Obstructive sleep apnoea and frequency of occupational injury.

We sought to determine whether patients with obstructive sleep apnoea (OSA) are at increased risk of occupational injury (OI). Patients referred to the University of British Columbia Hospital Sleep Laboratory for suspected OSA (May 2003 to July 2011 were recruited and rates and types of validated OI (that caused at least 1 day of disability) in the 5 years prior to polysomnography were calculated. In a sample of 1236, patients with OSA were twice as likely (OR=1.93, 95% CI 1.06 to 3.50, p=0.03) to suffer at least one OI compared with patients without OSA. This association was attenuated (OR=1.76, CI 0.86 to 3.59, p=0.12) after controlling for confounders. In a secondary analysis, patients with OSA were almost three times more likely (OR=2.88, CI 1.02 to 8.08, p=0.05) to suffer from an injury more likely related to reduced vigilance (eg, a fall or commercial motor vehicle crash) when compared with patients without OSA, and this again was attenuated after controlling for confounders (OR=2.42, CI 0.085 to 6.93, p=0.10).

Society of Anesthesia and Sleep Medicine Guidelines on Preoperative Screening and Assessment of Adult Patients With Obstructive Sleep Apnea.

The purpose of the Society of Anesthesia and Sleep Medicine guideline on preoperative screening and assessment of adult patients with obstructive sleep apnea (OSA) is to present recommendations based on the available clinical evidence on the topic where possible. As very few well-performed randomized studies in this field of perioperative care are available, most of the recommendations were developed by experts in the field through consensus processes involving utilization of evidence grading to indicate the level of evidence upon which recommendations were based. This guideline may not be appropriate for all clinical situations and all patients. The decision whether to follow these recommendations must be made by a responsible physician on an individual basis. Protocols should be developed by individual institutions taking into account the patients' conditions, extent of interventions and available resources. This practice guideline is not intended to define standards of care or represent absolute requirements for patient care. The adherence to these guidelines cannot in any way guarantee successful outcomes and is rather meant to help individuals and institutions formulate plans to better deal with the challenges posed by perioperative patients with OSA. These recommendations reflect the current state of knowledge and its interpretation by a group of experts in the field at the time of publication. While these guidelines will be periodically updated, new information that becomes available between updates should be taken into account. Deviations in practice from guidelines may be justifiable and such deviations should not be interpreted as a basis for claims of negligence.

Sleep Stage Coordination of Respiration and Swallowing: A Preliminary Study.

Swallowing is an important physiological response that protects the airway. Although aspiration during sleep may cause aspiration pneumonia, the mechanisms responsible have not yet been elucidated. We evaluated the coordination between respiration and swallowing by infusing water into the pharynx of healthy young adults during each sleep stage. Seven normal subjects participated in the study. During polysomnography recordings, to elicit a swallow we injected distilled water into the pharynx during the awake state and each sleep stage through a nasal catheter. We assessed swallow latency, swallow apnea time, the respiratory phase during a swallow, the number of swallows, and coughing. A total number of 79 swallows were recorded. The median swallow latency was significantly higher in stage 2 (10.05 s) and stage 3 (44.17 s) when compared to awake state (4.99 s). The swallow latency in stage 3 showed a very wide interquartile range. In two subjects, the result was predominantly prolonged compared to the other subjects. There was no significant difference in the swallow apnea time between sleep stages. The presence of inspiration after swallowing, repetitive swallowing, and coughing after swallowing was more frequent during sleep than when awake. This study suggests that the coordination between respiration and swallowing as a defense mechanism against aspiration was impaired during sleep. Our results supported physiologically the fact that healthy adult individuals aspirate pharyngeal secretions during sleep.

Swallowing and breathing patterns during sleep in patients with obstructive sleep apnea.

