The effect of longitudinal sleep monitoring on clinician agreement in obstructive sleep apnea diagnosis: The ELSA study.

There is strong evidence for clinically relevant night-to-night variability of respiratory events in patients with suspected obstructive sleep apnea. Sleep experts retrospectively evaluated diagnostic data in 56 patients with suspected obstructive sleep apnea. Experts were blinded to the fact that they were diagnosing the same case twice, once based on a short report of a single in-laboratory respiratory polygraphy and once with the additional information of 14 nights of pulse oximetry at home. All experts (n = 22) were highly qualified, 13 experts (59.1%) treated > 100 patients with suspected obstructive sleep apnea per year. In 12 patients, the apnea-hypopnea index in the respiratory polygraphy was < 5 per hr, but the mean oxygen desaturation index of 14 nights of pulse oximetry was ≥ 5 per hr. The additional information of 14 nights of pulse oximetry helped to diagnose obstructive sleep apnea with a 70% consensus in two of those patients (16.7% [95% confidence interval: 4.7/44.8]). In eight patients, experts could not agree to a 70% consensus regarding continuous positive airway pressure therapy recommendation after respiratory polygraphy. The additional information of multiple-night testing led to a consensus in three of those cases (37.5% [95% confidence interval: 14/69]). Change of obstructive sleep apnea diagnosis and continuous positive airway pressure recommendation was significantly negatively associated with the number of treated obstructive sleep apnea patients > 100 per year compared with 0-29 patients per year (Coef. [95% confidence interval] -0.63 [-1.22/-0.04] and -0.61 [-1.07/-0.15], respectively). Experts found already a high level of consensus regarding obstructive sleep apnea diagnosis, severity and continuous positive airway pressure recommendation after a single respiratory polygraphy. However, longitudinal sleep monitoring could help increase consensus in selected patients with diagnostic uncertainty.

Relationship between ODI and sleep structure of obstructive sleep apnea and cardiac remodeling.

PURPOSE: The purpose of the study was to evaluate the quantitative relationship between Oxygen Desaturation Index (ODI) and sleep structure of obstructive sleep apnea (OSA) and cardiac remodeling. METHODS: In this study, patients were enrolled from January 2015 to October 2022, and were divided into 3 groups according to AHI: patients with AHI < 15, patients with 15 ≤ AHI < 30, and 260 patients with AHI ≥ 30. Stratified linear regression was used to analyze independent risk factors for cardiac remodeling in OSA. RESULTS: A total of 479 patients were enrolled. We found that compared with AHI < 15 group (n = 120), the group with AHI > 30 (n = 260) had increased left atrial anteroposterior diameter, left ventricular end-diastolic internal diameter, left ventricular posterior wall thickness, right ventricular anteroposterior diameter, and interventricular septal thickness (P < 0.05). The group with 15 ≤ AHI ≤ 30 (n = 99) had increased left atrial anteroposterior diameter (P < 0.05). Multivariate linear regression revealed that N2 sleep was an independent risk factor for left ventricular posterior wall thickness, with positive correlation (p < 0.05). N3 sleep was an independent risk factor for transverse right atrial diameter and right ventricular anteroposterior diameter, with negative correlation (P < 0.05). ODI was an independent risk factor for interventricular septal thickness, with positive correlation (P < 0.05). The arousal index was an independent risk factor for increased left atrial anteroposterior diameter, with positive correlation (P < 0.05). CONCLUSIONS: Increased ODI is an independent risk factor for interventricular septal thickness, while decreased slow wave sleep is an independent risk factor for right heart remodeling in OSA.

Effect of functional appliances on sleep-disordered breathing in Class II division 1 malocclusion children: Randomized controlled trial.

