Neck circumference and other clinical features in the diagnosis of the obstructive sleep apnoea syndrome.

BACKGROUND: Neck circumference has been suggested to be more predictive of obstructive sleep apnoea than general obesity, but the statistical validity of this conclusion has been questioned. Combining neck circumference with other signs and symptoms may allow the clinical diagnosis or exclusion of sleep apnoea to be made with reasonable confidence. This study examines these issues. METHODS: One hundred and fifty patients referred to a sleep clinic for investigation of sleep related breathing disorders completed a questionnaire covering daytime sleepiness, snoring, driving, and nasal disease. Body mass index and neck circumference corrected for height were measured and obstructive sleep apnoea severity was quantified as number of dips in arterial oxygen saturation (SaO2) of more than 4% per hour of polysomnography. Multiple linear regression was used retrospectively to identify independent predictors of SaO2 dip rate, and the model derived was then prospectively tested in a further 85 subjects. RESULTS: The retrospective analysis showed that the question "Do you fall asleep during the day, particularly when not busy?" was the best questionnaire predictor of variance in the SaO2 dip rate (r2 = 0.13); no other question improved this correlation. This analysis also showed that neither body mass index nor any of the questionnaire variables improved the amount of variance explained by height corrected neck circumference alone (r2 = 0.35). A statistically similar prospective analysis confirmed this relationship (r2 = 0.38). CONCLUSIONS: Prospective study of these patients referred to a sleep clinic with symptoms suggesting sleep apnoea shows that neck circumference corrected for height is more useful as a predictor of obstructive sleep apnoea than general obesity. None of the questionnaire variables examined add to its predictive power, but alone it is inadequate to avoid the need for sleep studies to diagnose this disease.     

Predictors and prevalence of obstructive sleep apnoea and snoring in 1001 middle aged men.

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 greater than 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 greater than 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.     

Relationships between nasal obstruction, observed apnea, and daytime sleepiness.

OBJECTIVE: We administered a questionnaire survey to a working population in an attempt to clarify the relationships between self-reported nasal obstruction, observed apnea during sleep, and daytime sleepiness. STUDY DESIGN: A total of 7980 daytime workers were asked to complete questionnaires about nasal obstruction, apnea during sleep, and daytime sleepiness. Of the 7702 responses, the data from 4818 subjects were analyzed. Nasal obstruction and observed apnea were graded into 3 categories. Daytime sleepiness was assessed by the Epworth Sleepiness Scale. RESULTS: Subjects with chronic nasal obstruction had 5.22 and 2.17 times higher odds for having habitual observed apnea and excessive daytime sleepiness (EDS), respectively, compared with those without nasal obstruction (P < 0.001). After adjusting for 3 potential confounding factors (age, sex, and body mass index) and the presence of habitual observed apnea, odds ratios for having EDS decreased, but still remained significant. CONCLUSION: Nasal obstruction is likely to cause daytime sleepiness, at least in part, by causing sleep-disordered breathing including apnea during sleep.     

Wrist actigraphic assessment of sleep in 116 community based subjects suspected of obstructive sleep apnoea syndrome.

BACKGROUND--The combined use of wrist actigraphic assessment and self assessment of sleep in the screening of obstructive sleep apnoea syndrome was evaluated in a community based sample. METHODS--One hundred and sixteen community based subjects clinically suspected of having obstructive sleep apnoea (syndrome) were evaluated by means of simultaneous ambulatory recording of respiration (oronasal flow thermistry), motor activity (wrist actigraphy), and subjective sleep (sleep log) during one night of sleep. RESULTS--The subjects were distributed according to their apnoea index (AI); AI < 1 (non-apnoeic snorers) 44%; AI 1- < 5 39%; and AI > or = 5 17%. High apnoea index values were associated with self reported disturbed sleep initiation and more fragmented and increased levels of motor activity and decreased duration of immobility periods, particularly in those with an apnoea index of > or = 5. Across subjects the duration of immobility periods was the only predictor of the apnoea index, explaining 11% of its variance. Use of the multiple regression equation to discriminate retrospectively between those with an apnoea index of < 1 and > or = 5 resulted in sensitivity and specificity values of 75% and 43%, and 5% and 100%, respectively. CONCLUSIONS--The combined use of a sleep log and actigraphic assessment of sleep failed to identify reliably those subjects who suffered from obstructive sleep apnoea (syndrome) in a sample of community based subjects reporting habitual snoring combined with excessive daytime sleepiness and/or nocturnal respiratory arrests.     

