Sleep-related breathing disorders. 4. Consequences of sleep disordered breathing

Economic evaluation of telemonitoring as a follow-up approach for patients with obstructive sleep apnea syndrome starting treatment with continuous positive airway pressure

Telemonitoring of obstructive sleep apnea patients is increasingly being adopted though its cost-effectiveness evidence base is scanty. This study investigated whether telemonitoring is a cost-effective strategy compared with the standard follow-up in patients with obstructive sleep apnea who are starting continuous positive airway pressure treatment. In total, 167 obstructive sleep apnea patients were randomised into telemonitoring (n = 79) or standard follow-up (n = 88), initiated continuous positive airway pressure treatment, and were followed up for 6 months. The frequencies of healthcare contacts, related costs (in USD 2021 prices), treatment effect and compliance were compared between the follow-up approaches using generalised linear models. The cost effectiveness analysis was conducted from a healthcare perspective and the results presented as cost per avoided extra clinic visit. Additionally, patient satisfaction between the two approaches was explored. The analysis showed no baseline differences. At follow-up, there was no significant difference in treatment compliance, and the mean residual apnea-hypoapnea index. There was no difference in total visits, adjusted incidence rate ratio 0.87 (0.72-1.06). Participants in the telemonitoring arm made eight times more telephone visits, 8.10 (5.04-13.84), and about 73% fewer physical healthcare visits 0.27 (0.20-0.36). This translated into significantly lower total costs for the telemonitoring approach compared with standard follow-up, -192 USD (-346 to -41). The form of follow-up seemed to have no impact on the extent of patient satisfaction. These results demonstrate the telemonitoring of patients with obstructive sleep apnea initiating continuous positive airway pressure treatment as a cost saving strategy and can be argued as a potential worthy investment.

Obstructive sleep apnea and its association with humoral immunity against varicella zoster virus

OBJECTIVE

This study aimed to evaluate the association between obstructive sleep apnea (OSA) and humoral immunity to varicella zoster virus (VZV).

METHODS

This retrospective cohort study included patients who underwent polysomnography and concurrently agreed for blood collection between January 2018 and February 2021. Habitual snorers and patients with severe obstructive sleep apnea were evaluated to compare the VZV immunoglobulin G (IgG) antibody titer between habitual snorer group and OSA group. Correlation between VZV IgG antibody titer and various sleep related respiratory parameters were also evaluated.

RESULTS

We found that the VZV IgG antibody titer of the habitual snorer group (n = 60) was significantly higher than that of the severe OSA group (n = 54) (244.1 ± 80.9 and 163.09 ± 48.39, respectively. Data are presented as mean ± standard deviation, P < 0.001). According to Spearman's correlation analysis, the VZV IgG antibody titer was moderately negatively correlated with apnea hypopnea index (r = -0.477, P < 0.001), apnea index (r = -0.496, P < 0.001), hypopnea index (r = -0.398, P < 0.001), respiratory disturbance index (r = -0.467, P < 0.001), arousal index (r = -0.467, P < 0.001) and oxygen desaturation index (r = -0.475, P < 0.001). Minimal oxygen saturation was moderately positively correlated with VZV IgG antibody titer (r = 0.474, P < 0.001).

CONCLUSION

Humoral immunity to VZV is significantly reduced in patients with severe OSA, and VZV IgG antibody titer was inversely correlated with respiratory events during sleep.

Significance of sleep stability using cardiopulmonary coupling in sleep disordered breathing

OBJECTIVES

The aim of this study was to assess the sleep quality and sleep stability according to the severity of obstructive sleep apnea (OSA) by using questionnaires and cardiopulmonary coupling (CPC) analysis.

METHODS

Two hundred and twenty-one adults were evaluated using subjective sleep questionnaires, CPC parameters, and respiratory parameters measured during full-night polysomnography. We measured the differences in the CPC parameters of each OSA group and the correlation between the apnea-hypopnea index (AHI) and CPC parameters.

RESULTS

AHI and CPC parameters were not associated with sleep questionnaires. AHI is negatively correlated with high frequency coupling (HFC, r = -0.725, P < 0.001) and very low frequency coupling (VLFC, r = -0.475, P < 0.001), but it is positively correlated with low frequency coupling (LFC, r = 0.786, P < 0.001) and narrow- and broadband-elevated low frequency coupling (e-LFC_NB and e-LFC_BB ; r = 0.522, P < 0.001 and r = 0.668, P < 0.001, respectively). We also found similar results regarding the correlation between the arousal index and CPC parameters. In addition, there were significant differences in HFC, LFC, VLFC, e-LFC_NB , and e-LFC_BB (all P < 0.001) between the severe OSA group and all other groups.

CONCLUSION

We found that CPC parameters significantly correlated with AHI. In addition, sleep stability-related parameters differ significantly based on OSA severity, and apneic parameters in the severe OSA group are significantly different from those in the other groups.

