Oxygen Desaturation Index Research Articles

Assessing the contribution of mild high-altitude exposure to obstructive sleep apnea-hypopnea syndrome comorbidities.

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a common sleep disorder. The lower atmospheric pressure and decreased oxygen levels of high-altitude areas can exacerbate the severity of OSAHS, but research into OSAHS in high-altitude areas remains limited. This study, from June 2015 to January 2020, involved 4,667 patients with suspected OSAHS and 38 healthy volunteers. The non-OSAHS group (AHI <5/h) had 395 patients, while the larger OSAHS group (AHI ≥5/h) comprised 4,272 patients. The significant size difference between the groups emphasized the study's focus on OSAHS, using the non-OSAHS mainly for comparison. Sleep technicians monitored the OSAHS patient group overnight by polysomnography (PSG), the apnea-hypopnea index (AHI), the mean oxygen saturation (MSpO2), lowest oxygen saturation (LSpO2), the oxygen desaturation index (ODI) and the total sleep time with oxygen saturation less than 90% (TST-SpO2 <90%). Healthy volunteers self-monitored sleep patterns at home, using the CONTEC RS01 respiration sleep monitor with a wristwatch sleep apnea screen meter. The RSO1 wristwatch-style device has already been studied for consistency and sensitivity with the Alice-6 standard multi-lead sleep monitor and can be used for OSAHS screening in this region. LSpO2 recordings from healthy volunteers (86.36 ± 3.57%) and non-OSAHS (AHI <5/h) cohort (78.59 ± 11.99%) were much lower than previously reported normal values. Regression analysis identified no correlations between AHI levels and MSpO2 or TST-SpO2 <90%, weak correlations between AHI levels and LSpO2 or MSpO2, and a strongly significant correlation between AHI levels and the ODI (r = 0.76, p < 0.05). The data also indicated that the appropriate clinical thresholds for OSAHS patients living at mild high altitude are classified as mild, moderate, or severe based on LSpO2 saturation criteria of 0.85-0.90, 0.65-0.84, or <0.65, respectively. The study findings suggest that individuals with an AHI score below 5 in OSAHS, who reside in high-altitude areas, also require closer monitoring due to the elevated risk of nocturnal hypoxia. Furthermore, the significant correlation between ODI values and the severity of OSAHS emphasizes the importance of considering treatment options. Additionally, the assessment of hypoxemia severity thresholds in OSAHS patients living in high-altitude regions provides valuable insights for refining diagnostic guidelines.

The impact of study type and sleep measurement on oxygen desaturation index calculation.

The oxygen desaturation index (ODI) is an important measure of sleep-disordered breathing during polysomnography (PSG); however, the AASM Manual (V3) does not specify whether to include oxygen desaturations occurring during wake epochs. Additionally, an ODI obtained from PSG can differ from an ODI using home sleep apnea tests (HSATs) that do not measure sleep, hampering diagnostic and treatment decision reliability. This study aimed to (1) compare an ODI that included all desaturations with an ODI that excluded desaturations occurring during wake epochs in PSG and (2) compare ODIs obtained from PSG with HSAT. 100 consecutive PSGs for investigation of obstructive sleep apnea were compared. ODIs were calculated including all desaturations (ODIall) and by excluding desaturations entirely during wake epochs (ODIsleep). Additionally, we compared ODIall with an ODI calculated using monitoring time as the denominator (ODIHSAT). The median (interquartile range) 3% ODI for ODIall was 22.8 (13.1, 44.1) events/h and ODIsleep was 17.6 (11.5, 35.2) events/h (median difference: -3.9 events/h [-8.2, -0.9]; 21.0% [8.7%, 33.2%]). This discrepancy was larger with increasing ODI and decreasing sleep efficiency. The ODIHSAT was 17.4 (11.3, 35.2) events/h and the median reduction in ODIHSAT vs ODIall was -4.5 (-10.9, -2.0) events/h (21.6%; 11.1%, 33.8). ODI was significantly reduced when desaturations in wake epochs were excluded, and when ODI was based on monitoring time rather than sleep time, with the potential for underestimation of disease severity. Results suggest that ODI can differ substantially depending on the calculation and study type used, and that there is a need for standardization to ensure consistent diagnosis and treatment outcomes. Whenn CB, Wilson DL, Ruehland WR, Churchward TJ, Worsnop C, Tolson J. The impact of study type and sleep measurement on oxygen desaturation index calculation. J Clin Sleep Med. 2024;20(5):709-717.

