Patient In Position Research Articles

Positional sleep apnea phenotyping using machine learning and digital oximetry biomarkers * *The work was performed at the Technion Institute of Technology, Haifa, Israel.

Study Objectives. To examine the feasibility of using digital oximetry biomarkers (OBMs) and body position to identify positional obstructive sleep apnea (POSA) phenotypes. Methods. A multiclass extreme gradient boost (XGBoost) was implemented to classify between three POSA phenotypes, i.e., positional patients (PP), including supine-predominant OSA (spOSA), and supine-isolated OSA (siOSA), and non-positional patients (NPP). A total of 861 individuals with OSA from the multi ethnic study of atherosclerosis (MESA) dataset were included in the study. Overall, 43 OBMs were computed for supine and non-supine positions and used as input features together with demographic and clinical information (META). Feature selection, using mRMR, was implemented, and nested cross validation was used for the model’s performance evaluation. Results. The best performance for the multiclass classification yielded a median weighted F1 of 0.79 with interquartile range (IQR) of 0.06. Binary classification between PP to NPP achieved weighted F1 of 0.87 (0.04). Conclusion. Using OBMs computed in PP and NPP with OSA, it is possible to distinguish between the different phenotypes of POSA. This data-driven algorithm may be embedded in portable home sleep tests.

Standardized framework to report on the role of sleeping position in sleep apnea patients.

Sleep apnea is a multifactorial illness which can be differentiated in various physiological phenotypes as a result of both anatomical and non-anatomical contributors (e.g., low respiratory arousal threshold, high loop gain). In addition, the frequency and duration of apneas, in the majority of patients with OSA, are influenced by sleeping position. Differences in characteristics between non-positional patients (NPP) and positional patients (PP) suggest another crucial phenotype distinction, a clinical phenotype focusing on the role of sleeping position on sleep apnea. Since this clinical phenotype distinction has therapeutic implications, further research is necessary to better understand the pathophysiology behind this phenotypic trait and to improve management of PP. Therefore, we suggest a standardized framework that emphasizes the role of sleeping position when reporting clinical and research data on sleep apnea. We identified 5 key topics whereby a standardized framework to report on the role of sleeping position would be of added value: (1) sleep study data, (2) anatomical, morphological and physiological factors, (3) drug-induced sleep endoscopy (DISE) findings, (4) sleep apnea management, and (5) effectiveness versus efficacy of positional therapy in sleep apnea management. We performed a literature search to identify evidence to describe and support the rationale behind these5 main recommendations. In this paper, we present the rationale behind this constructand present specific recommendations such as reporting sleep study indices (disease severity) and sleep time spent in various sleeping positions. The same is suggested for DISE findings and effect of treatment. Sleep study indices (disease severity), anatomical, morphological, and physiological factors in sleep apnea patientsshould be reported separately for PP and NPP. Applying these suggestions in future research will improve patient care, assist in better understanding of this dominant phenotype, and will enhance accurate comparisons across studies and future investigations.

The influence of position dependency on surgical success in patients with obstructive sleep apnea undergoing maxillomandibular advancement.

(1) To evaluate surgical success in patients with obstructive sleep apnea undergoing maxillomandibular advancement (MMA) stratifying for the reduction of both the total apnea-hypopnea index (AHI) and the AHI in the supine and nonsupine position; (2) to evaluate the influence of position dependency on surgical outcome; and (3) to analyze the prevalence of residual position-dependent obstructive sleep apnea (OSA) in nonresponders after MMA. A single-center retrospective study including a consecutive series of patients with OSA undergoing MMA between August 2011 and February 2019. In total, 57 patients were included. The overall surgical success was 52.6%. No significant difference in surgical success between nonpositional patients (NPP) and positional patients (PP) with OSA was found. Surgical success of the supine AHI was not significantly different between NPP and PP, but surgical success of the nonsupine AHI was significantly greater in NPP than in PP. Of the 17 preoperative NPP, 13 of them moved to being PP with less severe OSA postoperatively. In total, 21 out of 27 nonresponders (77.8%) were PP postoperatively. No significant difference in surgical success between NPP and PP undergoing MMA was found. However, the improvement of total and nonsupine AHI in NPP was significantly greater compared to PP. In nonresponders, a postoperative shift from severe OSA in NPP to less severe OSA in PP was found, caused by a greater reduction of the nonsupine AHI than the supine AHI postoperatively. In patients with residual OSA in the supine position after MMA, additional treatment with positional therapy can be indicated.

Obstructive Sleep Apnea: Do Positional Patients Become Nonpositional Patients With Time?

Obstructive sleep apnea (OSA) patients with breathing abnormalities only or mainly in the supine posture are designated positional patients (PPs), whereas nonpositional patients (NPPs) have many breathing abnormalities in both lateral and supine postures. Positional therapy (PT), the avoidance of the supine posture during sleep, is the obvious treatment for PPs. The stability over time of being PP and leading factors that are involved in converting a PP to an NPP are addressed. We analyzed polysomnographic (PSG) recordings of 81 consecutive adult patients with OSA who were judged to be PPs at the first PSG evaluation, and their follow-up PSGs were obtained after an average period of 6.6 years. The follow-up PSGs indicated that 57 PPs (70.4%) remained PPs, whereas 24 (29.6 %) converted to NPPs. Among PPs and NPPs, body mass index (P ≤ 0.05), overall Apnea-Hypopnea Index (AHI, P ≤ 0.087), and lateral AHI (P ≤ 0.046) increased and minimum SpO2 during rapid eye movement (REM) sleep (P ≤ 0.028) decreased significantly during the follow-up. However, among patients who became NPPs, the changes in these parameters were significantly (P ≤ 0.05) more pronounced compared to the patients who remained PPs. After an average of 6.6 years, 70.4% of PPs remained PPs. Therefore, if adherence for PT is good, they could continue to benefit from this therapy. For those who turned to NPPs, PT will not be the optimal treatment anymore; thus, these patients should be frequently monitored. Furthermore, an early treatment of PPs with PT would be highly beneficial to prevent worsening of their OSA. 2b Laryngoscope, 130:2263-2268, 2020.

