Causal role of immune cells in obstructive sleep apnea hypopnea syndrome:Mendelian randomization study

BACKGROUND Despite being one of the most prevalent sleep disorders,obstructive sleep apnea hypoventilation syndrome(OSAHS)has limited information on its immunologic foundation.The immunological underpinnings of certain major psychiatric diseases have been uncovered in recent years thanks to the extensive use of genome-wide association studies(GWAS)and genotyping techniques using highdensity genetic markers(e.g.,SNP or CNVs).But this tactic hasn't yet been applied to OSAHS.Using a Mendelian randomization analysis,we analyzed the causal link between immune cells and the illness in order to comprehend the immunological bases of OSAHS.AIM To investigate the immune cells'association with OSAHS via genetic methods,guiding future clinical research.METHODS A comprehensive two-sample mendelian randomization study was conducted to investigate the causal relationship between immune cell characteristics and OSAHS.Summary statistics for each immune cell feature were obtained from the GWAS catalog.Information on 731 immune cell properties,such as morphologic parameters,median fluorescence intensity,absolute cellular,and relative cellular,was compiled using publicly available genetic databases.The results'robustness,heterogeneity,and horizontal pleiotropy were confirmed using extensive sensitivity examination.RESULTS Following false discovery rate(FDR)correction,no statistically significant effect of OSAHS on immunophenotypes was observed.However,two lymphocyte subsets were found to have a significant association with the risk of OSAHS:Basophil%CD33dim HLA DR-CD66b-(OR=1.03,95%CI=1.01-1.03,P<0.001);CD38 on IgD+CD24-B cell(OR=1.04,95%CI=1.02-1.04,P=0.019).CONCLUSION This study shows a strong link between immune cells and OSAHS through a gene approach,thus offering direction for potential future medical research.

Epidemiological and Clinical Profile of Hypertensive Patients with Obstructive Sleep Apnea at CHU-B

Objectives: To detect obstructive sleep apnea syndrome (OSAS) in a population of hypertensive patients, using the Berlin questionnaire and to establish the epidemiological and clinical profile of patients. Patients and Method: This was a cross-sectional and analytical study, carried out from March to August 2019 at the CHU Brazzaville. Included are hypertensive patients followed as outpatients. The diagnosis of the OSAS was based on the answers to the Berlin questionnaire. Results: A total of 315 patients were included, including 210 women (64.9%). Prevalence of OSAS was 75.8% (n = 239). The average age of patients with sleep apnea was 58.5 ± 12.4 years with female predominance (64.9%). In the mixed analysis, the factors associated with (OSAS) were: occupation OR (2.56) 95% CI (1.15 - 5.69), obesity OR 7.50 (1.60 - 35.1) and abdominal obesity OR 2.36 CI 95% (1.36 - 4.08). Living standards were high in 59 cases (18.7 per cent). The medical history of previous hospitalization was present in 209 cases (66.3%), diabetes 95 (30.2%), and heart failure 57 cases (18.1%). Lifestyle patterns were: sedentary (n = 181;57.5%) alcohol consumption (n = 97;30.8%). On physical examination, overweight was noted in 96 cases (30.5%) and obesity in 91 cases (28.8%). The anomalies in the Berlin questionnaire were: snoring (n = 197;62.5%), waking fatigue (n = 127;40.3%), fatigue during the day (n = 97;30.8%). Conclusion: The prevalence of obstructive sleep apnea syndrome is high during arterial hypertension in our setting. Hence the need for sleep exploration through polysomnography, and prevention through the fight against the associated risk factors.

Turbulent Kinetic Energy of Flow during Inhale and Exhale to Characterize the Severity of Obstructive Sleep Apnea Patient

This paper aims to investigate and present the numerical investigation of airflow characteristics using Turbulent Kinetic Energy(TKE)to characterize the upper airway with obstructive sleep apnea(OSA)under inhale and exhale breathing conditions.The importance of TKE under both breathing conditions is that it showan accuratemethod in expressing the severity of flow in sleep disorder.Computational fluid dynamics simulate the upper airway’s airflow via steady-state Reynolds-averaged Navier-Stokes(RANS)with k–ωshear stress transport(SST)turbulencemodel.The three-dimensional(3D)airway model is created based on the CT scan images of an actual patient,meshed with 1.29 million elements using Materialise Interactive Medical Image Control System(MIMICS)and ANSYS software,respectively.High TKE were noticed around the region after the necking(smaller cross-sectional area)during the inhale and exhale breathing.The turbulent kinetic energy could be used as a valuablemeasure to identify the severity of OSA.This study is expected to provide a better understanding and clear visualization of the airflow characteristics during the inhale and exhale breathing in the upper airway of patients for medical practitioners in the OSA research field.