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 10s. This study investigated the association between reduced SpO2 and parasympathetic nervous system activity (PSNA) during night sleep in young adults (n=63; aged 20-32years). Changes in PSNA were measured every minute for 24h 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.

Improving CPAP Therapy with Superimposed Pressure Oscillation

Background: Continuous positive airway pressure (CPAP) is considered the gold standard therapy for Obstructive Sleep Apnea (OSA); however, many side effects, such as uncomfortable high titration pressure (TP) and mouth dryness, are associated with this treatment. This work proposes using pressure oscillations superimposed on a mean pressure to modulate the upper airways, reduce TP, and stimulate the salivary glands to reduce mouth dryness. Methods: Two nonconsecutive overnight randomized controlled clinical trials were designed, one with a standard CPAP setup but reduced TP and the other by adding superimposed pressure oscillations (SIPO) to the reduced TP CPAP setup. 33 OSA patients who usually received CPAP treatment with predetermined TP settings participated in the two trials. Complete polysomnography was performed for sleep and patient assessments. However, a spitting technique protocol was used on 15 randomly selected patients from the same group to investigate the effect of SIPO on mouth dryness. These trials are registered under ACTRN12622001518752. Results: The apnea-hypopnea index (AHI) was significantly reduced from 25.08 ± 2.32 to 17.56 ± 2.11 (p = 0.020*) with SIPO, indicating a 29.95% reduction in AHI and a decrease in breathing obstructions during enhanced therapy. Additionally, SIPO significantly decreased the oxygen desaturation index (ODI) (p = 0.002), maintaining the blood oxygen level within the normal range during the trials. ODI≥3 decreased significantly by 38.04% with SIPO. Saliva test results demonstrated that SIPO significantly increased saliva volume by 23.13% in non-stimulation and by 39.09% during stimulation compared to the CPAP trial. Conclusions: This work demonstrates that SIPO reduces the TP to 70% of its standard clinical setting and stimulates salivary secretion to reduce mouth dryness. Further, significant improvements in AHI, respiratory arousal index (RAI), Arousal index (AI), and sleep efficiency (SE) are observed. This work is proof of concept, and further trials should be undertaken to generalize the proposed technique.

Clinical and PSG Characteristics Comparison of Central Sleep Apnea in the Elderly and Non-Elderly Patients.

To explore the characteristics of elderly patients with central sleep apnea (CSA). This retrospective study divided 123 patients with CSA into elderly and non-elderly groups, and compared them in terms of demographic characteristics (age, BMI, etc), underlying diseases (hypertension, coronary heart disease, and cardiac arrhythmias, etc). and polysomnography parameters. Multiple linear regression analysis was conducted to investigate the potential risk factors of central apnea index (CAI). Compared with the non-elderly group, patients in the elderly group had lower body mass index, a higher proportion of comorbidities of coronary heart disease, arrhythmias, and diabetes, lower apnea-hypopnea index (AHI), obstructive apnea index (OAI) and oxygen desaturation index (ODI). CAI of the elderly group showed a trend higher than that of the non-elderly group with no statistical difference. However, the ratio of CAI to AHI in the elderly group was significantly higher (0.264 vs 0.154, P=0.003). True CSA was less prevalent than companion CSA in both groups. The results of multiple regression analysis indicated CAI was independently associated with age (β=0.256, P=0.005), OAI (β=-0.543, P<0.001), MAI (β=-0.267, P=0.005), ODI (β=0.538, P<0.001), heart failure (β=0.300, P<0.001). CSA typically coexists with other types of sleep apnea. Elderly CSA patients have characteristics such as a lower BMI, and a milder decrease in blood oxygen saturation, along with higher prevalence of arrhythmia and coronary heart disease. Age may be a potential risk factor for CSA.

Artificial intelligence augmented home sleep apnea testing device study (AISAP study).

