Positional Obstructive Sleep Apnea Patients Research Articles

Analysis of the difference of therapeutic effect and predictive factors between postural and non-postural OSA after modified uvulopalatopharyngoplasty

Objective:To analyze the factors influencing the outcome of uvulopalatopharyngoplasty in positional obstructive sleep apnea（POSA） and non-positional OSA（NPOSA） patients, and to explore the differences between the two groups. Methods:The data of 101 patients with obstructive sleep apnea who received treatment from November 2020 to November 2023 were retrospectively analyzed. Among them, 45 positional patients（POSA group） and 56 non-positional patients（NPOSA group）, who underwent overnight polysomnography were included. The upper airway（UA） anatomy was evaluated by three-dimensional computer tomography（3D-CT）. All patients received revised uvulopalatopharyngoplasty with uvula preservation and were followed using polysomnography for at least three months postoperatively. Results:The overall effective rate was 55.45%. The surgical success rate in POSA undergoing UPPP was higher than NPOSA（POSA 30/45, 66.7% versus NPOSA 26/56, 46.4%, P=0.042）. The H-UPPP effect of POSA was negatively correlated with the minimum lateral airway of the Velopharyngeal airway（r=-0.505, P<0.001）, the minimum lateral airway of the glossopharyngeal airway（r=-0.474, P=0.001） and the minimum cross-sectional area（r=-0.394, P=0.007）. Logistic analysis showed that minimal lateral airway of the glossopharynxgeum（mLAT）（OR 0.873; 95%CI 0.798-0.955, P=0.003） was a significant predictor for surgical outcomes among POSA patients. In NPOSA, age（OR 0.936; 95%CI 0.879-0.998, P=0.042） was a significant predictor for surgical outcomes. Conclusion:The effect of H-UPPP was higher in POSA than in NPOSA. The width of glossopharyngeal mLAT was an important predictor of POSA efficacy. Age was a predictor of NPOSA efficacy.

Effectiveness of Mandibular Advancement Devices in Positional OSA Patients: A Retrospective Analysis of Predictive Variables in a Sample of Adult Patients.

Objectives To evaluate the efficacy of mandibular advancement devices (MADs) in improving apnea-hypopnea index (AHI) in positional obstructive sleep apnea (POSA), compared with a control group of nonpositional OSA (NPOSA) patients, from mild to very severe degree, in order to to find the main variables characterizing the examined group as potential predictors of treatment success. Materials and Methods In the present observational study, we retrospectively collected polysomnographic records of 39 positional adult patients, divided into 30 supine isolated OSA (siOSA) and 9 supine predominant OSA (spOSA) undergoing MADs from 2003 to 2019, and compared with those of a control group of 47 NPOSA patients. Demographics and anthropometrical data, home sleep apnea test (HSAT) records, drug-induced sleep endoscopy (DISE) results, and dental casts evaluation were analyzed pre- and post-treatment with MADs. Results A prevalence of the male sex (86%), mean age of 49,4 ± 14.98 years, and mean body mass index (BMI) of 26.74 ± 4.29 kg/m 2 were found among the OSA patients with significant differences between the three groups for sex and BMI. After MADs, the HSAT revealed significant reduction of AHI in all of the groups, with greater reduction of the supine AHI in POSA and significant reduction of the snore index for NPOSA. The hypopharynx section (H) of the NOHL Index, a fourth degree of hypopharyngeal collapse and an anteroposterior pattern was the most frequent to occur (19.9%) from DISE exam. No significant correlation between the initial total AHI and the dental variables was found, except for a reduced maxillary intermolar distance. Conclusion MADs are effective in reducing AHI in POSA and NPOSA patients from mild to very severe degree. Supine AHI decreased after treatment with MADs mainly in siOSA and spOSA patients compared with the NPOSA group. The snore index decreased significantly after treatment with MADs in all groups, showing the greater reduction in the NPOSA group. The tongue base (H) represented the most frequent anatomic area of collapse and there was a high prevalence of upper maxillary constriction.

Evaluating Positional Obstructive Sleep Apnea in Children: Prevalence, Characteristics, and Risk Factors.

