Apnea del sueño en atención primaria. Puntos clave
Resumen
La problemática de la Apnea Obstructiva del Sueño (AOS), tiene un innegable impacto en la calidad de vida de las personas que lo sufren y es un potencial factor de riesgo que puede empeorar problemas de salud, pero en España apenas un 25% de los pacientes reciben tratamiento.
Se ha demostrado que los costes de salud de los pacientes que no tratados aumentan entre un 50-100% y que el ahorro medio por paciente tratado es de 777€.
Este documento, elaborado por un grupo de expertos de SEPAR, actualiza el documento previo, en función de la nueva evidencia científica y pone al día aspectos generales de esta enfermedad, como el diagnóstico y modalidades de tratamiento, centrándose en el tratamiento con CPAP, las nuevas indicaciones, su seguimiento y control, y el papel de las empresas proveedoras de servicio. Se incide en la gestión del cumplimiento, la estratificación de pacientes y la responsabilidad de las Unidades de sueño, los canales de atención e información, y se analizan aspectos técnicos y de calidad alrededor de los distintos actores implicados, para alcanzar un sistema de gestión sostenible.
Se actualizan las nuevas indicaciones de CPAP, en coordinación con el nuevo Consenso Internacional del AOS, ampliando aspectos logísticos, y se elabora un resumen ejecutivo para ser empleado por la Administración en la licitación de concursos públicos de Terapias Respiratorias Domiciliarias y se establecen recomendaciones sobre qué hacer y no hacer en el abordaje del diagnóstico y tratamiento del AOS.
Background:
Polysomnography (PSG) is currently the "gold standard" for the diagnosis of the sleep apnoea hypopnoea syndrome (SAHS). Nocturnal oximetry (NO) has been used with contradictory results. A prospective study was performed to determine the accuracy of NO as a diagnostic tool and to evaluate the reduction in the number of PSGs if the diagnosis of SAHS had been established by this method.
Methods:
Two hundred and seventy five patients with a clinical suspicion of SAHS were admitted to undergo, in the same night, full PSG and NO. Desaturation was defined as a fall in the haemoglobin saturation level (SaO(2)) to lower than 4% from the baseline level and an oxygen desaturation index per hour (ODI) was obtained in each patient with three cut off points: >/= 5 (ODI-5), >/= 10 (ODI-10), and >/= 15 (ODI-15).
Results:
SAHS was diagnosed in 216 patients (194 men). After withdrawing patients with abnormal lung function (forced expiratory volume in one second (FEV(1)) lower than 80% predicted), sensitivity (SE), specificity (SP), positive and negative predictive values (PPV and NPV) of NO were: ODI-5 (80%, 89%, 97%, 48%); ODI-10 (71%, 93%, 97%, 42%); ODI-15 (63%, 96%, 99%, 38%). The accuracy for each ODI was 0.81, 0.75, and 0.70, respectively. If NO had been considered as a diagnostic tool and PSG had been performed only in patients with a negative NO (false negative and true negative) and those with a positive NO and abnormal pulmonary function tests, 135/275 (ODI-5), 156/275 (ODI-10), and 170/275 (ODI-15) PSGs would have been performed, a reduction of 140, 119, and 105, respectively.
Conclusion:
Nocturnal oximetry in patients with suspected SAHS and normal spirometric values permits the institution of therapeutic measures in most patients.
Objective
Overnight polysomnography (PSG) is the gold standard diagnostic tool for sleep apnea-hypopnea syndrome (SAHS) in children. The aim of the present study was to evaluate the usefulness of diagnostic respiratory polygraphy in children with clinically suspected SAHS referred to our sleep-disordered breathing clinic.
Patients and methods
We studied 53 children referred with clinical suspicion of SAHS; 29 (54.7%) were boys and the mean (SD) age was 6.4 (2.9) years. After a medical history was taken and a physical examination performed, patients underwent respiratory polygraphy (Edentec) simultaneously with overnight PSG in the sleep laboratory. The 2 diagnostic tools were compared using statistical analysis.
Results
SAHS was defined by an obstructive apnea-hypopnea index (OAHI) of 3 or more in overnight PSG and a respiratory disturbance index (RDI) of 3 or more in respiratory polygraphy. The rate of diagnostic agreement was 84.9%. The difference between the mean OAHI and RDI values was not significant (0.7 [5.4]; P=.34). The intraclass correlation coefficient between the OAHI and RDI was 89.4 (95% confidence interval, 82.4-93.7; P<.001).
When receiver operating characteristic curves were calculated for the OAHI cutoff points used for the diagnosis of SAHS (≥1, ≥3, and ≥5), the best RDI cutoff for all 3 OAHI values considered was found to be 4.6. When age strata were considered, in children 6 years or older the best RDI cutoff for the 3 OAHI values was 2.1. In children younger than 6 years the best RDI cutoff was 3.35 for OAHI ≥1 and 5.85 for OAHI ≥3 and ≥5.
Conclusions
Respiratory polygraphy in the sleep laboratory is a valid method for the diagnosis of SAHS in children.
Gender-related differences in the symptom profile of patients with suspected sleep disordered breathing (SDB) may be one explanation of the clinical underrecognition of SDB in women.
The aim of this study was to prospectively assess gender-related differences in presenting symptoms in a clinical sample of patients with suspected sleep disordered breathing.
Administration of the Sleep Disorders Questionnaire prior to clinical and polysomnographic evaluation. Responses obtained from the questionnaire were used to construct 4 independent symptom scales: sleep apnea (SA), periodic limb movement syndrome (PLM), psychiatric sleep disorder (PSY), and narcolepsy (NAR). Analyses of variance were used to examine the effect of gender, AHI, and age on the symptom scales. Associations between gender and each diagnostic scale of the questionnaire were determined by multiple analyses of covariance.
Tertiary pulmonary referral center.
2739 men and 782 women with suspected SDB. All patients who were referred to the sleep laboratory underwent full-night polysomnography, irrespective of the likelihood of SDB.
N/A.
Overall, men scored significantly higher on items related to worsening of snoring/breathing with alcohol (P < 0.001) and smoking history (P < 0.01) than women. Complaints such as witnessed apneas (P < 0.001) and worsening of snoring in supine position (P < 0.05), however, were more frequently reported by men with an apnea-hypopnea index (AHI) < 5/hr, compared with AHI-matched women. There were no significant differences in these items in patients with an AHI > 15/hr. In contrast, women complained significantly more often of insomnia, restless legs, depression, nightmares, palpitations at night, and hallucinations than men. As a result, women had significantly higher scores on the PLM, PSY, and NAR scales of the Sleep Disorders Questionnaire (P < 0.001, for all). After adjustments for age, body mass index, AHI, arousal index, oxygen saturation data, and smoking history, by means of multiple analyses of covariances, gender differences remained significant (P < 0.001, for all scales).
