International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Positive airway pressure therapy for sleep-disordered breathing confers short-term benefits to patients with spinal cord injury despite widely ranging patterns of use

STUDY DESIGN

Prospective, cohort study.

OBJECTIVES

To evaluate the effectiveness of bi-level positive airway pressure (PAP) therapy and the patterns of use for sleep-disordered breathing (SDB) in individuals with spinal cord injury (SCI).

SETTING

Academic tertiary care center, USA.

METHODS

Overall, 91 adults with C1-T6 SCI for ≥3 months were recruited and 74 remained in the study to be evaluated for SDB and follow-up. Individuals with SDB but no nocturnal hypercapnia (NH) were prescribed auto-titrating PAP. Those with NH were prescribed PAP with volume-assured pressure support. Device downloads and overnight transcutaneous capnography were performed at 3, 6, and 12 months to quantify PAP use and effectiveness. Participants kept daily event logs, and quality of life (QOL) questionnaires were performed after 3, 6, and 12 months.

RESULTS

Overall, 45% of 91 participants completed the study. There was great diversity among SCI patients in PAP utilization; after 3 months, 37.8% of participants used PAP for ≥70% nights and ≥240 min per night, whereas 42.2% seldom used PAP and 20% used PAP sporadically or for short periods. PAP therapy was effective in improving OSA in 89% and nocturnal hypercapnia in 77%. Higher PAP pressures predicted higher levels of device use. There were marked reductions in symptoms of autonomic dysreflexia (AD) and orthostatic hypotension as well as some improved indices of QOL.

CONCLUSIONS

Despite widely diverse patterns of use, PAP therapy may have short-term benefits with regard to QOL and reducing episodes of dizziness and autonomic dysreflexia.

Simplified Approach to Diagnosing Sleep-Disordered Breathing and Nocturnal Hypercapnia in Individuals With Spinal Cord Injury

OBJECTIVE

To evaluate a strategy of home-based testing to diagnose sleep-disordered breathing and nocturnal hypercapnia in individuals with spinal cord injury (SCI).

DESIGN

Case series.

SETTING

Referral center.

PARTICIPANTS

Adults with C1-T6 SCI (N=81). Individuals were eligible if ≥ 18 years old, with SCI of ≥ 3 months' duration, living within 100 miles of the study site, and not meeting exclusion criteria. Of the 161 individuals recruited from the SCI Model System database who were not enrolled, reasons were not interested in participating, change of location, prior positive pressure ventilation use, or medical contraindication. Ten individuals did not complete the study.

INTERVENTIONS

Performance of an unsupervised home sleep apnea test combined with transcutaneous partial pressure of carbon dioxide/oxygen saturation by pulse oximetry monitoring.

MAIN OUTCOME MEASURES

Prevalence of sleep-disordered breathing and nocturnal hypercapnia. Clinical and physiological variables were examined to determine which, if any, correlate with the severity of sleep-disordered breathing.

RESULTS

Obstructive sleep apnea (OSA) was found in 81.3% of individuals, central sleep apnea (CSA) was found in 23.8%, and nonspecific hypopnea events, where respiratory effort was too uncertain to classify, were present in 35%. Nonspecific hypopnea events correlated strongly with CSA but weakly with OSA, suggesting that conventional sleep apnea test scoring may underestimate central/neuromuscular hypopneas. Nocturnal hypercapnia was present in 28% and oxygen desaturation in 18.3%. Neck circumference was the primary predictor for OSA, whereas baclofen use and obstructive apnea/hypopnea index weakly predicted CSA. Awake transcutaneous partial pressure of carbon dioxide and CSA were only marginally associated with nocturnal hypercapnia.

CONCLUSIONS

Unsupervised home sleep apnea testing with transcutaneous capnography effectively identifies sleep-disordered breathing and nocturnal hypercapnia in individuals with SCI.

Development of a Measure of Knowledge and Attitudes About Obstructive Sleep Apnea in Children (OSAKA-KIDS)

BACKGROUND

Primary care physicians play an important role in screening for childhood obstructive sleep apnea syndrome (OSAS) that, if untreated, can result in serious complications.

OBJECTIVE

To describe the development of the Obstructive Sleep Apnea Knowledge and Attitudes in Children (OSAKA-KIDS) questionnaire for use in measuring physicians' knowledge and attitudes about childhood OSAS and its treatment.

