Obstructive Respiratory Events Research Articles

0788 Effect of Sleep State and Position on Obstructive Respiratory Events in 12 - 24-month-old Toddlers

0788 Effect of Sleep State and Position on Obstructive Respiratory Events in 12 - 24-month-old Toddlers

0915 Actual Condition Survey of Obstructive Respiratory Events in Convalescent Post-stroke Patients with Dysphagia

0915 Actual Condition Survey of Obstructive Respiratory Events in Convalescent Post-stroke Patients with Dysphagia

Prevalence and predictors of sleep bruxism in patients withobstructive sleep apnea and the effect of positive airway pressure treatment.

Sleep bruxism (SB) is often found to co-exist with obstructive sleep apnea (OSA). However, there are no data on prevalence and risk factors of SB in patients withOSA patients regarding the effect of optimal positive airway pressure (PAP). This study aimed to study prevalence and risk factors of SB in OSA and to compare SB episodes during pre-treatment versus during optimal PAP therapy. This investigation was a retrospective study including randomly selected patients with OSA who underwent split-night polysomnography. Data were collected from August 2021 to October 2022. Clinical demographic data and SB data were analyzed. The association between SB episodes and obstructive respiratory events were manually reviewed. If most of the SB episodes were observed within 5s following obstructive respiratory events, SB was defined as SB associated with OSA. Comparison of SB index (SBI) was made between baseline portion of the study versus during optimal PAP. Among 100 patients enrolled, mean age was 50.8 ± 16.7yearsand 73 subject (73%) were male. Mean respiratory disturbance index (RDI) and mean nadir oxygen saturation were 52.4 ± 33.4 and 79.3 ± 11.2% respectively. During the baseline portion of the study, 49 patients (49%) had SBand 31 patients (31%) had severe SB (SBI ≥ 4). Sleep bruxism associated with OSA was observed in 73.5% of all SB. The risk factor for SB was endorsement ofnocturnal tooth grinding (odds ratio (OR) 5.69, 95%CI 1.74-18.58). Risk factors for severe bruxism were male sex (OR 4.01, 95%CI 1.02-15.88) and endorsementofnocturnal tooth grinding (OR 9.63, 95%CI 2.54-36.42). Risk factors for SB associated with OSA were non-supine RDI (OR 1.02, 95%CI 1.001-1.034) and endorsement ofnocturnal tooth grinding (OR 5.4, 95%CI 1.22-23.93). In SB group, when comparison was made between baseline portion and during optimal PAP, significant reduction of SBI was observed (5.5 (3.2, 9.3) vs. 0 (0, 2.1), p < 0.001). Median difference of SBI between baseline portion and during optimal PAP was 4.4 (2.0, 8.3) (p < 0.001). In this group of patients with OSA, almost half was observed to have SB in which the majority were associated with OSA. Optimal PAP resulted in a significant reduction in SB episodes. In addition to endorsement of nocturnal tooth grinding, non-supine RDI was observed to be a potential risk factor for SB associated with OSA.

Inhibition of the acetylcholine-regulated potassium current prevents transient apnea-related atrial arrhythmogenic changes in a porcine model

BackgroundMore than 50% of patients with atrial fibrillation (AF) suffer from sleep disordered breathing (SDB). Obstructive respiratory events contribute to a transient, vagally mediated atrial arrhythmogenic substrate, which is resistant to most available antiarrhythmic drugs. ObjectiveThe purpose of this study was to investigate the effect of pharmacologic inhibition of the G-protein–gated acetylcholine-regulated potassium current (IK,ACh) with and without acute autonomic nervous system activation by nicotine in a pig model for obstructive respiratory events. MethodsIn 21 pigs, SDB was simulated by applying an intermittent negative upper airway pressure (INAP). AF inducibility and atrial effective refractory periods (aERPs) were determined before and during INAP by an S1S2 atrial pacing-protocol. Pigs were randomized into 3 groups—group 1: vehicle (n = 4); group 2: XAF-1407 (IK,ACh inhibitor) (n = 7); and group 3: nicotine followed by XAF-1407 (n = 10). ResultsIn group 1, INAP shortened aERP (ΔaERP –42.6 ms; P = .004) and transiently increased AF inducibility from 0% to 31%. In group 2, XAF-1407 prolonged aERP by 25.2 ms (P = .005) during normal breathing and prevented INAP-induced aERP shortening (ΔaERP –3.6 ms; P = .3) and AF inducibility. In group 3, INAP transiently shortened aERP during nicotine perfusion (ΔaERP –33.6 ms; P = .004) and increased AF inducibility up to 61%, which both were prevented by XAF-1407. ConclusionSimulated obstructive respiratory events transiently shorten aERP and increase AF inducibility, which can be prevented by the IK,ACh-inhibitor XAF-1407. XAF-1407 also prevents these arrhythmogenic changes induced by obstructive respiratory events during nicotine perfusion. Whether IK,ACh channels represent a target for SDB-related AF in humans warrants further study.

