Severe Obstructive Sleep Apnea Patients Research Articles

Cluster Headache Characteristics and the Severity of Obstructive Sleep Apnea: Insights from Polysomnography Analysis

Purpose: Cluster headache (CH) is characterized by circadian rhythmicity of the attacks, and it is known to respond exceptionally well to oxygen therapy. Furthermore, obstructive sleep apnea (OSA) frequently co-occurs with CH, and both conditions may be parallel outcomes of hypothalamic dysfunction rather than being causally related. The aim of this study was to analyze the association between CH characteristics and polysomnographic factors stratified by the severity of OSA in patients diagnosed with CH and OSA.Methods: We retrospectively analyzed the data of OSA patients with CH who were enrolled in the Korean Cluster Headache Registry and underwent polysomnography due to clinical suspicion of OSA. Basic demographic data, headache-related parameters, and polysomnographic parameters were analyzed according to the severity of OSA (apnea-hypopnea index: <15 or ≥15 per hour).Results: Twelve CH patients with OSA were evaluated. The onset age of CH was higher (38.5 years vs. 19.0 years, p=0.010), and the maximal duration of cluster bouts was longer (156.5 days vs. 47.0 days, p=0.037) in the moderate-to-severe OSA group than in the mild OSA group. Unlike other polysomnographic parameters, the apnea-hypopnea index and respiratory arousal index during rapid eye movement (REM) sleep were comparable across different OSA severity levels.Conclusion: The onset age and duration of cluster bouts were associated with the severity of OSA in CH patients. Additionally, the relatively high susceptibility to hypoxia during REM sleep in patients with mild OSA implies that interventions may be potentially advantageous, even in CH patients with mild OSA.

Association Between Obstructive Sleep Apnea (OSA) Severity and Optimal Continuous Positive Airway Pressure (CPAP); Do Severe OSA Patients Always Need High CPAP Pressure?

Objective: Obstructive sleep apnea (OSA) is a prevalent sleep disorder associated with an increased risk of cardiovascular disease. Severity of OSA is assessed using the apnea-hypopnea index (AHI), but the optimal continuous positive airway pressure (CPAP) does not always correlate proportionally with AHI. This study aims to identify factors leading to the need for high CPAP pressure despite low AHI or vice versa.Methods: The study includes 91 patients diagnosed with OSA through polysomnography. Participants undergoing CPAP titration were categorized in three groups based on AHI (30/h) and optimal CPAP pressure (10 cm H<sub>2</sub>O); low AHI and high CPAP pressure group (LH group), high AHI and low CPAP pressure group (HL group), direct proportion group (DP group). The Kruskal–Wallis nonparametric statistical test is used to identify significant differences between the three groups.Results: Among the subjects, 78% were male, with no significant age or BMI differences between groups. There were 36 (39.6%) subjects with mild to moderate OSA and 55 (60.4%) subjects with severe OSA. The study revealed that patients requiring high CPAP pressure despite low AHI (LH group) had lower AHI, oxygen desaturation index, and various other parameters compared to other groups as expected. However, certain factors like the percentage of hypopnea in AHI, limb movement (LM) arousal index, and spontaneous arousal index were higher in the LH group.Conclusion: Patients with mild to moderate OSA requiring high CPAP pressure are more likely associated with specific aspects such as hypopnea in AHI, LM arousal, and spontaneous arousal index, presenting unpredictable outcomes.

Obstrüktif Uyku Apnede (OUA) Ortalama Trombosit Hacmi (OTH) ve OUA'da Sürekli Pozitif Hava Yolu Basıncı (CPAP) Tedavisinin OTH Üzerine Etkisi

