Apnea-hypopnea Index Measures Research Articles

0572 Weight reduction and the impact on apnea-hypopnea index: a meta-analysis

Abstract Introduction The occurrence of obstructive sleep apnea (OSA) is strongly associated with obesity. Behavioral, pharmacological, and surgical interventions that promote weight reduction can reduce OSA severity and improve other common obesity related complications and quality of life. While the relationship between weight reduction and apnea-hypopnea index (AHI) improvement has been documented, it does not seem to have been quantified adequately. The objective of this analysis was to quantify the association between percent change in body weight and percent change in AHI using results from the literature. Methods A literature search identified 13 studies with AHI and weight measurements before and after weight intervention in people living with obesity and OSA; 6 studies from bariatric surgery, 4 studies from diet and exercise intervention, and 3 studies from anti-obesity medications (including 2 placebo-controlled randomized clinical trials). A polynomial and a linear meta regression model as well as 95% prediction intervals were used to assess the relationship between % weight change from baseline and % change in AHI from baseline. Results Both the polynomial and linear models show, on average, weight reduction in patients living with obesity and OSA has a clinical benefit in reducing AHI. The linear meta-regression model that we developed suggests a mean AHI decrease of 2.6% per 1% weight reduction. As the prediction intervals are relatively wide, a precise relationship could not be established. For example, based on the linear model for a patient with 20% weight reduction we expect to see a mean 52.8% reduction in AHI with a 95% prediction interval (89.8%, 15.8%) AHI reduction. Conclusion Evidence shows that intentional weight reduction in people living with obesity and OSA results in improvements in OSA severity, and this was confirmed by our meta-analysis and modeling. The model shows that the degree of AHI improvement is dependent on the magnitude of weight reduction. However, establishing a precise relationship between percent change in AHI and percent weight reduction is challenging given the sparsity of data, variability in populations studied, and variability in AHI change following weight reduction. Support (if any) Eli Lilly and Company

Efficacy of portable sleep monitoring device in diagnosing central sleep apnea in patients with congestive heart failure.

Central sleep apnea (CSA) is a common and serious comorbidity mainly occurring in patients with heart failure (HF), which tends to be underdiagnosed and has not been widely studied. Overnight polysomnography (PSG) is the gold standard for diagnosing CSA; however, the time and expense of the procedure limit its applicability. Portable monitoring (PM) devices are convenient and easy to use; however, they have not been widely studied as to their effectiveness in detecting CSA in patients with HF. In the current study, we examined the diagnostic value of PM as a screening tool to identify instances of CSA among patients with HF. A total of 22 patients under stable heart failure conditions with an ejection fraction of <50% were enrolled. All patients underwent PM and overnight PSG within a narrow time frame. The measurements of the apnea-hypopnea index (AHI), hypopnea index (HI), central apnea index (CAI), and obstructive apnea index (OAI) obtained from PSG, automatic scoring, and manual scoring of PM were recorded. The results obtained from PSG and those from PM (automatic and manual scoring) were compared to assess the accuracy of PM. Among the patients, CSA in 11 patients was found by PSG. The AHI measurements performed using manual scoring of PM showed a significant correlation with those performed using PSG (r = 0.69; P = 0.01). Nonetheless, mean AHI measurements showed statistically significant differences between PSG and automatic scoring of PM (40.0 vs. 23.7 events/hour, respectively; P < 0.001), as well as between automatic and manual scoring of PM (23.7 vs. 29.5 events/hour; P < 0.001). Central sleep apnea was detected by PM; however, the results were easily misread as obstructive apnea, particularly in automatic scoring. PM devices could be used to identify instances of central sleep apnea among patients with HF. The results from PM were well-correlated with standard PSG results, and manual scoring was preferable to automated scoring.

Diagnostic value of smartphone in obstructive sleep apnea syndrome: A systematic review and meta-analysis.

