Apnea-hypopnea index: time to wake up.
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ABSTRACT:
SUBMITTER: Shahar E
PROVIDER: S-EPMC3982973 | biostudies-other | 2014
REPOSITORIES: biostudies-other
Publications
Despite the widespread use of the apnea-hypopnea index in research, its scientific and statistical properties have not been examined thoroughly. The index may be viewed either as a rate (number of events per hour of sleep) or as a ratio of two variables (number of events/number of hours of sleep). When considered as a rate, the apnea-hypopnea index may be modeled as the dependent variable, provided that researchers explicitly state which physical property they assume to be measuring. On the othe ...[more]
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Project description:Rationale: Patients with obstructive sleep apnea (OSA) experience respiratory events with greater frequency and severity while in the supine sleeping position. Postural preference (associated with the sleep monitoring device) and "first night effect" could explain a night-to-night variability in OSA severity. Objectives: We evaluated the variability of internight polysomnography (PSG) in a large group of OSA patients and explored factors explaining this variability. Methods: 188 patients referred for probable OSA (aged 54.9 ± 11.8 y) underwent two consecutive nights of at-home PSG. The effect of age, gender, obesity, neck circumference, sleep position and sleep parameters were considered to explain changes in respiratory parameters. Main Results: The mean apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) were respectively, 36.3 ± 27.5 and 22.0 ± 22.7 in the first night, with a tendency to decrease during the second night. While in mild cases (5 ? AHI < 15) there was a significant increase in AHI related to an increase in dorsal position time during the second night, there were no changes in moderate cases (15 ? AHI < 30); and in severe cases (AHI ? 30) there was a significant decrease in both AHI and ODI during the second night independent of sleep position. Conclusion: The internight variability in AHI and ODI was related to changes in sleep structure with a contribution of indices of sleep fragmentation and dorsal position. Since the changes were greater in mild OSA cases, a second night could be routinely proposed in cases with relevant clinical uncertainty.
| S-EPMC6630080 | biostudies-literature
Project description:BackgroundThe relationship between the Epworth sleepiness scale (ESS) and the apnea-hypopnea index (AHI) is uncertain and even poor. The major problem associated with the ESS might be a lack of consideration of weight in prediction in clinical practice. Would awarding different item-scores to the four scales of ESS items to develop a weighted ESS scoring system improve the accuracy of the AHI prediction? It is warranted to explore the intriguing hypotheses.MethodsSeven hundred fifty-six adult patients with suspicion of obstructive sleep apnoea syndrome (OSAS) were prospectively recruited to a derivation cohort. This was tested against a prospective validation cohort of 810 adult patients with suspected OSAS. Each ESS item’s increased odds ratio for the corresponding AHI was calculated using univariate logistic regression. The receiver operating characteristic curves were created and the areas under the curves (AUCs) were calculated to illustrate and compare the accuracy of the indices.ResultsThe higher the ESS item-score, the closer the relationship with the corresponding AHI. The odds ratios decreased as a result of the increased AHI. The ESS items were of unequal weight in predicting the corresponding AHI and a weighted ESS was developed. The coincidence rates with the corresponding AHI, body mass indices, and neck circumferences rose as the scores increased, whereas nocturnal nadir oxygen saturations decreased, and the weighted ESS was more strongly associated with these indices, compared with the ESS. The capability in predicting the patients without OSAS or with severe OSAS was strong, especially the latter, and the weighted ESS orchestrated manifest improvement in screening the patients with simple snoring. The patterns of sensitivities, specificities, and Youden’s indices of the four ranks of weighted ESS for predicting the corresponding AHI were better than those of the ESS, and the AUCs of weighted ESS were greater than the corresponding areas of ESS in the two cohorts.ConclusionsThe weighted ESS orchestrated significant improvement in predicting the AHI, indicating that the capability in predicting the patients without OSAS or with severe OSAS was strong, which might have implications for clinical triage decisions to prioritize patients for polysomnography.