Clinical and Cardiovascular Characteristics of Patients with Obstructive Sleep Apnoeas without Excessive Daytime Sleepiness

ObjectivesTo investigate whether patients with obstructive sleep apnoea (OSA) without excessive daytime sleepiness (EDS) have cardiovascular problems and different clinical characteristics to OSA with EDS.MethodsTwo groups of patients were compared retrospectively, one without EDS (Epworth<11) and another control group with EDS (Epworth>10), adjusted for sex, age, body mass index (BMI) and apnoea-hypopnoea index (AHI). The diurnal and nocturnal symptoms of OSA were analysed along with polysomnography variables, prevalence of hypertension, diabetes mellitus, hyperlipaemia, and history of previous cardiovascular events. After adjusting for multiple confounding factors, a logistic regression was performed to identify the variables associated with OSA without EDS.ResultsA total of 166 patients without EDS were studied (Epworth 7.2 [2.4]) and 295 with EDS (Epworth 14.5 [2.5]). In the adjusted multivariate logistic regression, OSA without EDS is independently associated with a feeling of restful sleep (95%CI 1.70–3.93), less intellectual deterioration (95%CI, 0.30–0.95) and less effective sleep (95%CI, 0.96–0.99). No differences were found as regards prevalence of cardiovascular comorbidity, previous cardiovascular events, sleep structure, or nocturnal clinical symptoms of OSA. When the patients, who were in the extreme quartiles of the Epworth scale, were analysed, the results obtained were equivalent to those of the whole series, with only intellectual deterioration disappearing from the final model.ConclusionsAfter adjusting for confounding variables, OSA without EDS has a similar prevalence of cardiovascular comorbidity and less diurnal symptoms than OSA with EDS.     

Extended follow-up of palatal implants for OSA treatment.

OBJECTIVE: Evaluate long-term safety and outcomes of palatal implants for patients with mild to moderate obstructive sleep apnea (OSA). STUDY DESIGN AND SETTING: Continuation of a prospective case series of patients with palatal implants. Polysomnography, daytime sleepiness, and snoring intensity were measured at baseline, 90 days, and extended follow-up. RESULTS: Twenty-two (42%) patients from the previous study were followed for a median of 435.5 days. Thirteen were classified as responders, based on their 90-day evaluation. 76.9% of initial responders maintained improvements in apnea-hypopnea index (AHI), daytime sleepiness, and snoring at extended follow-up. Nine patients were initial nonresponders for AHI and daytime sleepiness and remained unchanged at extended follow-up. However, snoring for these nine patients initially improved, and the improvement continued through extended follow-up. CONCLUSION: Initial response or nonresponse to palatal implants remains stable over an extended period. The generalizability of these results is unknown because of significant loss to follow-up. SIGNIFICANCE: Study results report safety and beneficial long-term outcomes of palatal implants for mild to moderate OSA treatment in selected patients.     

Familial glaucoma with sleep apnoea: a new syndrome?

Sleep apnoea was combined with glaucoma in five members of two generations of a family The three surviving members with heavy snoring and glaucoma with intraocular pressure maxima in the morning and a fourth with heavy snoring only all had clinical sleep apnoea. The more severe glaucoma, resistant to surgery and medication, correlated with a greater number and duration of episodes of sleep apnoea. In all those who had recordings made episodes of sleep apnoea tended to occur and be more prolonged in rapid-eye-movement sleep. Oxygen desaturation was greater in rapid-eye-movement sleep and could occur without evidence of impaired respiration. In the third generation of this family there is as yet no evidence of impaired respiration in sleep or of glaucoma.     