ObjectivesTo assess the diagnostic utility of smartphone-based measurement in detecting moderate to severe obstructive sleep apnea syndrome (OSAS).MethodsSix databases were thoroughly reviewed. Random-effect models were used to estimate the summary sensitivity, specificity, negative predictive value, positive predictive value, diagnostic odds ratio, summary receiver operating characteristic curve and measured the areas under the curve. To assess the accuracy and precision, pooled mean difference and standard deviation of apnea hypopnea index (AHI) between smartphone and polysomnography (95% limits of agreement) across studies were calculated using the random-effects model. Study methodological quality was evaluated using the QUADAS-2 tool.ResultsEleven studies were analyzed. The smartphone diagnostic odds ratio for moderate-to-severe OSAS (apnea/hypopnea index > 15) was 57.3873 (95% confidence interval [CI]: [34.7462; 94.7815]). The area under the summary receiver operating characteristic curve was 0.917. The sensitivity, specificity, negative predictive value, and positive predictive value were 0.9064 [0.8789; 0.9282], 0.8801 [0.8227; 0.9207], 0.9049 [0.8556; 0.9386], and 0.8844 [0.8234; 0.9263], respectively. We performed subgroup analysis based on the various OSAS detection methods (motion, sound, oximetry, and combinations thereof). Although the diagnostic odds ratios, specificities, and negative predictive values varied significantly (all p < 0.05), all methods afforded good sensitivity (> 80%). The sensitivities and positive predictive values were similar for the various methods (both p > 0.05). The mean difference with standard deviation in the AHI between smartphone and polysomnography was -0.6845 ± 1.611 events/h [-3.8426; 2.4735].ConclusionsSmartphone could be used to screen the moderate-to-severe OSAS. The mean difference between smartphones and polysomnography AHI measurements was small, though limits of agreement was wide. Therefore, clinicians should be cautious when making clinical decisions based on these devices.

Berlin and Epworth Surveys to Predict Obstructive Sleep Apnea for Adults on Biomimetic Oral Appliance Therapy: A Nonrandomized Clinical Trial.

Background Two questionnaires (Berlin Questionnaire (BQ) and Epworth Sleepiness Scale (ESS)) are the widely used screening instruments for subjects suffering from sleep disorders. Obstructive sleep apnea (OSA) is the most common form of sleep-disordered breathing. The biomimetic oral appliance therapy (BOAT) offers an alternative nonsurgical method, which can improve symptoms and indices of OSA on objective sleep testing. Aim To describe testing the ability of BQ and EES for prediction of BOAT outcomes during OSA. Methods Seventeen adults (9 males, 8 females; age, mean (SD): 45.76 (10.31), BMI mean (SD): 33.5(13.43)) who underwent an overnight sleep study were diagnosed by a sleep specialist physician. The BQ and EES were recorded before and after BOAT treatment. Subjects with mild-to-moderate OSA had 2 months of follow-up visits and underwent a final overnight sleep study to measure apnea-hypopnea index (AHI). The subjects were asked to wear the appliance for 10–12 hours/day and at night. Findings were analyzed statistically using paired t-tests. Result As per sleep test results, pre-BOAT AHI measures versus post-BOAT AHI measures showed significant improvement. Comparing the BQ before versus after treatment showed that at the pretreatment stage, 66.0% of patients had high-risk score, whereas 34% had low-risk score. After treatment, 66.0% of patient had low-risk scores, whereas 34% had high-risk scores. As for the ESS, treatment resulted in significant reduction of total score from 10.43 ± 6.32 to 5.00 ± 5.20 (P < 0.01, paired t-test). Finally, there was a mild negative correlation between AHI and each of the BQ and ESS scores that was not statistically significant (r = −0.420, N = 26, P > 0.05, and r = −0.41, N = 26, P > 0.05, respectively). Conclusion The BOAT device may provide a useful form of therapy to improve OSA-related PSG parameters such as AHI. Both BQ and ESS were predictive to improvements detected by the sleep study during BOAT device use.

Effect of Maternal Obstructive Sleep Apnea-Hypopnea on 24-Hour Blood Pressure, Nocturnal Blood Pressure Dipping and Arterial Stiffness in Hypertensive Disorders of Pregnancy.