This study aimed to prospectively validate the performance of an artificially augmented home sleep apnea testing device (WVU-device) and its patented technology. The WVU-device, utilizing patent pending (US 20210001122A) technology and an algorithm derived from cardio-pulmonary physiological parameters, comorbidities, and anthropological information was prospectively compared with a commercially available and Center for Medicare and Medicaid Services (CMS) approved home sleep apnea testing (HSAT) device. The WVU-device and the HSAT device were applied on separate hands of the patient during a single night study. The oxygen desaturation index (ODI) obtained from the WVU-device was compared to the respiratory event index (REI) derived from the HSAT device. A total of 78 consecutive patients were included in the prospective study. Of the 78 patients, 38 (48%) were women and 9 (12%) had a Fitzpatrick score of 3 or higher. The ODI obtained from the WVU-device corelated well with the HSAT device, and no significant bias was observed in the Bland-Altman curve. The accuracy for ODI > = 5 and REI > = 5 was 87%, for ODI> = 15 and REI > = 15 was 89% and for ODI> = 30 and REI of > = 30 was 95%. The sensitivity and specificity for these ODI /REI cut-offs were 0.92 and 0.78, 0.91 and 0.86, and 0.94 and 0.95, respectively. The WVU-device demonstrated good accuracy in predicting REI when compared to an approved HSAT device, even in patients with darker skin tones.

An exploratory study evaluating the use of coping strategies while driving in obstructive sleep apnoea syndrome patients and controls.

Sleepiness while driving is potentially fatal, and it is recommended that a driver who starts to feel tired should stop and have a rest. However, some may use various countermeasures to try to stay alert. We devised a questionnaire that assessed various potential coping strategies that might be used against fatigue and compared them between obstructive sleep apnoea syndrome (OSAS) patients and controls and with sleepiness in general (Epworth Sleepiness Scale (ESS)), specifically while driving (Driving Sleepiness Scale (DSS)) and driving incidents. 119 untreated OSAS patients (male 82%, body mass index (BMI) 37±8 kg·m-2, ESS 14±5, DSS 3±2, oxygen desaturation index (ODI) 39±15) and 105 controls (male 70%, BMI 28±6 kg·m-2, ESS 4±3, DSS 7±6) matched for age and driving experience were recruited. All completed a questionnaire relating to their experience over the last year, which included sleepiness in general, sleepiness specifically while driving, 10 questions about various coping strategies they might adopt in order to avoid sleepiness and their history of incidents while driving. As compared to controls, nearly a third of OSAS patients (29.4%) used more than three coping strategies "frequently". OSAS patients who used more than three such strategies had worse ESS (17±4 versus 12±5, p<0.0001); were more likely to feel sleepy while driving (10±8 versus 5±7, p=0.0002) and had more reported accidents (22.85% versus 2.38%, p=0.0002) as compared to OSAS patients who used less than three strategies. There was no difference in patient demographics, severity of OSAS, driving experience or episodes of nodding at the wheel and reported near miss events. Untreated OSAS patients frequently use certain strategies which could be surrogate markers of sleepiness. Enquiring about such strategies in clinical practice may aid the clinician in identifying the patients who are at risk of driving incidents and to advise appropriately.

Bidirectional Association Among the Type of Atrial Fibrillation, Sleep-Disordered Breathing Severity, Heart Failure Progression, and Left Atrial Enlargement, in Patients with Atrial Fibrillation.

This study aimed to clarify (1) the association among the atrial fibrillation (AF) type, sleep-disordered breathing (SDB), heart failure (HF), and left atrial (LA) enlargement, (2) the independent predictors of LA enlargement, and (3) the effects of ablation on those conditions in patients with AF. The study's endpoint was LA enlargement (LA volume index [LAVI] ≥ 78 mL/m2).Of 423 patients with nonvalvular AF, 236 were enrolled. We evaluated the role of the clinical parameters such as the AF type, SDB severity, and HF in LA enlargement. Among them, 141 patients exhibiting a 3% oxygen desaturation index (ODI) of ≥ 10 events/hour underwent polysomnography to evaluate the SDB severity measured by the apnea-hypopnea index (AHI). The LA enlargement and HF were characterized by the LA diameter/LAVI, an increase in the B-type natriuretic peptide level, and a lower left ventricular ejection fraction.This study showed that non-paroxysmal AF (NPAF) rather than paroxysmal AF (PAF), the SDB severity, LA enlargement, and HF progression had bidirectional associations and exacerbated each other, which generated a vicious cycle that contributed to the LA enlargement. NPAF (OR = 4.55, P < 0.001), an AHI of ≥ 25.10 events/hour (OR = 1.55, P = 0.003), and a 3% ODI of ≥ 15.43 events/hour (OR = 1.52, P = 0.003) were independent predictors of an acceleration of the LA enlargement. AF ablation improved the HF and LA enlargement.To break this vicious cycle, AF ablation may be the basis for suppressing the LA enlargement and HF progression subsequently eliminating the substrates for AF and SDB in patients with AF.