The prevalence of clinically significant sleep apnoea syndrome in the Netherlands

BACKGROUND—Figures forthe prevalence of sleep apnoea syndrome range from 0.3% to 8.5%.These widely ranged estimates are probably due to differences in thedefinitions used, study designs, and study populations. A study wasundertaken to determine the lower limit of the prevalence of clinicallysignificant sleep apnoea syndrome.
METHODS—A crosssectional survey by postal questionnaire was carried out in a generalpractice of a small town in which three doctors serve 93% of itspopulation of 6747 inhabitants of all ages. All men aged 35 and overand women aged 50 and over were invited to fill in a specially designedquestionnaire on snoring and sleep. All men and women whose answerssuggested the possible occurrence of sleep apnoea were invited toundergo further investigation. Oronasal thermistry was performed in thesubjects' homes and the results were scored to provide an apnoea index(AI). Those subjects with an AI of 5 were referred to a sleeplaboratory for investigation by polysomnography.
RESULTS—Of the 2466 questionnaires issued, 2182 (88.5%) were completed and returned. Theoccurrence during the previous three months of regular snoring,together with daytime sleepiness and/or partners' observation ofinterruptions in breathing at night, was reported by 194 subjects (169 men, 25 women). In 173 subjects oronasal thermistry applied in theirhomes provided satisfactory recordings and, of these, 24 men and onewoman had an AI of 5. Analysis of the polysomnographic findingsshowed that 14 men and one woman met the criteria for sleep apnoeasyndrome. Scrutiny of their case records disclosed that in seven menthis was clinically significant.
CONCLUSIONS—Ourfindings suggest that the prevalence of clinically significant sleepapnoea syndrome in men aged 35 and over is at least 0.45%.Extrapolation to the population of the Netherlands suggests that atleast 16 000 men suffer from sleep apnoea syndrome that should berelieved by medical care. A large proportion of these subjects remainsto be diagnosed.

     

Concurrent respiratory resistance training and changes in respiratory muscle strength and sleep in an individual with spinal cord injury: case report

Context

Quality sleep possesses numerous benefits to normal nighttime and daytime functioning. High-level spinal cord injury (SCI) often impacts the respiratory muscles that can lead to poor respiratory function during sleep and negatively affect sleep quality. The impact of respiratory muscle training (RMT) on sleep quality, as assessed by overnight polysomnography (PSG), is yet to be determined among the spinal cord-injured population. This case report describes the effects of 10 weeks of RMT on the sleep quality of a 38-year-old male with cervical SCI.

Methods

Case report.

Findings/results

The subject completed overnight PSG, respiratory muscle strength assessment, and subjective sleepiness assessment before and after 10 weeks of RMT. The post-test results indicated improvements in sleep quality (e.g. fewer electroencephalographic (EEG) arousals during sleep) and daytime sleepiness scores following RMT.

Conclusion/clinical relevance

Respiratory activity has been proven to impact EEG arousal activity during sleep. Arousals during sleep lead to a fragmented sleeping pattern and affect sleep quality and daytime function. Our subject presented with a typical sleep complaint of snoring and excessive sleepiness. The subject''s pre-test PSG demonstrated a large number of arousals during sleep. It is important for all individuals complaining of problems during sleep or daytime problems associated with sleep (i.e. excessive daytime sleepiness) to seek medical attention and proper evaluation.     

Identification of sleep disruption and sleep disordered breathing from the systolic blood pressure profile.