Obstructive Sleep Apnea and Smoking Increase the Risk of Cardiovascular Disease: Smoking Cessation Pharmacotherapy.

Tobacco smoking has been a recognized risk factor for cardiovascular diseases (CVD). Smoking is a chronic relapsing disease and pharmacotherapy is a main component of smoking cessation. Obstructive sleep apnea (OSA) and smoking both increase the risk of CVD and are associated with significant morbidity and mortality. There are few existing data examining how pharmacological treatment, such as nicotine replacement therapy (NRT), bupropion, and varenicline, affect smokers suffering with OSA and especially their cardiovascular effects. The aim of this review was to evaluate the effects of smoking cessation pharmacotherapy on OSA with a special emphasis on the cardiovascular system. Results: Only small studies have assessed the effect of NRTs on OSA. Nicotine gum administration showed an improvement in respiratory events but with no permanent results. No specific studies were found on the effect of bupropion on OSA, and a limited number evaluated varenicline's effects on sleep and specifically OSA. Varenicline administration in smokers suffering from OSA reduced the obstructive respiratory events, especially during REM. Studies on second-line medication (nortriptyline, clonidine, cytisine) are even more limited. There are still no studies evaluating the cardiovascular effects of smoking cessation medications on OSA patients. Conclusions: Sleep disturbances are common withdrawal effects during smoking cessation but could be also attributed to pharmacotherapy. Smokers should receive personalized treatment during their quitting attempts according to their individual needs and problems, including OSA. Future studies are needed in order to evaluate the efficacy and safety of smoking cessation medications in OSA patients.

O040 Assessment of Heart Rate Variability During Respiratory Events and Arousals Using Symbolic Dynamics

Abstract Introduction Beat-to-beat heart rate dynamics vary during obstructive respiratory events and in both respiratory and spontaneous arousals. However, conventional quantifications of heart rate variability (HRV) require segments of data substantially longer than the typical respiratory event or arousal. Subsequently, previous studies investigating dynamics in these significantly shorter segments have utilised simple quantifications such as peak heart rate. This study aimed to more-richly characterise HRV during obstructive respiratory events and arousals using symbolic dynamics. Methods One hundred individuals with suspected obstructive sleep apnoea (55 male, 57.1±12.9 years) were studied with diagnostic polysomnography, including electrocardiography. R-wave intervals were calculated and extracted during respiratory events terminating with/without arousals and during spontaneous and respiratory arousals. The symbolic dynamics tool “heart rate fragmentation” was applied to quantify HRV during the events, whereby the percentage of inflection points (PIP), defined as beat-to-beat transitions from heart-rate acceleration to heart-rate deceleration, were calculated. Statistical analysis was conducted with the Wilcoxon rank sum test. Results PIP was higher during respiratory events terminated with arousal compared with those without arousal (52.9±6.4% vs. 48.5±6.7%, P&amp;lt;0.05). PIP was also higher during spontaneous arousals than during respiratory arousals (51.3±6.1% vs. 45.8±6.7%, P&amp;lt;0.05). Discussion Previous mechanistic experiments have associated increased PIP with greater parasympathetic activity. Thus, our preliminary results suggest greater parasympathetic activity during respiratory events terminated by arousal than those without; and during spontaneous arousals compared with respiratory arousals. Further work is required to understand the pathophysiology underlying this and other similar metrics, potentially leading to novel obstructive sleep apnoea-related cardiorespiratory pathology biomarkers.