Role of Sleep-Disordered Breathing and Epicardial Connections in the Recurrence of Atrial Fibrillation.

The presence of epicardial connections (ECs) between the pulmonary veins (PVs) and atrium may contribute to atrial fibrillation (AF) recurrence. This study aimed to determine the impact of sleep-disordered breathing (SDB) on the presence of ECs and the interplay between SDB and ECs on AF recurrence.We retrospectively reviewed 400 consecutive non-valvular AF patients. Among them, 235 patients exhibiting a 3% oxygen desaturation index (ODI) of ≥ 10 events/hour underwent polysomnography to evaluate the SDB severity, measured by the apnea-hypopnea index (AHI). To facilitate the ablation of AF and ECs, a high-density mapping catheter (HDMC) was employed. AF recurrence was evaluated over a 12-month period post-AF ablation.The key findings included: 1) 63% of AF patients with ECs had SDB with an AHI ≥ 20 events/hour. 2) Despite achieving complete PV isolations and precise EC ablation using an HDMC, SDB presence was associated with an increased AF recurrence. 3) Continuous positive airway pressure therapy for SDB improved AF recurrence among the AF patients with both ECs and SDB (57% versus 73%; P = 0.016). 4) AHI (odds ratio [OR] = 1.91, ≥ 28.4 events/hour) and left atrial volume (LAV) (OR = 1.42, ≥ 128.3 mL) were independent predictors of the presence of ECs, and AHI (OR = 1.44, ≥ 27.8 events/hour) was an independent predictor of the presence of AF recurrence.It is essential for physicians to recognise the potential complexity of ECs and SDB in AF patients. Thus, screening and treating SDB in AF patients presenting with ECs might play a pivotal role in suppressing AF recurrence.

Brain-derived neurotrophic factor in the acute and early recovery period of ischemic stroke: the role of nocturnal hypoxemia

To study the relationship between brain-derived neurotrophic factor (BDNF) and the severity of nocturnal hypoxemia in patients in the acute and early recovery period of ischemic stroke (IS). We enrolled 44 patients (27 men, 17 women), aged 18-85 years, in the acute phase of IS. At 3-month follow-up, 35 people were examined (21 men and 14 women). In the acute period, in addition to routine diagnostic procedures, respiratory monitoring was carried out, and the serum level of BDNF was measured by enzyme-linked immunosorbent assay. BDNF level was also evaluated at 3-month follow-up visit. Neurological status and its dynamics in the acute period of stroke were assessed as part of the clinical routine according to the National Institutes of Health Stroke Scale (NIHSS) at admission and discharge. We found a direct correlation between the duration of hypoxemia with SpO2 less than 90% (r=0.327, p=0.035) and less than 85% (r=0.461, p=0.003) and BDNF level in the acute phase of IS. BDNF level in the acute period of IS was negatively correlated with the minimum saturation value (r=-0.328, p=0.034). There was a direct relationship between BDNF level in the early recovery period and the duration of hypoxemia with SpO2 less than 85% (r=-0.389, p=0.028). A regression model showed that BDNF level was associated with the minimum SpO2 level. No significant associations were found with indicators of sleep-disordered breathing severity, such as the apnea-hypopnea index and the oxygen desaturation index. The severity of nocturnal hypoxemia is associated with the increase in BDNF levels both in the acute and recovery periods of IS, regardless of the presence of concomitant breathing disorders during sleep.