Aims: In this study, our objective was to evaluate mean platelet volume (MPV), an indirect marker of platelet activation, in patients with obstructive sleep apnea (OSA), and assess the effect of OSA treatment with continuous positive airway pressure (CPAP) on MPV
 Methods: In this study, records of consecutive patients who underwent polysomnographic evaluation for OSA symptoms in the Sleep Disorders Laboratory during a one-year period were reviewed retrospectively. Patients who had both complete blood count and MPV measurements were included in the study.
 Results: A total of 158 patients, including 51 females (32.3%) and 107 males (67.7%), were included in the study. The mean age of the patients was 51±13 (min-18, max-82) years. OSA was detected in 74.1% (117/158) of the patients. It was determined that as the severity of OSA increased, hemoglobin and hematocrit values increased significantly. There was no significant difference in platelet count according to the presence and severity of OSA. The MPV was significantly lower in severe OSA cases compared to those without OSA and mild OSA cases. A negative correlation was observed between MPV and the apnea-hypopnea index, desaturation index, and the amount of oxygen saturation below 90% during sleep. There was no significant difference in median erythrocyte and thrombocyte counts, hematocrit percentage and hemoglobin values before and after treatment in OSA patients who used CPAP therapy. However, a significant decrease in MPV was observed after OSA treatment compared to pre-treatment. (p=0.021).
 Conclusions: The results of the study do not support an increase in MPV and hence platelet activation in severe OSA patients compared with those without OSA. However, the results suggest that one month of CPAP treatment reduces MPV and thus platelet activation in severe OSA patients. Further controlled, prospective studies including treatment outcomes are needed on this subject.

Nocturnal gastro-oesophageal reflux and respiratory symptoms are increased in sleep apnoea: comparison with the general population

AimTo assess respiratory symptoms and nocturnal gastro-oesophageal reflux (nGER) among untreated obstructive sleep apnoea (OSA) patients, compared with the general population. Also, if nGER associates differently with respiratory symptoms among...

Are there any differences at gray matter sites between severe obstructive sleep apnea patients and healthy controls?

ObjectivesObstructive sleep apnea (OSA) is a disease that may cause many medical conditions. Neurocognitive disorders may be triggered by OSA. In recent studies, selectively decreased gray matter tissue was observed in patients with OSA. We aimed to determine if there was a substantial difference in patients with extreme OSA by comparing the microstructural changes in different gray matter sub-areas with healthy controls using diffusion-weighted imaging methods. MethodsWe studied 15 diagnosed severe OSA subjects before any treatment and 32 healthy control subjects. High resolution Magnetic Resonance Imaging (MRI) T1 and T2-weighted scans were visually examined to assess any major brain lesions. ResultsThere were no statistically significant differences of age and gender between the groups.The left and right globus pallidus, putamen and thalamus values did not differ significantly between OSA and control subjects. Right putamen values was negatively correlated with Apnea Hypopnea Index (AHI), supine AHI and non-REM AHI in OSA subjects, but no correlations appeared with left putamen values. The other gray matter parameters did not show any correlations with PSG parameters. AHI, Supine AHI, Non-Supine AHI, REM and NON-REM AHI values was not show any correlation with Right and Left Putamen volume sizes. ConclusionsWe made a morphological comparison of various gray matter areas of OSA patients and healthy volunteers in our study. We observed a significant decrease in right putamen gray matter volumes in patients with higher AHI values. Decreased cognitive functions are found in patients with OSA. In order to demonstrate this cognitive loss in patients with morphologically there is a need for further prospective studies with larger sample sizes.

Physical discomfort and longer sleep time important influencing factors in CPAP adherence in moderate and severe obstructive sleep apnea patients

Physical discomfort and longer sleep time important influencing factors in CPAP adherence in moderate and severe obstructive sleep apnea patients

The Epworth sleepiness scale may have more advantages than the multiple sleep latency test in assessing sleepiness in patients with obstructive sleep apnea.

This study aimed to analyze the brain function of severe obstructive sleep apnea patients with various sleepiness assessment methods and explore the brain imaging basis for the differences between these methods. This study included 30 severe obstructive sleep apnea patients and 19 healthy controls. Obstructive sleep apnea patients were divided into a subjective excessive daytime sleepiness group and a subjective non-excessive daytime sleepiness group according to the Epworth sleepiness scale. Moreover, they were divided into an objective excessive daytime sleepiness group and an objective non-excessive daytime sleepiness group according to the multiple sleep latency test. The fractional amplitude of low-frequency fluctuation was used to assess the features of brain function. Compared with healthy controls, participants in the subjective excessive daytime sleepiness group exhibited higher fractional amplitude of low-frequency fluctuation signals in the right thalamus, left cerebellar lobe 6, left putamen, and pallidum. Participants in the objective excessive daytime sleepiness group showed higher fractional amplitude of low-frequency fluctuation signals in the right thalamus and lower fractional amplitude of low-frequency fluctuation signals in the right superior frontal gyrus, the dorsolateral and superior frontal gyrus, and the medial orbital. We concluded that the thalamus may be involved in subjective and objective sleepiness regulation. Functional abnormalities in the putamen and pallidum may be involved in subjective sleepiness, whereas the frontal lobe may be involved in objective sleepiness.