This study investigates the prevalence, risk factors, and clinical characteristics of positional obstructive sleep apnea (POSA) among pediatric patients diagnosed with obstructive sleep apnea (OSA). A total of 1,236 children aged 0 to 17 years who underwent nocturnal polysomnography (PSG) and completed the Sleep Questionnaire were included. After excluding those with an AHI <1, neurological or muscular disorders, or insufficient sleep time in specific positions, 908 patients remained: 158 with POSA and 750 with non-positional OSA (NPOSA). Propensity score matching (PSM) was applied at a 1:2 ratio, resulting in a final sample of 153 POSA and 306 NPOSA patients. Data analyses were performed using R software (version 4.2.3). The prevalence of POSA was 12.8%. After PSM, patients with POSA had a lower overall AHI (8.66 vs 10.30), REM-AHI (14.30 vs 17.40), and NREM-AHI (7.43 vs 8.77) compared to those with NPOSA. POSA patients also had a shorter total sleep time (411 vs 427minutes), spent less time in the supine position (168 vs 225minutes), and more time in non-supine positions (241 vs 202minutes) than NPOSA patients. Additionally, while the supine AHI was higher in POSA patients (15.60 vs 10.30), the non-supine AHI was lower (5.00 vs 11.00) compared to NPOSA patients. The minimum oxygen saturation was slightly higher in POSA patients (0.88 vs 0.87). All differences were statistically significant (P < 0.05). Risk factors for POSA included mild OSA, allergic rhinitis, non-allergic rhinitis, and obesity. The prevalence of POSA in children is lower than in adults, and its severity is less than that of NPOSA. Compared to NPOSA patients, POSA patients had significantly higher AHI during supine sleep and lower AHI during non-supine sleep. POSA patients also spent more time in non-supine positions, suggesting that avoiding supine sleep may help reduce apnea events. These findings highlight the importance of monitoring and managing sleep posture in POSA patients.

Comparing the characteristics of positional and nonpositional sleep apnea patients among the Jordanian population.

Obstructive sleep apnea (OSA) is a common cause of sleep-disordered breathing with a large proportion of the patients exhibiting positional OSA (POSA). In this study, we aimed to evaluate the differences in the demographics, comorbidities, and polysomnographic features between POSA and non-POSA (NPOSA) in a Jordanian sample to further discern the propulsive elements for each group. In this study, we evaluated 1037 adult patients with OSA. POSA was defined as an overall apnea and hypopnea index (AHI) >5, an overall AHI severity at least 1.4 times the nonsupine severity (overall/NS-AHI), and a minimum amount of time (i.e., 20 min) in the supine and nonsupine positions. To compare the clinical characteristics between POSA and NPOSA patients, statistical analyses were performed. The prevalence of POSA was 41.7%. In comparison to NPOSA patients, POSA patients had higher female sex prevalence, milder OSA, lower body mass index, lower hypertension prevalence, and lower hemoglobin A1C levels compared to NPOSA patients. Moreover, sleep efficiency, total sleep time, and supine sleep time were significantly higher in POSA patients. Nonsupine sleep time, total AHI, rapid eye movement (REM) AHI, non-REM (NREM) AHI, supine AHI, nonsupine AHI, left and right AHI, mean oxyhemoglobin saturation (SpO2) awake, mean REM and NREM SpO2, SpO2 nadir, and time SpO2 below 90% were significantly lower among POSA patients. The multivariate regression analysis showed that only female gender and hypertension were significantly associated with POSA. POSA is common among OSA patients and demonstrates different clinical characteristics in comparison to NPOSA. Future prospective studies are needed to better characterize the POSA patients and investigate the benefit of positional therapy.