PURPOSE: The aims of this study were to determine the frequencies of swallowing and swallowing associated with arousals during sleep in patients with obstructive sleep apnea (OSA) and to determine whether these were associated with the severity of OSA and differed according to the preceding breathing route. METHODS: Standard audio-video polysomnography including an evaluation of swallowing-related elevation of the thyroid cartilage and breathing route (i.e., nasal or oronasal) was undertaken in an academic sleep laboratory. Fifty-six patients were analyzed (13 non-OSA patients, 17 mild, 10 moderate, and 16 severe OSA). RESULTS: The frequency of swallowing per hour of sleep was significantly higher in the severe OSA patients when compared to mild OSA patients (mild OSA, 3.1/h and severe OSA, 8.4/h). This was mainly due to the significantly higher frequency of swallowing associated with a respiratory event-related arousal in the severe OSA patients when compared to non- and mild OSA patients (non-OSA, 0.6/h; mild OSA, 1.0/h; severe OSA, 6.0/h), especially when swallowing was preceded by oronasal breathing (non-OSA, 0.2/h; mild OSA, 0.4/h; severe OSA, 4.2/h). CONCLUSIONS: Swallowing frequency during sleep can increase with increasing OSA severity in most OSA patients. These events are predominately associated with respiratory event-related arousals and are more frequent when preceded by oronasal breathing. The observed swallowing under high ventilatory needs may compromise the maintenance of the pharynx as a conduit for airflow in OSA patients.

Carotid intima media thickness in patients with obstructive sleep apnea: comparison with a community-based cohort.

BACKGROUND: The impact of obstructive sleep apnea (OSA) on the development of atherosclerotic cardiovascular disease (CVD) in the absence of overt CVD or risk factors is unclear. Our purpose was to assess whether patients with OSA without overt CVD or risk factors have subclinical atherosclerosis as evaluated by carotid intima medial thickness (CIMT) compared to matched controls. METHODS: We measured CIMT in patients >40 years old, who underwent polysomnography for suspected OSA and did not have a history of CVD or risk factors (smoking, hypertension, diabetes, hyperlipidemia). OSA severity was classified according to apnea-hypopnea index. Serum levels of high-sensitivity C-reactive protein, fibrinogen, and lipids were assessed and relationships with OSA severity explored. CIMT measurements from patients with OSA were compared those of to age-, gender-, and BMI-matched controls from a community-based cohort without known CVD or OSA. RESULTS: Fifty-one patients were studied. Of these, patients with severe OSA had an increased CIMT compared to patients without OSA, but the relationship was not significant after controlling for age (p = 0.10). However, 37 patients had OSA and were matched to 105 controls. CIMT was significantly increased in OSA patients versus controls (0.77 vs. 0.68 mm, p = 0.03). The difference between patients and controls was greater for patients with severe OSA (0.83 vs. 0.71 mm) than for patients with mild-to-moderate OSA (0.71 vs. 0.67 mm). CONCLUSIONS: Patients with OSA but without a history of or risk factors for CVD have increased CIMT compared to a BMI-, age-, and gender-matched cohort. This provides evidence that OSA is an independent risk factor for the development of CVD.

Patient preferences and experiences of CPAP and oral appliances for the treatment of obstructive sleep apnea: a qualitative analysis.

OBJECTIVES: The aim of this study is to better understand patients' perspectives and preferences about treatment with continuous positive airway pressure (CPAP) and oral appliance (OA) devices for obstructive sleep apnea. METHODS: The current study used qualitative analysis of four focus group sessions with current CPAP and OA users. Twenty-two participants with OSA who currently use either CPAP or OA participated in the sessions at the University of British Columbia. RESULTS: Five topics from the focus group sessions were descriptively analyzed using NVivo software: goals and expectations of treatment, benefits of treatment for bed partners, side effects and inconveniences of CPAP, side effects and inconveniences of OA, and factors impacting treatment choice. In order of most to least frequently mentioned, patients expressed six expectations of treatment: improved health, apnea elimination, improved sleep, reduced fatigue, reduced snoring, and bed-partner benefits. The most to least mentioned factors impacting treatment choice were device effectiveness, transportability, embarrassment, and cost. CONCLUSIONS: This qualitative study showed that many factors impact patients' experience with their treatment device and that their treatment needs are not only physical but also relate to their lifestyle. This preliminary study provides treatment characteristics and attributes necessary to develop a quantitative questionnaire study, to assist in the selection of therapy, weighing the relative importance of patient and OSA treatment characteristics on treatment preference and adherence. Matching therapy to patient preferences may help identify the most appropriate treatment, and this may achieve greater likelihood of adherence.