The relationship between aerodynamic characteristics of the upper airway and severity of obstructive sleep apnea in adults

ABSTRACT Objective To investigate the relationship between aerodynamic characteristics of theupper airway and severity of obstructive sleep apnea (OSA)in adults. Methods Ninety-seven adult OSA patients underwent polysomnography and cone beam computedtomography (CBCT). The anatomical and aerodynamic characteristics were measuredbased on CBCT images and computational fluid dynamics modelling of the upper airway. Results Aftercontrolling for patients’ gender, age, and body mass index (BMI), the maximumvelocity during inspiration (In-Vmax) led to the largest increase in theexplanatory power of apnea-hypopnea index (AHI) variation. The In-Vmax was closely correlated with theminimum axial area, and their relationship was represented by an inverselyproportional fitted curve. Conclusions TheIn-Vmax was the most relevant to OSA severity, and it could be used to assistin recognizing severe OSA patients and as a primary variable to evaluate treatmentoutcomes of OSA. The In-Vmax was closely related to the most constricted areaof the upper airway.

Urinary metabolite signatures reflect the altered host metabolism in severe obstructive sleep apnea

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder. The onset and progression of OSA are often linked with severe cardiovascular and metabolic comorbidities. At the same time, given the increasing prevalence of OSA, novel methods to screen OSA and its follow-up are needed. Untargeted metabolic profiling of OSA patients and healthy controls was planned to capture a snapshot of urinary metabolites and potential biomarkers using the gas chromatography-mass spectrometry (GC–MS) method.Polysomnography (PSG) confirmed severe OSA patients with AHI index ≥ 30 were considered for urine sample collection. The sample size was constituted of OSA (n = 36) and healthy controls (n = 36). Metabolite extraction and derivatization were performed and metabolomic analysis was performed by using GC–MS.The obtained data set was statistically analyzed using univariate and multivariate analysis. The Orthogonal partial least-squares discriminant analysis (OPLS-DA) was performed to screen differential metabolites between OSA patients and healthy controls.The metabolomic analysis revealed a total of 142 significantly altered metabolites of interest.Biomarker analysis allows for the creation of a list of putative urinary biomarkers including GABA, malic acid, glutamic acid, epichoric acid etc., with an accuracy of 99.8 % to 100 % for OSA screening. Subsequently, pathway analysis revealed that related biochemical pathways like the tricarboxylic acid cycle (TCA), glutamate/glutamine, amino acid and fatty acid metabolism, that are significantly interlinked with these metabolic biomarkers can play a crucial role in the pathogenesis of OSA. This study paves the way to undertake mass screening in a larger population to identify specific and reliable biomarkers.

Characteristics of genioglossus neuromuscular activity in patients with obstructive sleep apnea during drug-induced sleep