OBJECTIVES: A randomized controlled trial was undertaken to investigate the orthopaedic effect of functional appliances on the pharyngeal airway space and nocturnal breathing of children with skeletal class II due to mandibular retrusion. MATERIALS AND METHODS: Forty patients were randomized into a 1:1 ratio study (Twin block) group and a control (fixed appliance) group. Each group included equal numbers of boys and girls. Diagnosis with sleep-disordered breathing was not an inclusion criterion. The duration of the trial was 12 months (T0 - T12). Eligibility criteria included skeletal Class II division 1 malocclusion with mandibular retrognathism, SNA ≥82, SNB ≤78, ANB ≥4, overjet ≥6 mm, and patients in circumpubertal stage CVM2 and CVM3. The main outcomes were pharyngeal airway volume, oxygen desaturation index (ODI), and maximum expiratory pressure (MEP), while the secondary outcomes were skeletal and dental changes of the maxilla and mandible. Randomization was accomplished with random blocks of 20 patients with allocation concealed in sequentially numbered, opaque, and sealed envelopes. Blinding was only applicable for data analysis of radiographic measurements and data extracted from the pulse oximeter. RESULTS: The mean age of the patients was 10 ± 1.5 and 10 ± 1.2 at (T0) for the Twin Block and the control groups, respectively. The changes in the oropharyngeal (2.66 cc and 0.056; P = .03) and nasopharyngeal (1.3 cc and 0.84; P = .053) airway volumes for the Twin block and control groups, respectively, were significantly different for the oropharynx. There was a significant decrease in ODI by [median -3.55 (-5.05 to 0.50); P ≤ .001] and a significant increase [median 45 (0.0-110); P ≤ .001] in MEP for the Twin block group. A significant inverse correlation (r = -.589; P = .006) could be found between the total volume of the oropharynx and ODI. No serious harm was observed. CONCLUSIONS: The Twin block group showed significant change in oropharyngeal airway volume and improvement of nocturnal breathing. REGISTRATION: This trial was registered at https://www. CLINICALTRIALS: gov, registration number NCT04255511.

Relevance Between Reduction of SpO2 and Parasympathetic Nervous Activity During Sleep.

Sleep apnea syndrome (SAS) is associated with cardiopulmonary and dental nasopharyngeal diseases. The blood oxygen saturation (SpO2) detected using pulse oximetry is a diagnostic screening method for SAS. SAS severity is assessed using the oxygen desaturation index (ODI), which measures the number of times the SpO2 decreases by more than 3% for longer than 10 s. This study investigated the association between reduced SpO2 and parasympathetic nervous system activity (PSNA) during night sleep in young adults (n = 63; aged 20-32 years). Changes in PSNA were measured every minute for 24 h during a free-moving day using an ActiveTracer accelerometer. Pulse oximetry was performed simultaneously during sleep. All participants had significantly lower PSNA when the SpO2 decreased by 3% or more than when it did not. There were no significant differences in PSNA when an ODI cutoff of 5 events/h was used. However, participants with an ODI >5 events/h had significantly lower PSNA during normal SpO2 than those with an ODI <5 events/h, suggesting an association between SpO2 desaturation and PSNA decline during sleep. A high ODI may indicate reduced PSNA levels during sleep, affecting sleep efficiency. Treatment aimed at reducing the ODI may improve sleep quality, even in young adults.

Nocturnal hypoxia and age-related macular degeneration.

BACKGROUND: Nocturnal hypoxia is common, under-diagnosed and is found in the same demographic at risk of age-related macular degeneration (AMD). The objective of this study was to determine any association between nocturnal hypoxia and AMD, its severity, and the high-risk sub-phenotype of reticular pseudodrusen (RPD). METHODS: This cross-sectional study included participants aged ≥50 years with AMD, or normal controls, exclusive of those on treatment for obstructive sleep apnoea. All participants had at home, overnight (up to 3 nights) pulse oximetry recordings and multimodal imaging to classify AMD. Classification of Obstructive Sleep Apnea (OSA) was determined based on oxygen desaturation index [ODI] with mild having values of 5-15 and moderate-to-severe >15. RESULTS: A total of 225 participants were included with 76% having AMD, of which 42% had coexistent RPD. Of the AMD participants, 53% had early/intermediate AMD, 30% had geographic atrophy (GA) and 17% had neovascular AMD (nAMD). Overall, mild or moderate-to-severe OSAwas not associated with an increased odds of having AMD nor AMD with RPD (p ≥ 0.180). However, moderate-to-severe OSA was associated with increased odds of having nAMD (odds ratio = 6.35; 95% confidence interval = 1.18 to 34.28; p = 0.032), but not early/intermediate AMD or GA, compared to controls (p ≥ 0.130). Mild OSA was not associated with differences in odds of having AMD of any severity (p ≥ 0.277). CONCLUSIONS: There was an association between nocturnal hypoxia as measured by the ODI and nAMD. Hence, nocturnal hypoxia may be an under-appreciated important modifiable risk factor for nAMD.