LEVEL OF EVIDENCE

4 Laryngoscope, 130: 2069-2075, 2020.

Obstructive Sleep Apnea in Elective Spine Surgery: National Prevalence and Inpatient Outcomes

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Epidemiologic studies suggest that the prevalence of moderate to severe obstructive sleep apnea (OSA) is increasing. OSA has been linked to increased rates of postoperative complications following surgery. Large studies, however, regarding surgical outcomes in this patient population, particularly in the spine literature, are limited. Consequently, the purpose of this study was to assess the prevalence of and postoperative risks conferred by OSA in the elective spine population.

METHODS

Using data from the National Inpatient Sample from 2008 to 2012, an estimated 56 372 (5.1%) patients with OSA undergoing elective cervical and thoracolumbar spine surgery were selected and compared to 1 052 837 patients without OSA undergoing the same procedures. Our primary outcome measures included postoperative complication rates, inpatient mortality, length of stay, and total hospital charges.

RESULTS

Patients with OSA were, on average 2.6 years older than those without OSA (P < .001) and had a higher comorbidity burden. The prevalence of OSA increased between 2008 and 2012 from 3.5% to 6.8%; P < .001. OSA was associated with a 3-fold increase in major complications (P < .001) and was confirmed as an independent risk factor for major complications based on multivariate analysis (odds ratio [OR] = 2.82; 95% CI = 2.59-2.79; P < .001). Rates of deep venous thrombosis were doubled in patients with OSA. OSA was determined to be an independent predictor of pulmonary complications (OR = 2.69; 95% CI = 2.59-2.79; P < .001). OSA did not increase the risk of postoperative mortality.

CONCLUSIONS

Patients with OSA often have multiple concomitant comorbidities and consequently are at increased risk of experiencing a more difficult postoperative course following elective spine surgery. Specifically, increased risks of pulmonary complications and deep venous thrombosis should be anticipated.

The effectiveness of oral appliances for obstructive sleep apnea syndrome: A meta-analysis

OBJECTIVE

To evaluate the effectiveness of oral appliances (OAs) for managing patients with obstructive sleep apnea (OSA).

METHODS

PubMed, Embase, Web of Science, CENTRAL and SIGLE were electronically searched from January 1980 to September 2015 for randomized or nonrandomized controlled trials that assessed the effectiveness of OAs on OSAS. The processes of study search, selection, data extraction, assessment of risk of bias and evaluation of evidence quality were conducted independently by two reviewer authors. Meta-analyses were performed in Review Manager 5, Stata11.0 and StatsDirect 2.7.9.

RESULTS

Finally, we included 17 eligible studies which compared OAs and placebo or blank control. Six outcomes were assessed in this meta-analysis, i.e., apnea hypopnea index (AHI), respiratory arousal index (RAI), minimum oxygen saturation(MinSaO2), rapid eye movement (REM) sleep, sleep efficiency and Epworth Sleepiness Scale (ESS). Meta-analysis revealed that the pooled mean differences were -10.26 [95% CI: (-12.59, -7.93)], -9.03 [95% CI: (-11.89, -6.17)], 3.08 [95% CI: (1.97, 4.19)], 0.36 [95% CI: (-0.30, 1.02)], 1.34 [95% CI: (-0.05, 2.73)] and -1.76 [95% CI: (-2.57, -0.94)], respectively. The sensitivity analysis and subgroup analysis displayed generally robust results except for MinSaO2, REM sleep and sleep efficiency. Furthermore, publication bias was detected in RAI and MinSaO2.

CONCLUSIONS

The available evidence indicates benefits in respiration and sleep quality with oral appliances as compared to placebo devices or blank control, while we cannot determine its effectiveness in sleep efficiency and sleep architecture alterations. However, due to low evidence quality as revealed by GRADE, this finding should be interpreted with caution.

CLINICAL SIGNIFICANCE

Through critical meta-analyses, we found that oral appliances are effective in respiration improving and sleep quality. The existing evidence supports the employment of OAs as a recommendable treatment option for OSA. This meta-analysis helps to direct clinical practice and future research, and promises to be of great interest for both practitioners and researchers.

Effects of varying mandibular protrusion and degrees of vertical opening on upper airway dimensions in apneic dentate subjects

INTRODUCTION

Despite numerous studies investigating the dimensional and therapeutic effects of mandibular advancement splints (MASs), data regarding the effects of differently designed individual and non-adjustable MASs on the upper airway in fully dentate apneic subjects in the sagittal plane including comparison of these effects with a placebo device are sparse. The present study aimed to determine the dimensional changes in the sagittal plane created by differently designed MASs in the upper airway in fully dentate apneic subjects and to compare these changes with the effects of a placebo device.

MATERIALS AND METHODS

Magnetic resonance (MR) images of 9 dentate apneic subjects with 5 differently designed MASs and without a MAS were obtained. We measured the area of the entire pharynx (velopharynx, oropharynx, hypopharynx) on these MR images and compared the dimensional changes.

RESULTS

The dimensional changes triggered by two specific MASs (75% of the maximum mandibular protrusion with 5 mm vertical opening, and 75% of the maximum mandibular protrusion with 10 mm of vertical opening) in the entire pharynx in the sagittal plane were statistically significant compared to the other MASs (p < 0.05). The MAS effecting 75% of the maximum mandibular protrusion and 10 mm of vertical opening created a significant dimensional increase only in the velopharyngeal area among the three pharyngeal sites (p ≤ 0.003).