Objective: To analyze genioglossus (GG) activation responses to the negative pressure of upper airway cavity during awake and different sleep stages in patients with different obstructive sleep apnea (OSA) graduation. Methods: This prospective cohort study started from August 2019 to January 2021, recruited 42 male OSA patients aged from 21 to 59 (38.77±8.42) years. After completing whole night polysomnography (PSG) and upper airway CT, each subject underwent drug-induced sleep with simultaneous monitoring of genioglossal electromyography (GGEMG) and pressure of epiglottis (Pepi). Subjects were divided into three groups of mild OSA(7 males), moderate OSA(12 males), and severe OSA(23 males). The differences in upper airway CT measurements, parameters of GGEMG and Pepi during awake and induced sleep were compared. Statistical analysis was conducted by SPSS 21.0. Results: There was no significant difference in the GGEMG parameters between the mild and moderate groups. In wakefulness, the peak phasic GGEMG of the severe group was higher than the mild group (t=1.249, P=0.025), with no statistically difference in the corresponding Pepi. In the sleep onset, the GGEMG parameters and Pepi in severe group were higher than the other two groups. Linear regression analysis of the maximum GGEMG and maximum Pepi at the end of obstructive apnea (OA) in all moderate plus severe patients (n=35) was shown nonlinear correlation (r=0.28, P=0.694). The airway length of the glossopharyngeal cavity was linearly correlated with the maximum Pepi of OA (r=0.468, R2=0.219, P=0.005). Conclusions: The individual difference of GG activation in OSA patients is related to the severity of the disease (frequency of respiratory events) and negative pressure stimulation. In moderate and severe OSA patients, GG activity is not in harmony with the corresponding negative pressure stimulation, which may be one of the mechanisms leading to the aggravation of OSA.

Triglyceride-glucose index as a predictor of obstructive sleep apnoea severity in the absence of traditional risk factors.

We evaluated the association between the triglyceride-glucose (TG) index, a marker of insulin resistance, and obstructive sleep apnoea (OSA) severity in patients without diabetes mellitus, obesity, and metabolic syndrome. This retrospective cohort study included 1,527 patients. We used univariate and multivariate analyses to identify the independent predictors associated with OSA. Most patients were males (81.5%) with a mean age of 43.9 ± 11.1 (15-90) years. Based on the apnoea-hypopnea index (AHI), 353 (23.1%) patients were included in the control group, whereas 32.4%, 23.5%, and 21% had mild, moderate, and severe OSA, respectively. The TG index values demonstrated significant associations with OSA patients compared with the control group (p = 0.001). In addition, the mean values of the oxygen desaturation index (ODI), AHI, minimum oxygen saturation, and total sleep time percentage with saturation below 90% demonstrated statistically significant differences among the TG index groups (p: 0.001; p:0.001; p:0.001; p:0.003). The optimal TG index cutoff value to predict OSA was 8.615 (AUC = 0.638, 95% CI = 0.606-0.671, p = 0.001). In multivariate logistic regression analysis, after adjusting for age, sex, and body mass index, the TG index was independently associated with OSA patients. The TG index is independently associated with increased risk for OSA. This indicates that this index, a marker for disease severity, can be used to identify severe OSA patients on waiting lists for PSG.

A Novel Clinical Tool to Detect Severe Obstructive Sleep Apnea.

Obstructive sleep apnea (OSA) is a disease with high morbidity and is associated with adverse health outcomes. Screening potential severe OSA patients will improve the quality of patient management and prognosis, while the accuracy and feasibility of existing screening tools are not so satisfactory. The purpose of this study is to develop and validate a well-feasible clinical predictive model for screening potential severe OSA patients. We performed a retrospective cohort study including 1920 adults with overnight polysomnography among which 979 cases were diagnosed with severe OSA. Based on demography, symptoms, and hematological data, a multivariate logistic regression model was constructed and cross-validated and then a nomogram was developed to identify severe OSA. Moreover, we compared the performance of our model with the most commonly used screening tool, Stop-Bang Questionnaire (SBQ), among patients who completed the questionnaires. Severe OSA was associated with male, BMI≥ 28 kg/m2, high blood pressure, choke, sleepiness, apnea, white blood cell count ≥9.5×109/L, hemoglobin ≥175g/L, triglycerides ≥1.7 mmol/L. The AUC of the final model was 0.76 (95% CI: 0.74-0.78), with sensitivity and specificity under the optimal threshold selected by maximizing Youden Index of 73% and 66%. Among patients having the information of SBQ, the AUC of our model was statistically significantly greater than that of SBQ (0.78 vs 0.66, P = 0.002). Based on common clinical examination of admission, we develop a novel model and a nomogram for identifying severe OSA from inpatient with suspected OSA, which provides physicians with a visual and easy-to-use tool for screening severe OSA.