Effects of obstructive sleep apnea on retinal microvasculature

AIM:To detect retinal microvascular variations in obstructive sleep apnea syndrome patients.METHODS:This prospective,observational case-control study included healthy controls and patients with mild,moderate,and severe obstructive sleep apnea syndrome.Vascular parameters,foveal avascular area,and flow areas in macula-centered,6.00×6.00 mm2 scan size optical coherence tomography angiography images were compared.RESULTS:The control group had the highest whole image,parafoveal,and perifoveal vessel density among the groups in both superficial and the deep capillary plexus(all P<0.05).Rapid eye movement sleep apnoea-hypopnoea index was reversely correlated with whole(Rho=-0.195,P=0.034),parafoveal(Rho=-0.242,P=0.008),perifoveal(Rho=-0.187,P=0.045)vessel density in the superficial capillary plexus,and whole(Rho=-0.186,P=0.046),parafoveal(Rho=-0.260,P=0.004),perifoveal(Rho=-0.189,P=0.043)vessel density in the deep capillary plexus,though the mean and non-rapid eye movement sleep apnoeahypopnoea index related with only parafoveal vessel density in the superficial capillary plexus(Rho=-0.213,P=0.020;Rho=-0.191,P=0.038)and the deep capillary plexus(Rho=-0.254,P=0.005;Rho=-0.194,P=0.035).CONCLUSION:This study shows decreased vessel density and its reverse correlation with the apnoea-hypopnoea index in patients with obstructive sleep apnea syndrome.

Cognitive and Emotional Factors Related to Obstructive Sleep Apnea Diagnoses: A Brief Review

Sleep apnea is a clinical condition characterized by cessation of breathing in the sleeper due to pharyngeal airway closure. The reduction in air exchange results in decreased cerebral blood circulation with consequential behavioral deficits cognitively and emotionally. Untreated sleep apnea is associated with chronic illnesses of depression, cardiovascular disorder, obesity and diabetes mellitus. Measured cognitive behavior before and following CPAP treatment demonstrates the cognitive deficit as the effectiveness of CPAP treatment. Emotional factors related to sleep apnea diagnosis and adherence to treatment are facilitated in patients with cognitive behavior therapy (CBT) interventions by sleep specialists. This is a brief review paper that presents findings about cognition and emotional factors related to sleep apnea. This is a brief review paper.

High risk for obstructive sleep apnea and risk of hypertension in military personnel: The CHIEF sleep study

BACKGROUND Epidemiological studies have revealed an association between obstructive sleep apnea(OSA)and hypertension in the general population,while the association in military personnel was rarely investigated.AIM To examine the association between high risk for OSA and hypertension by phenotypes in military young adults.METHODS A total of 746 military personnel,aged 27.9 years,were included in the cardiorespiratory fitness and health in armed forces(CHIEF)-sleep study in Taiwan in 2020.Antihypertensive medications were not used by the subjects.High risk for OSA was assessed using the Berlin Questionnaire.Hypertension was defined using the 7th Report of the Joint National Committee on Prevention,Detection,Evaluation,and Treatment of High Blood Pressure(JNC 7)and the 2017 American College of Cardiology(ACC)/American Heart Association(AHA)guidelines.The cutoff levels of systolic and diastolic blood pressure(SBP and DBP)for the 2017 ACC/AHA-and JNC 7-based guidelines were 130/140 mmHg and 80/90 mmHg,respectively.Hypertension phenotypes included isolated systolic and diastolic hypertension(ISH,high SBP only and IDH,high DBP only)and combined hypertension(both high SBP and DBP).Multivariable logistic regression analysis with adjustment for demographics,lifestyle and metabolic biomarkers.RESULTS The prevalence of high risk for OSA,JNC 7-based hypertension and 2017 ACC/AHA-based hypertension were 8.0%,5.2%and 22.0%,respectively.Those with a high risk for OSA had a higher probability of JNC 7-based overall and combined hypertension(odds ratios(ORs))and 95%confidence intervals:2.82(1.07-7.42)and 7.54(1.10-51.54),although the probabilities of ISH and IDH were unaffected by a high risk for OSA(ORs:1.96 and 2.35,respectively,both P>0.05).In contrast,no associations for any hypertension phenotypes were found according to the 2017 ACC/AHA criteria.CONCLUSION A high risk for OSA was associated with severe hypertension and combined hypertension among Asian military young adults.