Rationale: Maternal obstructive sleep apnea-hypopnea (OSAH) is associated with hypertensive disorders of pregnancy (HDP). Attenuation of the normal nocturnal blood pressure (BP) decline (non-dipping) is associated with adverse pregnancy outcomes. OSAH is associated with nocturnal non-dipping in the general population, but this has not been studied in pregnancy. We therefore analyzed baseline data from an ongoing RCT (NCT03309826) assessing the impact of OSAH treatment on HDP outcomes, to evaluate the relationship of OSAH to 24-h BP profile, in particular nocturnal BP dipping, and measures of arterial stiffness.Methods: Women with a singleton pregnancy and HDP underwent level II polysomnography. Patients with OSAH (apnea-hypopnea index (AHI) ≥ 5 events/h) then underwent 24-h ambulatory BP monitoring and arterial stiffness measurements (applanation tonometry, SphygmoCor). Positive dipping was defined as nocturnal systolic blood pressure (SBP) dip ≥ 10%. The relationships between measures of OSAH severity, measures of BP and arterial stiffness were evaluated using linear regression analyses.Results: We studied 51 HDP participants (36.5 ± 4.9 years, BMI 36.9 ± 8.6 kg/m2) with OSAH with mean AHI 27.7 ± 26.4 events/h at 25.0 ± 4.9 weeks’ gestation. We found no significant relationships between AHI or other OSA severity measures and mean 24-h BP values, although BP was generally well-controlled. Most women were SBP non-dippers (78.4%). AHI showed a significant inverse correlation with % SBP dipping following adjustment for age, BMI, parity, gestational age, and BP medications (β = −0.11, p = 0.02). Significant inverse correlations were also observed between AHI and DBP (β = −0.16, p = 0.01) and MAP (β = −0.13, p = 0.02) % dipping. Oxygen desaturation index and sleep time below SaO2 90% were also inversely correlated with % dipping. Moreover, a significant positive correlation was observed between carotid-femoral pulse wave velocity (cfPWV) and REM AHI (β = 0.02, p = 0.04) in unadjusted but not adjusted analysis.Conclusion: Blood pressure non-dipping was observed in a majority of women with HDP and OSAH. There were significant inverse relationships between OSAH severity measures and nocturnal % dipping. Increased arterial stiffness was associated with increasing severity of OSAH during REM sleep in unadjusted although not adjusted analysis. These findings suggest that OSAH may represent a therapeutic target to improve BP profile and vascular risk in HDP.

Variable negative external pressure-an alternative to continuous positive airway pressure for the treatment of obstructive sleep apnea: a pilot study.

To assess variable negative external pressure (vNEP) therapy using a range of pressures and varying collar sizes and shapes to identify combinations that improve the efficacy and comfort of this emerging therapy for obstructive sleep apnea (OSA). This prospective, open-label pilot study included 28 eligible patients (71% men) having documented moderate OSA (apnea-hypopnea index [AHI] 15 events/h ≤ AHI ≤ 30 events/h) at 1 sleep clinic for an overnight, in-lab sleep trial. Each participant tested at least 2 of 6 available vNEP devices during sleep periods ≥ 2 hours. During the assessment of AHI by polysomnography, negative pressures of -20 cm H2O to -35 cm H2O were adjusted to improve each patient's response. Participants' therapeutic preferences were assessed by a questionnaire and interviews. Twenty (71%) of the participants responded to vNEP therapy: excellent response (AHI ≤ 5 events/h) was observed in 14 (50%); 6 (21%) achieved a partial response (AHI ≤ 50% baseline). For the 20 responders, the therapy reduced the fraction of total sleep time when peripheral oxygen saturation < 90% and improved minimum pulse oximetry oxygen saturation. Six patients experienced a minor, self-limited adverse event. Twenty-six participants (93%) stated that they would use vNEP nightly. In this pilot study, vNEP therapy markedly improved AHI and oxygenation in most patients with moderate OSA. The majority of participants found vNEP comfortable and preferable to prevailing OSA therapies. Further development and studies of vNEP are warranted. Registry: ClinicalTrials.gov; Name: Study of Variable Negative External Pressure (vNEP) in Reducing Respiratory Event in Individuals With OSA; URL: https://clinicaltrials.gov/ct2/show/NCT04718142; Identifier: NCT04718142. Kram JA, Pelayo R. Variable negative external pressure-An alternative to continuous positive airway pressure for the treatment of obstructive sleep apnea: A pilot study. J Clin Sleep Med. 2022;18(1):305-314.

Questionnaire and Portable Sleep Test Screening of Sleep Disordered Breathing in Acute Stroke and TIA.

Sleep disordered breathing (SDB) is highly prevalent, but frequently unrecognized among stroke patients. Polysomnography (PSG) is difficult to perform soon after a stroke. We evaluated the use of screening questionnaires and portable sleep testing (PST) for patients with acute stroke, subarachnoid hemorrhage, or transient ischemic attack to expedite SDB diagnosis and management. We performed a single-center retrospective analysis of a quality improvement study on SDB screening of consecutive daytime, weekday, adult admissions to a stroke unit. We excluded patients who were unable to communicate and lacked available family members. Patients were screened with the Epworth Sleepiness Scale, Berlin Questionnaire, and STOP-BANG Questionnaire and underwent overnight PST and/or outpatient PSG. The 4-item STOP Questionnaire was derived from STOP-BANG for a secondary analysis. We compared the sensitivity and specificity of the questionnaires for the diagnosis of at least mild SDB (apnea hypopnea index (AHI) ≥5) on PST and correlated AHI measurements between PST and PSG using the Spearman correlation. Out of sixty-eight patients included in the study, 54 (80%) were diagnosed with SDB. Only one (1.5%) had a previous SDB diagnosis. Thirty-three patients completed all questionnaires and a PST. The STOP-BANG questionnaire had the highest sensitivity for at least mild SDB (0.81, 95% CI (confidence interval): 0.65–0.92) but a low specificity (0.33, 95% CI 0.10, 0.65). The discrimination of all questionnaires was overall poor (C statistic range 0.502–0.640). There was a strong correlation (r = 0.71) between the AHI results estimated using PST and outpatient PSG among 28 patients. The 4-item STOP Questionnaire was the easiest to administer and had a comparable or better sensitivity than the other questionnaires. Inpatient PSTs were useful for screening in the acute setting to facilitate an early diagnosis of SDB and to establish further outpatient evaluations with sleep medicine.