O070 Prevalence of central sleep apnoea in people with tetraplegic spinal cord injury: a retrospective analysis of research and clinical data

Abstract Study Objectives Over 80% of people with tetraplegia have sleep disordered breathing, but whether this is predominantly obstructive or central is unclear. This study aimed to estimate the prevalence of central sleep apnoea (CSA) in tetraplegia and the contributions of central, obstructive and hypopnoea respiratory events to sleep disordered breathing summary indices in tetraplegia. Methods Research and clinical data from 606 individuals with tetraplegia and full overnight polysomnography were collated. The proportions of different respiratory event types were calculated; overall and for mild, moderate, and severe disease. The prevalence of Predominant CSA (central apnoea index 5 and more central than obstructive apnoeas) and Any CSA (central apnoea index  5) was estimated. Prevalence of sleep-related hypoventilation was estimated in a clinical sub-cohort. Results Respiratory events were primarily hypopnoeas (71%), followed by obstructive (23%), central (4%) and mixed apnoeas (2%). As severity increased, the relative contribution of hypopnoeas and central apnoeas decreased, while that of obstructive apnoeas increased. The prevalence of Predominant CSA and Any CSA were 4.3% (26/606) and 8.4% (51/606) respectively. Being male, on opiates and having a high tetraplegic spinal cord injury were associated with CSA. Sleep-related hypoventilation was identified in 26% (26/113) of the clinical sub-cohort. Conclusions This is the largest study to characterize sleep disordered breathing in tetraplegia. It provides strong evidence that obstructive sleep apnoea is the predominant sleep disordered breathing type; 9-18 times more prevalent than CSA. The prevalence of CSA was estimated to be 4-8%, significantly lower than previously reported.

O018 Improvement in Obstructive Sleep Apnoea Improves Heart Rate response to Obstructive Respiratory events in Children with Down syndrome.

Abstract Background Children with Down syndrome (DS) have a much higher predisposition to obstructive sleep apnoea (OSA) compared to typically developing (TD) children. Children with DS have a lower heart rate (HR) response to respiratory event termination compared with TD children matched for age, sex and OSA severity, but the effect of improvement in OSA severity over time or with treatment is unknown. We compared the HR surge at event termination in children with DS with improved OSA to those with unimproved OSA 2 y following baseline study. Methods 24 children (3-19 y at baseline) were included. Children were grouped into Improved (decrease in obstructive apnoea hypopnoea index (OAHI) to ≤ 50% of baseline OAHI; n=12; 7 treated between studies) and Unimproved (n=12; 2 treated between studies). Beat-to-beat HR was averaged 10s before (pre), during and the peak after (post) each obstructive event during sleep, and expressed as percentage change. Results 583 obstructive events at baseline and 435 at follow up were identified. % change in HR from during the event to post event was greater at follow up (mean±sem, 22.4%±0.9%) than baseline (19.0%±0.8%; p&amp;lt;0.01) in the improved group, but reduced at follow up (16.8%±1.1%) compared with baseline (21.1%±0.7%; p&amp;lt;0.001) in the unimproved group and was greater at follow up in the improved group than in the unimproved group (p&amp;lt;0.001). Conclusion These results suggest that the dampened HR response to events seen in DS is reversible, adding weight to the need for diagnosis and management of OSA in this population.

Impact of sleep-disordered breathing on overnight changes in arterial stiffness in patients with acute heart failure.