Recommendations for clinical management of excessive daytime sleepiness in obstructive sleep apnoea - A Delphi consensus study.

STUDY OBJECTIVE: Excessive daytime sleepiness is common with obstructive sleep apnoea and can persist despite efforts to optimise primary airway therapy. The literature lacks recommendations regarding differential diagnosis and management of excessive daytime sleepiness in obstructive sleep apnoea. This study sought to develop expert consensus statements to bridge the gap between existing literature/guidelines and clinical practice. METHODS: A panel of 10 international experts was convened to undertake a modified Delphi process. Statements were developed based on available evidence identified through a scoping literature review, and expert opinion. Consensus was achieved through 3 rounds of iterative, blinded survey voting and revision to statements until a predetermined level of agreement was met (≥80 % voting "strongly agree" or "agree with reservation"). RESULTS: Consensus was achieved for 32 final statements. The panel agreed excessive daytime sleepiness is a patient-reported symptom. The importance of subjective/objective evaluation of excessive daytime sleepiness in the initial evaluation and serial management of obstructive sleep apnoea was recognised. The differential diagnosis of residual excessive daytime sleepiness in obstructive sleep apnoea was discussed. Optimizing airway therapy (eg, troubleshooting issues affecting effectiveness) was addressed. The panel recognised occurrence of residual excessive daytime sleepiness in obstructive sleep apnoea despite optimal airway therapy and the need to evaluate patients for underlying causes. CONCLUSIONS: Excessive daytime sleepiness in patients with obstructive sleep apnoea is a public health issue requiring increased awareness, recognition, and attention. Implementation of these statements may improve patient care, long-term management, and clinical outcomes in patients with obstructive sleep apnoea.

The efficacy of a titrated tongue-stabilizing device on obstructive sleep apnea: a quasi-experimental study.

STUDY OBJECTIVES: To evaluate the short-term efficacy and self-reported outcomes of tongue-stabilizing device (TSD) therapy as compared to those of mandibular advancement device (MAD) therapy in an adult population diagnosed with obstructive sleep apnea. METHODS: This study is a parallel, nonrandomized clinical trial of the TSD and MAD therapies. The efficacy of both interventions was evaluated objectively by level 3 home sleep apnea testing and by self-report using the Epworth Sleepiness Scale, the Functional Outcomes of Sleep Questionnaire, the Chalder Fatigue Scale, and the 36-Item Short-Form Health Survey. Adherence and adverse effects were self-reported. RESULTS: Of the 39 patients who received TSD therapy, 27 managed to adapt and complete the trial and were matched with 26 patients who received MAD therapy. At the 2-month follow-up, the acceptance rate of the TSD therapy was 53.8%. Both patients receiving TSD therapy and patients receiving MAD therapy showed significant improvements in their respiratory event index (P < .05), with no difference between the treatments (P > .05). In those receiving TSD therapy (n = 27), the only self-reported efficacy measure that significantly improved with TSD therapy was the Chalder Fatigue Scale (P < .05). In contrast, all 4 self-reported measures (Epworth Sleepiness Scale, Functional Outcomes of Sleep Questionnaire, 36-Item Short-Form Health Survey, and Chalder Fatigue Scale) showed a significant improvement with MAD therapy. CONCLUSIONS: This study revealed similar improvements in apneas and oxygen saturation between TSD and MAD therapies. Whereas MAD therapy was a better treatment for obstructive sleep apnea in terms of daytime sleepiness and quality-of-life improvements, TSD therapy had a low treatment acceptance rate. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: The Efficacy of Tongue Stabilizing Device in Patients with Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/ct2/show/NCT02329925; Identifier: NCT02329925; and Registry: ClinicalTrials.gov; Name: Adherence and Preference of Continuous Positive Airway Pressure vs Mandibular Advancement Splints in Obstructive Sleep Apnea Patients: A Randomized Trial (CHOICE); URL: https://clinicaltrials.gov/ct2/show/NCT02242617; Identifier: NCT02242617. CITATION: Alshhrani WM, Hamoda MM, Okuno K, et al. The efficacy of a titrated tongue-stabilizing device on obstructive sleep apnea: a quasi-experimental study. J Clin Sleep Med. 2021;17(8):1607-1618.