We observed significant gender-related differences in presenting symptoms of patients with sleep disordered breathing at a tertiary level. These differences should be taken into consideration in clinical evaluation of women with suspected sleep disordered breathing.
SUMMARY:Sleep disordered breathing (SDB) is a common condition in children. Sleep Apnea/Hypopnea syndrome (SAHS) in children is a frequent sleep disorder, with a prevalence estimated to be 1 - 3% of all children. The most frequent cause of SAHS in children is the adenotonsillar hypertrophy. SAHS in children can result in severe complications if left untreated such as impaired physical growth, delayed development, poor school performance and in severe cases, hypertension and cor pulmonale, nevertheless, yet it is an under recognized condition. The gold standard diagnostic technique is the nocturnal polysomnography (PSG), guidelines for performing laboratory-based polysomnography in children have been established, the sleep laboratory should be a nonthreatening environment and personnel with pediatric training should record, score and interpret the study. The diagnostic criteria for SAHS in adults is not useful for diagnosis of SAHS in children. Adenotonsillectomy is the most common treatment for children with SAHS.RESUMEN:Los trastornos respiratorios del sueño en los niños, en particular el Síndrome de Apneas/Hipopneas durante el sueño (SAHS), es una patología frecuente, que afecta entre el 1 - 3% de la población infantil, siendo su causa más frecuente la hipertrofia adenoamigdalar. Es una enfermedad infradiagnosticada y que conlleva importantes complicaciones como son alteraciones del crecimiento, alteraciones cognitivas e incluso en casos severos Cor Pulmonale. La polisomnografía nocturna (PSG), es la técnica diagnóstica de elección para el diagnóstico del SAHS en los niños, pero en la población infantil es necesario tener en cuenta una serie de consideraciones, como son la edad de la población que se estudia, entorno adecuado y la necesidad de técnicos entrenados en el cuidado de los niños. Los criterios diagnósticos del SAHS para adultos no son útiles en los niños. El tratamiento de elección en los niños con SAHS es la adenoamigdalectomia.
One thousand and one men, aged 35-65 years, were identified from the age-sex register of one group general practice. Over four years 900 men were visited at home and asked questions about symptoms potentially related to sleep apnoea and snoring. Height, weight, neck circumference, resting arterial oxygen saturation (SaO2), and spirometric values were also determined. All night oximetry was then performed at home and the tracing analysed for the number of dips in SaO2 of more than 4%. Subjects with more than five dips of 4% SaO2 or more per hour were invited for sleep laboratory polysomnography. Seventeen per cent of the men admitted to snoring 'often'. Multiple linear regression techniques identified and ranked neck circumference (r2 = 7.2%), cigarette consumption (r2 = 3.4%), and nasal stuffiness (r2 = 2%) as the only significant independent predictors of snoring. Together these account for at least a sixfold variation in the likelihood of being an 'often' snorer. Forty six subjects (5%) had > 4% SaO2 dip rates of over five an hour and 31 of these had full sleep studies. Three subjects had clinically obvious and severe symptomatic obstructive sleep apnoea, giving a prevalence of three per 1001 men (0.3%; 95% confidence interval 0.07-0.9%). Eighteen men had obstructive sleep apnoea only when supine and in 10 the cause of the SaO2 dipping on the original home tracing was not elucidated. The > 4% SaO2 dip rates correlated with the history of snoring. Multiple linear regression techniques identified and ranked neck circumference (r2 = 7.9%), alcohol consumption (r2 = 3.7%), age (r2 = 1%) and obesity (r2 = 1%) as the only significant independent predictors of the rate of overnight hypoxic dipping. This study shows that snoring in this randomly selected population correlates best with neck size, smoking, and nasal stuffiness. Obstructive sleep apnoea, defined by nocturnal hypoxaemia, correlates best with neck size and alcohol, and less so with age and general obesity.
The role of drug therapy in the treatment of the sleep apnea/hypopnea syndrome is unclear. In a randomised, double-blind, placebo-controlled study, we investigated the value of 14-day therapy with protriptyline (20 mg daily) or acetazolamide (250 mg 4 times per day) on symptoms and on the frequency of apneas, hypopneas, arousals, and 4% desaturations in 10 patients with obstructive sleep apnea/hypopnea syndrome. Overall, protriptyline did not have a significant effect either on symptoms or on any of the above polysomnographic criteria. Acetazolamide reduced the apnea/hypopnea frequency [placebo 50 +/- 26 (SD); acetazolamide 26 +/- 20/h of sleep, p less than 0.03] and tended to decrease the frequency of 4% desaturations (placebo 29 +/- 20; acetazolamide 19 +/- 16/h of sleep, p = 0.06). Despite these physiological improvements, acetazolamide did not significantly improve symptoms and paraesthesiae were common. Contrary to earlier studies, we conclude that protriptyline may have a limited role in the treatment of the sleep apnea syndrome. The reason why acetazolamide produced a physiological, but not a symptomatic, response requires further investigation.
Although obstructive sleep apnea (OSA) has been studied in detail for over a decade, the mortality of this disorder is unclear. We calculated cumulative survival in 385 male OSA patients. We found that those with an apnea index (AI) greater than 20 had a much greater mortality than those with AI = less than 20. The probability of cumulative eight-year survival was .96 +/- 0.02 (SE) for AI = less than 20 vs. 63 +/- 0.17 for AI greater than 20 (p less than .05). This difference in mortality related to AI was particularly true in the patients less than 50 years of age in whom mortality from other causes is not common. None of the patients treated with tracheostomy or nasal CPAP died. Eight of the patients treated with uvulopalatopharyngoplasty (UPPP) died and the cumulative survival of the UPPP-alone treated group was not different from the survival curve of untreated OSA patients with an apnea index of greater than 20. We conclude that OSA patients with an apnea index of greater than 20 have a greater mortality than those below 20 and that UPPP patients be restudied after therapy. If the latter patients are found not to have marked amelioration of their AI, then they should be treated by nasal CPAP or tracheostomy.