The Change of Interleukin-6 and Tumor Necrosis Factor in Patients with Obstructive Sleep Apnea Syndrome

The levels of lipopolysaccharide (LPS) induced interleukin 6 (IL 6) and tumor necrosis factor α (TNF α) expression in culture of peripheral blood mononuclear cells (PBMC) and the plasma levels of IL 6 and TNF α in the patients with obstructive sleep apnea syndrome (OSAS) were measured and the relationship between OSAS and IL 6 or TNF α expression studied. Both IL 6 and TNF α were detected by using ELISA in 22 patients with OSAS and 16 normal controls. The levels of LPS induced IL 6 (787.82±151.97 pg/ml) and TNF α (4165.45±1501.43 pg/ml) expression in the supernatant of the culture of PBMC and plasma level of IL 6 (50.67±4.70 pg/ml) and TNF α (299.09±43.57 pg/ml) in the patients with OSAS were significantly higher than those in the normal controls (in the supernatant of the culture of PBMC: 562.69±197.54 pg/ml and 1596.25±403.08 pg/ml respectively; in the plasma: 12.69±2.75 pg/ml and 101.88±21.27 pg/ml respectively). There were significantly positive correlation between the levels of IL 6 and TNF α and the percentage of time of apnea and hyponea, as well as the percentage of time spending at SaO 2 below 90 % in the total sleep time. It was concluded that LPS induced IL 6 and TNF α levels as well as plasma IL 6 and TNF α levels in the patients with OSAS were up regulated, which may be associated with the pathogenesis of OSAS.

Development of New Machine Learning Based Algorithm for the Diagnosis of Obstructive Sleep Apnea from ECG Data

In this study,a machine learning algorithm is proposed to be used in the detection of Obstructive Sleep Apnea(OSA)from the analysis of single-channel ECG recordings.Eighteen ECG recordings from the PhysioNet Apnea-ECG dataset were used in the study.In the feature extraction stage,dynamic time warping and median frequency features were obtained from the coefficients obtained from different frequency bands of the ECG data by using the wavelet transform-based algorithm.In the classification phase,OSA patients and normal ECG recordings were classified using Random Forest(RF)and Long Short-Term Memory(LSTM)classifier algorithms.The performance of the classifiers was evaluated as 90% training and 10%testing.According to this evaluation,the accuracy of the RF classifier was 82.43% and the accuracy of the LSTM classifier was 77.60%.Considering the results obtained,it is thought that it may be possible to use the proposed features and classifier algorithms in OSA classification and maybe a different alternative to existing machine learning methods.The proposed method and the feature set used are promising because they can be implemented effectively thanks to low computing overhead.

Detection of cognitive impairment in patients with obstructive sleep apnea hypopnea syndrome using mismatch negativity

In this experiment, 97 patients with obstructive sleep apnea hypopnea syndrome were divided into three groups （mild, moderate, severe） according to minimum oxygen saturation, and 35 healthy subjects were examined as controls. Cognitive function was determined using the mismatch negativity paradigm and the Montreal Cognitive Assessment. The results revealed that as the disease worsened, the mismatch negativity latency was gradually extended, and the amplitude gradually declined in patients with obstructive sleep apnea hypopnea syndrome. Importantly, mismatch negativity latency in severe patients with a persistent time of minimum oxygen saturation 〈 60 seconds was significantly shorter than that with a persistent time of minimum oxygen saturation 〉 60 seconds. Correlation analysis revealed a negative correlation between minimum oxygen saturation latency and Montreal Cognitive Assessment scores. These findings indicate that intermittent night-time hypoxemia affects mismatch negativity waveforms and Montrea Cognitive Assessment scores. As indicators for detecting the cognitive functional status of obstructive sleep apnea hypopnea syndrome patients, the sensitivity of mismatch negativity is 82.93%, the specificity is 73.33%, the accuracy rate is 81.52%, the positive predictive value is 85.00%, the negative predictive value is 70.21%, the positive likelihood ratio is 3, and the negative likelihood ratio is 0.23. These results indicate that mismatch negativity can be used as an effective tool for diagnosis of cognitive dysfunction in obstructive sleep apnea hypopnea syndrome patients.