Correlation between nocturnal intermittent hypoxemia and mild cognitive impairment in the older adult and the role of BDNF Val66Met polymorphism: a hospital-based cross-sectional study.

PURPOSE: To explore the prevalence of nocturnal intermittent hypoxemia (NIH) in a tertiary hospital geriatric department and the relationship between NIH and mild cognitive impairment (MCI) in older adults, and to examine the role of brain-derived neurotrophic factor (BDNF) Val66Met polymorphism. METHODS: Older adults aged ≥ 60 were enrolled. NIH and cognitive assessments were conducted. BDNF concentrations and BDNF Val66Met polymorphism were detected for a preliminary exploration of the possible mechanism of the process. RESULTS: Of 325 older adults enrolled, 157 (48%) had NIH and were further divided into mild, moderate, and severe NIH groups according to their oxygen desaturation of ≥ 4% per hour of sleep (ODI4). MCI detection rate in the four groups gradually increased, and the differences were statistically significant (chi-square = 4.457, P = 0.035). ODI4 was negatively correlated with MoCA score in all participants (r = - 0.115, P = 0.039) and patients with NIH (r = - 0.199, P = 0.012). After adjusting for sex, age, and cardiovascular risk factors, NIH and MCI remained independently associated (OR = 3.13, 95% CI 1.03-9.53, P = 0.045). BDNF levels were positively correlated with MoCA score (r = 0.169, P = 0.028) and negatively correlated with nocturnal average oxygen saturation in patients with NIH (r = - 0.288, P = 0.008). Older adults with different BDNF Val66Met genotypes did not show significant differences in MCI rate and BDNF levels (P > 0.05). CONCLUSION: The older adults with NIH have a higher MCI detection rate. BDNF levels may be a potential biomarker for cognitive dysfunction in patients with NIH.

Oximetry Indices in the Management of Sleep Apnea: From Overnight Minimum Saturation to the Novel Hypoxemia Measures.

Obstructive sleep apnea (OSA) is a multidimensional disease often underdiagnosed due to the complexity and unavailability of its standard diagnostic method: the polysomnography. Among the alternative abbreviated tests searching for a compromise between simplicity and accurateness, oximetry is probably the most popular. The blood oxygen saturation (SpO2) signal is characterized by a near-constant profile in healthy subjects breathing normally, while marked drops (desaturations) are linked to respiratory events. Parameterization of the desaturations has led to a great number of indices of severity assessment commonly used to assist in OSA diagnosis. In this chapter, the main methodologies used to characterize the overnight oximetry profile are reviewed, from visual inspection and simple statistics to complex measures involving signal processing and pattern recognition techniques. We focus on the individual performance of each approach, but also on the complementarity among the great amount of indices existing in the state of the art, looking for the most relevant oximetric feature subset. Finally, a quick overview of SpO2-based deep learning applications for OSA management is carried out, where the raw oximetry signal is analyzed without previous parameterization. Our research allows us to conclude that all the methodologies (conventional, time, frequency, nonlinear, and hypoxemia-based) demonstrate high ability to provide relevant oximetric indices, but only a reduced set provide non-redundant complementary information leading to a significant performance increase. Finally, although oximetry is a robust tool, greater standardization and prospective validation of the measures derived from complex signal processing techniques are still needed to homogenize interpretation and increase generalizability.

Relationship between salt intake and sleep disordered breathing in dialysis patients.