Prevalence, characteristics, and respiratory arousal threshold of positional obstructive sleep apnea in China: a large scale study from Shanghai Sleep Health Study cohort

PurposeTo evaluate the prevalence, characteristics, and respiratory arousal threshold (ArTH) of Chinese patients with positional obstructive sleep apnea (POSA) according to the Cartwright Classification (CC) and Amsterdam Positional Obstructive Sleep Apnea Classification (APOC).MethodsA large-scale cross-sectional study was conducted in our sleep center from 2007 to 2018 to analyze the clinical and polysomnography (PSG) data of Chinese POSA patients. Low ArTH was defined based on PSG indices.ResultsOf 5,748 OSA patients, 36.80% met the CC criteria, and 42.88% the APOC criteria, for POSA. The prevalence of POSA was significantly higher in women than men (40.21% and 46.52% vs. 36.13% and 42.18% for CC and APOC, respectively). Chinese POSA patients had a lower apnea hypopnea index (AHI) and lower oxygen desaturation index, shorter duration of oxygen saturation (SaO2) < 90%, and a higher mean SaO2 and higher lowest SaO2 value compared to subjects with non-positional OSA (NPOSA). More than 40% of the POSA patients had a low ArTH; the proportion was extremely high in the supine-isolated-POSA (si-POSA) group and APOC I group. In multivariate logistic regression analyses, higher mean SaO2 and lower AHI during sleep were positive predictors of POSA.ConclusionsAccording to the CC and APOC criteria, more than 1/3 of our Chinese subjects with OSA had POSA. Chinese POSA patients had less severe OSA and nocturnal hypoxia. Compared to NPOSA patients, significantly more patients with POSA had a low ArTH. A low ArTH may be an important endotype in the pathogenesis of POSA, especially in patients with si-POSA and APOC I. Further studies are necessary to develop personalized management strategies for POSA patients.Trial registration: Chinese Clinical Trial Registry; URL: http://www.chictr.org.cn; No. ChiCTR1900025714 (retrospectively registered).

Polysomnographic and clinical characteristics of positional obstructive sleep apnea patients

BackgroundObstructive sleep apnea is a condition characterized by the complete or partial obstruction of the upper airway during sleep. This study aimed to compare the clinical and polysomnographic characteristics of our obstructive sleep apnea patients according to their positional and non-positional features.ResultsTwo hundred eighty patients were included in the study. One hundred two patients (36.43%) were female, while 178 patients (63.57%) were male. While 88 (31.43%) of these patients were defined as positional patients, 192 (68.57%) were defined as non-positional patients. The mean age of the positional patients (46.78 ± 9.66) was lower than the mean age of the non-positional patients (50.90 ± 10.96) (p 0.001). Similarly, the mean body mass index of the positional patients (29.39 ± 3.80) was lower than the mean body mass index of the non-positional patients (33.30 ± 6.45) (p < 0.001). Neck circumference values of the positional patients (40.36 ± 2.65) were lower compared to the non-positional patients (43.32 ± 2.54) (p < 0.001).Sleep values were compared based on the presence of positional sleep apnea. In the positional patients, sleep duration, sleep efficiency (percentage), duration of stage N3, minimum, and mean saturation values were found to be higher compared to the non-positional patients, while nightlong apnea hypopnea index, apnea index, percentage of sleep time with oxygen saturation below 90%, oxygen desaturation index, mean heart rate, and periodic limb movement index values were found to be lower (p < 0.05).The rate of severe sleep apnea (7.95%) in the positional patients was lower than the non-positional patients (53.65%) (p < 0.001).ConclusionIn the light of these data, positional OSA is a very important condition presented in 31.43% of OSA patients and it was determined that these patients were younger, had less body mass index, and shorter neck circumference. The rate of severe disease was found to be lower in positional OSA patients

Risk factors for non-positional obstructive sleep apnea-hypopnea syndrome.