Ear oximetry is commonly employed in screening patients for the sleep apnea syndrome, but the lack of objective information regarding the duration of sleep, including the presence of rapid-eye-movement (REM) sleep, is a major limitation. Based on the premise that both apnea and sleep-state-dependent changes in ventilation give rise to distinctive patterns in the arterial oxygen saturation, we developed a systematic technique to analyze ear oximetric tracings for wakefulness, REM sleep, and non-REM (NREM) sleep. Fifty-four patients were studied by both all-night polysomnography and ear oximetry. A careful comparison of ear oximetric data for sleep states and apnea was then made, using polysomnography as the correct classification to determine sensitivity, specificity, predictive value positive, and predictive value negative of the ear oximetric tracings. When classification of sleep state was compared, ear oximetry correctly classified 280.5 (82 percent) of 340.9 hours of sleep that was either REM or NREM sleep. The sensitivity for classifying NREM sleep was 0.85, for REM sleep was 0.70, and for wakefulness was 0.49. The sensitivity by ear oximetry for apnea was 0.80, with a predictive value negative of 0.87. We conclude that although polysomnography must be performed for definitive evaluation, ear oximetry is a valuable screening test for sleep apnea because the presence or absence of apnea can be determined, total duration of sleep can be estimated, and NREM vs REM sleep can be differentiated.
El protagonista de la novela de Dickens "los documentos póstumos del club Pickwick", Mr. Pickwick (no Joe, el enfermo) ha dado nombre durante años al SAOS. Hoy, el término se ha abandonado por ser incompleto, al referirse sólo a los relativamente raros enfermos más severos,...
We examined the predictive value of history and physical examination in the diagnosis of obstructive sleep apnea (OSA) syndrome. This was achieved by studying a set of 594 patients referred to the sleep clinic because of suspicion of sleep apnea. All patients were asked a set of standard sleep-related questions and all had nocturnal polysomnography. We used stepwise multiple linear regression analysis to examine the relationship between the apnea/hypopnea index (AHI), defined as the number of episodes of cessation of breathing per hour of sleep (dependent variable), and age, sex, body mass index (BMI) and replies to the sleep questionnaire (independent variables). We found that age, sex, body mass index, bed partner observation of apnea and pharyngeal examination were significant predictors of AHI, explaining 36% of the variability. Subjective impression of the examining clinician was also an independent significant predictor of AHI, accounting for 10% of the variability. Using a conventional cutoff value of 10 to divide patients into apneics (AHI > 10) and nonapneics (AHI ≤ 10), the sensitivity of subjective impression was 60% and the specificity 63%. We conclude that although clinical features obtained during history and physical examination explain a relatively high percent of the variability in AHI, subjective clinical impression alone is not sufficient to reliably identify patients with or without sleep apnea.
Background
A variety of devices are used to evaluate patients with a potential diagnosis of obstructive sleep apnea (OSA). A committee comprised of members of the American Academy of Sleep Medicine, American Thoracic Society, and American College of Chest Physicians systematically evaluated data on the use of these devices and developed practice parameters.
Devices reviewed
Three categories of portable monitoring (PM) devices were reviewed with regard to assessing the probability of identifying an apnea-hypopnea index (AHI) of greater or less than 15 in attended and unattended settings. Type 2 (minimum of seven channels, including EEG, EOG, chin EMG, ECG or heart rate, airflow, respiratory effort, oxygen saturation), Type 3 (minimum of four channels, including ventilation or airflow (at least two channels of respiratory movement, or respiratory movement and airflow), heart rate or ECG and oxygen saturation) and Type 4 (most monitors of this type measure a single parameter or two parameters ) devices were evaluated, and in-laboratory, attended polysomnography was used as a reference.
Specific recommendations
(1) Insufficient evidence is available to recommend the use of Type 2 PM devices in attended or unattended settings.
(2) Type 3 PM devices appear to be capable of being used in an attended setting to increase or to decrease the probability that a patient has an apnea-hypopnea index greater than 15.
(3) The use of Type 3 PM devices in an unattended setting is not recommended to rule in, rule out, or both rule in and rule out a diagnosis of OSA.
(4) There is some evidence that the use of Type 3 PM devices in an attended in-laboratory setting may be acceptable to both rule in and rule out a diagnosis of OSA if certain limitations are in place. These limitations
include manually scoring the records, using the devices only in patients without significant comorbid conditions, having an awareness that symptomatic patients with a negative study should have a Type 1 study, and not using these devices for titrating positive airway pressure or conducting split-night studies.
(5) The use of Type 4 PM devices in attended or unattended settings is not recommended.
General Recommendations
Type 3 and 4 PM devices cannot score sleep and, therefore, do not meet some current Medicare guidelines. The use of PM devices is not recommended for general-population screening or in the absence of a pretest probability of the patient having a diagnosis of OSA, for complaints other than those associated with OSA, without review of raw data during interpretation, by physicians without familiarity with their use and limitations, and without trained personnel to perform technical scoring. Future research should address the use of PM devices in patients with comorbid conditions; non-White patients and women; larger, better-controlled studies; studies focused on the use of Type 2 and 3 devices; studies focusing on decision making and outcomes rather than simple classification using arbitrary cutoffs; and studies that seek to elucidate cost-effectiveness data on the use of PM devices.
To investigate the association between sleep apnea syndrome (SAS) and automobile accidents, and to evaluate potential underlying mechanisms, we prospectively recruited 60 consecutive patients with SAS (apnea-hypopnea index, 58 +/- 3 h(-1)) and 60 healthy control subjects, matched for sex and age. The number of automobile accidents during the past 3 yr was obtained from participants and insurance companies. We quantified the degree of daytime sleepiness (Epworth scale), anxiety and depression (Beck tests), and we assessed the level of vigilance (PVT 192) and driving performance (Steer-Clear). Patients had more accidents than control subjects (OR: 2.3; 95% CI: 0.97 to 5.33) and were more likely to have had more than one accident (OR: 5.2; 95% CI: 1.07 to 25.29, p < 0.05). These differences persisted after stratification for km/yr, age, and alcohol consumption. Patients were more somnolent, anxious, and depressed than control subjects (p < 0.01), and they had a lower level of vigilance and poorer driving performance (p < 0.01). Yet, we did not find any correlation between the degree of daytime sleepiness, anxiety, depression, the number of respiratory events, nocturnal hypoxemia, level of vigilance, or driving simulator performance and the risk of automobile accidents among SAS patients. In conclusion, patients with SAS have an increased risk of automobile accidents. None of the clinical or physiological markers commonly used to define disease severity appear able to discriminate those patients at higher risk of having an automobile accident.
Since the original clarification of the obstructive nature of obstructive sleep apnea (OSA) in 1965, much has been learned about the disorder. It is a condition with a high prevalence with obesity as a major risk factor. It aggregates in families, a relationship that is not simply explained by obesity. Premenopausal women are relatively protected from the disorder because OSA is uncommon in this group. Its prevalence in women rises after menopause. Although OSA is a risk factor for excessive sleepiness, there is developing evidence that it is also a risk factor for hypertension, acute cardiovascular events, and insulin resistance. The first line of therapy is nasal continuous positive airway pressure. Data as to the efficacy of continuous positive airway pressure in severe OSA have come from randomized, placebo-controlled clinical trials with the endpoints being sleepiness, quality of life, and 24-h ambulatory blood pressure. Data are currently less convincing for treatment outcomes in mild to moderate OSA, and new clinical trials to assess outcomes in this group are underway. Thus, even though this field only began toward the end of the first century of the American Thoracic Society, substantial progress has been made, and OSA has increasingly emerged as a major public health concern.