BACKGROUND: The prevalence of sleep disordered breathing is high in patients with end-stage renal disease. Salt intake is related to the severity of obstructive sleep apnea in patients with resistant hypertension and hyperaldosteronism. We investigated the relationship between salt intake and sleep disordered breathing in patients on maintenance hemodialysis. PATIENTS AND METHODS: We studied 128 dialysis outpatients (mean age 63 ± 11 years) who were followed at Kokura Daiichi Hospital. We estimated each patient's salt intake using an InBody S10 body composition analyzer and measured the 3% oxygen desaturation index (ODI) during sleep using a Pulsewatch: PMP-200 GplusX. RESULTS: The average estimated salt intake was 8.0 ± 2.6 g/day, and the median value of that was 7.5 g/day. Blood pressure (BP) before and after dialysis were 140 ± 18/78 ± 11 and 127 ± 13/72 ± 8 mmHg, respectively. The geometric average number of 3% ODI was 7.1, and sleep disordered breathing was detected in 30% of all subjects. The patients with ≥ 7.5 g/day salt intake were younger and more frequently male and had higher body mass index (BMI) and BP before dialysis compared to those with salt intakes < 7.5 g/day. Patients with ≥ 7.5 g/day salt intake had a significantly higher geometric average number of 3% ODI; however, this relationship became weaker after adjusting for BMI. The same relationship was obtained for the prevalence of sleep disordered breathing. CONCLUSION: The prevalence of sleep disordered breathing in patients on maintenance hemodialysis was high, and the sleep disordered breathing was associated with salt intake and BMI.

Parasympathetic Nervous Activity Associated with Discoordination Between Physical Acceleration and Heart Rate Variability in Patients with Sleep Apnea.

Sleep apnea syndrome (SAS) often accompanies alterations in heart rate variability (HRV). The severity of SAS is sometimes evaluated using the oxygen desaturation index (ODI). We hypothesized that effects of the autonomic nervous system could be involved in the coordination between HRV and physical acceleration during free movement in patients with SAS. Among 33 women aged 60 years or older, 19 had a high ODI (>5). Their HRV and physical acceleration were simultaneously obtained every minute for 24 hours. The low frequency/high frequency (LF/HF) ratio and the high frequency in normalized units (HFnu) were used as HRV indices. Low levels of %Lag0, defined as the percentage of the lag = 0 min in 1 h, indicated coordination between physical acceleration and HRV. Nineteen participants were divided into group A (high %Lag0 before sleep [n = 9]) or group B (low %Lag0 [n = 10]). In group B participants with a high ODI and low %Lag0 in the hour after waking, HFnu was significantly increased compared to that in group A participants with high ODI and high %Lag0 in the hour after waking (p < 0.05). These results suggest that close associations between high ODI and discoordination between HRV and physical acceleration may be due to higher parasympathetic nervous system activity after waking.

The comparison of multilevel surgery (hyoid myotomy and suspension with uvulopalatopharyngoplasty) with CPAP in moderate to severe OSAS patients.

PURPOSE: The study aimed to determine the efficacy of multilevel surgery (hyoid myotomy and suspension with uvulopalatopharyngoplasty) and continuous positive airway pressure (CPAP) for the treatment of moderate to severe obstructive sleep apnea syndrome (OSAS) and to clarify whether our surgical protocol could be as effective as CPAP. METHODS: We conducted a case series study comparing the effects of multilevel surgery and CPAP in the same subjects to minimize the influence of confounding factors. Fifteen subjects were enrolled with a pretreatment apnea-hypopnea index (AHI) ≥ 15. RESULTS: Both CPAP and multilevel surgery could improve the AHI and oxygen desaturation index (ODI). The median AHI for baseline, CPAP and surgery were 38.9, 1.2 and 12.6, respectively (p < 0.001). The medina ODI for baseline, CPAP and surgery were 34.8, 0.9 and 7.2, respectively (p < 0.001). However, the results indicated CPAP as the more efficacious treatment modality compared with multilevel surgery. Moreover, CPAP not only decreased N1 sleep but also had beneficial effects on blood pressure control, whereas multilevel surgery did not have any significant difference. CONCLUSION: CPAP is efficacious in improving OSAS severity, oxygen desaturation, sleep stage, and blood pressure control; while hyoid myotomy and suspension with uvulopalatopharyngoplasty are only efficacious in improving OSAS severity and oxygen desaturation. This study suggested that CPAP is the first choice when considering treatment of OSAS, especially in patients with hypertension or other cardiovascular diseases.