BACKGROUND--Respiratory sleep studies are frequently performed to identify sleep disruption resulting from upper airway obstruction. Traditional polysomnographic studies may not detect brief recurrent sleep disruption and thus fail to recognise a significant problem when apnoea, hypopnoea, or arterial desaturation are not present. Arousal from sleep causes a transient blood pressure rise, and each inspiration causes a transient blood pressure fall. This study assesses whether these blood pressure changes are a useful indirect marker of disturbed sleep, obstructed sleep apnoea, and snoring related sleep disturbance. METHODS--Computer algorithms were developed to identify blood pressure falls caused by inspiration and rises related to arousal from 286 sleeping blood pressure samples of a consistent respiratory state drawn from 51 polysomnographic studies. From these samples, normal ranges for the number of arousal related systolic rises and the average size of the inspiratory falls were established. These were then applied prospectively to all night unedited blood pressure recordings from a further 20 subjects. RESULTS--The size of the inspiratory falls in blood pressure progressively increased from normal sleep, through snoring, to frank obstructive sleep apnoea. The 95th centile of normal was 12.5 mm Hg. The number of arousal related blood pressure rises also increased during obstructive sleep apnoea and periods of snoring with associated arousals, compared with normal undisturbed sleep, and all these periods of disturbed sleep included more than 30 such rises per hour. When these blood pressure features were examined in the 20 subjects studied prospectively, the six with a sleep related breathing disorder could all have been identified from their systolic blood pressure profile alone. CONCLUSIONS--The systolic blood pressure profile may be helpful in identifying patients with obstructive sleep apnoea, snoring with arousals, or other sleep disruption syndromes.     

Effects of submental stimulation for several consecutive nights in patients with obstructive sleep apnoea.

BACKGROUND--It has previously been reported that short term submental stimulation can reduce the frequency of apnoea and improve sleep architecture in patients with obstructive sleep apnoea. The effects of submental stimulation during consecutive nights on apnoea or on daytime sleepiness have not, however, been studied. METHODS--Patients with obstructive sleep apnoea were studied by polysomnography on a control night, for five consecutive nights of submental stimulation, and on three following nights (n = 8). A multiple sleep latency test (MSLT) (n = 8) and measurement of the upper airway resistance (n = 5) were performed during the day after the polysomnographic study, on the control night, and on the fifth stimulation night. In an additional five patients with obstructive sleep apnoea, matched for age, sex, and weight, the effects of two nights of stimulation were examined for comparison. Submental stimulation began when an apnoea lasted for five seconds and stopped with the resumption of breathing as detected by oronasal flow. RESULTS--The apnoea index, the number of times per hour that SaO2 dropped below 85% (SaO2 < 85%/hour), and the total apnoea duration expressed as a percentage of total sleep time during stimulation nights decreased to approximately 50% of the corresponding values on the control night. This improvement persisted for at least two nights after the five consecutive stimulation nights, but not after the two consecutive stimulation nights. Sleep architecture and MSLT following the stimulation nights improved but upper airway resistance did not change. CONCLUSIONS--Submental stimulation for five consecutive nights in patients with obstructive sleep apnoea improved the breathing disturbance, sleep quality, and daytime sleepiness. The effect lasted for the following two nights, but did not completely abolish the sleep disordered breathing.     

Non-invasive beat to beat arterial blood pressure during non-REM sleep in obstructive sleep apnoea and snoring.

BACKGROUND--Obstructive sleep apnoea, and possibly snoring, are associated with a poorly understood increase in cardiovascular mortality which may be explained by their effects on systemic blood pressure during sleep. This study compares changes in mean blood pressure during obstructive sleep apnoea and snoring without apnoeas with those in matched control subjects during non-REM sleep. METHODS--Eighteen men with obstructive sleep apnoea, 16 men who snored without apnoeas, and 34 control subjects matched for age, sex, obesity, smoking, and alcohol intake were studied. During polysomnography non-invasive mean blood pressure (Finapres) was recorded from each cardiac cycle during non-REM sleep and averaged over a 10 minute period. This was compared with the blood pressure during 10 minutes before sleep onset. The changes in the patients' sleeping blood pressure were compared with those in their individually matched control subjects. RESULTS--Compared with the control subjects the change in mean (SD) arterial blood pressure between being awake and asleep was higher during obstructive sleep apnoea (+6.5 (9) mm Hg v-2 (6.5), difference 8.5 (11)), and the rise from wakefulness to sleep in the obstructive sleep apnoea group was itself significant. The average mean arterial pressure was not raised in those who snored without apnoeas compared with either the control subjects or during wakefulness. CONCLUSIONS--Average mean arterial pressure is higher during obstructive sleep apnoea than it is during wakefulness, while normal subjects show a fall in blood pressure at sleep onset. This sleep related rise in blood pressure may contribute to the excess cardiovascular morbidity and mortality experienced by patients with this condition.     