Assessing the Utility of Oxygen Desaturation Index as a Diagnostic Tool for Obstructive Sleep Apnoea: A Cross-sectional Study

Assessing the Utility of Oxygen Desaturation Index as a Diagnostic Tool for Obstructive Sleep Apnoea: A Cross-sectional Study

Barbed stitch reposition pharyngoplasty as a surgical treatment for sleep apnea patients

&lt;b&gt;&lt;br&gt;Introduction:&lt;/b&gt; Surgical methods for obstructive sleep apnea syndrome play an increasingly important role. The development of surgical techniques makes the procedure less invasive, achieves better treatment results, and has a greater possibility of restoring the normal function of the upper airway. One of the sleep surgery for obstructive sleep apnea syndrome is pharyngoplasty. Barbed Stitch Reposition Pharyngoplasty is a relatively new surgical technique introduced in 2012.&lt;/br&gt; &lt;b&gt;&lt;br&gt;Aim:&lt;/b&gt; Description of Barbed Stitch Reposition Pharyngoplasty, indications, and contraindications for this procedure as well as the risk of complications and a success rate.&lt;/br&gt; &lt;b&gt;&lt;br&gt;Material and method:&lt;/b&gt; A literature review and own experience were conducted in the PubMed database, from 2012–2023, on the surgical technique, e.g. Barbed Stitch Reposition Pharyngoplasty.&lt;/br&gt; &lt;b&gt;&lt;br&gt;Results:&lt;/b&gt; A significant decrease in apnea/hypopnea index and oxygen desaturation index as well as daily sleepiness is observed in the majority of patients who underwent Barbed Stitch Reposition Pharyngoplasty. All patients suffer from postoperative sore throats of varying intensity. The pain may last up to 2 weeks postoperatively. The most common complications reported by patients include odynophagia – 71%, swallowing disorders – 51%, and short-term feeling of a foreign body in the throat – 52% [1–3]. The postoperative surgical success rate ranged 65.4–93% of cases.&lt;/br&gt; &lt;b&gt;&lt;br&gt;Conclusions:&lt;/b&gt; Barbed Stitch Reposition Pharyngoplasty is a relatively safe and effective method of surgical treatment for obstructive sleep apnea syndrome. The success of the procedure is enhanced by proper patient selection, surgical experience, and knowledge of functional upper airway anatomy.&lt;/br&gt;

Effect of comprehensive rehabilitation on apnea hypopnea index in patients with obstructive sleep apnea: a protocol for randomized controlled trial

PurposeThe aim of this study is to investigate the effect of comprehensive rehabilitation on apnea hypopnea index (AHI) in patients with obstructive sleep apnea (OSA).MethodsPatients diagnosed with OSA and meeting the eligibility criteria will be randomly allocated in the groups. The experimental group will receive comprehensive rehabilitation, and the control group will receive myofunctional therapy. CPAP will be continued by all the participants. Both the groups will receive the interventions for 12 weeks. The primary outcome measures are AHI and Epworth Sleepiness Scale (ESS), and secondary outcomes are Pittsburg Sleep Quality Index (PSQI), Oxygen Desaturation Index (ODI), Snoring Index (SI), Manual Assessment of Respiratory Motion (MARM), Breath Hold Test (BHT), and Self Evaluation of Breathing Questionnaire (SEBQ). The outcomes will be assessed at baseline and at the end of 12 weeks. A follow-up will be taken at the end of 24 weeks. Power analysis suggests that enrollment of 118 patients will required. Repeated measures ANOVA will be used to analyze the effect of the intervention.ConclusionBy performing this research, we may develop insights on a novel comprehensive approach for treatment of patients with OSA.Trial registrationCTRI/2023/10/058486.