Increasing and high prevalence of moderate to severe obstructive sleep apnea in acute ischemic stroke in Taiwan

The prevalence of obstructive sleep apnea (OSA) after stroke is variable, likely due to the time of examination and patient population. Although risk factors for OSA are well established, those for OSA in patients with ischemic stroke have not yet been fully identified. Therefore, we examined the prevalence of OSA and identified risk factors for OSA in the acute stage of ischemic stroke in the Taiwanese population. A total of 103 patients with acute ischemic stroke were screened for OSA by performing polysomnography. The demographic and clinical data, Epworth Sleepiness Scale score, and other stroke risk factors were recorded. Sleep parameters, namely sleep efficiency, sleep stages, apnea-hypopnea index, and oxygen desaturation index were recorded. Logistic regression analysis was conducted to determine clinical and demographic risk factors for moderate to severe OSA in patients with stroke. We determined that 91.2% of the patients had OSA in the acute stage of ischemic stroke, and 70% of the patients had moderate to severe OSA. Multivariate logistic regression analysis revealed that patients aged ≥65 years had a significantly higher risk of moderate to severe OSA (adjusted OR: 3.04, 95% CI: 1.20-7.69, p<0.05) compared with patients with ischemic stroke aged <50 years. OSA is highly prevalent among patients with ischemic stroke in the acute stage, and those aged ≥65 years had a significantly increased risk of moderate to severe OSA. In clinical practice, routine PSG screening of OSA may be necessary among older patients with stroke.

Auto-adjusted versus fixed positive airway pressure in patients with severe OSA: A large randomized controlled trial.

Continuous positive airway pressure (CPAP) in the treatment of severe obstructive sleep apnoea (OSA) can be used in fixed CPAP or auto-adjusted (APAP) mode. The aim of this prospective randomized controlled clinical study was to evaluate the 3 month-efficacy of CPAP used either in fixed CPAP or APAP mode. Eight hundred one patients with severe OSA were included in twenty-two French centres. After 7 days during which all patients were treated with APAP to determine the effective pressure level and its variability, 353 and 351 patients were respectively randomized in the fixed CPAP group and APAP group. After 3 months of treatment, 308 patients in each group were analysed. There was no difference between the two groups in terms of efficacy whatever the level of efficient pressure and pressure variability (p = 0.41). Exactly, 219 of 308 patients (71.1%) in the fixed CPAP group and 212 of 308 (68.8%) in the APAP group (p = 0.49) demonstrated residual apnoea hypopnoea index (AHI) <10/h and Epworth Score <11. Tolerance and adherence were also identical with a similar effect on quality of life and blood pressure evaluation. The two CPAP modes, fixed CPAP and APAP, were equally effective and tolerated in severe OSA patients.

Association of Perceived Stress Scale with the Severity of Obstructive Sleep Apnea in Pakistani Population

Background: Obstructive Sleep Apnea (OSA) is a prevalent sleep disorder characterized by recurrent episodes of partial or complete upper airway obstruction during sleep, leading to disruptions in breathing patterns and, consequently, reduced oxygen level. OSA has traditionally been viewed as a sleep-related physiological disorder, there is growing recognition that psychological factors, such as stress, may play a role in its onset and progression. Objective: To evaluate the association of Perceived Stress Scale with the severity of Obstructive Sleep Apnea in Pakistani Population. Study Design: Prospective cross-sectional study. Settings: untreated OSA individuals at Pulmonary Vascular and Sleep Disorders division of Dow University Hospital in Karachi, Pakistan. Duration: Study was done during a period of six months from May 2022 to October 2022. Methods: Patients OSA diagnosis through overnight Polysomnography with AHI of more than 5, and OSA participants above 18 years of age were included. A stress questionnaire was filled out when the individual came for overnight Polysomnography. The Sleep technologist measures the anthropometric measurements like height, and weight through height scales and weight machines, the neck circumference through the inch tape, BMI was computed through a formula which is weight in kg/height in meter2, and stress was evaluated through the Perceived Stress Scale (PSS). Data analysis was performed by using IBM SPSS statistics 26. Results: A total of 167 OSA patients participated in the study. There were 100 (60%) male and 67 (40%) female individuals. The mean age of females who perceived stress was 53.7 ± 10.5years which is higher from males 47.9 ± 13.1 years. Low stress was found in moderate and severe OSA as compare to mild OSA, similarly 49% moderate stress in Moderate OSA and 52% moderate stress in Severe OSA patients respectively. The percentage of high stress was significantly prominent in Mild OSA in comparison to Moderate and Severe OSA. The result of the study shows that the perceived stress scale is significantly correlated with Obstructive sleep apnea (p&lt;0.001). Conclusion: The outcomes of this study reveal a direct significant correlation between OSA and the Perceived Stress Scale. The findings underscore the importance of ongoing investigation to delve into potential underlying mechanisms.