Prevalence and characteristics of positional obstructive sleep apnea (POSA) in patients with severe OSA.

We assessed the prevalence of positional patients (PPs) and the main predictors of positional dependency in severe obstructive sleep apnea (OSA). A simulated effect of positional therapy (PT) vs. continuous positive airway pressure (CPAP) was also assessed. Polysomnographic recordings of 292 consecutive patients with severe OSA (Apnea-Hypopnea Index (AHI) ≥ 30) who slept > 4h and had ≥ 30min sleep in both supine and lateral positions were assessed. PPs were defined to have a supine AHI/lateral AHI ratio ≥ two and non-positional patients (NPPs) a supine AHI/lateral AHI ratio < two. A total of 35.3% of the severe OSA patients were PPs. They were less obese and had less severe OSA (p < 0.001) compared with NPPs. The percentage of total apnea-hypopnea time from total sleep time (AHT%) was the most significant predictor for positional dependency. By sleeping in the lateral posture(i.e. after simulated PT), 78 (75.7%) PPs obtained significant improvement of their OSA severity and 9 (8.7%) of them became "non-OSA". Moreover, if CPAP was used only for 50% of total sleep time, 53 patients (18.2%) gained more benefit from avoiding the supine posture than from CPAP therapy. More than a third of the studied severe OSA patients were PPs. These patients could achieve a significant decrease in the number and severity of apneas and hypopneas by adopting the lateral posture, suggesting that PT may be a valuable therapy for a significant portion of these severe OSA patients who for whatever reason are not being treated by CPAP. ClinicalTrials.gov Identifier: NCT03232658.

Decision making for position-dependent obstructive sleep apnea syndrome on the basis of patient information and physical examinations of the upper airway, acquired on an outpatient basis

Conclusions: Patients with body mass index (BMI) < 25 kg/m2 and obstructive sleep apnea syndrome (OSAS) are highly suspicious for position-dependent OSAS. Diagnosis of position-dependent/position-independent OSAS can be difficult in patients satisfying both ‘BMI >25 kg/m2’ and ‘any of tongue enlargement (TE), palatine tonsil hypertrophy (PTH) and obstruction by Muller’s maneuver (OMM)’. Polysomnography is warranted in such patients.Objectives: The objective was to retrospectively elucidate criteria for differentiating position-dependent OSAS on the basis of patient information and physical examinations of the upper airway obtainable in clinics.Methods: The 643 patients were categorized as positional patients (PPs) or non-positional patients (NPPs). The patient background factors examined were sex, age, BMI, and hypertension. TE, PTH, pharyngeal tonsil hypertrophy, and OMM were evaluated. Cross-validation was performed using even-numbered registrations as the training set group (Group A) and odd-numbered registrations as the test case group (Group B).Results: In Group A, patients with BMI <25 kg/m2 were clearly more frequent among PP than among NPP. In Group A with BMI ≥25 kg/m2, significant differences were found for TE, PTH and OMM. Significant differences were found between 0 and 1/2/3 for number of factors. Results generated from Group A were validated in Group B.

Association between Positional Dependency and Obstruction Site in Obstructive Sleep Apnea Syndrome

ObjectivesThe purpose of this study is to find out associations between positional dependency and obstructive levels based on sleep videofluoroscopy (SVF) in patients with obstructive sleep apnea syndrome (OSAS).MethodsRetrospective review was made of 91 OSAS patients who underwent polysomnography and SVF from August 2009 through June 2010. Polysomnography variables including apnea-hypopnea index (AHI), supine AHI, non-supine AHI, time spent in supine sleep position of the total sleep time and positional dependency (PD) were analyzed. Obstruction sites were evaluated as SVF variables.ResultsOf 91 patients, 65 (71.4%) were positional patients (PP) and 26 (28.6%) were non-positional patients (NPP). An analysis of polysomnography variables according to PD revealed that overall AHI, non-supine AHI and supine AHI in PP was significantly lower than that in NPP. The patients with soft palate obstruction (SP type) were more likely to have PD than the patients with tongue base obstruction (TB type; P=0.046). PD was inversely related to OSAS severity significantly (P=0.001).ConclusionThese results provide evidence that positional dependent patients may have higher success rate of soft palate OSA surgery alone than non-positional dependent patients. Although PD may be associated with obstruction site, PD only itself may not be useful in planning surgical treatment for OSAS.

The role of sleep position in obstructive sleep apnea syndrome

We analyzed the role of sleep position in obstructive sleep apnea syndrome (OSAS). The polysomnograms of 120 patients with sleep apnea syndrome were analyzed. We associated the apnea hypopnea index (AHI) of the supine position with the AHI of the other positions. Patients were stratified in a group of positional patients (PP) (AHI supine >or= 2 x AHI other positions) and a group of non-positional patients (NPP). In 55.8% of our patients, OSAS was position dependent. PP patients were significantly (6.7 years) younger. BMI and AHI were higher in the NPP group, but the difference was not significant. Level of obstruction in the upper airway (retropalatinal vs retrolingual vs both levels) as assessed by sleep endoscopy was not significantly different between the two groups. Total sleep time (TST) was equal in both groups, but the average time in supine position was 37 min longer in the PP group. This study confirms the finding that in more than 50% of patients, OSAS is position dependent. Apart from age, no patient characteristics were found indicating the position dependency. Overall AHI does not identify positional OSAS.