Retinal nerve fiber layer thickness changes in obstructive sleep apnea syndrome: one year follow-up results

·AIM: To investigate the retinal nerve fiber layer(RNFL)thickness changes in patients with obstructive sleep apnea syndrome(OSAS) for one year follow-up. To discuss the possibility of detecting tendency of glaucoma in this population by using spectral domain optical coherence tomography(3D-OCT-2000 Spectral domain).·METHODS: After polysomnographic study, all subjects(64 OSAS patients and 40 controls) underwent detailed ophthalmological examination. After these examinations,patients with glaucoma and patients who had ophthalmological and/or systemic disease were excluded from the study.Totally, 20 patients in OSAS group and five patients in controls were excluded from the study in the first examination and follow-up period. The RNFL thickness was assessed with OCT. Forty-four OSAS patients and 35 control subjects were followed up for12 mo. RNFL thickness change and OSAS patients were evaluated for severity of disease by Apnea-Hypopnea Index(AHI).·RESULTS: Forty-four OSAS patients and 35 controls were enrolled in the study. Statistically significance was found between OSAS patients and controls at the 12 thmo.Average RNFL thickness was found to be significantly lower in last measurements in OSAS patients when compared with first measurements and control subjects(P 【0.001, 0.002, respectively). There was a statistically significant correlation among AHI, and RNFL thickness(P 【0.05).·CONCLUSION: The results suggest that the patients with OSAS were related with a proportional decrease in the RNFL thickness. These patients should be followed up regularly for glaucomatous changes. Detecting more RNFL thinning in severe OSAS was important.

Chronic intermittent hypoxia induces cardiac inflammation and dysfunction in a rat obstructive sleep apnea model

Chronic intermittent hypoxia is considered to play an important role in cardiovascular pathogenesis during the development of obstructive sleep apnea（OSA）.We used a well-described OSA rat model induced with simultaneous intermittent hypoxia.Male Sprague Dawley rats were individually placed into plexiglass chambers with air pressure and components were electronically controlled.The rats were exposed to intermittent hypoxia 8 hours daily for 5weeks.The changes of cardiac structure and function were examined by ultrasound.The cardiac pathology,apoptosis,and fibrosis were analyzed by H＆E staining,TUNNEL assay,and picosirius staining,respectively.The expression of inflammation and fibrosis marker genes was analyzed by quantitative real-time PCR and Western blot.Chronic intermittent hypoxia/low pressure resulted in significant increase of left ventricular internal diameters（LVIDs）,endsystolic volume（ESV）,end-diastolic volume（EDV）,and blood lactate level and marked reduction in ejection fraction and fractional shortening.Chronic intermittent hypoxia increased TUNNEL-positive myocytes,disrupted normal arrangement of cardiac fibers,and increased Sirius stained collagen fibers.The expression levels of hypoxia induced factor（HIF）-l α,NF-κB,IL-6,and matrix metallopeptidase 2（MMP-2） were significantly increased in the heart of rats exposed to chronic intermittent hypoxia.In conclusion,the left ventricular function was adversely affected by chronic intermittent hypoxia,which is associated with increased expression of HIF-lα and NF-κB signaling molecules and development of cardiac inflammation,apoptosis and fibrosis.

