets to allot to an area of practice with such potential to consume money and vulnerability to abuse. As a result, funding for sleep disorders medicine has lagged behind that for many other disciplines and is dealt with by each province differently. In Alberta, for example, neither diagnostic investigations such as polysomnography nor beneficial treatments such as continuous positive airway pressure to manage sleep apnea are funded; in Ontario, by contrast, funding for diagnosis and therapy is comprehensive and open ended.
Dr. Whitelaw is Head of the Division of Respiratory Medicine and Dr. Flemons is Clinical Assistant Professor in the Faculty of Medicine, University of Calgary,
Calgary, Alta. Reprint requests to: Dr. William A. Whitelaw, Heritage Medical Research Building, University of Calgary, 3330 Hospital Dr. NW, Calgary AB T2N 4N1;
wwhitelai?ars.uc,algary.ca © 1996 Canadian Medical Association (text and abstract/resume)
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Unfortunately, because evidence of the importance of most sleep disorders is still poorly defined, the need for diagnostic testing is not always clear. The funding priority given to a diagnostic procedure should rest on certain criteria. First, the test should perform well and be reproducible; this requires, among other things, a definition of the population in whom it will yield useful diagnostic information. Second, the problems that it diagnoses should have a significant impact on longevity or quality of life. Third, some benefit - an effective treatment, helpful counselling or a useful prognosis - should stem from a diagnosis. Sleep disturbances are not responsible for many deaths, but they can cause prolonged misery and impair energy and mental function. Controlled outcome trials are difficult to carry out and may in some cases be unethical. Validated measures of quality of life in patients with sleep disorders are still being developed. A high percentage of patients with severe sleep apnea or periodic leg movements, for example, get dramatically better with treatment and only then recognize how badly impaired they were before. Nevertheless, there are only loose correlations between mild to moderate physiologic disturbances as demonstrated by polysomnography and clinical signs and symptoms.2 To provide evidence on which to found reasonable clinical decisions, we need to establish a favourable climate for excellence in clinical care and research. This would involve establishing a network of Canadian sleep centres for those purposes.
Much-needed standards The publication of standards for polysomnography by the Canadian Sleep Society and the Canadian Thoracic Society (CSS/CTS) in this issue (see pages 1673 to 1678) takes the field of sleep disorders medicine a decisive step forward. Only with reputable sleep laboratories that adhere to such standards, conduct careful patient assessments and order prudent clinical investigations will the discipline acquire the respect it so urgently needs. Given the huge demand for very limited diagnostic resources, the focus of recent research in Canada has been to determine whether some sleep disorders, especially sleep apnea, can be diagnosed and managed without polysomnography. Because the forecast for increased funding for polysomnography is unpromising, this hypothesis is a necessary and attractive one. It may be argued that the CSS/CTS standards should have made room for practitioners with less extensive training and experience to supervise testing for sleep apnea using simplified, home-based monitoring that relies mainly on oximetry. However, this argument is premature. Although many different types of monitors are in use, published evidence of their reliability is weak at best, coming from poorly designed trials with small samples. It can be expected that portable monitors and clinical approaches that can be used by general physicians to assess straight1694
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forward cases of sleep apnea will become established over the next few years, but standards for portable testing, including its indications, need to await the results of more extensive and rigorous clinical trials. In the meantime, patients will be much better served if testing, whether by full-scale polysomnography or by simple portable monitors, is supervised and interpreted by professionals whose training and experience allow them to fully appreciate the nuances of the clinical problems they are examining and the pitfalls of various assessment techniques. Because polysomnography is expensive and likely to remain a limited resource, the strategy proposed by the CSS/CTS of using sleep disorders specialists as gatekeepers who decide whether testing is needed should also be supported. There is simply not enough evidence on which to base simple recommendations about indications for sleep disorders testing. Most patients with prevalent disorders such as obstructive sleep apnea and insomnia are separated from the rest of the population only by a degree. Who has not had some sleepless nights or felt unduly tired on some days? Most people who snore may have occasional apnea, especially after an evening of alcoholic revelling. Many other complaints are sometimes associated with a sleep disorder and could lead to a request to perform polysomnography; these include impotence, hypertension, headache, chronic fatigue, nephrotic syndrome, depression, fibromyalgia, snoring, bruxism, nightmares, anxiety attacks, chronic obstructive pulmonary disease, asthma, memory loss and restless legs. A wellness practitioner might want to check that the sleep of each patient is perfectly optimal. If polysomnography were as simple and cheap as electrocardiography - that is, if it did not require the recording of 10 to 16 channels of electrical signals for 8 hours and did not demand expertise in the use of both electronic and cerebral software for its interpretation - then perhaps everyone could undergo testing. As it stands, leaving some constraint on the number of tests performed and giving the responsibility for the wise use of this diagnostic resource to people who are knowledgeable and experienced in the field is a reasonable way to manage tiings while the evidence accumulates. Sleep disorders medicine needs to find its proper place in the health care system. An important step is to establish credibility for its practitioners and diagnostic procedures. Following the CSS/CTS standards will go a long way toward assuring patients, physicians and payers that assessments performed in sleep laboratories are reliable and that the recommendations that stem from them are appropriate.
1.
Report of the National Commission on Sleep Disorders Research. Washington: US Department of Health and Human Services, 1992.
2.
Strohl KP, Redline S. Recognition of obstructive sleep apnea. Am J Respir Crit Care Med 1996;154:279-89.
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