CONCLUSION

While the degree of mandibular protrusion created by the MAS affects the dimensions of the upper airway, the degree of the vertical opening exerts no significant dimensional effect in the sagittal plane in fully dentate apneic patients. The mandibular protrusion effect is comparatively larger in the velopharyngeal region.

PFO and right-to-left shunting in patients with obstructive sleep apnea

BACKGROUND

Patent foramen ovale (PFO) with right-to-left shunt has a prevalence of 10% to 34% in the general population. It can cause an ischemic stroke, transient ischemic attack, and paradoxical peripheral or coronary embolization. Its influence on migraine and several other diseases and conditions is currently under debate. Attention has recently been turned to the correlation between PFO and obstructive sleep apnea. Thus far, studies on the prevalence of right-to-left shunts as a surrogate for PFO in these patients were limited by small sample sizes and the results have been conflicting. Here, we evaluate the prevalence of right-to-left shunting (RLS) through transcranial Doppler ultrasound (TCD) in a large patient group with obstructive sleep apnea (OSA).

METHODS

One hundred consecutive patients (mean age 59.5 y) with OSA underwent TCD with intravenous injection of agitated saline. The grading of right-to-left-shunts was in accordance with the Spencer PFO Grading Scale.

RESULTS

RLS was detected in 72 of 100 patients (72%). Thirty-four out of these 72 patients (47%) had a shunt grade I or II; 15 (21%) had a shunt Grade III or IV; and 23 (32%) had a large shunt (Grade V or V+). In 47 of 72 patients (65%), a right-to-left shunt was detectable at rest without Valsalva maneuver.

CONCLUSION

The prevalence of a RLS in patients with OSA is high. Provided other intracardiac or pulmonary shunts were absent, the high prevalence of a RLS suggests a high prevalence of PFO in patients with OSA.

The effect of continuous positive airway pressure treatment for obstructive sleep apnea syndrome on the ocular surface

PURPOSE

To evaluate the effect of continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea syndrome on the ocular surface.

METHODS

This is a prospective, sectional cohort study of 80 eyes of 40 patients diagnosed with obstructive sleep apnea syndrome. Routine ophthalmologic examination and ocular surface evaluation, including biomicroscopy, Schirmer 1 testing, tear break-up time measurement, ocular surface staining, and conjunctival impression cytology, were performed in both of each patient's eyes before and 4 months after starting CPAP therapy.

RESULTS

After CPAP therapy, increases in squamous metaplasia (Nelson classification: t = 0.34, P = 0.014) and Schirmer 1 score (t = 3.20, P = 0.008), and decreases in tear break-up time (t = -1.38, P = 0.008) in the right eyes were statistically significant, as compared with the pretreatment values. Although these parameters changed in a similar fashion in the left eyes, differences between the pre-CPAP and post-CPAP values were not significant.

CONCLUSIONS

The findings indicate that CPAP therapy increased ocular irritation, tear evaporation, and squamous metaplasia in the conjunctiva of the patients' right and left eyes. Although the parameters measured were similar in both eyes before CPAP therapy, these parameters changed significantly after CPAP therapy only in the right eyes. The observed differences between the right and left eyes require further investigation to determine the possible effects of sleeping position, CPAP mask displacement, and the other factors involved.

Effect on quality of life of continuous positive airway pressure in patients with obstructive sleep apnea syndrome: a meta-analysis

Continuous positive airway pressure (CPAP) is the standard treatment for obstructive sleep apnea syndrome (OSAS). However, the impact of CPAP on quality of life (QOL) is controversial. The aim of this study was to systematically review and determine whether CPAP improves QOL in patients with OSAS. We performed a comprehensive literature search to identify studies published between 1966 and 2007 comparing values of CPAP with control. Weighted mean difference (WMD) was used to analyze the data. The pooled WMD was calculated by using a fixed or random-effect model. The outcomes for 1,256 patients from 16 studies, of whom 656 patients underwent CPAP and 600 were controls, were included. CPAP led to significant improvements in the Nottingham health profile part 2 (WMD=1.657; 95% CI=3.005, -0.308; p=0.016), but there was no difference in other general QOL scores. Patients undergoing CPAP scored better in physical function (WMD=3.457; 95% CI=0.144, 6.771; p=0.041), body pain (WMD=4.017; 95% CI= -0.008, 8.042; p=0.05), energy vitality (WMD=6.984; 95% CI = 0.557, 13.411; p=0.033) and physical component summary (PCS) (WMD=2.040; 95% CI=0.045, 4.035; p=0.045) using the SF-36 tool. This meta-analysis shows that CPAP does not improve general QOL scores but does improve physical domains and vitality. Study design and QOL questionnaire tools are important to capture and evaluate information efficiently. However, generic QOL instruments may not be adequate in detecting important changes in quality of life in patients with OSAS.