DESIGN

Cross-sectional survey to pilot administration of the 23-item OSAKA-KIDS questionnaire, mailed to 1195 community- and academic-based physicians in Louisville, Ky; Philadelphia, Pa; and St Louis, Mo.

MAIN OUTCOME MEASURES

Analysis of variance measured differences in knowledge and attitudes between academic- and community-based physicians and between pediatricians and family practitioners. Using stepwise multiple linear regression, we analyzed the associations between various predictors (including specialty, practice setting, and years since medical school graduation) and each item of knowledge and attitudes. All tests were 2-tailed.

RESULTS

Questionnaires for 497 respondents (44% female; mean [SD] age, 45.7 [10.5] years; and mean [SD] number of years since medical school graduation, 18.7 [11.0] years) were analyzed. The mean (SD) knowledge score (percentage of 18 possible) was 69.6% (14.6%). In regression analyses, more knowledge was associated with more positive attitudes overall and more recent graduation from medical school; having a more positive attitude was associated with having completed a pediatrics residency and more knowledge about OSAS.

CONCLUSIONS

Deficits in basic knowledge about childhood OSAS were observed regardless of physician practice setting and specialty training. More education focusing on the diagnosis and treatment of childhood OSAS and identifying children at risk for OSAS is recommended.

Development of the obstructive sleep apnea knowledge and attitudes (OSAKA) questionnaire

STUDY OBJECTIVES

To develop and validate a questionnaire that assesses physicians' knowledge and attitudes about obstructive sleep apnea (OSA): the Obstructive Sleep Apnea Knowledge and Attitudes (OSAKA) questionnaire.

DESIGN

Questionnaire study.

SETTING

Physicians associated with the Washington University Physicians Network.

PARTICIPANTS

Twenty physicians in the pilot testing and 115 physicians in the final testing of the instrument.

INTERVENTIONS

Physicians completed the OSAKA questionnaire containing sections regarding knowledge about OSA (18 items), attitudes about OSA (five items), and demographics of the study participants.

MEASUREMENTS AND RESULTS

Knowledge scores ranged from 0 to 18 (mean+/-SD=13.3+/-2.8). Individual knowledge items did not differ significantly by gender or by whether or not respondents had completed subspecialty training. The five attitude items were significantly correlated with one another. Knowledge scores correlated with the 5-item attitude scale. There was a negative correlation between age and knowledge (r=-0.368, P<0.001) and between age and the single attitude item pertaining to physicians' confidence in managing patients with OSA (r=-0.198, P=0.036); thus, the older the respondent, the lower the knowledge score and the less confident they were in managing patients with OSA.

CONCLUSIONS

The OSAKA appears to be a useful instrument to measure physicians' knowledge about OSA, their views on its importance as a clinical disorder, and their confidence in identifying and managing patients with this disorder.

Quantitative magnetic resonance imaging demonstrates alterations of the lingual musculature in obstructive sleep apnea

Upper airway musculature is important in the pathogenesis of obstructive sleep apnea. Electromyographic studies of patients with obstructive sleep apnea demonstrate increased activity of upper airway dilator muscles. Biopsy studies of these muscles show both adaptation and muscle injury. In this study we utilized quantitative magnetic resonance imaging to characterize changes in the upper airway musculature of patients with obstructive sleep apnea. This technique provides measurements of the T2 relaxation times of upper airway muscles (genioglossus, geniohyoid, sternohyoid/sternothyroid) spatially localized to submillimeter resolution. Our results demonstrate that the mean T2 values of genioglossus (p = 0.04) and geniohyoid (p = 0.06) differ between the apneic and control groups, while the values for the sternohyoid/sternothyroid muscles (p = 0.6) are similar between groups. In both apneics and normals respectively the T2 values for the genioglossus (p = 0.0003, 0.0001) and geniohyoid (p = 0.0054, 0.001) were significantly greater than for the sternohyoid/sternothyroid muscles. The changes observed are compatible with the hypothesis that there is increased edema and possibly increased fat content of the tongue muscles in patients with obstructive sleep apnea.