New technologies for the noninvasive assessment of oxygen and carbon dioxide are transforming clinical practice. Transcutaneous monitoring of PO2 (PtcO2) and PCO2 (PtCO2) provides an approximation of PaO2 and PaCO2 values in hemodynamically normal individuals, but both PtcO2 and PtcCO2 diverge from the corresponding arterial values when cardiac output is reduced, even in the absence of hypotension. Transcutaneous monitors also have relatively slow equilibration and response times. Pulse oximeters rapidly assess arterial O2 saturation, but give spurious results when dyshemoglobins (for example, carboxyhemoglobin, methemoglobin) are present in significant quantity. End-tidal CO2 (PetCO2) monitoring tracks breath-by-breath changes in ventilation, and PetCO2 approximates PaCO2 when significant physiologic dead-space is not present. Respiratory inductive plethysmography provides a semiquantitative assessment of tidal volume and the relative contribution of the thorax and abdomen to ventilation; among other uses, this technology may allow for the early detection of respiratory muscle fatigue prior to the onset of respiratory failure.
Correspondencia: Unidad de Trastornos Respiratorios del Sueño. Sección de Neumología. Hospital General Yagüe. Avda. del Cid s/n. 09005 Burgos.
Background:
Recent evidence indicates that the prevalence of sleep-disordered breathing is remarkably high (24% for men and 9% for women) and that the public health burden attributable to sleep-disordered breathing is substantial. This investigation examines current and former cigarette smoking as potential risk factors for sleep-disordered breathing.
Methods:
Data were from 811 adults enrolled in the University of Wisconsin Sleep Cohort Study, Madison. The Sleep Cohort Study is a longitudinal, epidemiologic study that uses nocturnal polysomnography to investigate sleep-disordered breathing and other disorders of sleep. The presence and severity of sleep-disordered breathing was quantified by the frequency of apneas and hypopneas per hour of sleep.
Results:
Logistic regression analyses were used to control for potential confounding factors. Compared with never smokers, current smokers had a significantly greater risk of snoring (odds ratio, 2.29) and of moderate or worse sleep-disordered breathing (odds ratio, 4.44). Heavy smokers (≥40 cigarettes per day) had the greatest risk of mild sleep-disordered breathing (odds ratio, 6.74) and of moderate or worse sleep-disordered breathing (odds ratio, 40.47). Former smoking was unrelated to snoring and sleep-disordered breathing after adjustment for confounders.
Conclusions:
Current cigarette smokers are at greater risk for sleep-disordered breathing than are never smokers. Heavy smokers have the greatest risk while former smokers are not at increased risk for sleep-disordered breathing. Thus, smoking cessation should be considered in the treatment and prevention of sleep-disordered breathing.(Arch Intern Med. 1994;154:2219-2224)
Background
The risk of sudden death from cardiac causes in the general population peaks from 6 a.m. to noon and has a nadir from midnight to 6 a.m. Obstructive sleep apnea is highly prevalent and associated with neurohormonal and electrophysiological abnormalities that may increase the risk of sudden death from cardiac causes, especially during sleep.
Methods
We reviewed polysomnograms and the death certificates of 112 Minnesota residents who had undergone polysomnography and had died suddenly from cardiac causes between July 1987 and July 2003. For four intervals of the day, we compared the rates of sudden death from cardiac causes among people with obstructive sleep apnea and the following: the rates among people without obstructive sleep apnea, the rates in the general population, and the expectations according to chance. For each interval, we assessed the median apnea–hypopnea index and the relative risk of sudden death from cardiac causes. We similarly analyzed sudden death from cardiac causes during three time intervals that correlate with usual sleep–wake cycles.
Results
From midnight to 6 a.m., sudden death from cardiac causes occurred in 46 percent of people with obstructive sleep apnea, as compared with 21 percent of people without obstructive sleep apnea (P=0.01), 16 percent of the general population (P<0.001), and the 25 percent expected by chance (P<0.001). People with sudden death from cardiac causes from midnight to 6 a.m. had a significantly higher apnea–hypopnea index than those with sudden death from cardiac causes during other intervals, and the apnea–hypopnea index correlated directly with the relative risk of sudden death from cardiac causes from midnight to 6 a.m. For people with obstructive sleep apnea, the relative risk of sudden death from cardiac causes from midnight to 6 a.m. was 2.57 (95 percent confidence interval, 1.87 to 3.52). The analysis of usual sleep–wake cycles showed similar results.
Conclusions
People with obstructive sleep apnea have a peak in sudden death from cardiac causes during the sleeping hours, which contrasts strikingly with the nadir of sudden death from cardiac causes during this period in people without obstructive sleep apnea and in the general population.
Objective
To analyze the relationship between sleep-disordered breathing and difficult-to-control arterial hypertension.
Patients and methods
Patients were considered to have difficult-to-control hypertension when mean systolic blood pressure was 125 mm Hg or higher and/or mean diastolic blood pressure was more than or equal to 80 mm Hg (as recorded during 2 24-hour ambulatory monitoring studies) despite the use of 3 or more antihypertensive drugs. Respiratory polygraphy using the AutoSet device (ResMed Corp, Sydney, Australia) was then performed to study sleep-disordered breathing in all patients.
Results
Forty-nine patients with a mean (SD) age of 68.1 (9.1) years, mean systolic and diastolic pressures of 152.5 (13)/89.2 (8.5) mm Hg, and an average of 3.5 prescribed drugs were included in the study. The mean apnea-hypopnea index (AHI) was 26.2 (19.5) and events were predominantly obstructive. Patients with severe sleep apnea-hypopnea syndrome (SAHS) (AHI ≥ 30; 40.8%) showed more uncontrolled daytime (P=.017) and nighttime (P=.033) systolic pressure than the rest, as well as higher daytime diastolic pressure (P=.035) and a greater consumption of drugs than those without severe SAHS (AHI < 0; 28.6%) (P=.041). The study population as a whole showed a significant correlation between blood pressure and obesity. There was a significant correlation (adjusted for age and sex) with AHI only in patients with SAHS. AHI was found to be the independent predictor with the greatest effect on blood pressure in these patients.
Conclusions
Prevalence of SAHS was very high in patients with difficult-to-control hypertension. In patients with SAHS, AHI was found to be the independent predictor with the greatest affect on arterial blood pressure.