To explore the main risk factors for non-positional obstructive sleep apnea (NPOSA). A total of 560 patients withobstructive sleep apnea-hypopnea syndrome (OSAHS) were divided into non-positional obstructive sleep apnea (NPOSA) and positional obstructive sleep apnea (POSA) groups. All patients were assessed by the Friedman staging system and anthropometry before overnight polysomnography. Blood tests were performed to determine the fasting blood glucose level and lipid profile. Forward logistic regression analysis was performed to evaluate the effects of all parameters on positional dependency. The study sample consisted of 318 NPOSA patients and 242 POSA patients (88% and 85% were men, respectively). The mean apnea-hypopnea index (AHI) was 57.0 events/h in the NPOSA group, compared with 25.7 events/h in the POSA group. The POSA group had a significantly smaller neck circumference (NC), waist circumference (WC), hip circumference (HC), lower body mass index (BMI), AHI, fasting blood glucose, and apolipoprotein-B (apoB) levels than did the NPOSA group (all, P < 0.01). The minimal nocturnal oxyhemoglobin saturation (minSpO2) and apoB/apoA ratio were higher in the POSA group than in the NPOSA group (both, P < 0.001). The AHI, minSpO2, WC, and fasting blood glucose level were included in the logistic regression models. The AHI, WC, minSpO2, and fasting blood glucose level are the main independent risk factors for NPOSA.

Total durations of respiratory events are modulated within REM and NREM sleep by sleeping position and obesity in OSA patients

BackgroundSupine sleeping position and obesity are well-known risk factors for obstructive sleep apnea (OSA) and modulate the risk for OSA-related daytime symptoms. Although respiratory event durations are associated with OSA-related severe health consequences, it is unclear how sleeping position, obesity, and daytime sleepiness are associated with respiratory event durations during REM and NREM sleep. We hypothesize that irrespective of the apnea-hypopnea index (AHI), respiratory event durations differ significantly between various OSA subgroups during REM and NREM sleep. MethodsOne night in-lab polysomnographic recordings were retrospectively analyzed from 1910 untreated suspected OSA patients. 599 patients (AHI ≥ 5) were included in study and divided into subgroups based on positional dependency, BMI, and daytime sleepiness (Epworth Sleepiness Scale and Multiple Sleep Latency Test). Differences in total hypopnea time (THT), total apnea time (TAT), and total apnea-hypopnea time (TAHT) within REM and NREM sleep between the subgroups were evaluated. ResultsDuring REM sleep, positional OSA patients had lower THT (OR = 0.952, p < 0.001) and TAHT (OR = 0.943, p < 0.001) than their non-positional counterparts. Compared to normal-weight patients (BMI < 25 kg/m2), obese patients (BMI ≥ 30 kg/m2) had lower THT, TAT, and TAHT (ORs = 0.942–0.971, p ≤ 0.009) during NREM sleep but higher THT (OR = 1.057, p = 0.001) and TAHT (OR = 1.052, p = 0.001) during REM sleep. No significant differences were observed in THT, TAT, and TAHT between patients with and without daytime sleepiness. ConclusionRegardless of the AHI, respiratory event durations vary significantly between OSA sub-groups during REM and NREM sleep. Therefore, to personalize OSA severity estimation the diagnosis should be tailored based on patient's demographics, clinical phenotype, and PSG characteristics.

Assessment of Nocturnal Autonomic Cardiac Imbalance in Positional Obstructive Sleep Apnea. A Multiscale Nonlinear Approach.

Positional obstructive sleep apnea (POSA) is a major phenotype of sleep apnea. Supine-predominant positional patients are frequently characterized by milder symptoms and less comorbidity due to a lower age, body mass index, and overall apnea-hypopnea index. However, the bradycardia-tachycardia pattern during apneic events is known to be more severe in the supine position, which could affect the cardiac regulation of positional patients. This study aims at characterizing nocturnal heart rate modulation in the presence of POSA in order to assess potential differences between positional and non-positional patients. Patients showing clinical symptoms of suffering from a sleep-related breathing disorder performed unsupervised portable polysomnography (PSG) and simultaneous nocturnal pulse oximetry (NPO) at home. Positional patients were identified according to the Amsterdam POSA classification (APOC) criteria. Pulse rate variability (PRV) recordings from the NPO readings were used to assess overnight cardiac modulation. Conventional cardiac indexes in the time and frequency domains were computed. Additionally, multiscale entropy (MSE) was used to investigate the nonlinear dynamics of the PRV recordings in POSA and non-POSA patients. A total of 129 patients (median age 56.0, interquartile range (IQR) 44.8–63.0 years, median body mass index (BMI) 27.7, IQR 26.0–31.3 kg/m2) were classified as POSA (37 APOC I, 77 APOC II, and 15 APOC III), while 104 subjects (median age 57.5, IQR 49.0–67.0 years, median BMI 29.8, IQR 26.6–34.7 kg/m2) comprised the non-POSA group. Overnight PRV recordings from positional patients showed significantly higher disorderliness than non-positional subjects in the smallest biological scales of the MSE profile (τ = 1: 0.25, IQR 0.20–0.31 vs. 0.22, IQR 0.18–0.27, p < 0.01) (τ = 2: 0.41, IQR 0.34–0.48 vs. 0.37, IQR 0.29–0.42, p < 0.01). According to our findings, nocturnal heart rate regulation is severely affected in POSA patients, suggesting increased cardiac imbalance due to predominant positional apneas.