Overnight increases in arterial stiffness associated with sleep-disordered breathing may adversely affect patients with acute heart failure. Thus, we investigated overnight changes in arterial stiffness and their association with sleep-disordered breathing in patients hospitalized for acute heart failure. Consecutive patients with acute heart failure were enrolled. All participants underwent overnight full polysomnography following the initial improvement of acute signs and symptoms of acute heart failure. The arterial stiffness parameter, cardio-ankle vascular index (CAVI), was assessed before and after polysomnography. Overall, 60 patients (86.7% men) were analyzed. CAVI significantly increased overnight (from 8.4 ± 1.6 at night to 9.1 ± 1.7 in the morning, P < 0.001) in addition to systolic and diastolic blood pressure (from 114.1 mmHg to 121.6 mmHg, P < 0.001; and from 70.1 mmHg to 78.2 mmHg, P < 0.001, respectively). Overnight increase in CAVI (ΔCAVI ≥ 0) was observed in 42 patients (70%). The ΔCAVI ≥ 0 group was likely to have moderate-to-severe sleep-disordered breathing (i.e., apnea-hypopnea index ≥15, 55.6% vs 80.9%, P = 0.047) and greater obstructive respiratory events (29.4% vs 58.5%, P = 0.041). In multivariable analysis, moderate-to-severe sleep-disordered breathing and greater obstructive respiratory events were independently correlated with an overnight increase in CAVI (P = 0.033 and P = 0.042, respectively). In patients hospitalized for acute heart failure, arterial stiffness, as assessed by CAVI, significantly increased overnight. Moderate-to-severe sleep-disordered breathing and obstructive respiratory events may play an important role in the overnight increase in cardio-ankle vascular index.

Prevalence of central sleep apnea in people with tetraplegic spinal cord injury: a retrospective analysis of research and clinical data.

Over 80% of people with tetraplegia have sleep-disordered breathing (SDB), but whether this is predominantly obstructive or central is unclear. This study aimed to estimate the prevalence of central sleep apnea (CSA) in tetraplegia and the contributions of central, obstructive, and hypopnea respiratory events to SDB summary indices in tetraplegia. Research and clinical data from 606 individuals with tetraplegia and full overnight polysomnography were collated. The proportions of different respiratory event types were calculated; overall and for mild, moderate, and severe disease. The prevalence of Predominant CSA (Central Apnea Index [CAI] ≥ 5 and more central than obstructive apneas) and Any CSA (CAI ≥ 5) was estimated. Prevalence of sleep-related hypoventilation (SRH) was estimated in a clinical sub-cohort. Respiratory events were primarily hypopneas (71%), followed by obstructive (23%), central (4%), and mixed apneas (2%). As severity increased, the relative contribution of hypopneas and central apneas decreased, while that of obstructive apneas increased. The prevalence of Predominant CSA and Any CSA were 4.3% (26/606) and 8.4% (51/606) respectively. Being male, on opiates and having a high tetraplegic spinal cord injury were associated with CSA. SRH was identified in 26% (26/113) of the clinical sub-cohort. This is the largest study to characterize SDB in tetraplegia. It provides strong evidence that obstructive sleep apnea is the predominant SDB type; 9-18 times more prevalent than CSA. The prevalence of CSA was estimated to be 4%-8%, significantly lower than previously reported.

Prevalence, associated risk factors, and respiratory event distribution of obstructive sleep apnea in children with Down syndrome.

Children with Down Syndrome (DS) have a high prevalence of obstructive sleep apnea (OSA). We aimed to assess OSA prevalence in a single center cohort of children with DS, identify associated risk factors of obstructive respiratory events, and examine the influence of different sleep stages and body positions on respiratory events distribution. Single center retrospective study that included children with DS who underwent overnight polysomnogram (PSG). OSA severity was categorized by obstructive apnea-hypopnea index (OAHI) as mild (1.5-4.9 events/h), moderate (5-9.9 events/h), and severe (≥ 10 events/h). A logistic regression analysis was used to examine the association between OSA-related risk factors in normal and abnormal OAHI category and in REM and Non-REM predominant AHI groups. PSG data were available for 192 children with a median age of 5years (IQR 7). OSA prevalence was 82.3% (27.1% mild, 19.8% moderate, and 35.4% severe). A logistic regression model identified BMI and being an African American as significant predictors for OAHI severity. In children with OSA, the median OAHI was 7.6 and obstructive respiratory events were more common in REM sleep and in thesupine position. The median REM OAHI was 20 events/h (IQR: 24.4), whereas the median Non-REM OAHI was 5.2 events/h (IQR: 12.6 p < 0.0001). Similarly, supine OAHI was 11.6 (IQR: 19.3) and off supine OAHI was 6.6 (IQR: 11.6, p = 0.0004). Age was a significant predictor (p = 0.012) for Non-REM predominant OSA which was present in 15.2% of children with OSA. Children with DS have a high prevalence of OSA. Higher BMI and being an African American were significant associated risk factors for higher OAHI. Obstructive respiratory events in children with DS occur predominantly in REM sleep and in thesupine position. Non-REM predominant distribution of respiratory events was noted in older children with DS.