Analysis of dynamic functional connectivity states and influencing factors of brain network in male patients with obstructive sleep apnea

Objective: To analyze dynamic functional connectivity (dFNC) states and influencing factors of brain network in male patients with obstructive sleep apnea (OSA). Methods: A total of 111 male patients diagnosed with obstructive sleep apnea or presenting with simple snoring, who visited the Sleep Clinic at the Second Affiliated Hospital of Soochow University between August 2020 and December 2021, were prospectively selected for this study. General information was collected, and polysomnography (PSG) was performed. Based on the oxygen desaturation index (ODI), the participants were divided into three groups: primary snoring group (ODI<5 events/hour, n=34), mild to moderate OSA group (5 events/hour≤ODI<30 events/hour, n=43), and sever OSA group (ODI≥30 events/hour, n=34). Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) scale, and daytime sleepiness was evaluated using the Epworth Sleepiness Scale (ESS). Resting-state functional magnetic resonance imaging (fMRI) data were collected and preprocessed. dFNC matrices were constructed using a sliding time window approach. The number of dFNC states was determined using k-means clustering analysis. Three parameters, namely, fractional time (FT), mean dwell time (MDT), and number of transitions (NT), were used to characterize the temporal properties of dFNC states. Differences in the temporal properties of dFNC states among the groups were compared. The correlations between temporal properties and PSG parameters, as well as MoCA and ESS scores, were further analyzed. Multiple stepwise linear regression analysis was performed to identify the influencing factors of the temporal properties of dFNC states. Results: The age of the patients was (40.2±8.6) years (range: 25-65 years). There were no significant differences in age, smoking history and alcohol history, and MoCA scores among the three groups (all P>0.05). Three dFNC states were extracted through k-means clustering analysis: state 1, characterized by strong connections within the visual and sensorimotor networks with a frequency of 31.7% (4 611/14 541); state 2, characterized by strong connections within the default mode network, attention network, and other cognitive networks, with the lowest frequency of 22.1% (3 213/14 541); state 3, characterized by weaker connections across the whole brain, with the highest frequency of 46.2% (6 717/14 541). The FT [0.28 (0.05, 0.35) vs 0.39 (0.26, 0.53)] and MDT [8.20 (4.35, 12.54) vs 11.68 (8.50, 16.69)] of state 2 in the sever OSA group were lower than those in the primary snoring group (both P<0.05), while there were no significant differences in the temporal properties of states 1 and 3 among the three groups (all P>0.05). The FT and MDT of state 2 were correlated with body mass index (BMI), apnea-hypopnea index (AHI), ODI, and minimum oxygen saturation (MinSaO2) (FT: r values were -0.218, -0.230, -0.249, 0.198, respectively; MDT: r values were 0.269, -0.253, -0.265, 0.209, respectively; all P<0.05). There were no significant correlations between the temporal properties and MoCA or ESS scores (all P>0.05). ODI was found to be an influencing factor for the temporal properties of state 2 (FT: β=-0.225, 95%CI:-0.227 to -0.223; MDT: β=-0.241, 95%CI:-0.289 to -0.195). Conclusions: Male patients with OSA exhibit alterations in specific temporal properties of brain network dynamic functional connectivity, which are associated with nocturnal oxygen parameters. This may be one of the mechanisms underlying brain functional damage in patients with OSA.

Expedition 5300: limits of human adaptations in the highest city in the world.

Exposure to chronic hypobaric hypoxia imposes a significant physiological burden to more than 80 million humans living above 2500m throughout the world. Among them, 50000 live in the world's highest city, La Rinconada, located at 5000-5300m in southern Peru. Expedition 5300 is the first scientific and medical programme led in La Rinconada to investigate the physiological adaptations and altitude-related health issues in this unique population. Dwellers from La Rinconada have very high haemoglobin concentration (20.3±2.4g/dL; n=57) and those with chronic mountain sickness (CMS) exhibit even higher concentrations (23.1±1.7g/dL; n=150). These values are associated with large total haemoglobin mass and blood volume, without an associated iron deficit. These changes in intravascular volumes lead to a substantial increase in blood viscosity, which is even larger in CMS patients. Despite these large haematological changes, 24h blood pressure monitoring is essentially normal in La Rinconada, but some results suggest impaired vascular reactivity. Echocardiography revealed large right heart dilatation and high pulmonary arterial pressure as well as left ventricle concentric remodelling and grade I diastolic dysfunction. These changes in heart dimension and function tend to be more severe in highlanders with CMS. Polygraphy evaluations revealed a large reduction in nocturnal pulse oxygen saturation (median SpO2 =79%), which is even more severe in CMS patients who also tended to show a higher oxygen desaturation index. The population of La Rinconada offers a unique opportunity to investigate the human responses to chronic severe hypoxia, at an altitude that is probably close to the maximum altitude human beings can permanently tolerate without presenting major health issues.