Comparison of apnoea-hypopnoea index and oxygen desaturation index when identifying obstructive sleep apnoea using type-4 sleep studies.

The concordance of different indices from type-4 sleep studies in diagnosing and categorising the severity of obstructive sleep apnoea is not known. This is a critical gap as type-4 sleep studies are used to diagnose obstructive sleep apnoea in some settings. Therefore, we aimed to determine the concordance between flow-based apnoea-hypopnoea index (AHIflow50% ) and oxygen desaturation index (ODI3% ) by measuring them concurrently. Using a random sub-sample of 296 from a population-based cohort who underwent two-channel type-4 sleep studies, we assessed the concordance between AHIflow50% and ODI3% . We compared the prevalence of obstructive sleep apnoea of various severities as identified by the two methods, and determined their concordance using coefficient Kappa(κ). Participants were aged (mean ±â€…SD) 53 ±â€…0.9 years (48% male). The body mass index was 28.8 ±â€…5.2 kg m-2 and neck circumference was 37.4 ±â€…3.9 cm. The median AHIflow50% was 5 (inter-quartile range 2, 10) and median ODI3% was 9 (inter-quartile range 4, 15). The obstructive sleep apnoea prevalence reported using AHIflow50% was significantly lower than that reported using ODI3% at all severity thresholds. Although 90% of those with moderate-severe obstructive sleep apnoea classified using AHIflow50% were identified by using ODI3% , only 46% of those with moderate-severe obstructive sleep apnoea classified using ODI3% were identified by AHIflow50% . The overall concordance between AHIflow50% and ODI3% in diagnosing and classifying the severity of obstructive sleep apnoea was only fair (κ = 0.32), better for males (κ = 0.42 [95% confidence interval 0.32-0.57] versus 0.22 [95% confidence interval 0.09-0.31]), and lowest for those with a body mass index ≥ 35 (κ = 0.11). In conclusion, ODI3% and AHIflow50% from type-4 sleep studies are at least moderately discordant. Until further evidence is available, the use of ODI3% as the measure of choice for type-4 sleep studies is recommended cautiously.

Validation of the oxygen desaturation index in the diagnostic workup of obstructive sleep apnea.

INTRODUCTION: Obstructive sleep apnea (OSA) is common, and diagnosis requires expensive and laborious testing to assess the apnea hypopnea index (AHI). We performed an analysis to explore the relationship between the oxygen desaturation index (ODI) as measured with pulse oximetry and the AHI in our large portable monitoring (PM) database to find an optimal cutoff value for the ODI in order to be able to exclude AHI ≥ 5 on PM. METHODS: Three thousand four hundred thirteen PM recordings were randomly divided into a training set (N = 2281) and a test set (N = 1132). The optimal cutoff for the ODI to exclude an AHI ≥ 5 on PM was determined in the training set and subsequently validated in the test set. RESULTS: Area under the curve of the ODI to exclude an AHI ≥ 5 on PM was 0.997 in the training set and 0.996 in the test set. In the training set, the optimal cutoff to predict an AHI < 5 was an ODI < 5. Using this cutoff in the test set provided a sensitivity of 97.7%, a specificity of 97.0%, a positive predictive value of 99.2%, and a negative predictive value of 91.4%. CONCLUSION: An ODI < 5 predicts an AHI < 5 with high sensitivity and specificity when measured simultaneously using the same oximeter during PM recording.

Factors associated with undiagnosed obstructive sleep apnoea among hypertensive patients: A multisite cross-sectional survey study in Taiwan.