CPAP Devices: Encouraging Patients with Sleep Apnea

Continuous positive airway pressure devices (CPAP) used at night prevent apnea, hypoxia, and sleep disturbance. Although CPAP is more effective than placebo in improving sleepiness and quality of life measures in people with obstructive sleep apnea, patients often prefer a less-effective oral appliance. This article examines help-seeking experiences in support groups of individuals with sleep apnea who use CPAP devices. To understand patients' experiences and difficulties using CPAP, an urban medical center and a rural hospital shared data collected from 17 individuals with sleep apnea who use CPAP for treatment and attend a support group. Four related themes emerged including (a) becoming motivated to persist with help from the group, (b) accommodating to the device, (c) listening and telling stories to gain practical knowledge, and (d) implementing a support group as a caring community. Healthcare providers could recommend support groups on CPAP use while nurses guide discussion, provide technical information, and promote empowerment.

Surgery for obstructive sleep apnoea

BACKGROUND

Obstructive sleep apnoea/hypopnoea syndrome(OSAHS) is the periodic reduction or cessation of airflow during sleep. The syndrome is associated with loud snoring, disrupted sleep and observed apnoeas. Surgery for obstructive sleep apnoea/hypopnoea syndrome aims to alleviate symptoms of daytime sleepiness, improve quality of life, and reduce the signs of sleep apnoea recorded by polysomnography.

OBJECTIVES

The objective of this review was to assess the effects of any type of surgery for the treatment of the symptoms of obstructive sleep apnoea/hypopnoea syndrome in adults.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register and reference lists of articles. We contacted experts in the field, research dissemination bodies and other Cochrane Review Groups. Searches were current as of July 2005.

SELECTION CRITERIA

Randomised trials comparing any surgical intervention for obstructive sleep apnoea/hypopnoea syndrome with other surgical or non-surgical interventions or no intervention.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed electronic literature search results for possibly relevant studies. Characteristics and data from studies meeting the inclusion criteria were extracted and entered into RevMan 4.2.

MAIN RESULTS

In the 2005 update for this review eight studies (412 participants) of mixed quality met the inclusion criteria. Data from seven studies were eligible for assessment in the review. No data could be pooled. Uvulopalatopharyngoplasty (UPPP) versus conservative management (one trial): An un validated symptom score showed intermittent significant differences over a 12-month follow-up period. No differences in Polysomnography (PSG) outcomes were reported. Laser-assisted uvulopalatoplasty (LAUP) versus conservative management/placebo (two trials): One study recruited mixed a population, and separate data could not be obtained for this trial. In the other study no significant differences in Epworth scores or quality of life reported. A significant difference in favour of LAUP was reported in terms of apnoea hypopnoea index (AHI) and frequency and intensity of snoring. UPPP versus oral appliance (OA) (one trial): AHI was significantly lower with OA therapy than with UPPP. No significant differences were observed in quality of life. UPPP versus lateral pharyngoplasty (lateral PP) (one trial): No significant difference in Epworth scores, but a greater reduction in AHI with lateral PP was reported. Tongue advancement (mandibular osteotomy) + PPP versus tongue suspension + PPP (one trial): There was a significant reduction in symptoms in both groups, but no significant difference between the two surgery types. Complications reported with all surgical techniques included nasal regurgitation, pain and bleeding. These did not persist in the long term. An additional study assessed the effects of four different techniques. No data were available on between group comparisons. Multilevel temperature-controlled radiofrequency tissue ablation (TCRFTA) versus sham placebo and CPAP (one trial): There was an improvement in primary and secondary outcomes of TCRFTA over sham placebo and but no difference in symptomatic improvement when compared with CPAP.

AUTHORS' CONCLUSIONS

There are now a small number of trials assessing different surgical techniques with inactive and active control treatments. The studies assembled in the review do not provide evidence to support the use of surgery in sleep apnoea/hypopnoea syndrome, as overall significant benefit has not been demonstrated. The participants recruited to the studies had mixed levels of AHI, but tended to suffer from moderate daytime sleepiness where this was measured. Short-term outcomes are unlikely to consistently identify suitable candidates for surgery. Long-term follow-up of patients who undergo surgical correction of upper airway obstruction is required. This would help to determine whether surgery is a curative intervention, or whether there is a tendency for the signs and symptoms of sleep apnoea to re-assert themselves, prompting patients to seek further treatment for sleep apnoea.

Effect of titrated mandibular advancement and jaw opening on the upper airway in nonapneic men: a magnetic resonance imaging and cephalometric study

The aim of this study was to examine adaptive changes in the cross-sectional area of the upper airway during mandibular advancement and jaw opening and to explore whether these changes are directly related to morphologic features of the mandible. Fourteen nonapneic men participated in this study. A custom-made oral device was used to keep the mandible at 0% (F(0)V(0)), 50% (F(50)V(0)), 75% (F(75)V(0)), or 100% (F(100)V(0)) of maximum advancement, and at 50% (F(75)V(50)), 75% (F(75)V(75)), or 100% (F(75)V(100)) of maximum gape at F(75)V(0). Magnetic resonance imaging was used to investigate differences in the upper-airway cross-sectional area in these 7 positions. To eliminate excessive individual variation, changes in the mean (mean%) and minimum (min%) cross-sectional area of the upper airway were calculated as percentages of those at F(0)V(0). Cephalograms were taken to analyze morphologic features of the mandible. A dose-dependent change was seen when the mandible was advanced. The min% in F(100)V(0) was significantly greater than those in F(50)V(0) and F(75)V(0). The change in the upper airway size varied between subjects during jaw opening. At F(75)V(0), the min% of the whole upper airway was significantly associated with morphologic features of the mandible, such as the mandibular plane angle and lengths of the mandibular body and ramus.