Compliance and side effects of tongue stabilizing device in patients with obstructive sleep apnea.

Objective: To evaluate the long-term effectiveness, compliance, and side effects of tongue stabilizing devices (TSDs).Methods: Thirty-nine patients were followed up after 12 and 30 months. The subjective effectiveness was assessed using the Epworth Sleepiness Scale (ESS), the Functional Outcomes Sleep Questionnaire (FOSQ-10), the Chalder Fatigue Scale (CFQ), and a sleep-related quality of life questionnaire (QoL). Compliance and side effects were assessed.Results: At 12-months, 35.9% of patients confirmed continuing the therapy, compared to only 15.4% of patients at 30 months. At 30 months, a significant average improvement of ESS (2.0 ± 2.8) was observed compared to baseline levels in six patients. Six patients demonstrated an average increase in blood pressure. The most frequently reported side effects were mouth dryness and excessive salivation. The 3D analysis revealed small tooth movements.Conclusion: The TSD therapy demonstrated a good long-term subjective effectiveness against OSA but had a relatively low treatment acceptance rate.

Screening for Obstructive Sleep Apnea in an Atrial Fibrillation Population: What's the Best Test?

BACKGROUND: Among individuals with nonvalvular atrial fibrillation (AF), the prevalence of obstructive sleep apnea (OSA) can be as high as 85%. Continuous positive airway pressure treatment for moderate or severe OSA might improve AF outcomes and quality of life, so early identification of OSA might be of value. However, screening questionnaires for OSA are suboptimal because they are weighted toward tiredness and loud snoring, which might be absent in AF patients. NoSAS (Neck, Obesity, Snoring, Age, Sex) is a new OSA questionnaire that excludes these parameters. Acoustic pharyngometry (AP) is a potential novel screening technique that measures pharyngeal cross-sectional area, which is reduced in patients with OSA. METHODS: We prospectively compared the accuracy of the NoSAS, the STOP-BANG questionnaire (Snoring, Tiredness, Observed apnea, blood Pressure, Body mass index, Age, Neck circumference and Gender), and AP with home sleep apnea testing (HSAT) in consecutive patients with nonvalvular AF. RESULTS: Of 188 participants, 86% had OSA and 49% had moderate or severe OSA. Mean Epworth Sleepiness Scale scores were low; 5.9 (SD, 3.9), indicating that most participants were not sleepy. Receiver operating characteristic curves for comparisons of screening tests with HSAT showed suboptimal accuracy. For moderate plus severe and severe only groups respectively, the area under the curve was 0.50 (95% confidence interval [CI], 0.42-0.58) and 0.42 (95% CI, 0.34-0.52) for AP, 0.65 (95% CI, 0.58-0.73) and 0.63 (95% CI, 0.52-0.74) for the STOP-BANG questionnaire, and 0.68 (95% CI, 0.60-0.75) and 0.69 (95% CI, 0.59-0.80) for the NoSAS. CONCLUSIONS: AP and NoSAS are not sufficiently accurate for screening AF patients for OSA. Because of the high rates of OSA in this cohort, the potential benefits of OSA treatment, and the suboptimal accuracy of current screening questionnaires, cardiologists should consider HSAT for AF patients.