AIMS AND OBJECTIVES: To investigate the distribution and risk factors associated with undiagnosed obstructive sleep apnoea among hypertensive patients. BACKGROUND: Obstructive sleep Apnoea has been deemed a cardinal risk factor affecting cardiovascular event, and the condition is still frequently overlooked clinically. The lack of advanced diagnosis often causes hypertensive patients with obstructive sleep apnoea to miss opportunities for preventing chronic diseases. DESIGN: A cross-sectional design. METHODS: A total of 215 hypertensive participants were recruited from the cardiovascular outpatients of medical centre in northern and middle Taiwan. The Chinese version of Pittsburgh Sleep Quality Index, the Chinese version of the Epworth Sleep Scale and a portable sleep monitoring device were used for data collection. Logistic regression analysis was conducted to identify the factors affecting hypertensive patients with obstructive sleep apnoea, and a multinomial logistic regression analysis was used to examine the major influence factors for each obstructive sleep apnoea severity level. RESULTS: 81.9% of the hypertensive participants were found having obstructive sleep apnoea. Concerning to the obstructive sleep apnoea severity, 50.0% of participants had mild obstructive sleep apnoea. After controlling the confounding variables, the supine position (odds ratio, 1.04; 95% CI, 1.01-1.07), SO2 (odds ratio, 0.58; 95% CI, 0.38-0.89) and oxygen desaturation index (odds ratio, 2.70; 95% CI, 1.18-6.18) were significantly associated with obstructive sleep apnoea. Furthermore, severe obstructive sleep apnoea was significantly correlated with gender (odds ratio, 0.04; 95% CI, 0.00-0.66), excessive daytime sleepiness (odds ratio, 20.27; 95% CI, 1.58-26.97) and oxygen desaturation index (odds ratio, 4.05; 95% CI, 1.86-8.81). CONCLUSIONS: Nearly 82% of the hypertensive participants were found having undiagnosed obstructive sleep apnoea, and 80% of them were mild or moderate severity. Oxygen desaturation index, SO2 and the supine position were found to be major predictors for obstructive sleep apnoea. Remarkably, oxygen desaturation index was the most significant predictor for mild, moderate and severe obstructive sleep apnoea. RELEVANCE TO CLINICAL PRACTICE: Healthcare providers should enhance their sensitivities to hypertensive patients at a high risk for obstructive sleep apnoea by actively assessing common obstructive sleep apnoea symptoms and providing strategies to alleviate obstructive sleep apnoea symptoms.

Night-to-night variability of obstructive sleep apnea.

One night of a sleep study is the standard for diagnosis and exclusion of obstructive sleep apnea. Single testing requires high sensitivity of the test method and a stable disease of interest to warrant a low rate of false-negative tests. Obstructive sleep apnea is diagnosed and graded by conventional thresholds of apneas and hypopneas per hour of sleep, and treatment is usually initiated in the presence of symptoms. The aim of this study was to assess night-to-night variability of obstructive sleep apnea to reassess the current practice. Seventy-seven patients previously diagnosed with obstructive sleep apnea, randomised to continuous positive airway pressure withdrawal within four trials, performed nightly pulse-oximetry over 2 weeks while off continuous positive airway pressure. The main outcome of interest was the coefficient of variation of the oxygen desaturation index marking night-to-night variability in obstructive sleep apnea. Obstructive sleep apnea was categorised according to conventional thresholds using oxygen desaturation index (no obstructive sleep apnea: <5 per h; mild: 5-15 per h; moderate: 15-30 per h; and severe: >30 per h). High night-to-night variability of obstructive sleep apnea was evidenced by a coefficient of variation of oxygen desaturation index of 31.1% (SD 16.5). Differences in oxygen desaturation index of >10 per h between nights were found in 84.4% and shifts in obstructive sleep apnea severity category in 77.9% of patients. The probability of missing moderate obstructive sleep apnea was up to 60%. Variability was higher in less severe obstructive sleep apnea. Obstructive sleep apnea shows a considerable night-to-night variability. Single-night diagnostic sleep studies are prone to miscategorise obstructive sleep apnea if arbitrary thresholds are used. Thus, treatment decisions should be based less on the conventional derivatives from sleep studies, especially in patients with less severe obstructive sleep apnea. CLINICAL TRIAL REGISTRATION: www.controlled-trials.com (ISRCTN 93153804, ISRCTN 73047833) and www.clinicaltrials.gov (NCT01332175 & NCT02050425).