How does obstructive sleep apnea alter cerebral hemodynamics?

We aimed to characterize the cerebral hemodynamic response to obstructive sleep apnea/hypopnea events, and evaluate their association to polysomnographic parameters. The characterization of the cerebral hemodynamics in obstructive sleep apnea (OSA) may add complementary information to further the understanding of the severity of the syndrome beyond the conventional polysomnography. Severe OSA patients were studied during night sleep while monitored by polysomnography. Transcranial, bed-side diffuse correlation spectroscopy (DCS) and frequency-domain near-infrared diffuse correlation spectroscopy (NIRS-DOS) were used to follow microvascular cerebral hemodynamics in the frontal lobes of the cerebral cortex. Changes in cerebral blood flow (CBF), total hemoglobin concentration (THC), and cerebral blood oxygen saturation (StO2) were analyzed. We considered 3283 obstructive apnea/hypopnea events from sixteen OSA patients (Age (median, interquartile range) 57 (52-64.5); females 25%; AHI (apnea-hypopnea index) 84.4 (76.1-93.7)). A biphasic response (maximum/minimum followed by a minimum/maximum) was observed for each cerebral hemodynamic variable (CBF, THC, StO2), heart rate and peripheral arterial oxygen saturation (SpO2). Changes of the StO2 followed the dynamics of the SpO2, and were out of phase from the THC and CBF. Longer events were associated with larger CBF changes, faster responses and slower recoveries. Moreover, the extrema of the response to obstructive hypopneas were lower compared to apneas (p < .001). Obstructive apneas/hypopneas cause profound, periodic changes in cerebral hemodynamics, including periods of hyper- and hypo-perfusion and intermittent cerebral hypoxia. The duration of the events is a strong determinant of the cerebral hemodynamic response, which is more pronounced in apnea than hypopnea events.

Subjective Efficiency Evaluation after Maxillomandibular Advancement Surgery in Obstructive Sleep Apnea Patients.

To investigate subjective efficiency outcomes after maxillomandibular advancement (MMA) surgery in obstructive sleep apnea (OSA) patients. A prospective cohort study was carried out between December 2016 and May 2021, including 30 severe or treatment-refractory OSA patients treated by MMA surgery. All patients answered four validated questionnaires: the Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire (FOSQ), Mandibular Function Impairment Questionnaire (MFIQ), and EQ-5D-3L (i.e., EQ-5D and EQ-VAS). They also answered one custom-made questionnaire (AMCSQ). Questionnaires were requested to be filled out 1 week before surgery and at least 6 months after surgery. The total preoperative and postoperative scores on the questionnaires were compared. The mean total ESS (p < 0.01), FOSQ (p < 0.01), EQ-5D (p < 0.05), and EQ-VAS (p < 0.01) scores showed significant improvement, which was in accordance with an improvement in the mean postoperative apnea/hypopnea index score (p < 0.01). In contrast, the mean total MFIQ score (p < 0.01) indicated a decline in mandibular function. This study confirms the hypothesis that MMA surgery in OSA patients improves outcomes, both objectively and subjectively, with the exception of postoperative mandibular function.