Snoring significance in patients undergoing home sleep studies.

OBJECTIVE: To analyze the impact of snoring, independent of obstructive sleep apnea syndrome on patients referred for home sleep studies and to report a new technology for the reporting of snoring, using sophisticated sound collection and noise-canceling technology. STUDY DESIGN AND SETTING: A retrospective statistical review of consecutive anonymous data compiled from questionnaires and digital data of snoring loudness and duration measured at the upper lip during unattended home sleep studies in 4,860 patients referred for snoring and sleep-disturbed breathing. RESULTS: A strong relationship exists between a history of snoring and complaints of daytime sleepiness (80%), obesity (73%), and chronic fatigue (78%) (all yield P<0.001). By contrast, only 42% to 48% of patients without these symptoms complain of snoring. In 3 multiple-regression analyses, the percent of time snoring, average loudness, and peak loudness are all significantly predicted by the apnea hypopnea index (all P<0.003), body mass index (all P<0.001), and age (P=0.014). Daytime sleepiness was strongly predicted by percent time snoring (P=0.014), weakly by average loudness (P=0.046), and not at all by peak loudness (P=0.303). CONCLUSION: By using a pair of microphones placed at the upper lip, one that samples breath sounds and the other ambient sound and artifact noise, the NovaSOM QSG measures snoring while canceling ambient noise. The clinical impact of snoring on the patient as well as the bed partner, independent of obstructive sleep apnea syndrome, is an unrecognized factor in sleep-disturbed breathing. SIGNIFICANCE: Measurable criteria to define snoring are suggested. Snoring loudness is not measured in most laboratory Polysomnograms. EBM rating: B-3b.     

Palatal implants for the treatment of snoring and obstructive sleep apnea/hypopnea syndrome.

OBJECTIVE: Randomized, double-blinded, placebo-controlled, clinical trial to determine the effectiveness of palatal implants for treatment of mild/moderate obstructive sleep apnea/hypopnea syndrome (OSAHS). STUDY DESIGN AND SETTING: Sixty-two non-obese adults with history of snoring, daytime sleepiness, and mild/moderate OSAHS, were randomized to receive palatal implants (n = 31) or placebo procedure (n = 31). Complete follow-up including quality of life (QOL, SF-36), snoring visual analog scale (VAS), and Epworth Sleepiness Scale (ESS) data were obtained in 62 patients. Seven patients refused follow-up polysomnography for a total of 55 patients (29 implant and 26 placebo). RESULTS: The treatment group (change in score of -7.9 +/- 7.7) was significantly improved compared with the placebo group (change in score of 0.9 +/- 4.3) for apnea/hypopnea index (AHI) (P < 0.0001), QOL, SF-36 (P < 0.0001), snoring VAS (P < 0.0001), and ESS (P = 0.0002). CONCLUSIONS: Palatal implants improve AHI, QOL, snoring intensity, and daytime sleepiness for selected patients with mild/moderate OSAHS.     

Clinical predictors of apnoea-hypopnoea during propofol sedation in patients undergoing spinal anaesthesia