CONTEXTE: Chez les sujets présentant une fibrillation auriculaire (FA) non valvulaire, la prévalence de l'apnée obstructive du sommeil (AOS) peut atteindre 85 %. En cas d'AOS modérée ou sévère, un traitement par ventilation spontanée en pression positive continue peut améliorer les résultats liés à la FA et la qualité de vie du patient; un diagnostic précoce d'AOS pourrait donc être utile. Les questionnaires de dépistage de l'AOS ne sont toutefois pas optimaux parce qu'ils accordent une grande importance à la fatigue et aux ronflements sonores, des symptômes qui ne se manifestent pas nécessairement en cas de FA. Le questionnaire NoSAS (de l'anglais Neck, Obesity, Snoring, Age, Sex) est un nouvel outil d'évaluation de l'AOS qui ne tient pas compte de ces paramètres. La pharyngométrie acoustique (PA) pourrait aussi constituer une nouvelle technique de dépistage; elle mesure l'aire de section transversale du pharynx, qui est réduite chez les patients souffrant d'AOS. MÉTHODOLOGIE: Nous avons comparé de façon prospective la précision du score au questionnaire NoSAS, du score au questionnaire STOP-BANG (de l'anglais Snoring, Tiredness, Observed apnea, blood Pressure, Body mass index, Age, Neck circumference and Gender) et des résultats de la PA à celle du test d'apnée du sommeil à domicile (TASD) chez des patients consécutifs présentant une FA non valvulaire. RÉSULTATS: Sur les 188 participants, 86 % présentaient une AOS et 49 % souffraient d'AOS modérée ou sévère. Le score moyen sur l'échelle de somnolence d'Epworth était faible et se situait à 5,9 (écart-type : 3,9), ce qui indique que la plupart des participants ne ressentaient pas de somnolence. La comparaison entre les questionnaires de dépistage et le TASD effectuée au moyen des courbes caractéristiques de la performance des tests a révélé une précision sous-optimale. Dans les groupes souffrant d'AOS modérée ou sévère et d'AOS sévère seulement, les aires sous la courbe étaient respectivement de 0,50 (intervalle de confiance [IC] à 95 % : de 0,42 à 0,58) et de 0,42 (IC à 95 % : de 0,34 à 0,52) pour la PA, de 0,65 (IC à 95 % : de 0,58 à 0,73) et de 0,63 (IC à 95 % : de 0,52 à 0,74) pour le questionnaire STOP-BANG, et de 0,68 (IC à 95 % : de 0,60 à 0,75) et de 0,69 (IC à 95 % : de 0,59 à 0,80) pour le questionnaire NoSAS. CONCLUSIONS: La PA et le questionnaire NoSAS ne sont pas suffisamment précis pour dépister l'AOS chez les patients présentant une FA. Compte tenu de la forte prévalence de l'AOS dans cette cohorte, des bienfaits potentiels d'un traitement de l'AOS et de la précision sous-optimale des questionnaires de dépistage actuels, il conviendrait d'envisager un TASD chez les patients présentant une FA.

Cost-effectiveness of oral appliances in the treatment of obstructive sleep apnoea-hypopnoea.

PURPOSE: Oral appliances (OA) are commonly prescribed for the treatment of obstructive sleep apnoea-hypopnoea (OSAH), but there is limited evidence on their cost-effectiveness. MATERIALS AND METHODS: A model was designed to simulate the costs and benefits of treatment of OSAH with OA or continuous positive airway pressure (CPAP) based on their effects on quality of life, motor vehicle crashes, and cardiovascular effects. The primary outcome was the incremental cost-effectiveness ratio (ICER) in terms of costs per one quality-adjusted life year (QALY) gained 5 years after treatment. RESULTS: Compared with no treatment, OA results in $268 higher costs and an incremental QALY of 0.0899 per patient (ICER = $2,984/QALY). Compared with OA, CPAP resulted in $1,917 more costs and 0.0696 additional QALYs (ICER = $27,540/QALY). For the most part in the sensitivity analyses, CPAP remained cost-effective compared to OA, and OA remained cost-effective with respect to no treatment in almost all scenarios. CONCLUSIONS: OAs are less economically attractive than CPAP but remain a cost-effective treatment for patients who are unwilling or unable to adhere to CPAP therapy.