GENDER DIFFERENCES IN ASSOCIATIONS OF SLEEP INTRAINDIVIDUAL VARIABILITY AND MILD COGNITIVE IMPAIRMENT

Abstract Previous studies suggest that cognitive function in older adults is related to sleep, with females more vulnerable to poor sleep. Little is known about the relationship between cognition and intraindividual variability of sleep (IIV). We examined the cross-sectional relationship between sleep IIV and mild cognitive impairment (MCI) by gender using data from the Einstein Aging Study. We hypothesize that individuals with MCI have a greater IIV in daily sleep characteristics, and these associations will be stronger for females. Eighty-nine men (age = 76.81±4.73, 61% White, 28% Black, 27% MCI) and 197 women (age = 76.60 ± 4.93, 40% White, 46% Black, 29% MCI) were included in the analysis. Individuals completed 2 weeks of actigraphy (mean ± SD = 15.7 ± 1.1 days), and the Montreal Cognitive Assessment, and MCI was based on the Jack/Bondi criteria. Sleep IIV was estimated as within person standard deviation of nighttime sleep duration, 24-hour sleep duration, wake after sleep onset, and nighttime sleep midpoint. Linear regression models evaluated associations between sleep IIV and MCI status separately by gender, controlling for BMI, age, ethnicity/race, nocturnal hypoxemia, Oxygen Desaturation Index ≥15. Among women, having MCI was associated with greater IIV in nighttime sleep midpoint (b=0.19, p=.002), and in 24-hour total sleep duration (b=13.10, p = .047) with a similar trend in nighttime sleep duration (p = .050). No significant associations were found among men. Findings suggest the importance to keep considering gender in work to understand how sleep variability relates to MCI status in older adults.

Hypoglossal Nerve Stimulation Effects on Obstructive Sleep Apnea Over Time: A Systematic Review and Meta-analysis.

This study aimed to determine the efficacy of hypoglossal nerve stimulation (HGS) in the treatment of obstructive sleep apnea. PubMed, Cochrane database, Embase, Web of Science, SCOPUS, and Google Scholar. Five databases were reviewed to identify relevant studies that measured polysomnography parameters such as the apnea-hypopnea index (AHI) and oxygen desaturation index, as well as quality of life and functional outcomes of sleep questionnaire scores, before and after HGS. In total, 44 studies involving 8670 patients met the inclusion criteria. At 12 months after treatment, approximately 47%, 72%, and 82% of patients achieved AHI values of <5, < 10, and <15, respectively. The reported clinical success rates according to Sher criteria were 80% within 12 months and 73% between 12 and 36 months. While the favorable effects exhibited a gradual reduction up to 12 months postimplantation, they generally maintained a consistent level between the 12th and 36th months, as assessed by AHI < 5, <15, and success rate according to Sher criteria. HGS can enhance quality of life scores and polysomnography outcomes in obstructive sleep apnea patients. Although the positive effects gradually decreased until 12 months after implantation, they generally remained consistent between 12 and 36 months.

Longitudinally assessed maternal sleep position, measures of breathing during sleep, and fetal growth in high-risk pregnancies.

Subjective recall of supine sleep during pregnancy has been linked to increased risk of stillbirth, but longitudinal, objective data are lacking. We aimed to examine how sleep position and breathing parameters change throughout pregnancy, and investigated associations between maternal supine sleep, assessed objectively in early and late gestation, and fetal growth velocity in high-risk women. Women with singleton pregnancies and body mass index (BMI) ≥27 kg/m2 underwent level-III sleep apnea testing. Sleep position was assessed by accelerometry. We derived percentiles of estimated fetal weight and birthweight using FetalGPSR software, then calculated growth velocity as change in percentile/week between the second-trimester anatomy scan and birth. In total, 446 women were included, with N = 126 in the longitudinal sleep pattern analysis and N = 83 in the fetal growth analysis. Sleep-onset position and predominant sleep position were significantly correlated in both early (p = 0.001) and late (p < 0.01) pregnancy. However, supine going-to-bed position predicted predominant supine sleep in only 47% of women. Between early and late pregnancy there was a reduction in predominant supine sleepers (51.6% to 30.2%). Percent of sleep spent supine and oxygen desaturation index, in the third trimester, were significantly associated after BMI adjustment (B = 0.018, p = 0.04). Models did not suggest significant effects of early or late pregnancy supine sleep on growth velocity (p > 0.05). Going-to-bed position predicts predominant supine sleep in less than half of women with overweight and obesity. Time spent supine throughout pregnancy correlates with measures of sleep-disordered breathing. Maternal sleep position patterns did not affect fetal growth velocity in this high-risk population, but the study was not powered to detect differences.