A stepwise titration protocol for oral appliance therapy in positional obstructive sleep apnea patients: proof of concept

PurposeIn patients with positional obstructive sleep apnea (POSA), oral appliance therapy (OAT) is among the first-line treatments. The aim of this study was to evaluate the effects of a new standardized stepwise titration protocol for OAT in a group of patients with POSA.MethodsThis was an observational intervention trial. Patients who were previously randomized to the OAT intervention arm of a comparison study comprised the subjects for this study. These patients, who had mild to moderate POSA, were assessed after 3 and 12 months for treatment efficacy, objective adherence by temperature microsensor, and side effects. The titration of OAT was performed using a standardized stepwise titration protocol including advancement levels of 60%, 75%, and 90% of the maximum mandibular protrusion. The optimal advancement level per individual was based on a weighted compromise between efficacy and side effects.ResultsIn total, 36 patients were included and all completed the titration protocol after 3 months. At baseline, the OAT was set at 60% of the maximal mandibular protrusion position. At a 3-month evaluation, the advancement remained at 60% in 16 patients (44%) and reached 75% advancement in 20 patients (56%). Mean apnea-hypopnea index decreased from 12.9 events per hour (9.1–16.7) to 6.9 (3.7–10.3) (P < 0.001), and median objective adherence was 97.4 (61.4–100.00) after 3 months. The 12-month analysis showed consistent results and good OAT tolerance. Six patients (16.7%) terminated OAT and one patient (2.8%) was lost to follow-up.ConclusionsThis standardized stepwise titration protocol for OAT showed good efficacy, good OAT tolerance, and good objective adherence in patients with mild to moderate POSA. Therefore, the protocol is recommended in research projects to improve standardization of methods between studies and in clinical practice for its practical feasibility.

Evaluation of body position in upper airway stimulation for obstructive sleep apnea-is continuous voltage sufficient enough?

The definition of positional obstructive sleep apnea (POSA) is widely accepted as a difference of 50% or more in AHI between supine and non-supine position. Upper airway stimulation (UAS) is an effective treatment for OSA but the implant delivers a single voltage over sleep period without consideration of body position. Clinical practice suggests different outcomes for OSA in supine position under UAS treatment. Outcomes of 44 patients were analyzed 12months after implantation in a two-center, prospective consecutive trial in a university hospital setting. Total night and supine AHI were evaluated and the ratio of time spent in supine was considered. Correlation between the classic and the modified definition of POSA and treatment response were evaluated. The time ratio spent in supine position did not differ before implantation and after 12months. Total and supine AHI were reduced with the use of UAS therapy (p < 0.001) but both the baseline and final supine AHI were higher than total night AHI. Considering POSA definition as a ratio of supine to non-supine AHI, there was no clear cutoff for defining responders neither with nor without the additional component of time in supine position. The OSA reduction is strong for the total AHI and supine AHI. Nonetheless, here, there is no cutoff for defining POSA as critical for UAS therapy response. Therefore, there is no evidence for excluding POSA patients from UAS in general. Future technology improvement should take body position and adaptive voltage into account.

Towards a prediction model for drug-induced sleep endoscopy as selection tool for oral appliance treatment and positional therapy in obstructive sleep apnea.