Quantification of cerebral ventricular volume in English bulldogs

Quantitative measurement of cerebral ventricle volume of eight English bulldogs was performed using magnetic resonance (MR) imaging. The mean ventricular volume was 14.8 ml. with a range of 8.6 ml.-38.1 ml. The mean ventricular volume of two beagles was 2.2 ml with a range of 0.7 ml.-3.7 ml. The percent of intracranial volume occupied by ventricle was found to be significantly larger in bulldogs (14.0%; S.D. = 7.9%) than in beagles (Range = 1.0-4.8%). The relationship between the percent of intracranial volume occupied by ventricle and measurements of body weight, age, sex, and various measures of skull anatomy of the bulldog was also determined. The relationship between ventricular volume and neurologic dysfunction was examined. There was a possible trend between high percent of intracranial volume occupied by ventricle and low body weight. This study will serve as a pilot study for examining the relationship between ventricular volume and neurologic disease in bulldogs.

Modafinil decreases hypersomnolence in the English bulldog, a natural animal model of sleep-disordered breathing

The English bulldog is a natural model of sleep-disordered breathing (SDB). This condition is marked by 1) hypersomnolence and 2) disordered breathing episodes that are most frequent and severe during rapid eye movement (REM) sleep. Modafinil has been found to increase arousal levels in animals and decrease excessive daytime sleepiness in humans. Therefore, in this study we focused mainly on the effects of the drug on total sleep time and sleep latency and secondarily assessed its effect on REM SDB. Five English bulldogs were implanted with subcutaneous electroencephalographic/electrooculographic (EEG/EOG) electrodes and instrumented with respiratory oscillation belts to measure abdominal and rib cage movements and an ear oximeter to measure saturation. The dogs were studied for approximately 8 hours each subsequent day on two consecutive days. On the first day, they received the vehicle dimethyl sulfoxide (DMSO) i.v. as a control. On the following day they received 10 mg/kg body weight of modafinil i.v. dissolved in the DMSO vehicle. Our findings indicate that modafinil significantly alleviates hypersomnolence (p < 0.05) in the bulldog, as evidenced by dramatically decreased mean total sleep time (from a control value of 50.5% to 8.3% with the drug) and increased mean sleep latency (from a control value of 71.0 minutes to a value of 346.6 minutes with the drug). We obtained limited data on the effect of modafinil on SDB because the drug either greatly diminished or entirely eradicated REM sleep in all five dogs.

Quantitative magnetic resonance imaging of upper airways musculature in an animal model of sleep apnea

Electromyographic studies of patients with sleep apnea and of the English bulldog, an animal model of sleep apnea, indicate that there is increase activity of the airways dilator muscles. The muscles, when biopsied, show both adaptation and muscle injury. In this study we have utilized quantitative magnetic resonance imaging to characterize changes in the upper airway musculature of the bulldog in vivo. The imaging procedure utilized provided a quantitative measurement of the T2 relaxation times of airway muscle (geniohyoid, sternohyoid, sternothyroid, thyropharyngeus, and hyopharyngeus) and nonairway muscles spatially localized to submillimeter-resolution levels. Quantitative differences between the medians and distributions of T2 relaxation times of airway vs. nonairway muscles were demonstrated. These differences were related to the degree of sleep-disordered breathing. The changes observed are compatible with the hypothesis that there is both increased edema and fibrosis in upper airway muscle in sleep apnea.

Neurofibromatosis 1 and osseous fibrous dysplasia in a family

We report on the cosegregation of neurofibromatosis 1 (NF 1) and osseous fibrous dysplasia in a family. The father and 3 children by 2 women are affected. A fourth child had neither NF 1 nor osseous fibrous dysplasia. All 4 affected individuals had NF 1, i.e., café-au-lait spots in 4, neurofibromata in 4, Lisch nodules in 3, macrocrania in 3, scoliosis in 2, and curvature of the long bones in 2. Each demonstrated various fibroosseous lesions of the skeleton including non-ossifying fibromas in 3 and both non-ossifying fibromas and fibrous dysplasia in one. This pattern suggests that the fibrous bony lesions are a component of NF 1 in this family. Alternatively, a mutant gene resulting in the fibrous changes in bone could be linked to the gene for NF 1. Another possibility is the coincidence of the 2 non-linked traits segregating in the same family.