Electrical Stimulation Therapy Improves Sleep Respiratory Parameters in Obstructive Sleep Apnea Syndrome: A Meta-analysis

Recent clinical trials have shown that electrical stimulation has beneficial effects in obstruc- tive sleep apnea syndrome （OSAS）. The purpose of this study was to evaluate the efficacy of electrical stimulation therapy for OSAS with a meta-analysis. The meta-analysis of all relative studies was per- formed through searching international literature, including PUBMED, CNKI, and EMBASE databases. This literature analysis compared all patients undergoing electrical stimulation therapy with respect to the respiratory disturbance index （RDI） and changes in sleep structure. Six studies were selected in- volving a total of 91 patients. The meta-analysis indicated that electrical stimulation therapy reduced RDI, longest apnea time, and improved the minimum SaO2. Based on the evidence found, electrical stimulation may be a potential therapy for OSAS, warranting further clinical trials.

Clinical observation of soft palate-pharyngoplasty in the treatment of obstructive sleep apnea hypopnea syndrome in children

BACKGROUND Childhood obstructive sleep apnea hypopnea syndrome(OSAHS)is a common clinical disease that can cause serious complications if not treated in time.The preferred treatment for OSAHS in children is surgery.AIM To observe the effects of soft palate-pharyngoplasty on postoperative outcome,pharyngeal formation,and possible complications.METHODS A total of 150 children with snoring,hernia,and mouth breathing were selected.A polysomnography test was performed to confirm the diagnosis of OSAHS.The children were randomly divided into experimental and control groups.The experimental group underwent adenoidectomy,tonsillectomy,and soft palatepharyngoplasty.The control group underwent adenoidectomy and tonsillectomy.The t-test and chi-square test were used to compare conditions such as postoperative fever,postoperative hemorrhage,and pharyngeal reflux.Postoperative efficacy and complications were interrogated and observed in the form of outpatient follow-up and telephone follow-up at 6 mo and 1 year after surgery.The curative effects were divided into two groups:Cure(snoring,snoring symptoms disappeared)and non-cure.RESULTS The effective rate of the experimental group was significantly higher than that of the control group,but the difference was not statistically significant(P>0.05).The incidence of postoperative bleeding was lower in the experimental group.There was no postoperative pharyngeal reflux in either group.In the experimental group,the incidence of hyperthermia(body temperature exceeded 38.5°C)was lower than that in the control group.The difference in postoperative swallowing pain scores between the experimental and control groups was significant.CONCLUSION Soft palate-pharyngoplasty can more effectively enlarge the anteroposterior diameter and transverse diameter of the isthmus faucium.Compared with surgery alone,it can better treat OSAHS in children,improve the curative effect,reduce the risk of perioperative bleeding,close the surgical cavity,reduce the risk of postoperative infection,reduce the proportion of postoperative fever,and accelerate healing.Although this process takes more time,it is simple,safe,and effective.

Correlation of obstructive sleep apnea hypopnea syndrome with metabolic syndrome in snorers

Though obstructive sleep apnea hypopnea syndrome（OSAHS） and metabolic syndrome（MS） are correlated;the contributing factors for the occurrence of MS in Chinese snorers remain largely undefined.We aimed to investigate the associated pathogenesis of coexistence of OSAHS and MS in Chinese snorers.A total of 144 Chinese habitual snorers were divided into 3 groups,the control group（simple snorers）（n = 36）,the mild OSAHS group（n= 52）and the moderate-to-severe OSAHS group（n = 56）.The incidence of MS in the moderate-to-severe OSAHS group（26.8%） was significantly higher than that in the control group（8.3%）,the mild OSAHS group（11.1%） and all the OSAHS patients（19.45%）（all P 〈 0.05）.Homeostatic model assessment（HOMA） index and proinsulin（PI） were negatively correlated with nocturnal meanSpO2 and miniSpO2.Meanwhile,nocturnal SpO2 were negatively correlated with body mass index,waist and neck circumferences and diastolic blood pressure,but positively correlated with total cholesterol and high-density lipoprotein cholesterol.The study indicated that in Chinese snorers,moderate-to-severe OSAHS was closely associated with MS via nocturnal hypoxemia.