The impact of central and obstructive respiratory events on cerebral oxygenation in adults with sleep disordered breathing

Obstructive sleep apnea (OSA) and central sleep apnea (CSA) are two main types of sleep disordered breathing (SDB). While the changes in cerebral hemodynamics triggered by OSA events have been well studied using near-infrared spectroscopy (NIRS), they are essentially unknown in CSA in adults. Therefore, in this study, we compared the changes in cerebral oxygenation between OSA and CSA events in adult patients using NIRS. Cerebral tissue oxygen saturation (StO2) in 13 severe SDB patients who had both CSA and OSA events was measured using frequency-domain NIRS. The changes in cerebral StO2 desaturation and blood volume (BV) in the first hour of natural sleep were compared between different types of respiratory events (i.e., 277 sleep hypopneas, 161 OSAs and 113 CSAs) with linear mixed-effect models controlling for confounders. All respiratory events occurred during non-rapid eye movement (NREM) sleep. We found that apnea events induced greater cerebral desaturations and BV fluctuations compared to hypopneas, but there was no difference between OSA and CSA. These results suggest that cerebral autoregulation in our patients are still capable to counteract the pathomechanisms of apneas, in particularly the negative intrathoracic pressure (ITP) caused by OSA events. Otherwise larger BV fluctuations in OSA compared to CSA should be observed due to the negative ITP that reduces cardiac stroke volume and leads to lower systematic blood supply. Our study suggests that OSA and CSA may have similar impact on cerebral oxygenation during NREM sleep in adult patients with SDB.

Mechanisms underlying the prolonged activation of the genioglossus following arousal from sleep.

Transient arousal from sleep has been shown to elicit a prolonged increase in genioglossus muscle activity that persists following the return to sleep and which may protect against subsequent airway collapse. We hypothesized that this increased genioglossal activity following return to sleep after an arousal is due to persistent firing of inspiratory-modulated motor units (MUs) that are recruited during the arousal. Thirty-four healthy participants were studied overnight while wearing a nasal mask with pneumotachograph to measure ventilation and with 4 intramuscular genioglossus EMG electrodes. During stable N2 and N3 sleep, auditory tones were played to induce brief (3-15s) AASM arousals. Ventilation and genioglossus MUs were quantified before the tone, during the arousal and for 10 breaths after the return to sleep. A total of 1089 auditory tones were played and gave rise to 239 MUs recorded across arousal and the return to sleep in 20 participants (aged 23 ± 4.2 years and BMI 22.5 ± 2.2 kg/m2). Ventilation was elevated above baseline during arousal and the first post-arousal breath (p < .001). Genioglossal activity was elevated for five breaths following the return to sleep, due to increased firing rate and recruitment of inspiratory modulated MUs, as well as a small increase in tonic MU firing frequency. The sustained increase in genioglossal activity that occurs on return to sleep after arousal is primarily a result of persistent activity of inspiratory-modulated MUs, with a slight contribution from tonic units. Harnessing genioglossal activation following arousal may potentially be useful for preventing obstructive respiratory events.

Characterization of craniofacial-based clinical phenotypes in children with suspected obstructive sleep apnea.