Effects of a single night of continuous positive airway pressure on spontaneous brain activity in severe obstructive sleep apnea

This study aimed to investigate the effect of a single night of continuous positive airway pressure (CPAP) treatment on spontaneous brain activity and the underlying neuropathological mechanisms in patients with severe obstructive sleep apnea (OSA). The study involved 30 severe OSA patients and 19 healthy controls (HC). Fractional amplitude of low-frequency fluctuation (fALFF) and regional homogeneity (ReHo) methods were employed to evaluate spontaneous brain activity in all participants. Following a single night of CPAP treatment, ReHo values increased in the bilateral caudate and decreased in the right superior frontal gyrus. The fALFF values increased in the left orbital part of the middle frontal gyrus and the right orbital of the inferior frontal gyrus (Frontal_Inf_Orb_R). However, fALFF values decreased in the medial part of the left superior frontal gyrus and the right supramarginal part of the inferior parietal lobe. Pearson correlation analysis revealed a positive relationship between the change in the fALFF in the Frontal_Inf_Orb_R and the change in REM sleep duration (r = 0.437, p = 0.016) following a single night of CPAP treatment. We concluded that observing changes in abnormal fALFF and ReHo in OSA patients before and after a single night of CPAP treatment may enhance our understanding of the neurological mechanisms in patients with severe OSA.

Altered functional connectivity of the ascending reticular activating system in obstructive sleep apnea

Repeated arousals during sleep in obstructive sleep apnea (OSA) may lead to altered functional connectivity (FC) of the ascending reticular activating system (ARAS). We evaluated resting-state FC between eight ARAS nuclei and 105 cortical/subcortical regions in OSA patients and healthy controls. Fifty patients with moderate to severe OSA and 20 controls underwent overnight polysomnography and resting-state functional magnetic resonance imaging. Seed-to-voxel analysis of ARAS–cortex FC was compared between OSA patients and controls. The ARAS nuclei included the locus coeruleus (LC), laterodorsal tegmental nucleus (LDTg), and ventral tegmental area (VTA). FC values of three ARAS nuclei (the LC, LDTg, and VTA) significantly differed between the groups. FC of the LC with the precuneus, posterior cingulate gyrus, and right lateral occipital cortex (LOC) was stronger in OSA patients than controls. FC between the LDTg and right LOC was stronger in OSA patients than controls, but FC between the VTA and right LOC was weaker. Average LC–cortex FC values positively correlated with the arousal, apnea, and apnea–hypopnea index in OSA patients. Alterations in ARAS–cortex FC were observed in OSA patients. The strength of LC–cortex noradrenergic FC was related to arousal or OSA severity in patients.

0846 Prevalence of Obstructive Sleep Apnea Among Medical ICU Patients

Abstract Introduction The prevalence of Obstructive Sleep Apnea (OSA) among medical intensive care unit (MICU) patients is unknown. However, OSA prevalence in the general population and in conditions that are frequently comorbid in ICU populations (e.g., diabetes and cardiovascular disease) suggests that OSA may be common among MICU patients. Our objective is to prospectively examine the prevalence and severity of OSA in patients admitted to a tertiary academic MICU. Methods This was a prospective observational study that included patients admitted to the MICU from July to December 2022. Patient charts were reviewed for patient demographics, clinical characteristics, and evidence of pre-existing OSA. Pre-existing OSA was assessed via in depth review of the electronic medical record and included data fields such as the past medical history, documentation of OSA treatment, description of OSA diagnosis in outpatient provider notes, and/or sleep study records. Based on chart review, we also assigned confidence ratings for the OSA diagnosis (high versus low) and noted patients for whom outpatient providers had a high clinical suspicion for OSA in the absence of definitive sleep evaluation. Results Herein, we present preliminary analysis of 345 MICU patients. Mean age (SD) was 64 (18) years; 49% were female, 23% were Black, and 67% were White. Acute respiratory failure (36%) and septic shock (24%) were the leading reasons for admission. Mean (SD) APACHE II severity of illness score was 19.6 (8.8) and body mass index was 27.5 (8.5). Pre-existing OSA was identified in 19% of patients; 63% of pre-existing OSA patients were characterized as “high confidence” in OSA diagnosis. An additional 6% of patients had high clinical suspicion of OSA. Severity data was sparse in the chart with only 17% of OSA patients having severity data available; OSA severity distribution was as follows: mild 9%, moderate 27%, and severe 64%. Conclusion Our preliminary analysis indicates that OSA is notably prevalent among MICU patients. We hypothesize that OSA is under-recognized and consequently undertreated in MICU patients. With this in mind, future directions include investigation of the recognition, treatment, and outcomes related to pre-existing OSA in critically ill patients. Support (if any) NHLBI, NIH T35HL007649