Minimally Invasive Combined Nd:YAG and Er:YAG Laser-Assisted Uvulopalatoplasty for Treatment of Obstructive Sleep Apnea.

Objective: In this article, efficacy of minimally invasive outpatient laser-assisted uvulopalatoplasty (LAUP) procedure (NightLase® LAUP) to reduce apnea-hypopnea index (AHI) in patients with obstructive sleep apnea (OSA) is evaluated. Background: OSA is a serious condition, but its treatment is often not effective or is poorly accepted by patients. Newer modes of therapy that are more effective and also more accepted by patients need to be developed. The latest treatment approaches involve a minimally invasive LAUP procedure. This procedure involves thermal processing of the relaxed soft palate and surrounding tissues using neodimium-doped yttrium aluminum garnet (Nd:YAG) and erbium-doped yttrium aluminum garnet (Er:YAG) lasers, resulting in favorable collagen shrinkage and development of new collagen fibers. Procedure has previously been reported to safely and effectively reduce snoring, as well as increase the volume of the oropharyngeal airway, and is well accepted by patients. Materials and methods: The efficacy of the minimally invasive LAUP procedure, combining Nd:YAG laser (λ = 1064 nm) and Er:YAG laser (λ = 2940 nm) applied to the soft palate for treatment of OSA on 27 patients with different severities of OSA was evaluated based on AHI measurements before and after only three 20-min sessions in an outpatient setting over a period of 45-60 days. Results: A decrease in AHI for all the patients with different severities of OSA tested in this study was achieved, with 66.3% average improvement (32-100%). Fifty percent or more improvement was achieved in 78% (21) of all patients. Conclusions: Based on our observations, the NightLase® LAUP treatment of OSA represents an effective and safe therapeutic method. Further research and longer term prospective trials are needed to improve the evidence base for the potential integration of this treatment method into the current guidelines for treatment of OSA.

Brainstem lesions are associated with sleep apnea in multiple sclerosis.

BackgroundStudies linking MRI findings in MS patients with obstructive sleep apnea severity are limited.ObjectiveWe conducted a retrospective study to assess MRI abnormalities associated with obstructive sleep apnea (OSA) in patients with multiple sclerosis (MS).MethodsWe performed retrospective chart review of 65 patients with multiple sclerosis who had undergone polysomnography (PSG) for fatigue as well as brain MRI. We measured the number of lesions in the brainstem and calculated the standardized third ventricular width (sTVW) as a measure of brain atrophy, and subsequently performed correlation analyses of the apnea-hypopnea index (AHI) with brainstem lesion location, sTVW, and Expanded Disability Status Scale (EDSS).ResultsMS Patients with OSA were significantly older and had a higher body mass index (BMI) and higher AHI measures than patients without OSA. After adjustment for covariates, significant associations were found between AHI and lesion burden in the midbrain (p < 0.01) and pons (p = 0.05), but not medulla.ConclusionsMidbrain and pontine lesions burden correlated with AHI, suggesting MS lesion location could contribute to development of OSA.

Night-to-night variability in respiratory parameters in children and adolescents examined for obstructive sleep apnea