The teaching and treatment of upper airway sleep disorders in North American dental schools

STATEMENT OF PROBLEM

Many dental patients suffer from upper airway sleep disorders (UASD) that affect the quantity and quality of their sleep. These disorders vary from minor annoyances to life-threatening conditions. Even though dentists can play a role in the successful treatment of these patients with oral devices, few do. This lack of participation, in part, may be due to lack of education.

PURPOSE

The purpose of this study was to determine which North American dental schools include the treatment of UASD in their curriculum. This information may prove helpful to other schools in determining whether, and to what degree, they should teach about UASD and its treatment options.

MATERIAL AND METHODS

A survey instrument (questionnaire) was mailed to all of the North American dental schools (n = 64) affiliated with the American Association of Dental Schools. The questionnaire consisted of 9 multipart questions. Major categories of questions included the following: (1) Is the subject of UASD a part of the school curriculum? If so, in what department is it taught? (2) Are oral devices fabricated for patients or is the experience only at the didactic level? (3) What diagnostic procedures are required? (4) What types of oral devices are fabricated and what is the success rate/recall frequency? (5) What is the patient source? (6) If this subject area is not covered either didactically or clinically, why not? The data were analyzed by use of descriptive statistics.

RESULTS

Forty-three of the 64 schools that received the survey responded. Forty-two percent of the schools that responded are teaching the treatment of UASD with oral devices. There is no apparent consensus with regard to whether to teach the subject, at what level, or to what degree.

CONCLUSION

Even though many dental patients suffer from potentially life-threatening sleep disorders, many of which could be treated with oral devices, fewer than half of the reporting dental schools currently include this area as part of their curriculum. This lack of inclusion is caused primarily by a lack of familiarity with the information available and a lack of available curriculum time.

Home unattended vs hospital telemonitored polysomnography in suspected obstructive sleep apnea syndrome: a randomized crossover trial

STUDY OBJECTIVE

To compare home unattended polysomnography (H-PSG) with polysomnography performed in a local hospital and telemonitored by a sleep laboratory (T-PSG) in the diagnosis of obstructive sleep apnea syndrome (OSAS).

DESIGN

Randomized crossover trial.

PATIENTS

Ninety-nine patients with suspected OSAS who underwent H-PSG and T-PSG on 2 consecutive nights, according to a randomized order.

MEASUREMENTS

H-PSG and T-PSG were compared in terms of (1) effectiveness, only recordings providing interpretable signals from at least one EEG, the electro-oculograph, the electromyograph, air flow, thoracic or abdominal movements, and arterial oxygen saturation for 180 min of sleep were considered to be effective; (2) patient preference assessed by a questionnaire; and (3) polysomnographic indexes and final interpretative results in patients for whom both recordings were legible.

RESULTS

Recordings were considered to be ineffective in 11.2% of T-PSG (95% confidence interval [CI], 4.9 to 17.4%) and in 23.4% of H-PSG (95% CI, 19.12 to 27.68%). Thermistor problems were the main cause of failure of H-PSG. Forty-one percent of patients preferred H-PSG, and 55% preferred T-PSG. H-PSG and T-PSG did not differ in terms of sleep and respiratory indexes in the 65 patients in whom both recordings were legible. H-PSG and T-PSG were concordant in 58 of 65 patients using a 10-event-per-hour apnea-hypopnea index cutoff value for the diagnosis of OSAS.

CONCLUSIONS

T-PSG is clearly superior to H-PSG from a technical point of view and tends to be preferred by patients. The site of recording (home vs hospital) has no influence on polysomnographic indexes.

Neurologic complications of respiratory disease

The respiratory system and the central nervous system are interconnected in a delicate balance; disorders in this equilibrium can have devastating consequences. Respiratory dysfunction, whether acute or chronic, may cause neurologic disease, including headache, encephalopathy, and in extreme cases, coma and death. This article will discuss abnormalities in ventilation and gas exchange, their subsequent pathophysiologic effects on the nervous system, and mechanisms of treatment for these disorders.

A community study of sleep-disordered breathing in middle-aged Chinese men in Hong Kong

BACKGROUND

Sleep-disordered breathing (SDB) in Asian populations is being increasingly recognized. This study investigated the prevalence of SDB in Chinese middle-aged office-based male workers in Hong Kong.

METHODS

Sleep questionnaires were distributed to 1,542 men (age range, 30 to 60 years), and 784 questionnaires were returned. Subsequently, full polysomnographic (PSG) examinations were conducted in 153 questionnaire respondents. Subjects with an apnea-hypopnea index (AHI) > or =5 were recalled for clinical assessment.