Nocturnal Oxygen Desaturation Index is Inversely Correlated with Airflow Limitation in Patients with Chronic Obstructive Pulmonary Disease.

The concurrent diagnosis of chronic obstructive pulmonary disease (COPD) and sleep apnoea-hypopnoea syndrome (SAHS) (overlap syndrome), can contribute to worsening respiratory symptoms, but whether the severity of COPD is associated with co-morbid SAHS is unknown. We investigated whether the severity of COPD is associated with the complication of SAHS by examination of nocturnal oximetry as an alternative to polysomnography. Patients with COPD concurrently completed nocturnal oximetry, pulmonary function tests, a COPD assessment test, an Epworth sleepiness scale and a hospital anxiety and depression scale to evaluate the severity of COPD and possible concurrent presence of SAHS. We retrospectively analysed the data to assess correlation between the oxygen desaturation index (ODI) and each clinical variables and evaluated the predictors of ODI ≥ 15. This study included 103 patients (91 males, 88%) with a mean age of 72 ± 8 years and body mass index of 22 ± 3 kg/m(2). ODI was positively correlated with FEV1, FEV1/FVC and FEV1% predicted, which meant that ODI was inversely correlated with airflow limitation. Univariate logistic regression analysis revealed that FEV1% predicted and FEV1/FVC were predictors of ODI ≥ 15. ODI is inversely correlated with airflow limitation and milder COPD patients may have co-morbid SAHS.

Ambient ultrafine particles exacerbate oxygen desaturation during sleep in patients with chronic obstructive pulmonary disease: New insights into the effect spectrum of ultrafine particles on susceptible populations.

The health effects of ultrafine particles (UFPs) are of growing global concern, but the epidemiological evidence remains limited. Sleep-disordered breathing (SDB) characterized by hypoxemia is a prevalent condition linked to many debilitating chronic diseases. However, the role of UFPs in the development of SDB is lacking. Therefore, this prospective panel study was performed to specifically investigate the association of short-term exposure to UFPs with SDB parameters in patients with chronic obstructive pulmonary disease (COPD). Ninety-one COPD patients completed 226 clinical visits in Beijing, China. Personal exposure to ambient UFPs of 0-7 days was estimated based on infiltration factor and time-activity pattern. Real-time monitoring of sleep oxygen saturation, spirometry, respiratory questionnaires and airway inflammation detection were performed at each clinical visit. Generalized estimating equation was used to estimate the effects of UFPs. Exposure to UFPs was significantly associated with increased oxygen desaturation index (ODI) and percent of the time with oxygen saturation below 90 % (T90), with estimates of 21.50 % (95%CI: 6.38 %, 38.76 %) and 18.75 % (95%CI: 2.83 %, 37.14 %), respectively, per 3442 particles/cm3 increment of UFPs at lag 0-3 h. Particularly, UFPs' exposure within 0-7 days was positively associated with the concentration of alveolar nitric oxide (CaNO), and alveolar eosinophilic inflammation measured by CaNO exceeding 5 ppb was associated with 29.63 % and 33.48 % increases in ODI and T90, respectively. In addition, amplified effects on oxygen desaturation were observed in current smokers. Notably, individuals with better lung function and activity tolerance were more affected by ambient UFPs due to longer time spent outdoors. To our knowledge, this is the first study to link UFPs to hypoxemia during sleep and uncover the key role of alveolar eosinophilic inflammation. Our findings provide new insights into the effect spectrum of UFPs and potential environmental and behavioral intervention strategies to protect susceptible populations.

Relationship between obstructive sleep apnea and pulmonary hypertension: past, present and future.