We conducted this study to identify phenotypes of obstructive sleep apnea (OSA) in children based on lifestyle, sleep habits, age, obesity, sex, soft tissue facial features, and specific craniofacial abnormalities. Seventy-three children with symptoms of pediatric OSA who underwent overnight observed polysomnography participated in this study. Soft tissue facial features were assessed using a 3-dimensional stereophotogrammetric system. Craniofacial abnormalities were evaluated based on the most common facial features associated with orthodontic treatment needs. Data regarding lifestyle, sleep habits, age, obesity, and sex were also collected. To identify phenotypes of OSA, a sequential analysis was then performed on categories of variables using fuzzy clustering with medoids. Craniofacial abnormalities and soft tissue facial features defined clusters. Three clusters were identified. Cluster 1 comprised a group of younger children (5.9 ± 3.8 years) without obesity, without craniofacial abnormalities, and with smaller soft tissue facial features dimensions. Cluster 2 comprised a group of older children (9.6 ± 3.9 years) without obesity and with larger mandibular dimensions and mildly arched palates (71.4%). Cluster 3 comprised a group of older children (9.2 ± 3.9 years) with obesity and a history of health issues (68.4%), excessive lower facial height (63.2%), and midface deficiency (73.7%). No differences were observed across clusters regarding sleep features. A moderate severity of obstructive and mixed respiratory events was observed in all 3 clusters. The study results did not identify distinct phenotypes of pediatric OSA based on soft tissue facial features or craniofacial abnormalities alone. Age and body mass index likely modify the effect of soft tissue facial features and craniofacial abnormalities as risk factors for OSA in children. Fernandes Fagundes NC, Loliencar P, MacLean JE, Flores-Mir C, Heo G. Characterization of craniofacial-based clinical phenotypes in children with suspected obstructive sleep apnea. J Clin Sleep Med. 2023;19(11):1857-1865.

Time Spent with Saturation below 80% versus 90% in Patients with Obstructive Sleep Apnoea.

Nocturnal hypoxaemia measured as the percentage of total sleep time spent with saturation below 90% (TST90%) may better predict cardiovascular consequences of obstructive sleep apnoea (OSA) than the number of obstructive respiratory events measured with the apnoea-hypopnea index (AHI). Deeper hypoxaemia may potentially induce more severe pathophysiological consequences. However, the additional value of the percentage of total sleep time spent with saturation below 80% (TST80%) to TST90% is not fully explored. Comprehensive medical history was taken and fasting lipid and C-reactive protein levels were measured in 797 volunteers participating in two cohort studies in Hungary and Romania. Sleep parameters, including AHI, TST90% and TST80%, were recorded following a polysomnography (PSG, n = 598) or an inpatient cardiorespiratory polygraphy (n = 199). The performance of TST80% to predict cardiovascular risk was compared with TST90% using linear and logistic regression analyses as well receiver operating characteristics curves. Sensitivity analyses were performed in patients who had PSG, separately. Both parameters are significantly related to cardiovascular risk factors; however, TST80% did not show better predictive value for cardiovascular risk than TST90%. On the other hand, patients with more severe hypoxaemia reported more excessive daytime sleepiness. TST80% has limited additional clinical value compared to TST90% when evaluating cardiovascular risk in patients with OSA.

Respiratory Event-Induced Blood Pressure Oscillations Vary by Sleep Stage in Sleep Apnea Patients.

Obstructive sleep apnea (OSA) pathologically stresses the cardiovascular system. Apneic events cause significant oscillatory surges in nocturnal blood pressure (BP). Trajectories of these surges vary widely. This variability challenges the quantification, characterization, and mathematical modeling of BP surge dynamics. We present a method of aggregating trajectories of apnea-induced BP surges using a sample-by-sample averaging of continuously recorded BP. We applied the method to recordings of overnight BP (average total sleep time: 4.77 ± 1.64 h) for 10 OSA patients (mean AHI: 63.5 events/h; range: 18.3-105.4). We studied surges in blood pressure due to obstructive respiratory events separated from other such events by at least 30 s (274 total events). These events increased systolic (SBP) and diastolic (DBP) BP by 19 ± 7.1 mmHg (14.8%) and 11 ± 5.6 mmHg (15.5%), respectively, relative to mean values during wakefulness. Further, aggregated SBP and DBP peaks occurred on average 9 s and 9.5 s after apnea events, respectively. Interestingly, the amplitude of the SBP and DBP peaks varied across sleep stages, with mean peak ranging from 128.8 ± 12.4 to 166.1 ± 15.5 mmHg for SBP and from 63.1 ± 8.2 to 84.2 ± 9.4 mmHg for DBP. The aggregation method provides a high level of granularity in quantifying BP oscillations from OSA events and may be useful in modeling autonomic nervous system responses to OSA-induced stresses.