RESULTS

Questionnaire respondents were similar in age and body mass index (BMI) to the general community in the target age range and gender. Habitual snoring was reported by 23% of this cohort and was associated with excessive daytime sleepiness (EDS), hypertension, witnessed abnormal breathing pattern, BMI, and leg movements during sleep. Allowing for subject bias in undergoing PSG, the estimated prevalence of SDB and obstructive sleep apnea syndrome (OSAS) (defined as SDB in the presence of EDS) at various AHI cutoff threshold values was 8.8% and 4.1% (AHI > or =5), 6.3% and 3.2% (AHI > or =10), and 5.3% and 3.1% (AHI > or =15). Multiple stepwise logistic regression analysis identified BMI, habitual snoring, time taken to fall asleep, and age as predictors of SDB at AHI > or =5. Analysis of anthropometric parameters indicated that the relative risk of OSAS attributable to obesity was less than in white subjects.

CONCLUSION

This community-based study of sleep apnea among middle-aged men in Hong Kong using full PSG demonstrated an estimated prevalence of OSAS (AHI > or =5 and EDS) at 4.1%. Increasing BMI and age were associated with SDB, although factors other than adiposity may also have an important pathogenic role in OSA in Chinese subjects.

Circadian variation in onset of acute cardiogenic pulmonary edema is independent of patients' features and underlying pathophysiological causes

BACKGROUND

The present study aimed to confirm the existence of a circadian pattern in the onset of acute pulmonary edema (APE) and to verify whether sex, age, preexisting diseases, and clinical causes determining the event may influence it.

SUBJECTS AND METHODS

The study considered all consecutive cases of APE observed at the St. Anna General Hospital of Ferrara, Italy, during a 7-year period from January 1, 1992, to December 31, 1998. The sample population was divided into subgroups by sex, age (<75 and > or =75 years), presence or absence of diabetes and hypertension, clinical causes determining the event (i.e., acute myocardial infarction (AMI), pulmonary embolism, arrhythmias). The most important associated or concomitant diseases were also considered (i.e., coronary heart disease and angina, previous myocardial infarction, chronic cardiac failure, dilatative cardiopathy, chronic atrial fibrillation, valvular disease, chronic obstructive pulmonary disease, chronic cor pulmonale, malignancy, chronic renal failure). Time of symptom onset of each event was recorded accurately, then tabulated into 24 increments of 1h (e.g., 06:00 to 06:59 was reported as 6 A.M.). For statistical chronobiological analysis, partial Fourier series were used.

RESULTS

During the 7-year period, 1321 consecutive cases of APE in 1014 different subjects were observed. The majority of events occurred at night, and statistical analysis showed a 24h rhythmicity both in the total sample population and in all considered subgroups, with the only exception being patients with pulmonary embolism and arrhythmias, for which the small number of cases made the study of rhythms in APE impossible.

CONCLUSIONS

The nighttime preference in the occurrence of APE appears to be quite independent of all demographic features or underlying pathophysiological causes.

Effects of a mandibular repositioner on obstructive sleep apnea

The purpose of this study was to investigate the effects of a mandibular repositioner on airway, sleep, and respiratory variables in patients with obstructive sleep apnea. Twenty-two patients selected for this study were confirmed with a diagnosis of obstructive sleep apnea based on initial nocturnal polysomnography. The patients were fitted with a mandibular repositioner designed to hold the mandible anteroinferiorly. Six months later, an outcome polysomnographic study was undertaken for each patient with the appliance in place. Lateral cephalometric radiographs in the upright position were also obtained before and after 6 months of treatment. The respiratory disturbance index decreased in 21 of the 22 patients with the appliance in place. The mean respiratory disturbance index of the 22 patients decreased significantly from 40.3 to 11.7 events per hour (P <.01). Some 59.1% of subjects were considered a treatment success with follow-up respiratory disturbance index < 10 events per hour. The mean minimum blood oxygen saturation level during sleep also improved significantly from 73.4% to 81.3% (P <. 01). The mandibular repositioner was constructed to position the mandible at 75% of the maximal mandibular advancement and with a 7 mm opening between the upper and lower incisors, and no aberrant effect on temporomandibular joint was noted. The retropalatal airway space increased and the cross-sectional area of the soft palate and the vertical distance of the hyoid bone to the mandibular plane decreased significantly. The tongue posture became significantly flatter. A significant linear correlation was found between the reduction in apnea index and specific craniofacial skeletal structures (length of anterior cranial base, mandibular plane angle, and upper to lower facial height ratios, P <.05). Subjects with a smaller reduction in apnea index tended to have shorter anterior cranial bases, steeper mandibular planes, and smaller upper to lower facial height ratios. We conclude that a mandibular repositioner may be an effective treatment alternative for obstructive sleep apnea and that a reduction in the frequency of apneic episodes is mainly attributed to the effects of the appliance on oropharyngeal structures.