INTRODUCTION: Obstructive sleep apnea (OSA) is a widely prevalent condition with consequent multiple organ systems complications. There is consensus that OSA is associated with negative effects on pulmonary hemodynamics but whether it contributes to development of clinical pulmonary hypertension (PH) is unclear. AREAS COVERED: In this review, we (1) highlight previous studies looking into the possible bidirectional association of OSA and PH, focusing on those that explore clinical prognostic implications, (2) explore potential pathophysiology, (3) discuss the new metrics in OSA, (4) describe endo-phenotyping of OSA, (5) recommend possible risk assessment and screening pathways. EXPERT OPINION: Relying only on symptoms to consider a sleep study in PH patients is a missed opportunity to detect OSA, which, if present and not treated, can worsen outcomes. The potential prognostic role of sleep study metrics such as oxygen desaturation index (ODI), hypoxic burden (HB) and ventilatory burden (VB) in OSA should be studied in prospective trials to identify patients at risk for PH. AHI alone has not provided clarity. In those with PH, we should consider replacing ambulatory overnight pulse oximetry (OPO) with home sleep studies (HST). In PH patients, mild OSA should be sufficient to consider PAP therapy.

Correlation between polysomnographic parameters and volumetric changes generated by maxillomandibular advancement surgery in patients with obstructive sleep apnea: a fluid dynamics study.

STUDY OBJECTIVES: Maxillomandibular advancement surgery (MMA) is a therapeutic option for obstructive sleep apnea (OSA). The main objective of this study was to determine the impact of MMA on the physical and airflow characteristics of the upper airway based on data obtained by computational fluid dynamics (CFD) and to correlate these data with polysomnography parameters. Other objectives included the identification of presurgical variables that could help avoid surgeries likely to have a low success rate. METHODS: This was a retrospective observational study of 18 patients with moderate-severe OSA who underwent MMA. Polysomnography and computed axial tomography imaging were performed before and after the surgery. Three-dimensional models for CFD study were made based on the images obtained. RESULTS: MMA achieved an average increase in airway volume of 43.75%, with a mean decrease in the maximum airway velocity of 40.3%. We found significant correlations between improved apnea-hypopnea index values and both the increase in airway volume and decrease in maximum airway speed. Patients with a maximum velocity of less than 7.2 m/s before the intervention had a high rate of surgical failure (43%). CONCLUSIONS: MMA generates a significant increase in the volume of the upper airway, which was associated with improved flow conditions in the CFD simulation. These findings also correlated with improved polysomnography parameters. Thus, CFD simulation on three-dimensional anatomical models of patients with OSA could contribute to the better selection of candidates for MMA. CITATION: Furundarena-Padrones L, Cabriada-Nuño V, Brunsó-Casellas J, et al. Correlation between polysomnographic parameters and volumetric changes generated by maxillomandibular advancement surgery in patients with obstructive sleep apnea: a fluid dynamics study. J Clin Sleep Med. 2024;20(3):371-379.

Profile of Patients With Obstructive Sleep Apnea: An Initial Experience in a Tertiary Health Facility.

Introduction Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder with increasing prevalence worldwide. The disease is, however, underdiagnosed in many resource-limited countries, especially in sub-Saharan Africa with unknown prevalence. Study aim The aim of this study was to determine the demographic and clinical characteristics, as well as measured sleep study parameters of suspected OSA patients. Methods The study was a retrospective review of the clinical characteristics and home sleep study reports of patients seen at the respiratory and sleep clinic from January 2020 to June 2022. Descriptive statistics such as means, medians, and percentages were employed to summarize the data using tables and graphs. Spearman correlation coefficient and Fisher's exact test were used to determine associations between the variables. Findings The study participants were predominantly male, and 64.7% were ≥50 years of age. Approximately 76% of the cases had moderate-to-severe OSA based on the apnea-hypopnea index (AHI) scores with a mean BMI of 38.4kg/m2 and 43.1kg/m2, respectively (p=0.013), and a mean STOP-BANG score of 5.2 and 6.2, respectively (p <0.001). There was a positive correlation between AHI scores and BMI of the patients (r=0.252, p=0.003), as well as with their STOP-BANG scores (r=0.436, p< 0.001). Oxygen desaturation index (ODI) parameters of participants also positively correlated with the AHI scores (r=0.872, p<0.001). Conclusion The proportion of patients with moderate-to-severe OSA was high. Obesity was significantly associated with AHI scores, which also positively correlated with the STOP-BANG and ODI scores. These results suggest that the burden of OSA, which is closely linked with obesity, could be underestimated in Ghana and requires epidemiological studies in the very near future to clearly define and anticipate its impact on the health economy of Ghana.