Evaluation of a portable recording device (ApneaLink) for case selection of obstructive sleep apnea.

OBJECTIVE: This study was designed to assess the sensitivity and specificity of a portable sleep apnea recording device (ApneaLink) using standard polysomnography (PSG) as a reference and to evaluate the possibility of using the ApneaLink as a case selection technique for patients with suspected obstructive sleep apnea (OSA). MATERIALS AND METHODS: Fifty patients (mean age 48.7 +/- 12.6 years, 32 males) were recruited during a 4-week period. A simultaneous recording of both the standard in-laboratory PSG and an ambulatory level 4 sleep monitor (ApneaLink) was performed during an overnight study for each patient. PSG sleep and respiratory events were scored manually according to standard criteria. ApneaLink data were analyzed either with the automated computerized algorithm provided by the manufacturer following the American Academy of Sleep Medicine standards (default setting DFAL) or The University of British Columbia Hospital sleep laboratory standards (alternative setting, ATAL). The ApneaLink respiratory disturbance indices (RDI), PSG apnea-hypopnea indices (AHI), and PSG oxygen desaturation index (ODI) were compared. RESULTS: The mean PSG-AHI was 30.0 +/- 25.8 events per hour. The means of DFAL-RDI and ATAL-RDI were 23.8 +/- 21.9 events per hour and 29.5 +/- 22.2 events per hour, respectively. Intraclass correlation coefficients were 0.958 between PSG-AHI and DFAL-RDI and 0.966 between PSG-AHI and ATAL-RDI. Receiver operator characteristic curves were constructed using a variety of PSG-AHI cutoff values (5, 10, 15, 20, and 30 events per hour). Optimal combinations of sensitivity and specificity for the various cutoffs were 97.7/66.7, 95.0/90.0, 87.5/88.9, 88.0/88.0, and 88.2/93.9, respectively for the default setting. The ApneaLink demonstrated the best agreement with laboratory PSG data at cutoffs of AHI >or= 10. There were no significant differences among PSG-AHI, DFAL-RDI, and ATAL-RDI when all subjects were considered as one group. ODI at 2%, 3%, and 4% desaturation levels showed significant differences (p < 0.05) compared with PSG-AHI, DFAL-RDI, and ATAL-RDI for the entire group. CONCLUSION: The ApneaLink is an ambulatory sleep monitor that can detect OSA and/or hypopnea with acceptable reliability. The screening and diagnostic capability needs to be verified by further evaluation and manual scoring of the ApneaLink. It could be a better choice than traditional oximetry in terms of recording respiratory events, although severity may be under- or overestimated.

Pro-atherogenic cytokine profile of patients with suspected obstructive sleep apnea.

PURPOSE: Systemic inflammation is important in the pathogenesis of cardiovascular disease (CVD). We sought to characterize the systemic inflammatory profile associated with obstructive sleep apnea (OSA). METHODS: Adult patients referred for suspected OSA at the University of British Columbia Hospital Sleep Disorders Program were recruited for our study. Patients using HMG CoA inhibitors or a history of CVD were excluded. Fasting serum samples were obtained the morning after their diagnostic polysomnograms. Samples were tested for the following circulating inflammatory mediators: interferon gamma; interleukins 1B, 6, and 8; intercellular and vascular cell adhesion molecules (sICAM-1 and sVCAM-1); and leptin using a multiplex Luminex System. RESULTS: There were 176 patients; 68% were male, mean age = 50 +/- (SD) 11 years, mean apnea/hyponea index (AHI) = 22.9 +/- 22/h, mean desaturation (i.e. % of sleep time spent below an oxyhemoglobin saturation of 90%) = 5.4% +/- 15, and mean body mass index (BMI) = 32.2 +/- 8 kg/m(2). In univariate analyses, only leptin, sVCAM-1, and sICAM-1 were significantly associated with indices of OSA severity (i.e. AHI and/or desaturation). In multivariate linear regression analyses that controlled for BMI, gender, age, and current smoking; desaturation persisted as a significant independent predictor for elevated sVCAM-1 and leptin. CONCLUSIONS: We did not find significant associations between OSA and markers of activated innate immunity (IL-1B, 6, and 8). However, OSA severity was independently associated with serum levels of sVCAM-1 and leptin; these may represent mechanisms involved in the pathogenesis of OSA-related CVD.