Dentistry's role in the diagnosis and co-management of patients with sleep apnoea/hypopnoea syndrome

The sleep apnoea/hypopnoea syndrome (SAHS) is characterized by repeated upper airway narrowing or collapse during sleep. The obstruction is caused by the soft palate and/or base of tongue collapsing against the pharyngeal walls because of decreased muscle tone. These episodes are accompanied by hypoxaemia, surges in blood pressure, brief arousal from sleep and pronounced snoring. Individuals with occult disease are at heightened risk of motorway accidents because of excessive sleepiness, sustained hypertension, myocardial infarction, and stroke. The signs and symptoms of SAHS may be recognisable in the dental practice. Common findings in the medical history include daytime sleepiness, snoring, hypertension, and type 2 diabetes mellitus. Common clinical findings include male gender, obesity, increased neck circumference, excessive fat deposition in the palate, tongue (macroglossia) and pharynx, a long soft palate, a small recessive mandible and maxilla, and calcified carotid artery atheromas on panoramic and lateral cephalometric radiographs. Dentists who recognise these signs and symptoms have an opportunity to diagnose patients with occult SAHS. After confirmation of the diagnosis by a physician, dentists can participate in the management of the disorder by fabricating mandibular advancement appliances that enlarge the retroglossal space by anterior displacement of the tongue and performing corrective upper airway surgery that prevents recurrent airway obstruction.

Surgery for obstructive sleep apnoea

BACKGROUND

Obstructive sleep apnoea is the periodic reduction (hypopnoea) or cessation (apnoea) of airflow during sleep. The syndrome is associated with loud snoring, disrupted sleep and observed apnoeas. Beside conservative treatments there are a range of 8 broad categories of operative treatments for this condition. Surgical treatments aim to relieve the obstruction by either increasing the surface area

OBJECTIVES

Surgery for obstructive sleep apnoea aims to relieve the obstruction by increasing the surface area of the airway, bypassing the pharyngeal airways or removing a lesion. The objective of this review was to assess the effects of any type of surgery for the treatment of obstructive sleep apnoea.

SEARCH STRATEGY

We searched the Cochrane Airways Group trials register and reference lists of articles. We contacted experts in the field, research dissemination bodies and other Cochrane Review Groups.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing any surgical intervention for obstructive sleep apnoea with other surgical or non-surgical interventions for obstructive sleep apnoea or no intervention.

DATA COLLECTION AND ANALYSIS

No completed trials were identified.

MAIN RESULTS

No studies fulfilled the inclusion criteria.

REVIEWER'S CONCLUSIONS

There is an urgent need for high quality randomised controlled trials to be carried out in the field of surgery for obstructive sleep apnoea. More research should also be undertaken to identify and standardise techniques to determine the site of airways obstructions.

Neural network prediction of obstructive sleep apnea from clinical criteria

STUDY OBJECTIVES

Clinical prediction models for the diagnosis of obstructive sleep apnea (OSA) have lacked the accuracy necessary to confidently replace polysomnography (PSG). Artificial neural networks are computer programs that can be trained to predict outcomes based on experience. This study was conducted to test the hypothesis that a generalized regression neural network (GRNN) could accurately classify patients with OSA from clinical data.

STUDY DESIGN

Retrospective review.

SETTING

Regional sleep referral center.

PATIENTS

Randomly selected records of patients referred for possible OSA.

MEASUREMENTS

The neural network was trained using 23 clinical variables from 255 patients, and the predictive performance was evaluated using 150 other patients.

RESULTS

The prevalence of OSA in this series of 405 patients (293 men and 112 women) was 69%. The trained GRNN had an accuracy of 91.3% (95% confidence interval [CI], 86.8 to 95.8). The sensitivity was 98.9% for having OSA (95% CI, 96.7 to 100), and the specificity was 80% (95% CI, 70 to 90). The positive predictive value that the patient would have OSA was 88.1% (95% CI, 81.8 to 94.4), whereas the negative predictive value that the patient would not have OSA (if so classified) was 98% (95% CI, 94 to 100).

CONCLUSIONS

Appropriately trained GRNN has the ability to accurately rule in OSA from clinical data, and GRNN did not misclassify patients with moderate to severe OSA. In this study, use of the neural network could have reduced the number of PSG studies performed. Prospective validation of the neural network for the diagnosis of OSA is now required.

Nocturnal oxygen desaturation in coronary artery disease

Nocturnal oxygen desaturation and sleep apnea may provoke myocardial ischemia and arrhythmias in patients with coronary artery disease (CAD). Additionally, these factors may accelerate coronary atherosclerosis in the long term and they may play a role in the progression of the disease process. On the other hand, studies related to this subject are limited. This study was conducted to investigate the nocturnal oxygen desaturation and apneas during sleep in patients with CAD and to assess the possible association of these factors with CAD. We studied 22 male patients with CAD confirmed by coronary angiography who did not have symptomatic pulmonary disease and fourteen male healthy controls without known heart disease. Patients were randomly selected from men undergoing coronary angiography. Controls were age and sex matched and selected from the population registry. The normal controls were of similar body mass index to the patients. None of them were obese. The patients and controls underwent standard polysomnography. Men with CAD and controls had a similar apnea-hypopnea index (2.3 +/- 3.8 vs. 1.2 +/- 1.7). Mean oxygen desaturation index was higher among patients than controls (2.1 vs. 0.5, p < 0.05). Patients with CAD spent 3.1% (9.7 +/- 13.6) of total sleep time desaturated, while the same proportion in controls were 0.5% (1.9 +/- 4.1)(p < 0.05). Although both groups of patients were of similar heart rates at initial, the development of bradycardia during sleep was significantly higher in patients compared with controls (43.3% vs. 25.3%, p < 0.05). The results demonstrate that sleep disordered breathing, in particular nocturnal oxygen desaturation, occurs more common in patients with CAD compared to controls. Additionally, patients are at higher risk of developing bradycardia during sleep. This findings suggest that oxygen desaturation during sleep might contribute to the progression of CAD.