IntroductionThe diagnosis of obstructive sleep apnea (OSA) is routinely based on just a single night's sleep examination. The night-to-night variability in children and adolescents has previously been investigated using type 4 sleep monitors or PSG. However, there is a lack of studies investigating the night-to-night variability when using type 3 sleep monitors. Therefore, the main purpose was to investigate the night-to-night variability in respiratory parameters in children and adolescents using a portable type 3 monitor. Furthermore, the purpose was to investigate the clinical relevance of night-to-night variability. MethodsThe study population was recruited from an ongoing research project concerning the effect of weight loss in children and adolescents with OSA and overweight/obesity. The inclusion criterion was the successful recording of two consecutive nights of sleep. Sleep examinations were recorded at home using the Nox T3 device and then blindly scored by the same registered polysomnographic technologist. To compare the respiratory parameters measured each night, a paired t-test or a Wilcoxon signed-rank test was used. The apnea-hypopnea index (AHI) was further described graphically with a scatter plot and a Bland-Altman plot. The presence and severity of OSA were described in tables. ResultsA total of 30 children and adolescents with a median age of 14.8 years were included. When comparing respiratory parameters between nights, all p-values derived from paired t-tests and Wilcoxon signed-rank tests were >0.05. When considering the graphical depictions of AHI, it was evident that for some participants AHI measurements varied widely from night to night. Regarding the presence of OSA, 27% of participants changed diagnostic category between nights and 40% of those with a normal AHI on the first night had OSA on the second night. Regarding OSA severity, 50% of participants changed severity category between nights. ConclusionsAHI measurements varied widely between nights in some children and adolescents leading to frequent changes in both diagnosis and severity of OSA from night to night. We therefore suggest the presence of a clinically relevant night-to-night variability which should be taken into account when diagnosing pediatric OSA.

Comparison of 3‐months treatment adherence and estimating residual apnea hypopnea index between home versus in‐laboratory auto‐titrating positive airway pressure titration

We aimed to assess the accuracy of home titration in estimating apnea hypopnea index (AHI) and optimal pressure values and to compare improvements in subjective daytime sleepiness, sleep quality and quality of life, along with 3-months treatment adherence of patients that received at-home versus in-laboratory auto-titrating positive airway pressure (APAP) titration. In patients with a diagnosis of obstructive sleep apnea syndrome (OSAS), a study arm of laboratory attended APAP titration was compared with a study arm of home titration using an APAP device for three days. Subjective questionnaires were evaluated before and after 3 months of treatment. Fifty-three patients with newly diagnosed OSAS were enrolled. There was a significant positive correlation between PSG AHI and APAP AHI (rs =0.43, P=0.003) and the fixed pressure for the APAP arm was positively correlated with the APAP PSG arm of the study (rs =0.71, P<0.001). When the Bland-Altman graphs were compared, it was seen that the measurements obtained by the APAP AHI method were 0.3 units higher than the PSG AHI measurements, and that the mean of the measurement differences between the two methods was not different than 0 (P [H0 : Mean=0]=0.551). After 3 months of treatment, average nightly use was slightly higher in the APAP arm (P=0.387). The results indicate that both titration methods were not clinically inferior in terms of a fixed optimal pressure, residual events, 3-months treatment adherence and change in subjective sleepiness, sleep quality and quality of life after treatment.

Role of limited vs full polysomnography as a diagnostic tool of obstructive sleep apnea

Introduction Obstructive sleep apnea (OSA) is the commonest breathing disorder during sleep and usually presents with sleep fragmentation, hypoxia, and excessive day sleepiness. Polysomnography (PSG) is still the device of choice for OSA diagnosis. Objective The aim was to compare the validity of limited PSG (measuring nasal flow of air, effort of respiratory muscles, heart rate, and oxygen saturation) with full PSG in diagnosis of OSA. Patients and methods Any patient who presented with snoring associated with excessive daytime sleepiness, Epworth sleep scale greater than or equal to 10, BMI greater than 30, or apnea-hypopnea index (AHI) greater than or equal to 5 events/h admitted to Chest Department, Faculty of Medicine, Tanta University Hospitals during the period from June 2018 to April 2019 was included in the study and subjected to full and limited PSG for two consecutive nights. Limited PSG included the following channels: nasal cannula and nasal thermistor, snoring microphone, the abdominal belt, the thoracic belt, the SOMNO screen plus, and the pulse oximetry lead. Results Limited PSG was comparable to full one, with insignificant difference in measuring AHI in total, moderate, and severe OSA cases. There was a significant positive correlation between AHI measured by full and limited PSG in both moderate and severe OSA cases. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in measurement of AHI by limited PSG were higher in severe than in moderate OSA cases, which indicates that the limited PSG is more sensitive, more specific, and more accurate in the diagnosis of severe cases than moderate ones. Conclusion Limited PSG is a reliable diagnostic device of OSA, as it has excellent agreement with AHIs determined by full PSG besides its lower cost.

Adenoid hypertrophy causing obstructive sleep apnea in children after pharyngeal flap surgery.