Background and objective
Obesity is a chronic disease with a complex multifactorial nature which typically begins during childhood and adolescence. It represents one of today's most critical and escalating public health concerns for this segment of the population. The lack of obesity prevalence data at national level prompted the enKid Study (1998-2000), which was designed to evaluate the food habits and nutritional status of Spanish children and youth.
Subjects and method
Cross-sectional epidemiological study of a representative sample of the Spanish population aged 2 to 24 years (n = 3534). Height and weight measurements were carried out using standard procedures and equipment. Obesity and overweight were defined according to BMI values for the 97th and 85th percentiles, respectively using Spanish reference data provided by Hernández et al (1998).
Results
The prevalence of obesity in Spain is 13.9%, while the combination of overweight and obesity yields a prevalence of 26.3% (with a prevalence of overweight alone of 12.4%). Obesity is more common in males (15.6%) than in females (12%), which was also true for overweight. With regard to age, a higher prevalence is found among those aged 6 to 13 years. As for the geographic area, Canary Islands and Andalusia show the highest prevalence and the northeast region the lowest. Obesity is also more prevalent among those people with the lowest socioeconomic and educational levels, and in those who omitted or consumed a poor breakfast.
Conclusions
Compared to other countries, Spain shows an intermediate level of obesity in children and youth. Over the past decades, there has been an increasing trend towards overweight and obesity, which are more prevalent in males and during prepuberal ages.
TThe main problem in the treatment of obstructive sleep apnea syndrome (OSAS) with nasal continuous airway pressure (nCPAP) is the lack of compliance. One of the most important reasons for no compliance is the adverse effects of this treatment. We analyse, prospectively, 182 patients treated with nCPAP in order to show the relationship between previous nasal problems and adverse effects of nCPAP. Sixty percent of the population developed one o more side effects. Of this group, 69% showed nasal septum deviation at first examination in front of 31% that did not showed this problem (p=0,001). In the group of patients with nasal side effects we observed an increase of compliance in 80% of patients treated medically and in 89% of those treated by a septoplasty. We demonstrate that the adverse effects of nCPAP are related to previous nasal problems and, also, that treatment of those problems can achieve an increase in compliance to nCPAP therapy
Objective
The level of clinical suspicion of sleep apnea–hypopnea syndrome (SAHS) among primary care physicians is low. The aim of this study was to analyze the impact of a primary care training program on the quality and quantity of referrals made due to suspected SAHS.
Material and methods
A group of 16 primary care physicians were offered the option of participating in a training program consisting of 2 talks–workshops, the provision of up-to-date information on SAHS and a form for making referrals according to an established protocol, and the opportunity to contact the sleep department at our hospital directly. Twenty-one primary care physicians who did not receive training served as the control group. We gathered data on the quantity and quality of referrals made by both groups for the period January through June 2005 and 2006, and recorded the number of both SAHS diagnoses made and patients prescribed treatment with continuous positive airway pressure. Data were analyzed in function of the primary care population assigned to each group.
Results
The training program was completed by 81.3% of the physicians. The number of referrals made by the training group increased 2.38-fold after the program (intergroup comparison, P=.0001). There was also a 2.36-fold increase in the percentage of cases of SAHS detected in the population (P=.0008), a 1.85-fold increase in the percentage of serious cases detected (P=.001), and a 2-fold increase in the number of patients prescribed continuous positive airway pressure (P=.009). Agreement between the data gathered by the physicians and the sleep specialist was significantly higher in the training group for all the items studied.
Conclusions
The implementation of a training program on SAHS aimed at primary care physicians improved both the quantity and quality of referrals made due to suspected SAHS.
Obese adults have an increased prevalence of pulmonary disorders. Although childhood obesity is a common problem, few studies have evaluated the pulmonary complications of obesity in the pediatric population. We, therefore, performed pulmonary function tests (PFTs), polysomnography, and multiple sleep latency tests (MSLTs) in 22 obese children and adolescents [mean age, 10 ± 5 (SD) years; 73% female; 184 ± 36% ideal body weight], none of whom presented because of sleep or respiratory complaints. PFTs were normal in all but two subjects. Ten (46%) subjects had abnormal polysomnograms. There was a positive correlation between the degree of obesity and the apnea index (r = 0.47, P < 0.05), and an inverse correlation between the degree of obesity and the S2O2 nadir (r = −0.60, P < 0.01). The degree of sleepiness on MSLT correlated with the degree of obesity (r = −0.50, P < 0.05). We conclude that obese children and adolescents have a high prevalence of sleep-disordered breathing, although in many cases it is mild. Obstructive sleep apnea syndrome (OSAS) improved following tonsillectomy and adenoidectomy. We recommend that pediatricians have a high index of suspicion for OSAS when evaluating obese patients, and that polysomnography be considered for these patients. Pediatr Pulmonol. 1996; 21:176–183. © 1996 Wiley-Liss, Inc.
ObjetivoLa demanda de consultas y estudios diagnósticos del síndrome de apneas-hipopneas durante el sueño (SAHS) se ha incrementado, lo que ha llevado a importantes demoras. Por tanto, es precisa una evaluación actualizada de la situación del diagnóstico que sirva como herramienta de gestión a especialistas y las administraciones sanitarias que tienen la responsabilidad de solventar el problema. El objetivo del presente estudio ha sido realizar un análisis descriptivo de la situación del diagnóstico del SAHS en los hospitales españoles.MétodosSe ha realizado un estudio descriptivo, observacional y transversal. Se estableció contacto con los centros públicos y privados incluidos en el catálogo de instituciones sanitarias del Ministerio de Sanidad de 2005. Se incluyeron aquellos que evaluaban habitualmente a pacientes con SAHS. El responsable de cada centro rellenó un cuestionario sobre disponibilidad de recursos y demoras para el diagnóstico.ResultadosDe los 741 centros con los que se estableció contacto, 217 evaluaban habitualmente a pacientes con SAHS. El 88% disponía de poligrafía respiratoria (PR) (n = 168) o polisomnografía (PSG) (n = 97). La demora media en consulta fue de 61 días, y la demora media para realizar PR, de 224 días. La media de equipos de PR fue de 0,99/100.000 habitantes, cuando lo recomendable es 3/100.000. La demora media para PSG fue de 166 días. La media de camas de PSG fue de 0,49/100.000 habitantes y lo recomendable es 1/100.000.ConclusionesSe observa una notable deficiencia de recursos que lleva a inaceptables listas de espera. Aunque la situación del diagnóstico de SAHS ha cambiado favorablemente con respecto a estudios previos, sigue siendo mejorable y es imprescindible que las autoridades sanitarias dediquen más recursos a este problema de salud pública.ObjectiveThe demand for consultations and diagnostic studies for sleep apnea-hypopnea syndrome (SAHS) has increased, and this has led to considerable delays. We therefore need an updated evaluation of the diagnostic situation to serve as a management tool for specialists and health care administrations responsible for solving the problem. The objective of the present study was to carry out a descriptive analysis of the situation regarding the diagnosis of SAHS in Spanish hospitals.MethodsWe undertook a descriptive cross-sectional observational study. Public and private hospitals listed in the Ministry of Health's 2005 catalog of health care institutions were contacted, and those that routinely evaluate patients for SAHS were included in the study. The person in charge of each hospital filled in a questionnaire concerning the availability of resources and waiting periods for diagnosis.ResultsOf the 741 hospitals we contacted, 217 routinely evaluated patients for SAHS. In 88% of these, respiratory polygraphy (RP) (n = 168) or polysomnography (PSG) (n = 97) was available. The mean waiting period was 61 days for consultation and 224 days for RP. The mean number of RP systems was 0.99 per 100 000 inhabitants, while the recommended number is 3 per 100 000 inhabitants. The mean waiting period for PSG was 166 days. The mean number of PSG beds was 0.49 per 100000 inhabitants, while the recommended number is 1 per 100 000.ConclusionsWe observed a marked inadequacy of resources that has led to unacceptable waiting periods. While there has been a favorable change in the situation regarding SAHS diagnosis compared to previous studies, there is still room for improvement and it is urgent that healt hcare authorities allocate more resources to this public health problem.