Assessment of oropharyngeal respiratory volume and sleep apnoea scores using peripheral arterial tonometry may improve diagnosis and treatment planning of combined dysgnathia therapy approaches.

Increased daytime sleepiness is a frequently reported symptom in patients with pronounced dysgnathia. This study investigated possible correlations using home peripheral arterial tonometry (PAT) and oropharyngeal airway volume determination in patients with dysgnathia and daytime sleepiness. Twenty patients (13 male, median age 27.6 ± 6.8 years) with abnormal sleep history and 10 skeletal neutral configured controls (6 male, median age 29.5 ± 4.2 years) with normal sleep history were examined. Patients and controls were evaluated for apnoea-hypopnoea index (AHI), respiratory disturbance index (RDI), oxygen desaturation index (ODI), snoring volume (dB), total sleep time (TST) and REM-percentage (REM). Airway volumetry was measured via CBCT. Individual user experience for PAT was assessed using the User Experience Questionnaire (UEQ). Patients had significantly higher respiratory scores than controls. AHI increased 4.6-fold (p = .006), RDI 2.5-fold (p = .008) and ODI 6.4-fold (p < .001). Oropharyngeal volumes showed a 30% decrease (p = .003). dB, TST and REM showed no significant differences. AHI (r = -.51; p = .005), ODI (r = -.60; p < .001) and RDI (r = -.45; p = .016) correlated negatively with pharyngeal volume. Wits appraisal correlated negatively with oropharyngeal volume (r = -.47; p = .010) and positively with AHI (r = .41; p = .03) and ODI (r = .49; p = .007). dB and TST (r = -.49; p = .008) and REM and RDI (r = -.43; p = .02) correlated negatively. UEQ-KPI (2.17 ± 0.24) confirmed excellent usability of PAT. Patients with mandibular retrognathia and abnormal sleep history showed significantly higher respiratory indices and smaller oropharyngeal volumes than neutrally configured controls. The dygnathia severity directly influenced the risk of obstructive sleep apnoea.

The Baveno Classification as a Predictor of CPAP Titration Pressure in Obstructive Sleep Apnea Syndrome.

Obstructive sleep apnea syndrome (OSAS) is a clinical condition characterised by repeated periods of partial or full obstruction of airflow throughout sleep, with impairment of the quality of life and increased mortality with socioeconomic impacts. CPAP therapy is a simple and effective treatment option for OSAS patients. To overcome the clinical and prognostic limitations of AHI-as a sole index of OSAS-the Baveno classification was recently set out and introduced into clinical practice. This study aims to analyse the effect of the Baveno classification on the optimum CPAP titration pressure. A retrospective analysis of the records of sleep studies in two centres between 2018 and 2021 was carried out. Patients diagnosed with OSAS and recruited for CPAP titration were included. Based on the Baveno classification, the patients were categorised into four groups (A, B, C, and D). Consequently, 700 patients were analysed and 427 patients were included. A significant positive correlation was detected between the CPAP optimum titration pressure and OSAS severity, neck circumference, the oxygen desaturation index (ODI), mean oxygen saturation, the AHI, the BMI, and cumulative sleep time when the SpO2 was <90% (T90) on the other side (p: <0.0001). A non-significant correlation was seen between the Epworth Sleepiness Scale (ESS), symptom severity, end organ impact, and Baveno classification of the CPAP optimum titration pressure (p: 0.8, 0.4, 0.5, and 0.7, respectively). The Baveno classification is not useful in the prediction of CPAP optimum titration pressure. However, the ODI and neck circumference were significant independent predictors of a higher CPAP titration pressure.