Acute delirium as a manifestation of obstructive sleep apnea syndrome

Cognitive deficits and psychiatric manifestations such as depression and psychosis have been associated with obstructive sleep apnea (OSA) syndrome. We report a patient with OSA admitted to our center because of acute delirium of sudden onset at night, during sleep, and which impelled the patient to jump out of the window of his home. After exhaustive study, no other causes were found for the delirium, which resolved when nasal continuous positive airway pressure (nCPAP) was initiated. We believe that it is clinically important to be aware of this association, since it identifies a new, treatable cause of delirium.

The prevalence of calcified carotid artery atheromas in patients with obstructive sleep apnea syndrome

PURPOSE

Persons with obstructive sleep apnea syndrome (OSAS) suffer cerebrovascular accidents at three to six times the rate of other Americans. Atherosclerosis of the cervical portion of the carotid artery has been suggested as a possible cause of these strokes. Lateral cephalometric radiographs used to determine the site of upper airway obstruction in sleep apnea patients can also image calcified cervical carotid artery atheromas. However, their prevalence in this group of patients has not been previously reported.

PATIENTS AND METHODS

The radiographs of 47 male subjects (mean age 59.2 years, range 45 to 77 years) diagnosed as having OSAS (apnea/hypopnea index [AHI] of > or = 15 and a history of snoring and excessive daytime sleepiness) were assessed for calcified carotid atheromas. Healthy, age-matched (+/-18 months) controls were likewise assessed.

RESULTS

The radiographs of the subjects with OSAS showed that 21.3% had calcified atheromas. The radiographs of the controls showed that only 2.5% had calcified atheromas. This finding was statistically significant (P = < .000001). The lesions seen in both populations were similar, and located within the soft tissues of the neck at the level of C3 and C4. The lesions were superimposed over these tissues, the prevertebral fascia, and the pharyngeal airspace.

CONCLUSIONS

The results of this study seem to indicate that persons with OSAS have a greater prevalence of calcified carotid artery atheromas than healthy, age-matched persons. These lesions, a possible cause of future stroke, can be detected on lateral cephalometric radiographs.

Sleep apnoea/hypopnoea syndrome: a potential cause of graft failure following heart transplantation

A 54-year-old man presented 54 months after a successful heart transplant with cor pulmonale secondary to obstructive sleep apnoea/hypopnoea syndrome (SAHS). This unusual cause of reversible graft failure following heart transplantation is presented in this case report.

A short-term controlled trial of an adjustable oral appliance for the treatment of mild to moderate obstructive sleep apnoea

BACKGROUND

Although oral appliances are effective in some patients with obstructive sleep apnoea (OSA), they are not universally effective. A novel anterior mandibular positioner (AMP) has been developed with an adjustable hinge that allows progressive advancement of the mandible. The objective of this prospective crossover study was to compare efficacy, side effects, patient compliance, and preference between AMP and nasal continuous positive airway pressure (nCPAP) in patients with symptomatic mild to moderate OSA.

METHODS

Twenty four patients of mean (SD) age 44.0 (10.6) years were recruited with a mean (SD) body mass index of 32.0 (8.2) kg/m2, Epworth sleepiness score 10.7 (3.4), and apnoea/hypopnoea index 26.8 (11.9)/hour. There was a two week wash-in and a two week wash-out period and two treatment periods (AMP and nCPAP) each of four months. Efficacy, side effects, compliance, and preference were evaluated by a questionnaire and home sleep monitoring.

RESULTS

One patient dropped out early in the study and three refused to cross over so treatment results are presented on the remaining 20 patients. The apnoea/hypopnoea index (AHI) was lower with nasal CPAP 4.2 (2.2)/hour than with the AMP 13.6 (14.5)/hour (p < 0.01). Eleven of the 20 patients (55%) who used the AMP were treatment successes (reduction of AHI to < 10/hour and relief of symptoms), one (5%) was a compliance failure (unable or unwilling to use the treatment), and eight (40%) were treatment failures (failure to reduce AHI to < 10/hour and/or failure to relieve symptoms). Fourteen of the 20 patients (70%) who used nCPAP were treatment successes, six (30%) were compliance failures, and there were no treatment failures. There was greater patient satisfaction with the AMP (p < 0.01) than with nCPAP but no difference in reported side effects or compliance.

CONCLUSIONS

AMP is an effective treatment in some patients with mild to moderate OSA and is associated with greater patient satisfaction than nCPAP.