Introducción y objetivo: El síndrome de apneas-hipopneas durante el sueño está asociado a un deterioro del estado de salud y constituye un problema sanitario que en España sufren entre 1 y 2 millones de personas. El objetivo del estudio fue evaluar cuáles son los medios diagnósticos y terapéuticos disponibles en España, tanto en infraestructuras como en recursos humanos, para abordar este problema. Métodos: Se seleccionaron 461 hospitales generales y mediante contacto telefónico se administró un cuestionario a 457 (99,1%). Resultados: Realizan estudios de sueño 219 centros (47,5%). El 53% dispone de polisomnografía convencional, un 42% emplea la poligrafía respiratoria y un 5% la oximetría. Un 47% de los centros realiza titulaciones de presión positiva continua de la vía aérea de forma mayoritariamente empírica y existen en activo 109.752 aparatos, lo que representa 269 equipos por 100.000 habitantes. Conclusiones: El nivel de recursos para el diagnóstico y el tratamiento del síndrome de apneas-hipopneas durante el sueño, a pesar de haber mejorado, es claramente insuficiente. Son necesarios un polisomnógrafo convencional y 3 polígrafos, mientras que actualmente se cuenta con 0,49 y 0,72 por 100.000 habitantes, respectivamente. Sólo se ha diagnosticado el 5-10% de la población afectada y en el 47% de los centros la presión positiva continua de la vía aérea se titula de forma inadecuada. Estos resultados deberían suponer una importante llamada de atención a las autoridades sanitarias para abordar apropiadamente este problema sanitario.
The effect of sleep apnea on mortality and cardiovascular morbidity is mainly unknown. We aimed to study whether sleep apnea is related to stroke, death, or myocardial infarction in patients with symptomatic coronary artery disease.
A total of 392 men and women with coronary artery disease referred for coronary angiography were examined by use of overnight sleep apnea recordings. Sleep apnea, defined as an apnea-hypopnea index >or=5, was recorded in 54% of the patients. All patients were followed up prospectively for 10 years, and no one was lost to follow-up. Stroke occurred in 47 (12%) of 392 patients during follow-up. Sleep apnea was associated with an increased risk of stroke, with an adjusted hazard ratio of 2.89 (95% confidence interval 1.37 to 6.09, P=0.005), independent of age, body mass index, left ventricular function, diabetes mellitus, gender, intervention, hypertension, atrial fibrillation, a previous stroke or transient ischemic attack, and smoking. Patients with an apnea-hypopnea index of 5 to 15 and patients with an apnea-hypopnea index >or=15 had a 2.44 (95% confidence interval 1.08 to 5.52) and 3.56 (95% confidence interval 1.56 to 8.16) times increased risk of stroke, respectively, than patients without sleep apnea, independent of confounders (P for trend=0.011). Death and myocardial infarction were not related to sleep apnea. Intervention in the form of coronary artery bypass grafting or percutaneous coronary intervention was related to a longer survival but did not affect the incidence of stroke.
Sleep apnea is significantly associated with the risk of stroke among patients with coronary artery disease who are being evaluated for coronary intervention.
The arterial blood O2 saturation measurement obtained by the Hewlett-Packard ear oximeter was compared to that derived from the arterial PO2 in 41 patients with various pulmonary diseases and in 11 jaundiced patients with serum bilirubin concentrations between 2.7 and 35 mg per 100 ml. There was a good correlation between results obtained with the 2 methods in the jaundiced group (r = + 0.85, n = 19) and in the patients with pulmonary disease (r = + 0.90, n = 57); however, in the jaundiced patients, the ear oximeter arterial O2 saturation was significantly lower (-6.06 per cent, n = 19, P less than 0.01) than the arterial O2 saturation derived from the arterial PO2. There was a significant correlation between the serum bilirubin concentration and the magnitude of difference between the oximeter arterial O2 saturation and the arterial PO2-derived arterial O2 saturation (r = + 0.848, n = 16, P less than 0.001). In the nonjaundiced patients, the difference between the 2 measurements was small when the arterial P(02) was greater than 61 mm Hg; the variation increased with lower arterial PO2 concentrations, but the difference was not significant.
In this study we investigated the relationship between the size of adenoids and/or tonsils and obstructive sleep apnea syndrome (OSAS) in 19 children aged 3 to 7 years. After clinical examination by an ENT specialist, electrocardiogram (ECG), vectorcardiogram (VCG) and echocardiogram (EC) were performed while the patients were awake, and static charge sensitive bed (SCSB) method recording (noninvasive monitoring of ballistocardiogram, respiration and body movements) while asleep. After adenoidectomy and/or tonsillectomy, the volume of the tonsils and the adenoids was determined. RVH was found in 4 out of 19 children (21%). RVH findings correlated highly with the number of apneas but, surprisingly, not with measured adenotonsillar size in those children. However, at 6 months of follow-up, the VCG and EC changes had returned to normal. These results suggest that RVH is more common in children suffering from upper airway obstruction than previously believed, and that factors other than adenotonsillar size also have an influence on upper airway obstruction.
To determine whether presenting clinical history, pharyngeal examination, and the overall subjective impression of the clinician could serve as a sensitive screening test for sleep apnea.