Pharyngeal flap surgery used for treatment of velopharyngeal insufficiency (VPI) may be followed by obstructive sleep apnea (OSA) especially if the patient has developed adenoid hypertrophy. However, adenoidectomy may adversely affect speech in these patients. The aim of this study was to assess the effectiveness of transnasal endoscopic power-assisted adenoidectomy in relieving OSA in patients with adenoid hypertrophy who underwent pharyngeal flap surgery, and the impact of the procedure on their speech. Transnasal endoscopic power-assisted adenoidectomy for nine children presenting with adenoid hypertrophy was performed. The patients had previously undergone pharyngeal flap surgery for treatment of VPI. Flexible nasopharyngoscopy was used in the diagnosis of adenoid hypertrophy. Pre- and postoperative polysomnography with measurement of apnea-hypopnea index (AHI) was done. Additionally, auditory perceptual assessment of speech (APA) and nasalance scores was measured pre- and postoperatively. All patients were shown to have OSA by polysomnography, and a larger adenoid size was significantly associated with a higher AHI. We achieved a significant improvement in AHI after adenoidectomy. However, six patients still demonstrated OSA, albeit with a reduced severity. Speech was not adversely affected postoperatively as the APA and nasalance scores showed non-significant changes. Adenoid hypertrophy may be encountered in children who undergo pharyngeal flap surgery, which may cause OSA. Transnasal endoscopic power-assisted adenoidectomy is a safe and effective method for treatment of OSA in those patients without prejudicing the pharyngeal flap, and it has no adverse effect on speech.

Diagnosis of sleep apnea in patients with stable chronic heart failure using a portable sleep test diagnostic device.

ApneaLink is a portable device for the screening of sleep apnea, a prevalent and underdiagnosed comorbidity in heart failure patients. A prospective cross-sectional study in patients with chronic heart failure was carried out to assess the sensitivity and specificity of apnea-hypopnea index (AHI) measurements using ApneaLink against the standard polysomnography test. Adult patients with a prior hospitalization in an acute heart failure hospital unit were recruited for the study. All participants were tested for sleep apnea using ApneaLink and polysomnography simultaneously during an overnight stay at a sleep laboratory. Global sleep apnea was evaluated according to the AHI, which was analyzed and compared. Subpopulation comparison based on ejection fraction was not realized due to population size. Thirty-five patients with stable chronic heart failure completed the study (mean age 70.9 ± 10.5years and body mass index 30.0 ± 4.7kg/m2). Two patients were excluded due to insufficient study duration. ApneaLink had a sensitivity greater than 80% for all AHI measurements, and a specificity greater than 80% for all AHI measurements, except for AHI ≥ 5 events/h (61.5%). The results showed higher sensitivities and specificities at AHI values of ≥ 10 events/h (sensitivity 81.3% and specificity 84.2%) and ≥ 15 events/h (sensitivity 83.3% and specificity 91.3%). Correlation analysis showed that AHI measurements using ApneaLink and polysomnography had a strong and significant correlation (r = 0.794; P < 0.001). Our results suggest that ApneaLink could be used in clinical practice to identify heart failure patients with high (AHI ≥ 15 events/h) and low (AHI < 5 events/h) probability of having sleep apnea, sparing the need for a diagnostic polysomnography and thus potentially impacting prognosis by providing a more cost-effective and timely diagnosis of this non-cardiac comorbidity.

A Comprehensive Evaluation of a Two-Channel Portable Monitor to "Rule in" Obstructive Sleep Apnea.

We hypothesized that a dual-channel portable monitor (PM) device could accurately identify patients who have a high pretest probability of obstructive sleep apnea (OSA), and we evaluated factors that may contribute to variability between PM and polysomnography (PSG) results. Consecutive clinic patients (N = 104) with possible OSA completed a home PM study, a PM study simultaneous with laboratory PSG, and a second home PM study. Uniform data analysis methods were applied to both PM and PSG data. Primary outcomes of interest were the positive likelihood ratio (LR+) and sensitivity of the PM device to "rule-in" OSA, defined as an apnea-hypopnea index (AHI) ≥ 5 events/h on PSG. Effects of different test environment and study nights, and order of study and analysis methods (manual compared to automated) on PM diagnostic accuracy were assessed. The PM has adequate LR+ (4.8), sensitivity (80%), and specificity (83%) for detecting OSA in the unattended home setting when benchmarked against laboratory PSG, with better LR+ (> 5) and specificity (100%) and unchanged sensitivity (80%) in the simultaneous laboratory comparison. There were no significant night-night (all p > 0.10) or study order effects (home or laboratory first, p = 0.08) on AHI measures. Manual PM data review improved case finding accuracy, although this was not statistically significant (all p > 0.07). Misclassification was more frequent where OSA was mild. Overall performance of the PM device is consistent with current recommended criteria for an "acceptable" device to confidently "rule-in" OSA (AHI ≥ 5 events/h) in a high pretest probability clinic population. Our data support the utility of simple two-channel diagnostic devices to confirm the diagnosis of OSA in the home environment. A commentary on this article appears in this issue on page 411.