Evaluation of choroidal thickness using spectral-domain optical coherence tomography in patients with severe obstructive sleep apnea syndrome: a comparative study

AIM: To assess choroidal thickness in patients with severe obstructive sleep apnea syndrome(OSAS) and compare them with healthy controls, using spectral domain optical coherence tomography(OCT).METHODS: In this observational, cross-sectional study,choroidal thicknesses of 23 newly severe OSAS patients and 23 body mass index- age- and sex-matched healthy subjects were measured using a high-speed, high-resolution frequency domain- OCT device( λ = 840 nm,26 000 A-scans/s, 5 μm axial resolution). All patients underwent a complete ophthalmic examination before the measurements. OCT measurements were taken at the same time of day(9:00 a.m.), in order to minimize the effects of diurnal variation.RESULTS: There was a statistically significant difference in median choroidal thickness between the OSAS patients(201 μm; range 145-237 μm) and the controls(324 μm; range 296-383 μm;P 【0.001). There were significant differences at all measurement points(P 【0.001 for all). The apnea-hypopnea index(AHI)values were more than 30 in all OSAS patients and the mean AHI was 48.57 ±6.54. The interexaminer intraclass correlation coefficient(ICC) for the mean choroidal thickness was 0.938(95% CI, 0.908-0.985) and ICC was greater than 0.90 for all measurement points.CONCLUSION: The decreased choroidal thickness of patients with severe OSAS might be related to the the autonomic disregulation associated with this disease.Further studies are needed to evaluate the etiopathologic relationship between choroidal thickness and OSAS.

Retinal nerve fiber layer thickness changes in obstructive sleep apnea syndrome:a systematic review and Metaanalysis

AIM： To evaluate the retinal nerve fiber layer（RNFL）thickness changes in patients with obstructive sleep apnoea syndrome（OSAS）, and detect possible prevalence of glaucoma in this population.METHODS： Comprehensive studies were conducted on the Cochrane Library, Pub Med and Embase through March, 2015. Only studies that fit the selection criteria about RNFL and OSAS would be included. For the measures, we calculated the 95% confidence interval（CI）and weighted mean differences（WMD）. The systematic review and Meta-analysis was performed by Rev Man 5.2software.RESULTS： Nine case-control studies were analyzed containing a total of 1086 cases and 580 controls.Average RNFL thickness in OSAS was reduced significantly compared with healthy controls in random effects model（WMD =-2.56, 95% CI：-4.82 to-0.31, P =0.003, I2=57%）. A significant RNFL thickness reduction were found between the two groups in inferior quadrant（WMD =-3.11, 95% CI：-5.53 to-0.69, P =0.01）, superior quadrant（WMD =-2.37, 95% CI：-4.7 to 0.04, P =0.05）. In nasal quadrant（WMD =-2.54, 95% CI：-6.53 to 1.45, P =0.21） and temporal quadrant（WMD=-1.26, 95% CI：-2.19 to 0.47, P =0.15） there was no difference of RNFL thickness between the two groups.CONCLUSION： The results show that RNFL thickness is lower in patients with moderate or severe OSAS than in normal subjects or patients with mild OSAS according to the nine homogeneity studies.

Obstructive sleep apnea increases heart rhythm disorders and worsens subsequent outcomes in elderly patients with subacute myocardial infarction

OBJECTIVE Obstructive sleep apnea(OSA)is a potential cardiovascular risk.We aimed to investigate the association of OSA with heart rhythm disorders and prognosis in elderly patients with new-onset acute myocardial infarction(AMI).METHODS We prospectively enrolled 252 AMI elderly patients(mean age,68.5±6.9 years)who were undergoing revascularization and completed a sleep study during their hospitalization.All subjects were categorized into non-OSA(apnea–hypopnea index(AHI)<15,n=130)and OSA(AHI≥15,n=122)groups based on the AHI.The changes in the autonomic nervous system,incidence of arrhythmia during nocturnal sleep,and major adverse cardiovascular and cerebrovascular events(MACCEs)were compared between the groups.RESULTS The mean AHI value in all AMI patients was 22.8±10.9.OSA patients showed higher levels of body mass index and peak high-sensitivity C-reactive protein and lower levels of minimum nocturnal oxygen saturation(Min Sa O2),as well as greater proportion of multivessel coronary artery disease(all P<0.05).The OSA group also showed significant increases in heart rate variability and heart rate turbulence onset(both P<0.05)and higher incidence of arrhythmia(including sinus,atrial,and ventricular in origin).At a median follow-up of 6 months(mean 0.8–1.6 years),OSA(AHI≥15)combined with hypoxia(Min Sa O2≤80%)was independently associated with the incidence of MACCEs(hazard ratio[HR]:4.536;95%confidence interval[CI]:1.461-14.084,P=0.009)after adjusting for traditional risk factors.CONCLUSIONS OSA and OSA-induced hypoxia may correlate with the severity of myocardial infarction,increase the occurrence of heart rhythm disorders in elderly subacute MI patients,and worsen their short-term poor outcomes.