0814 Obstructive sleep apnea in asthmatic children: highly prevalent though no identifiable risk factors

Abstract Introduction Obstructive sleep apnea (OSA) and Asthma often coexist. There is some evidence that adults with asthma are more prone to developing OSA than the general population, as well as OSA may impact asthma control. Different than adults, OSA prevalence is equal in boys and girls, while puberty has strong influence in asthma, especially in pubescent girls. The objectives of this study were to analyze the prevalence of OSA in boys and girls and the impact of asthma severity in OSA prevalence. Methods Asthmatic children attending a tertiary pediatric pulmonology clinic performed clinical evaluation, Pulmonary Function Test, and Home Sleep Apnea Test. OSA was defined as habitual snoring and one or more obstructive respiratory events (OREI) per hour of recording. Control and severity of Asthma were evaluated according to Global Initiative for Asthma and puberal stage using Tanner figures for boys and girls Results We studied 80 consecutive patients, 7 to 18 years-old, mean age 11.6 years (SD: 2.7), 51.3% female. According to BMI z-score, nutritional status was: 2 (2.5%) underweight, 63 eutrophic (79%), and 15 obese (18.5%). Puberty was present in 17 volunteers. Pulmonary Function Tests were obtained from 71 volunteers, 45% presented obstruction pattern. Home Sleep Apnea Tests were available from 76 volunteers, with mean OREI of 1.8 events/h. OSA occurred in 69 volunteers (91%), while 66% were mild, 21% moderate, and 4% severe. We did not find associations of obstructive sleep apnea with sex or asthma severity. Conclusion OSA was highly prevalent among these asthmatic children, but most were mild. Sex and asthma severity were not associated to OSA. Considering the interrelationship of both diseases, it is worth to keep in mind the possibility of OSA among children and teenagers with asthma. Support (if any) AFIP (Associação Fundo de Incentivo à Pesquisa) and CNPq (Conselho Nacional de Pesquisas)

Description of a novel method for detection of sleep-disordered breathing in brachycephalic dogs.

Sleep-disordered breathing (SDB), defined as any difficulty in breathing during sleep, occurs in brachycephalic dogs. Diagnostic methods for SDB in dogs require extensive equipment and laboratory assessment. To evaluate the usability of a portable neckband system for detection of SDB in dogs. We hypothesized that the neckband is a feasible method for evaluation of SDB and that brachycephaly predisposes to SDB. Twenty-four prospectively recruited client-owned dogs: 12 brachycephalic dogs and 12 control dogs of mesocephalic or dolicocephalic breeds. Prospective observational cross-sectional study with convenience sampling. Recording was done over 1 night at each dog's home. The primary outcome measure was the obstructive Respiratory Event Index (OREI), which summarized the rate of obstructive SDB events per hour. Additionally, usability, duration of recording, and snore percentage were documented. Brachycephalic dogs had a significantly higher OREI value (Hodges-Lehmann estimator for median difference = 3.5, 95% confidence interval [CI] 2.2-6.8; P < .001) and snore percentage (Hodges-Lehmann estimator = 34.2, 95% CI 13.6-60.8; P < .001) than controls. A strong positive correlation between OREI and snore percentage was detected in all dogs (rs = .79, P < .001). The neckband system was easy to use. Brachycephaly is associated with SDB. The neckband system is a feasible way of characterizing SDB in dogs.