To evaluate the effect of different passive maneuvers on upper airway patency during drug-induced sleep endoscopy (DISE) compared to recent literature on treatment outcomes of positional therapy (PT), oral appliance therapy (OAT), and combined treatment in obstructive sleep apnea (OSA) patients. A retrospective, single-center cohort study including a consecutive series of 200 OSA patients. All patients underwent DISE with and without manually performed jaw thrust and lateral head rotation by using the VOTE classification. The effect of these maneuvers were analyzed by using the sum VOTE score comparing non-positional (NPP) and positional OSA patients (PP). Two hundred patients were included (80.5% male) with a mean age of 50.1 ± 11.7years, a BMI of 27.0 ± 3.1kg/m2, and a median AHI of 19.2 events per hour. Forty-four percent of the patients were NPP; of the remaining 56%, 34% was diagnosed with supine isolated and 66% with supine predominant POSA. Manually performed jaw thrust showed a reduction of sum VOTE score of 66.7% in all subgroups. The effect of lateral head rotation was a reduction of 33.3% in NPP and supine predominant PP and 50% in supine isolated PP. Combining these maneuvers a reduction of more than 75% was seen in all patients. The present model leaves room for improvement. The effect of manually performed jaw thrust is greater and the effect of lateral head rotation alone is less than what was expected compared to recent literature on treatment outcome of OAT, PT, and combined treatment.

Positional obstructive sleep apnea

The severity of obstructive sleep apnea (OSA) is, in 56–75 % influenced by body position. The prevalence of positional OSA (POSA) decreases as the severity of OSA increases, and 70–80% of POSA patients have mild to moderate OSA. The literature on POSA is reviewed. Many definitions have been applied using modified versions of Cartwright’s criteria (a difference in apnea index of 50% or more between supine and non-supine positions). Others have proposed a distinction among POSA patients (PP) between supine-isolated OSA (non-supine apnea–hypopnea index, AHI, < 5) and supine-predominant OSA (non-supine AHI ≥ 5). In PP, positional therapy (PT) as a standalone treatment or in combination with other treatment modalities has proven to be effective. To achieve high compliance, proper selection of PP suitable for treatment with PT remains of high importance. In 2014, the Amsterdam Positional OSA Classification (APOC) was proposed, which can be used to identify suitable candidates for PT. There is strong evidence that PT is effective in reducing AHI during short- and long-term follow-up in PP, and can be used as a standalone treatment or in combination with other treatment modalities. Recently, several studies have pointed out the complexity of POSA pathophysiology, which leaves room for more understanding and knowledge of this underestimated phenomenon in the future.

Discriminating between positional and non-positional obstructive sleep apnea using some clinical characteristics.

The primary objective of this paper was to identify significant factors associated with positional Obstructive Sleep Apnea (POSA) and to provide a clinical tool for discriminating non positional from POSA. Secondary objectives were about estimating the prevalence of POSA, comparing the polysomnographic variables across POSA and non-POSA patients. This was a cross sectional study on 278 patients who completed an overnight sleep study for OSA assessment. Patients were aged over 18years, without central sleep apnea or narcolepsy and slept no less than 20min in a non-supine position. POSA was defined as a total apnea/hypopnea index (AHI) ≥5 and a ratio supine AHI/non-supine AHI ≥2. The binary logistic regression was used for modeling the likelihood for OSA patient to be positional, and the LASSO method was used for selecting the optimal set of clinical characteristics associated with POSA. Overall, 53% of patients had POSA. These patients were younger (p=0.005), had lower BMI (p<0.0001), lower prevalence of hypertension (p=0.006), lower Berlin (p=0.01), and lower STOP (p=0.001) scores compared to non-POSA patients. Neck and waist circumference were higher in non-POSA (p=0.005, p=0.009, respectively) patients. Age, BMI, DBP, Mallampati, and Berlin scores were found to be the best clinical characteristics associated with POSA with an area under the ROC curve (AUC) of 0.71 (95% CI [0.63, 0.78]). Half of patients referred for the sleep study had POSA. Age, BMI, DBP, Mallampati, and Berlin scores, put together, were shown to act as good clinical characteristics to discriminate between POSA and non-POSA patients.