Numerical analysis for the effcacy of nasal surgery in obstructive sleep apnea hypopnea syndrome

In the present study, we reconstructed upper airway and soft palate models of 3 obstructive sleep apnea-hypopnea syndrome（OSAHS） patients with nasal obstruction. The airflow distribution and movement of the soft palate before and after surgery were described by a numerical simulation method. The curative effect of nasal surgery was evaluated for the three patients with OSAHS. The degree of nasal obstruction in the 3 patients was improved after surgery. For 2 patients with mild OSAHS, the upper airway resistance and soft palate displacement were reduced after surgery. These changes contributed to the mitigation of respiratory airflow limitation. For the patient with severe OSAHS, the upper airway resistance and soft palate displacement increased after surgery, which aggravated the airway obstruction. The effcacy of nasal surgery for patients with OSAHS is determined by the degree of improvement in nasal obstruction and whether the effects on the pharynx are beneficial. Numerical simulation results are consistent with the polysomnogram（PSG） test results, chief complaints, and clinical findings, and can indirectly reflect the degree of nasal patency and improvement of snoring symptoms, and further,provide a theoretical basis to solve relevant clinical problems.

Computational Fluid Dynamics Simulation of the Upper Airway of Obstructive Sleep Apnea Syndrome by Muller Maneuver

This study aimed to use computer simulation to describe the fluid dynamic characteristics in patients with obstructive sleep apnea syndrome（OSAS） and to evaluate the difference between during quiet respiration and the Muller maneuver（MM）. Seven patients with OSAS were involved to perform computed tomographic（CT） scanning during quiet respiration and the MM. CT data in DICOM format were transformed into an anatomically three-dimensional computational fluid dynamics（CFD） model of the upper airway. The velocity magnitude, relative pressure, and flow distribution were obtained. Numerical simulation of airflow was performed to discuss how the MM affected airflow in the upper airway. To measure the discrepancy, the SPSS19.0 software package was utilized for statistic analysis. The results showed that the shape of the upper airway became narrower, and the pressure decreased during the MM. The minimal cross-sectional area（MCSA） of velopharynx was significantly decreased（P〈0.05） and the airflow velocity in MCSAs of velopharynx and glossopharynx significantly accelerated（P〈0.05） during the MM. This study demonstrated the possibility of CFD model combined with the MM for understanding pharyngeal aerodynamics in the pathophysiology of OSAS.

The Diagnosis Value and Its Implication of Impulse Oscillometry in Obstructive Sleep Apnea Syndrome Patients

The change of measurements of impulse oscillometry (105) in obstructive sleep apnea syn- drome (OSAS) patients and its mechanism were observed. The respiratory impedance was measured by using IOS technique and polysomnography (PSG) was monitored synchronously in 36 OSAS pa- tients,14 patients with chronic obstructive pulmonary disease (COPD) and 12 normal controls. Re- sults showed that R20 in OSAS group was significantly higher than in COPD group and control group (P<0.01). R5-R20 in OSAS group was lower than that in COPD group, but significantly higher than that in control group(P<0. 01). The levels of R20 and R5-R20 were positively correlated with severity degree of the disease. In addition, apnea-hyponea index (AHI) was positively correlated with R5 and R20 with the correlation index (r)being 0. 66 and 0. 86 respectively. The lowest SO2 was negatively correlated with R5 and R5-R20, with r being-0. 66 and- 0. 79 respectively. The mean SO2 was negatively correlated with R5 and R5-R20 with r being-0. 81 and-0. 69 respectively. IOS technique could be used as a valuable tool for assessing the degree of upper airway obstruction in the patients with OSAS, and could help to explore its pathological mechanism.