Pediatric sleep disorder medicine training in Canada: past, present and future.

Pediatric sleep medicine is rapidly evolving in Canada. As pediatric sleep disorders are increasingly recognized, there is a growing need for clinicians educated in the evaluation and treatment of pediatric sleep disorders. Current pediatric sleep resources in Canada are inadequate to meet the needs of the population. Until this year, there was no formal pathway or specific requirements for pediatric sleep disorder medicine training in Canada and exposure to this field of medicine in post-graduate training was limited. In 2018, the Royal College of Physicians of Canada approved an Area of Focused Competence program for certification and maintenance of competence in Sleep Disordered Medicine. It was designed to ensure adequate breadth and depth of training experiences in this diverse field. The goals of the program are to ensure competence in the assessment and management of adults and children with a range of sleep-wake disorders and sleep-disordered breathing, to interpret sleep investigations, to administratively manage a sleep laboratory and to advance the discipline of Sleep Disorder Medicine through research. The program follows a competency-based model in which, within the year of training, trainees accumulate a dossier of experiences which are evaluated by a Royal College of Physicians and Surgeons committee. This new program will ensure that a critical mass of trained sleep medicine physicians is developed to meet the needs of the Canadian pediatric population and to contribute to advancement of the field of pediatric sleep medicine.

Tongue Stabilizing Device-Emergent Central Sleep Apnea: A Case Report.

ABSTRACT: Treatment-emergent central sleep apnea is a phenomenon that has been reported after many obstructive sleep apnea treatment modalities. We present a case of demonstrating treatment-emergent central sleep apnea while using the tongue stabilizing device therapy. This case adds to the evidence that showed the effect of the supine position on the severity of central sleep apnea and shows the advantage of polysomnography follow-up after oral appliance therapy for central apnea assessment.

Suppression of central sleep apnea by continuous positive airway pressure and transplant-free survival in heart failure: a post hoc analysis of the Canadian Continuous Positive Airway Pressure for Patients with Central Sleep Apnea and Heart Failure Trial (CANPAP).

BACKGROUND: In the main analysis of the Canadian Continuous Positive Airway Pressure (CPAP) for Patients with Central Sleep Apnea (CSA) and Heart Failure Trial (CANPAP), CPAP had no effect on heart transplant-free survival; however, CPAP only reduced the mean apnea-hypopnea index to 19 events per hour of sleep, which remained above the trial inclusion threshold of 15. This stratified analysis of CANPAP tested the hypothesis that suppression of CSA below this threshold by CPAP would improve left ventricular ejection fraction and heart transplant-free survival. METHODS AND RESULTS: Of the 258 heart failure patients with CSA in CANPAP, 110 of the 130 randomized to the control group and 100 of the 128 randomized to CPAP had sleep studies 3 months later. CPAP patients were divided post hoc into those whose apnea-hypopnea index was or was not reduced below 15 at this time (CPAP-CSA suppressed, n=57, and CPAP-CSA unsuppressed, n=43, respectively). Their changes in left ventricular ejection fraction and heart transplant-free survival were compared with those in the control group. Despite similar CPAP pressure and hours of use in the 2 groups, CPAP-CSA-suppressed subjects experienced a greater increase in left ventricular ejection fraction at 3 months (P=0.001) and significantly better transplant-free survival (hazard ratio [95% confidence interval] 0.371 [0.142 to 0.967], P=0.043) than control subjects, whereas the CPAP-CSA-unsuppressed group did not (for left ventricular ejection fraction, P=0.984, and for transplant-free survival, hazard ratio 1.463 [95% confidence interval 0.751 to 2.850], P=0.260). CONCLUSIONS: These results suggest that in heart failure patients, CPAP might improve both left ventricular ejection fraction and heart transplant-free survival if CSA is suppressed soon after its initiation.