This study assessed the relationship between the occurrence of apnoea-hypopnoea during propofol sedation for spinal anaesthesia and two different predictive tests of sleep apnoea: the STOP-Bang score (snoring while sleeping, daytime tiredness, observed breathing stoppages, high blood pressure-body mass index, age, neck circumference, gender); and the obstructive sleep apnoea (OSA) score. Thirty-four middle-aged men not diagnosed with obstructive sleep apnoea received propofol infusions adjusted to produce a bispectral index of 70-75. ApnoeaLink(TM) was used to estimate the incidence of apnoea-hypopnoea. The median (IQR [range]) apnoea-hypopnoea index was 17 (8-24 [0-70]) events.h(-1) and correlated weakly with the STOP-Bang score (p = 0.022, r = 0.423) and moderately with the OSA score (p < 0.001, r = 0.693). Severe apnoea-hypopnoea developed more frequently in patients with a higher OSA score (34.5% vs 0%) or higher STOP-Bang score (27.6% vs 6.9%). Both assessment tools have some predictive value for the occurrence of apnoea-hypopnoea during propofol sedation in patients undergoing spinal anaesthesia.     

Long-term results of palatal implants for primary snoring.

OBJECTIVE: To determine the safety and efficacy of the Pillar Palatal Implant System over a 1-year follow-up period. STUDY DESIGN AND SETTING: In this prospective study, 40 healthy adult patients with primary snoring due to palatal flutter were treated after clinical, polysomnographic, and endoscopic examination. Under local anesthesia 3 implants were placed into the soft palate. Postoperative morbidity and functional parameters were assessed. Snoring and daytime sleepiness were assessed before and 90, 180, and 360 days after surgery. Objective data were obtained by polysomnography and SNAP-recording before and 90 days after treatment. RESULTS: All implants were placed without complications. A total of 13 implants partially extruded uneventfully in 10 patients. Functional parameters remained unchanged. After 1 year, snoring was reduced from 7.1 +/- 1.9 to 4.8 +/- 2.5 (Visual-Analogue-Scale, P < 0.05) and daytime sleepiness from 6.1 +/- 3.2 to 4.9 +/- 3.1 (Epworth-Sleepiness-Scale, P < 0.05). SNAP data and polysomnography parameters showed clinically irrelevant changes. CONCLUSION: Our data demonstrate a significant decrease in snoring and daytime sleepiness over a period of one year.     

Habitual snoring with and without obstructive sleep apnoea: the importance of cephalometric variables.

BACKGROUND: The obstructive sleep apnoea syndrome is characterised by an increased apnoea-hypopnoea index and a reduction in the minimal arterial oxygen saturation (SaO2) values during sleep. The extent to which these variables can be predicted by cephalometric and otorhinolaryngological variables was tested. METHODS: One hundred consecutive habitual snorers (84% male), with a mean (SD) age of 50.1 (10.1) years, were studied. The 45 patients with less severe sleep apnoea, with an apnoea-hypopnoea index of 10 or less (group A), were compared with the 55 with an index above 10 (group B). RESULTS: Body mass index, some cephalometric variables, and some otorhinolaryngological variables differed significantly between group A and group B, in particular the soft tissue measures PNS-P (posterior nasal spine to palate), MP-H (mandibular plane to hyoid bone), degree of oropharynx stenosis, and tongue size. In a multiple regression correlation analysis MP-H, SNB (angle from sella to nasion to subspinale point), SNA (angle from sella to nasion to supramentale point), PAS (posterior airway space), tongue size, and body mass index contributed significantly to the equation explaining the severity of sleep apnoea. Nevertheless, these variables together explained only 33% of the variance of the apnoea-hypopnoea index in the total sample; they were more important for patients with moderate to severe stages of the disease. CONCLUSION: The lack of association between cephalometric variables and mild sleep apnoea suggests that the differences in these variables (soft tissue measures) may be the consequence rather than the cause of habitual snoring and the obstructive sleep apnoea syndrome.     