1018 Finally Awake: Treatment of Severe REM-Isolated Obstructive Sleep Apnea

Abstract Introduction Obstructive sleep apnea (OSA) is typically treated with positive airway pressure (PAP) therapy in symptomatic patients with ≥ 5 obstructive respiratory events (apneas, hypopneas or respiratory effort related arousals) per hour of sleep. In this case, we present a patient with severe OSA isolated to REM sleep who demonstrated significant symptomatic improvement on PAP therapy, despite an overall apnea-hypopnea index (AHI) of less than 5 events/hour. Report of case(s) A 73-year-old obese male with history of SVT, hypertension, and diabetes presented with symptoms of snoring, witnessed apneas, non-restorative sleep, restless sleep, excessive daytime sleepiness, and fatigue. A baseline polysomnogram (PSG) demonstrated severe OSA exclusively in REM sleep (overall AHI 2.9, REM AHI of 37.3, minimum SpO2 of 84%). A subsequent PAP titration study tested CPAP 5-17 and BPAP 19/15 cm of water but was unable to identify an effective pressure during REM sleep. Pressures as low as CPAP 5 cm of water appeared effective in NREM sleep. Ultimately, as the patient was unwilling to undergo a re-titration study, empiric treatment with auto-BPAP (min EPAP 5, max IPAP 25, PS 4) was initiated. With excellent adherence to BPAP therapy, the patient experienced profound symptomatic benefit, with resolution of daytime symptoms, less restlessness during sleep, and more restorative sleep. Conclusion This case highlights a gap, and potential pitfall, in current practice. Our patient 1) did not meet the overall AHI criteria for diagnosis of OSA yet had typical symptoms and high pretest probability for OSA; 2) had a PSG which showed severe OSA exclusively during REM sleep; and 3) experienced resolution of symptoms with PAP therapy. Presently, there is no consensus on whether REM-dependent OSA should be treated if the overall AHI is &amp;lt; 5 events/hour. In fact, there is no standardized definition for REM-dependent OSA. This patient with cardiovascular risk factors was able to receive PAP therapy through the Veterans’ Affairs, and access to PAP therapy changed the Veteran’s quality of life dramatically. Obtaining a PAP device for this patient through private payors would have been nearly impossible. More research is needed to understand the clinical implications of this condition. Support (if any)  

0526 Effect of Body Position and Sleep State on Sleep Disordered Breathing Distribution in Infants Ages 6 to 12 months

Abstract Introduction The effect of body position and sleep state on events distribution in infants ages 6 to 12 months needs further study. We aimed to study this distribution and determine the difference of body position in infants with and without sleep disordered breathing. Methods This was a single center, retrospective study that included infants ages 6 to 12 months who were evaluated for suspected sleep disordered breathing and underwent a full overnight polysomnography in an academic sleep disorders center over a period of 10 years. Infants with ages 6 to 12 months with obstructive sleep apnea hypopnea index (OAHI) and central apnea index (CAI) ≥ 1 (sleep disordered breathing [SDB] group) were compared with infants with normal AHI who represented the control group (CG). Total OAHI, CAI, apnea hypopnea index (AHI) in different body positions, rapid eye movement (REM), and Non-REM sleep were collected. Results A total of 36 infants had SDB and 18 infants had normal AHI. The median age was not significantly different between both groups with a median age of 10 months (IQR 7.75-11) in SDB group and 8.5 months in CG (IQR 7.25- 10.00) (p=0.258). Male sex was predominant in both groups (58.3% in SDB group and 61.1% in CG). There were no significant differences between both groups in the BMI, median total sleep time, REM% sleep time, and Non-REM% sleep time. The supine sleep time in the SDB group [258.90 minutes (IQR 149.35-381.25)] was significantly higher than the supine sleep time in the CG [165.90 minutes (IQR 54.55 to 285.05)] (p=0.035). In the SDB group, REM AHI [8.55 (IQR 5.02 – 15.25] was significantly higher than Non-REM AHI [0.50 (IQR 0.30-1.20)] (p&amp;lt; 0.001). In the SDB group, there were no significant differences in the supine vs. off-supine distribution of respiratory events. Conclusion Obstructive and central respiratory events in infants ages 6 to 12 months occurred predominantly in REM sleep compared to Non-REM sleep. Infants with SDB significantly spent more time in supine position when compared to infants without SDB but the respiratory events distribution in infants with SDB did not have a significant positional distribution. Support (if any)