Mandibular Advancement Device as a Comparable Treatment to Nasal Continuous Positive Airway Pressure for Positional Obstructive Sleep Apnea.

Positional obstructive sleep apnea (P-OSA) is a clinically common phenotype of OSA, which can be treated effectively with mandibular advancement devices (MADs). We hypothesized that the efficacy of an MAD is comparable to that of nasal continuous positive airway pressure (nCPAP) in P-OSA patients. Among patients diagnosed with OSA at a single sleep center from January 2008 to May 2014, male subjects with moderate OSA were recruited and stringently categorized as having P-OSA when the ratio of their lateral apnea-hypopnea index (AHI) to supine AHI was ≤ 0.5, their lateral sleep time was > 60 minutes, and their lateral REM sleep time was longer than 10 minutes. Treatment efficacy was compared between P-OSA subjects with an MAD (n = 34) and those with nCPAP (n = 34) after matching for age, body-mass index, and baseline AHI. There were no significant differences in baseline AHI (MAD: nCPAP = 20.6 ± 3.9/h: 21.3 ± 1.7/h, p = 0.35) or in follow-up AHI (MAD: nCPAP = 4.7 ± 3.5/h: 3.4 ± 3.7/h, p = 0.12) between the 2 treatment groups, and hence MADs lowered the AHI to the same extent as nCPAP. These findings suggest that an MAD is as efficacious as nCPAP for P-OSA patients. MAD treatment for this specific phenotype may be a promising patient-tailored and first-line approach to OSA. A commentary on this article appears in this issue on page 1079.

Ulnar nerve entrapment at elbow in obstructive sleep apnea patients: a randomized controlled trial.

Obstructive sleep apnea (OSA) is a highly prevalent disease. For diagnostic and therapeutic purposes, OSA has been divided into several subgroups. Positional OSA (POSA), the most frequent subgroup (56%), is described as overall apnea hypopnea index (AHI) ≥5 and supine AHI at least twice as high when compared to non-supine AHI. We aimed to investigate the frequency of ulnar nerve entrapment neuropathy at the elbow (UNEE) in OSA patients without clinical signs and symptoms of ulnar neuropathy and intended to find if sleeping position in OSA had an impact on UNEE development. Fifty POSA, 48 non-positional OSA (NPOSA) patients, and 45 healthy controls without diabetes mellitus, hypothyroidism, rheumatic diseases, and cervical radiculopathy underwent nerve conduction studies. We found that UNEE was highly frequent in OSA patients (42.9%) and significantly more frequent in moderate to severe POSA patients than mild POSA patients (65.4 vs. 33.3%, p<0.05). Furthermore, when compared to non-positional ones, UNEE was significantly more frequent in moderate to severe POSA patients (65.4 vs. 36.4%, p<0.05). Our results showed that the severity of OSA in positional patients was correlated with increased frequency of UNEE. OSA patients should be informed about the predisposition of UNEE and questioned for the symptoms in periodical controls. POSA patients should be alerted about the additional effect of sleeping position on UNEE and the necessity of OSA treatment should be emphasized.

Positional obstructive sleep apnea in bariatric surgery patients: risk factor for postoperative cardiopulmonary complications?