Continuous positive airway pressure reduces daytime sleepiness in mild to moderate obstructive sleep apnoea: a meta-analysis

BACKGROUND: Obstructive sleep apnoea syndrome (OSAS) affects an estimated 2-4% of the middle aged population. Meta-analyses of randomised controlled trials have shown that the severe presentation of the syndrome (apnoea hypopnoea index (AHI) >30/hour) is effectively treated with continuous positive airway pressure (CPAP). Until recently there have been insufficient data to determine whether CPAP improves sleepiness in the larger subgroup with mild to moderate OSAS (AHI 5-30/hour). METHODS: A systematic search of Medline and a hand search identified seven randomised controlled trials where CPAP was compared with either a placebo or with conservative management in the treatment of mild to moderate OSAS (AHI 5-30/hour). All trials used the Epworth Sleepiness Scale (ESS), four used the Multiple Sleep Latency Test (MSLT), and three used the Maintenance of Wakefulness Test (MWT) to measure sleepiness. RESULTS: Meta-analyses indicated that CPAP significantly reduced subjective daytime sleepiness (ESS) by 1.2 points (95% CI 0.5 to 1.9, p = 0.001), improved objective daytime wakefulness (MWT) by 2.1 minutes (95% CI 0.5 to 3.7, p = 0.011), but did not affect objective daytime sleepiness (MSLT, mean benefit -0.2 minutes, 95% CI -1.0 to 0.6, p = 0.6). The two significant effects were small (effect size <0.30). CONCLUSIONS: CPAP elicits small improvements in subjective sleepiness and objective wakefulness in people with mild to moderate OSAS. However, the effects on sleepiness are of limited clinical significance.     

Prevalence of obstructive sleep apnoea in men with type 2 diabetes

BACKGROUND: A study was undertaken to establish the prevalence of obstructive sleep apnoea (OSA) in men with type 2 diabetes. METHODS: Men with type 2 diabetes from local hospital and selected primary care practitioner databases received questionnaires about snoring, apnoeas, and daytime sleepiness based on the Berlin questionnaire. Selected respondents had overnight oximetry to establish whether they had OSA. Comparisons of oximetry were made with those from a previous general population study. HbA1c results were collected. RESULTS: 1682 men were sent questionnaires, 56% of whom replied. 57% scored as "high" and 39% as "low" risk for OSA; 4% were already known to have OSA. Oximetry was performed in 240 respondents from both risk groups: 31% of the "high" and 13% of the "low" risk group had significant OSA (more than 10 >4% Sao(2) dips/hour or Sao(2) tracing consistent with OSA). These results were verified by detailed sleep studies. Extrapolation of the oximetry data to the questionnaire respondent population suggests that 23% had OSA. Comparison of the oximetry results with men from a previous general population study (using only more than 10 >4% Sao(2) dips/hour to define OSA) showed the prevalence of OSA is significantly higher in this diabetes population (17% v 6%, p<0.001). Multiple linear regression revealed BMI and diabetes as significant independent predictors of OSA. Following correction for BMI (which explained 13% of the variance in OSA), diabetes explained a further 8% of the variance (p<0.001). There was a low correlation between OSA severity and HbA1c in the subgroup recruited from the hospital database (r = 0.2, p = 0.006) which remained significant after allowing for obesity (p = 0.03). CONCLUSIONS: OSA is highly prevalent in men with type 2 diabetes; most are undiagnosed. Diabetes itself may be a significant independent contributor to the risk of OSA.     

Obstructive sleep apnoea syndrome in morbidly obese children with tibia vara

Morbid obesity and its association with obstructive sleep apnoea syndrome have been increasingly recognised in children. Orthopaedic surgeons are often the primary medical contact for older children with tibia vara, which has long been associated with obesity, but are unfamiliar with the evaluation and treatment of sleep apnoea in children.We reviewed all children with tibia vara treated surgically at one of our institutions over a period of five years. Thirty-seven patients were identified; 18 were nine years of age or older and 13 of these (72%) had morbid obesity and a history of snoring.Eleven children were diagnosed as having sleep apnoea on polysomnography. The incidence of this syndrome in the 18 children aged nine years or older with tibia vara, was 61%. All these patients required pre-operative non-invasive positive-pressure ventilation; tonsillectomy and adenoidectomy were necessary in five (45%). No peri-operative complications related to the airway occurred.There is a high incidence of sleep apnoea in morbidly obese patients with tibia vara. These patients should be screened for snoring and, if present, should be further evaluated for sleep apnoea before corrective surgery is undertaken.