Improved Apnea-Hypopnea Index and Lowest Oxygen Saturation After Maxillomandibular Advancement With or Without Counterclockwise Rotation in Patients With Obstructive Sleep Apnea: A Meta-Analysis

This study investigated whether patients with obstructive sleep apnea (OSA) who undergo maxillomandibular advancement (MMA) with counterclockwise (CCW) rotation compared with those who undergo MMA without CCW rotation have better outcomes. This was a systematic review with meta-analysis. The Medline and Cochrane databaseswere searched for randomized controlled trials using Medical Subject Headings. The predictor variable was operative technique, namely MMA with or without CCW rotation of the maxillofacial complex. The key outcome variables were changes in pre- and postsurgical values of pharyngeal volume measured on computed tomogram or cone-beam computed tomogram and changes in Apnea-Hypopnea Index (AHI) and lowest oxygen saturation (LSAT) values after surgery. Data were subjected to a meta-analysis based on odds ratios (OR) with 95% confidence intervals (CIs) and P values lower than .05 by χ(2) test were considered significant. Twenty-one randomized controlled trials were identified and 4 were assessed for the variables of interest. Postoperative AHI and LSAT measurements showed vast improvement. The sample was not large enough to make a correlation between pharyngeal volume changes and surgical method used. Postoperative parameters included an AHI lower than 5 (OR= 14.9; 95% CI, 2.7-83.5; P= .002), an AHI lower than 20 (OR = 114.8; 95% CI, 23.5-561.1; P <.00001), pooled results of a 50% decrease in the AHI (OR= 6.1; 95% CI, 2.2-17.0; P= .0006), and an increase greater than 90% in LSAT measurements during sleep (OR= 6.0; 95% CI, 1.8-19.9; P= .003). The funnel plot showed no evidence of publication bias. CCW-MMA or MMA in patients with OSA results in a statistically meaningful decrease in postoperative AHI and a statistically meaningful increase in postoperative LSAT.

Nonlinear analysis of heart rate variability in patients with sleep apnea hypopnea syndrome (SAHS). A severity study

Introduction Patients with sleep apnea hypopnea syndrome (SAHS) show an increased risk of suffering from cardiovascular diseases. Although this is a multifactorial relationship, sympathetic activation seems to carry out an essential role. The analysis of heart rate variability (HRV) from ECG, i.e. the RR interval (time between consecutive R peaks) time series, has been widely used as a measure of autonomous control. HRV recordings have been mainly analyzed in the frequency domain. However, as other physiological signals, heart rate is not strictly periodic. Therefore, the use of nonlinear techniques could provide additional and essential information about HRV dynamics in SAHS patients. This study is aimed at quantifying different nonlinear metrics from HRV recordings of SAHS patients in order to characterize their dependence with the severity of the disease. Materials and methods A total of 240 subjects derived to the sleep-related breathing disorders unit were involved in the study. Standard in-hospital polysomnography (PSG) were carried out in order to diagnose SAHS. Subjects with an apnea–hypopnea index (AHI), 10 events per hour (e/h) from PSG were diagnosed as suffering from SAHS. According to PSG, 160 out of 240 patients suffered from SAHS. ECG was recorded at a sampling rate of 200 Hz. A QRS detection algorithm based on the Hilbert transform was applied to obtain the HRV signal. Three nonlinear methods were subsequently applied: Sample Entropy (SampEn), which quantifies irregularity; Lempel–Ziv complexity (LZC), which measures complexity; and Central Tendency Measure (CTM), which is a variability measure. Patients were divided into 4 groups according to their AHI: Non-SAHS subjects (0 30). Results Population under study had mean age of 52.2 years, mean body mass index (BMI) of 29.6 kg/m2, and 77.5% of patients were male. SAHS positive patients showed a mean AHI of 33.2 e/h. Regarding nonlinear analysis, HRV recordings from SAHS positive patients showed lower irregularity (0.370 vs. 0.432), lower complexity (0.333 vs. 0.363) and lower variability (0.946 vs. 0.880) than non-SAHS subjects. A significant correlation was found between AHI and nonlinear measures: −0.296 (SampEn), −0.268 (LZC), and 0.256 (CTM). These correlations remain significant when adjusted for age. In stratified analyses by sex, in female patients only lZC showed correlation between AIH and HRV. In male patients CTM, SampEn and LZC show a significant correlation between AIH and HRV. Conclusion Fluctuations of HRV decreases as SAHS severity increases(higher AHI index). Therefore, HRV recordings from severe SAHS patients (AHI > 30) show significantly lower nonlinear irregularity, complexity and variability. Acknowledgements Acknowledgements to the Sleep Group of Hospital Universitario Rio Hortega and Biomedical Engineering Group (GIB).