Up to 80 % of the bariatric surgery (BS) patients suffer from obstructive sleep apnea (OSA). BS patients with moderate to severe OSA (apnea-hypopnea index (AHI) ≥15) are usually treated with continuous positive airway pressure (CPAP). This is not indicated in mild OSA patients (AHI <15). However, >50 % of patients with mild OSA have positional OSA (POSA); their AHI is at least twice as high in supine sleeping position than in other positions. Since many patients sleep in supine position for surgical safety reasons after BS, evaluating the AHI in this position might be more relevant in this group. The aim of this study is to evaluate the postoperative cardiopulmonary complication rate in mild OSA patients with and without POSA. Secondary aim is to evaluate predictive factors for POSA. A single-institute retrospective analysis was achieved with all consecutive patients who underwent primary laparoscopic Roux-en-Y gastric bypass or laparoscopic sleeve gastrectomy between 2006 and 2014. All patients with an AHI between 5 and 15 were included. Postoperative complications were compared between POSA and non-POSA patients. Predictive factors were evaluated through univariate and multivariable logistic regression analysis. A total of 277 patients, 153 with and 124 without POSA, were included. After BS, three patients (1.1 %) experienced severe cardiopulmonary complications. No significant difference was found between POSA and non-POSA patients. In multivariate analysis, age and BMI were found to be negative predictors for POSA. In terms of 30-day postoperative cardiopulmonary outcome, CPAP therapy is not indicated in mild (P)OSA patients scheduled for BS.

Comparison of Neurocognitive Functions between Positional Obstructive Sleep Apnea Patients and Non-Positional Obstructive Sleep Apnea Patients in the Korean Elderly Population

MethodsZZForty-four subjects in OSA patients with total AHI≥5 participated as criteria for POSA (n=25) with 1) supine position AHI/non-supine position AHI≥2 and 2) total AHI≥5 or not (NPOSA, n=19). All participants completed clinical interview by physician and neurocognitive function assessments. Mann-Whitney U and chi-square test were performed for comparison of neurocognitive functions and sleep characteristics with polysomnography between two groups.

The effect of weight loss on OSA severity and position dependence in the bariatric population

The aims of this study were to determine the prevalence of positional obstructive sleep apnea (POSA) in patients undergoing bariatric surgery and to evaluate the effect of weight loss brought about by bariatric surgery on POSA. Furthermore, the authors investigated whether body mass index (BMI), neck circumference, apnea-hypopnea index (AHI), and age are predictors for POSA. A retrospective cohort study was conducted with data collected from patients who were screened for OSA pre-bariatric surgery and completed a follow-up polysomnography post bariatric surgery from August 2008 to November 2012. Descriptive statistics were used to characterize the prevalence of POSA patients, and the Mann-Whitney and Wilcoxon signed-rank tests were used to examine differences between the POSA and non-POSA groups. A logistic regression model was used to determine predictors for POSA. Thirty-four percent of patients had POSA, which is significantly lower (p<0.001) than in the general population. BMI, neck circumference, and AHI were significantly lower in POSA patients. AHI was the only significant independent predictor for POSA. Of the 91 patients analyzed following bariatric surgery, 35.2% (n=32) no longer had OSA. The prevalence of POSA in patients undergoing bariatric surgery is significantly lower than the prevalence noted in the general population. A low AHI was shown to be the only significant independent predictor for the presence of POSA.

Analysis of the influence of head rotation during drug-induced sleep endoscopy in obstructive sleep apnea

Currently, drug-induced sleep endoscopy (DISE) in obstructive sleep apnea (OSA) is predominantly performed in supine position. When positional therapy (avoidance of supine sleeping position in positional OSA (POSA) is implemented as (part of the) treatment, one should assess levels of obstruction in the other sleeping positions. Therefore, the current study examined the influence of difference head positions during DISE in patients with OSA and POSA. Consecutive prospective study. DISE was performed in patients with an apnea hypopnea index at baseline polysomnography greater than 5 events/h. The upper airway was assessed at velum, oropharynx, tongue base, and epiglottis level in supine position. The patients head were then tilted to the left and the right side and the DISE findings were recorded. One hundred consecutive patients were included. In positional apneics (n = 67), lateral position was associated with decreased frequency of complete anteroposterior collapse at velum (P < 0.01), tongue base (P < 0.01), and epiglottis (P < 0.01) level-and increased frequency of partial anteroposterior collapse at velum (P < 0.01), tongue base (P < 0.01), and epiglottis (P <0.05) level in comparison with supine position. DISE findings showed no difference between the right and left position, whereas findings after head rotation were significantly different in comparison with the supine position. Head rotation improves upper airway collapse during DISE in supine position. This improvement of upper airway patency is more predominant in POSA patients.