Blinded comparison of history and physical examination with results of nocturnal polysomnography.
Sleep clinic of a tertiary referral center.
A total of 410 patients referred for suspected sleep apnea syndrome. Most patients reported snoring.
All patients were asked standard questions and given an examination relevant to the diagnosis of the sleep apnea syndrome, and all had full nocturnal polysomnography. Patients with more than ten episodes of apnea or hypopnea per hour of sleep were classified as having sleep apnea. Stepwise linear logistic regression was used to develop two predictive models of sleep apnea: one based on the presence of characteristic clinical features, age, sex, and body mass index; and one based on subjective clinical impression.
The prevalence of sleep apnea in our patients was 46%. Only age, body mass index, male sex, and snoring were found to be predictors of sleep apnea. The logistic rule discriminated between patients with and without sleep apnea (receiver operating characteristic [ROC] area, 0.77 [95% Cl, 0.73 to 0.82]). For patients with a predicted probability of apnea of less than 20%, the clinical model had 94% sensitivity and 28% specificity. Subjective impression alone identified correctly only 52% of patients with sleep apnea and had a specificity of 70%.
In patients with a high predicted probability of the sleep apnea syndrome, subjective impression alone or any combination of clinical features cannot serve as a reliable screening test. However, in patients with a low predicted probability of sleep apnea, the model based on clinical data was sufficiently sensitive to permit about a 30% reduction in the number of unnecessary sleep studies.
The sensitivity and specificity of overnight recording of arterial oxygen saturation (SaO2) in routine clinical practice was evaluated in 41 subjects who were being investigated for possible sleep apnoea-hypopnoea syndrome. SaO2 was measured with an ear probe oximeter (Biox IIa) and chart recorder during an "acclimatisation" night immediately before a detailed polysomnographic study. The recordings were classified by two observers as positive, negative, or uninterpretable. Twelve of the 41 patients had the obstructive sleep apnoea syndrome when defined in terms of an apnoea-hypopnoea index greater than 15 events an hour on the second night. The sensitivity of nocturnal SaO2 on the acclimatisation night when the diagnostic criterion was an apnoea-hypopnoea index of greater than 5, greater than 15, and greater than 25/h was 60%, 75%, and 100% respectively. Corresponding values for specificity were 95%, 86%, and 80%. Oximetry alone therefore allowed recognition of a moderate or severe sleep apnoea syndrome. In routine practice an appreciable number of equivocal results is likely and repeat oximetry or more detailed polysomnography will then be required if clinical suspicion is high.
This is a preliminary report of a longitudinal assessment of sleep architectural changes over time and rate of progression of sleep apnea (SA) and sleep-related periodic leg movements (PLMs) in the elderly. Multiple night polysomnograms were performed in 11 community resident seniors (8 women and 3 men, aged 60-72 years) and repeated 3 years (34-38 months) later. Subjects were selected who exhibited at most mild SA or PLMs at initial testing. The respiratory disturbance index (but not the movement index) showed a significant increase over 3 years. Sleep architecture did not change significantly except for an increase in frequency of stage changes that was not solely attributable to the increase in frequency of apneas/hypopneas. Together with other published longitudinal studies, these findings suggest that elderly individuals with at most mild SA or PLMs can expect no more than a mild increase in the frequency of apneas/hypopneas or PLMs over the course of a few years.
We have investigated the ability of a statistical model developed from clinical data and questionnaire responses to predict disturbance of breathing during sleep. Data from 100 consecutive patients referred for sleep study for suspected sleep apnea were used to develop the model using logistic regression analysis. For each subject, the model predicted the probability of having an apnea-hypopnea index (AHI) greater than 15; this probability was compared with the AHI measured from sleep study. A probability cutoff point (= 0.15) was decided on that minimized the number of subjects with false-negative predictions. Four terms--apneas observed by bed partner, hypertension, body mass index, and age--were found to contribute significantly to the model with observed apneas being by far the most predictive term of the four (adjusted odds ratio 19.7). When the model was tested to estimate the probability of an AHI greater than 15 for 105 patients from a second group of consecutive patients referred for sleep study, the model correctly classified 33 of 36 patients with a measured AHI greater than 15 (sensitivity = 92%) and 35 of 69 patients with a measured AHI less than or equal to 15(specificity = 51%). This study shows that analysis of clinical features of patients presenting with suspected sleep apnea may reduce the need for sleep studies by about one-third yet still lead to the identification of the great majority of patients with abnormal breathing during sleep.
Measurements of arterial blood oxygen saturation from two ear oximeters were compared with 655 simultaneously drawn arterial blood samples in 187 patients grouped by skin color quantified by the Munsell color system. Technical problems including warning lights and messages with the two ear oximeters were recorded. There were significantly more technical problems in patients with the darkest skin color associated with inability to obtain a reading or warning message indicating poor tissue penetration of the signal (18 and 15 percent vs 1 percent). When readings could be obtained, the ear oximetry readings were found to be slightly less accurate in the darker patient groups. These findings suggest that dark skin color may affect the performance and accuracy of ear oximeters, including the newer type of pulse oximeters.
Administration of nocturnal oxygen for 1 night to patients with obstructive sleep apnea (OSA) causes a moderate reduction in apnea frequency without improving hypersomnolence. Therefore, we administered oxygen chronically to patients with OSA to determine: whether apnea frequency would be further reduced, whether the effect of oxygen upon apnea frequency is correlated with an increased ventilatory response to hypoxia and hypercapnia, and whether hypersomnolence improves with more prolonged oxygen administration. In a single-blinded, nonrandomized trial, we compared the effects of 1 month of oxygen (4 L/min by nasal cannula) with room air (4 L/min by nasal cannula) placebo during sleep in 7 men and 1 woman with obstructive sleep apnea. During non-REM sleep, acute oxygen administration elevated the average low oxy-hemoglobin saturation during apneic events and decreased apnea frequency. These acute effects persisted during chronic oxygen administration but reverted to the preoxygen effects immediately upon discontinuing oxygen. One month of oxygen did not affect the waking ventilatory response to hypoxia or hypercapnia; however, waking PaCO2 increased from 40 +/- 1 mm Hg (mean +/- SE) after placebo to 43 +/- 1 mm Hg after oxygen (p less than 0.01). Neither subjective nor objective hypersomnolence consistently improved after 1 month of oxygen administration. We conclude that: first, oxygen has no effect upon apnea frequency beyond the period of administration, and the reduction of apnea frequency is not correlated with an increased sensitivity to chemical ventilatory stimuli. The reduced apnea frequency may be related to an increased PaCO2 stimulating ventilation during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)
Although patients with obstructive sleep apnea often report falling asleep while driving, the frequency of auto accidents involving these patients has not been rigorously studied. Therefore, we compared the driving records of 29 patients with obstructive sleep apnea with those of 35 subjects without sleep apnea. The patients with sleep apnea had a sevenfold greater rate of automobile accidents than did the subjects without apnea (p less than 0.01). The percentage of persons with one or more accidents was also greater in the patients with apnea than in the control subjects without apnea (31% versus 6%, p less than 0.01). The percentage of persons having one or more accidents in which they were at fault was also greater in the patients with apnea than in the control subjects (24% versus 3%, p less than 0.02). The automobile accident rate of the patients with sleep apnea was 2.6 times the accident rate of all licensed drivers in the state of Virginia (p less than 0.02). In addition, 24% of patients with sleep apnea reported falling asleep at least once per week while driving. We conclude that patients with obstructive sleep apnea have a significantly higher frequency of auto accidents than do subjects without apnea. Impaired drivers with sleep apnea may cause many preventable auto accidents.