Continuous positive airway pressure for central sleep apnea and heart failure.

BACKGROUND: The Canadian Continuous Positive Airway Pressure for Patients with Central Sleep Apnea and Heart Failure trial tested the hypothesis that continuous positive airway pressure (CPAP) would improve the survival rate without heart transplantation of patients who have central sleep apnea and heart failure. METHODS: After medical therapy was optimized, 258 patients who had heart failure (mean age [+/-SD], 63+/-10 years; ejection fraction, 24.5+/-7.7 percent) and central sleep apnea (number of episodes of apnea and hypopnea per hour of sleep, 40+/-16) were randomly assigned to receive CPAP (128 patients) or no CPAP (130 patients) and were followed for a mean of two years. During follow-up, sleep studies were conducted and measurements of the ejection fraction, exercise capacity, quality of life, and neurohormones were obtained. RESULTS: Three months after undergoing randomization, the CPAP group, as compared with the control group, had greater reductions in the frequency of episodes of apnea and hypopnea (-21+/-16 vs. -2+/-18 per hour, P<0.001) and in norepinephrine levels (-1.03+/-1.84 vs. 0.02+/-0.99 nmol per liter, P=0.009), and greater increases in the mean nocturnal oxygen saturation (1.6+/-2.8 percent vs. 0.4+/-2.5 percent, P<0.001), ejection fraction (2.2+/-5.4 percent vs. 0.4+/-5.3 percent, P=0.02), and the distance walked in six minutes (20.0+/-55 vs. -0.8+/-64.8 m, P=0.016). There were no differences between the control group and the CPAP group in the number of hospitalizations, quality of life, or atrial natriuretic peptide levels. An early divergence in survival rates without heart transplantation favored the control group, but after 18 months the divergence favored the CPAP group, yet the overall event rates (death and heart transplantation) did not differ (32 vs. 32 events, respectively; P=0.54). CONCLUSIONS: Although CPAP attenuated central sleep apnea, improved nocturnal oxygenation, increased the ejection fraction, lowered norepinephrine levels, and increased the distance walked in six minutes, it did not affect survival. Our data do not support the use of CPAP to extend life in patients who have central sleep apnea and heart failure.

Three-dimensional computer-assisted study model analysis of long-term oral-appliance wear. Part 1: Methodology.

INTRODUCTION: The aim of this study was to test a 3-dimensional (3D) computer-assisted dental model analysis system that uses selected landmarks to describe tooth movement during treatment with an oral appliance. METHODS: Dental casts of 70 patients diagnosed with obstructive sleep apnea and treated with oral appliances for a mean time of 7 years 4 months were evaluated with a 3D digitizer (MicroScribe-3DX, Immersion, San Jose, Calif) compatible with the Rhinoceros modeling program (version 3.0 SR3c, Robert McNeel & Associates, Seattle, Wash). A total of 86 landmarks on each model were digitized, and 156 variables were calculated as either the linear distance between points or the distance from points to reference planes. Four study models for each patient (maxillary baseline, mandibular baseline, maxillary follow-up, and mandibular follow-up) were superimposed on 2 sets of reference points: 3 points on the palatal rugae for maxillary model superimposition, and 3 occlusal contact points for the same set of maxillary and mandibular model superimpositions. The patients were divided into 3 evaluation groups by 5 orthodontists based on the changes between baseline and follow-up study models. RESULTS: Digital dental measurements could be analyzed, including arch width, arch length, curve of Spee, overbite, overjet, and the anteroposterior relationship between the maxillary and mandibular arches. A method error within 0.23 mm in 14 selected variables was found for the 3D system. The statistical differences in the 3 evaluation groups verified the division criteria determined by the orthodontists. CONCLUSIONS: The system provides a method to record 3D measurements of study models that permits computer visualization of tooth position and movement from various perspectives.