Predictors of Uvulopalatopharyngoplasty Success in the Treatment of Obstructive Sleep Apnea Syndrome

Objectives: Uvulopalatopharyngoplasty (UPPP) has been described as an option for treating obstructive sleep apnea syndrome (OSAS), with variable success rates. The main purpose of this study is to correlate UPPP success to craniofacial bony structure and orofacial muscle function. Methods: Prospective longitudinal study in a tertiary clinical center. Fifty-four patients who underwent UPPP in the last 7 years were followed, and UPPP succeeded or failed based on the results of pre-operative and post-operative polysomnography. Clinical variables’ body mass index (BMI), age, and pre-operative apnea-hypopnea index (AHI)’s cephalometric measurements (craniofacial region and hyoid bone position), and muscle function variables (clinical protocol and tongue strength measures) were evaluated and compared between the groups (failure or success after UPPP). Results: The variables BMI, pre-operative AHI, and cephalometric measurements showed no influence on surgical success. The clinical muscle protocol was also similar between groups. However, the muscle strength of the anterior portion of the tongue was significantly greater in the group that showed surgical success compared to those with surgical failure. This movement is primarily performed by genioglossus muscle. Conclusions: OSAS is a multifactorial disease, and diagnostic symptom assessments should be individualized. In addition, special attention should be given to functional muscle alterations of the airways, because they might influence the evolution of the disease.

Predictors of uvulopalatopharyngoplasty success in the treatment of obstructive sleep apnea syndrome

ObjectiveUvulopalatopharyngoplasty (UPPP) has been described as an option for treating obstructive sleep apnea syndrome (OSAS), with variable success rates. The main purpose of our study was to correlate UPPP success to craniofacial bony structure and orofacial muscles function. MethodsClinical variables, including body mass index (BMI), age, and preoperative apnea-hypopnea index (AHI); cephalometric measurements of the craniofacial region and hyoid bone position; and muscle function variables including clinical protocol and tongue strength measures were evaluated in 54 patients who underwent UPPP in the last 7years. The measurements were related to the success or failure of UPPP based on the results of preoperative and postoperative polysomnography (PSG). ResultsThe variables BMI, preoperative AHI, and cephalometric measurements showed no influence on surgical success. The clinical muscle protocol also was similar between groups. However, the muscle strength of the anterior portion of the tongue was significantly greater in the group that showed surgical success compared to those with surgical failure. ConclusionOSAS is a multifactorial disease and diagnostic symptom assessments should be individualized. In addition, special attention should be given to functional muscle alterations of the airways, as they might influence the evolution of the disease.

The evaluation of adenotonsillectomy on TNF-α and IL-6 levels in obese children with obstructive sleep apnea

Objective(1) To evaluate the effect of adenotonsillectomy (T&A) on clinical signs in obese children with obstructive sleep apnea (OSA); (2) to evaluate the changes in tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 levels pre- and post-surgery; and (3) to determine a potential explanation for changes in cytokine levels after T&A therapy. Subjects and methodsIn brief, 90 obese children with OSA were enrolled. Polysomnographic data, such as an apnea–hypopnea index (AHI) and oxyhemoglobin saturation (SaO2), and demographic information, such as body mass index (BMI), were collected. TNF-α and IL-6 levels were determined before and 6 months after T&A treatment. ResultsIt was observed that 61.1% of obese children with OSA were persistent after T&A therapy. In general, AHI (events/h) measures decreased from 22.26±9.141 to 8.88±5.909 before and after a 6-month follow-up period, respectively, and nadir SaO2 (%) levels increased from 74.26±7.486 to 86.37±5.578 pre- and post-surgery, respectively. However, no discernible differences in BMI measures before and after a 6-month follow-up period (40.996±5.2486 vs. 40.597±5.0540) were observed. No significant differences in the TNF-α and IL-6 levels pre- and post-surgery were observed. TNF-α and IL-6 plasma levels were highly correlated with BMI measurements (TNF-α: r2=0.2350, P<0.001; IL-6: r2=0.6629, P<0.001). In contrast, there was no association between plasma levels and AHI measures (TNF-α: r2=0.03377, P=0.0829; IL-6: r2=0.03946, P=0.0605). ConclusionT&A therapy can improve clinical symptoms and signs but is not a cure for the treatment of obese children with OSA. The inflammation levels of TNF-α and IL-6 changed little. To reduce the risk for excessive daytime sleepiness, supplementary therapies should be introduced for OSA.