The therapeutic effects of weight loss were evaluated in 15 hypersomnolent patients with moderately severe obstructive sleep apnea. As patients decreased their body weight from 106.2 +/- 7.3 kg (mean +/- SE) to 96.6 +/- 5.9 kg, apnea frequency fell from 55.0 +/- 7.5 to 29.2 +/- 7.1 episodes/h (p less than 0.01) in non-rapid-eye-movement sleep with an associated significant decline in the mean oxyhemoglobin saturation during the remaining episodes of sleep apnea from 11.9 +/- 2.4% to 7.9 +/- 1.9% (p less than 0.02). Sleep patterns also improved, with a reduction in stage I sleep from 40.2 +/- 7.3% to 23.5 +/- 4.8% (p less than 0.01), and a rise in stage II sleep from 37.3 +/- 7.0% to 49.4 +/- 4.6% (p less than 0.03). In the 9 patients with the most marked fall in apnea frequency, the tendency toward daytime hypersomnolence was decreased (p less than 0.05). No significant changes in sleep patterns occurred in 8 age- and weight-matched control patients who did not lose weight. Moderate weight loss alone can alleviate sleep apnea, improve sleep architecture, and decrease daytime hypersomnolence.
Sleep deprivation appears to increase the severity of obstructive sleep apnea, and inadequate activation of the genioglossus muscle may play an important role in the pathogenesis of obstructive sleep apnea. Therefore, we investigated the effect of sleep deprivation on genioglossal electromyographic (EMG) activity. Eleven men were studied during room air breathing and CO2 rebreathing before sleep deprivation (control), after 1 night of sleep deprivation, and the day after sleep recovery. We measured inspired minute ventilation, tidal volume, respiratory frequency, and peak integrated inspiratory genioglossal EMG activity. After sleep deprivation, no significant changes in inspiratory minute ventilation or tidal volume occurred during room air breathing or CO2 rebreathing, but the breathing frequency during CO2 rebreathing increased significantly after sleep deprivation. Genioglossal EMG activity was diminished during CO2 rebreathing after sleep deprivation, but this was significant only in subjects 30 yr of age and older. The fall in EMG activity was independent of changes in tidal volume. All variables returned towards control levels after sleep recovery. We conclude that sleep deprivation selectively decreases genioglossal EMG activity during CO2 rebreathing in awake older subjects. This influence of sleep deprivation may play a role in the pathogenesis or severity of obstructive sleep apnea.
In a patient showing a typical pickwickian syndrome a study was made of respiratory functions and arterial gasometry, with polygraphic registrations carried out during the day and at night in an attempt to evaluate sleep, respiration, blood oxyhaemoglobin and CO2 concentration of the expiratory air.It was demonstrated that, at the onset of an authentic pickwickian syndrome, the symptomatology may be confined to obesity and diurnal drowsing episodes of the type described by Dickens in his novel. This means that the permanent alveolar hypoventilation regarded by some authors as an indispensable feature of the syndrome,In the patient under discussion, the numerous episodes of diurnal slumber which characterized his condition and occurred while the blood oxyhaemoglobin saturation and alveolar CO2 concentration were entirely normal, cannot be explained on the basis of hypoxia and hypercapnia as suggested by a majority of authors. One must resort to other hypotheses, bearing in mind that the one does not necessarily exclude the other.A first hypothesis suggests that the subject drowses during the day as a result of a primary disturbance of centres in the brain stem which regulate wakefulness and sleep by a mechanism not yet understood. According to this hypothesis, we are confronted with some sort of narcolepsy.A second hypothesis holds that the subject drowses during the day because he does not sleep sufficiently at night as a result of an exaggeration of the physiological phenomenon of hypnic hypoventilation. Nocturnal polygraphic registrations disclosed respiratory pauses which occurred in the initial phase of sleep, quite apart from hypotonia of the muscles of the floor of the mouth, so rapid and pronounced that the tongue moves back and causes the obstructive apnoea responsible for a hypoxia which arouses the subject, who returns to sleep after a short while. The cyclic repetition of arousal and slumber reduces nocturnal sleep to 2–3 h a night. This loss of nocturnal sleep is held responsible for the diurnal somnolence. Unfortunately the subject's diurnal sleep is disturbed even more than his nocturnal sleep because the slightest slumber immediately produces episodes of central or obstructive apnoea.Regardless of the respective values of these two hypotheses, the authors are convinced that the majority of individuals suffering from the pickwickian syndrome drowse during the day and sleep badly at night because of a primary disturbance in the wakefulness-sleep regulation which as such is based on their obesity. This affords an obvious explanation of the established fact that the only way to suppress hypnic disturbances in pickwickian patients is to have them lose weight.
To determine the incidence and frequency of sleep apnea in persons with hypothyroidism, 11 consecutive patients with newly diagnosed disease were studied before and during thyroid hormone replacement therapy. Nine patients had episodes of apnea, with the number of episodes per hour of sleep ranging from 17 to 176 (mean, 71.8). Six of the nine patients were obese and had 99.5 episodes per hour compared with 16.3 episodes per hour in the 3 nonobese patients (p less than 0.02). After 3 to 12 months of thyroxine replacement therapy, mean apnea frequency decreased from 71.8 +/- 18.0 (SE) to 12.7 +/- 6.1 episodes per hour, without reduction in body weight. There were fewer changes in sleep stage per hour during treatment (22.1 +/- 4.9) than pretreatment (57.6 +/- 14.5). Carbon dioxide response tests done under non-loaded and flow-resistive loaded conditions before and during thyroxine replacement therapy showed increases in the loaded respiratory effort and ventilation during thyroxine treatment. Sleep apnea episodes are common in persons with untreated hypothyroidism, even with normal lung function. Thyroxine replacement therapy decreases apnea frequency, even without change in body weight.