| S-EPMC7291446 | biostudies-literature
Project description:BACKGROUND:Diagnostics of obstructive sleep apnea (OSA) is based on apnea-hypopnea index (AHI) determined as full-night average of occurred events. We investigate our hypothesis that intra-night variation in the frequency of obstructive events affects diagnostics and prognostics of OSA and should therefore be considered in clinical practice. METHODS:Polygraphic recordings of 1989 patients (mean follow-up 18.3 years) with suspected OSA were analyzed. Number and severity of individual obstructive events were calculated hourly for the first 6 h of sleep. OSA severity was determined based on the full-night AHI and AHI for the 2 h when the obstructive event frequency was highest (AHI2h). Hazard ratios for all-cause, cardiovascular, and non-cardiovascular mortalities were calculated for different OSA severity categories based on the full-night AHI and AHI2h. RESULTS:Frequency and duration of obstructive events varied hour-by-hour increasing towards morning. Using AHI2h led to a statistically significant rearrangement of patients between the OSA severity categories. The use of AHI2h for severity classification showed clearer relationship between the OSA severity and mortality than the full-night AHI. CONCLUSIONS:Currently, the intra-night variation in frequency and severity of obstructive events is completely ignored by conventional, full-night AHI and considering this information could improve the diagnostics of OSA.
| S-EPMC7127992 | biostudies-literature
Project description:ObjectivesThe aim of this study was to identify correlations between sleep apnea severity and tongue volume or posterior airway space measured via three-dimensional reconstruction of volumetric computerized tomography (CT) images in patients with obstructive sleep apnea (OSA) for use in predicting OSA severity and in surgical treatment. We also assessed associations between tongue volume and Mallampati score.MethodsSnoring/OSA male patients (n = 64) who underwent polysomnography, cephalometry, and CT scans were enrolled in this retrospective study. OSA was diagnosed when the apnea-hypopnea index (AHI) was greater than 5 (mild 5-14; moderate 15-29; severe>30). The patients were also categorized into the normal-mild group (n = 22) and the moderate-severe group (n = 42). Using volumetric CT images with the three-dimensional reconstruction technique, the volume of the tongue, posterior airway space volume, and intra-mandibular space were measured. The volumes, polysomnographic parameters, and physical examination findings were compared, and independent factors that are related to OSA were analysed.ResultsNo associations between tongue volume or posterior airway space and the AHI were observed. However, multivariate linear analyses showed that tongue volume had significantly negative association with lowest O2 saturation (r = 0.365, p = 0.027). High BMI was related to an increase in tongue volume. Modified Mallampati scores showed borderline significant positive correlations with absolute tongue volume (r = 0.251, p = 0.046) and standardized tongue volume (absolute tongue volume / intramandibular area; r = 0.266, p = 0.034). Between the normal-mild and moderate-severe groups, absolute tongue volumes were not different, although the standardized tongue volume in the moderate-severe group was significantly higher.ConclusionAbsolute tongue volume showed stronger associations with lowest O2 saturation during sleep than with the severity of AHI. We also found that high BMI was a relevant factor for an increase in absolute tongue volume and modified Mallampati grading was a useful physical examination to predict tongue size.
| S-EPMC4539216 | biostudies-literature
Project description:Continuous positive airway pressure treatment aggravates airway obstruction in patients with epiglottis collapse. In these patients, partial epiglottectomy can resolve epiglottis collapse by partial excision of the obstructed epiglottis. However, patients with epiglottic collapse usually have simultaneous obstructions on multiple levels, such as the soft palate, base of the tongue, etc. Therefore, sleep apnea cannot be controlled merely by resolving epiglottis collapse. The use of additional continuous positive airway pressure treatment after partial epiglottectomy is considered essential. However, no studies have yet evaluated the effect of partial epiglottectomy on continuous positive airway pressure treatment. In this study, we report on 2 patients with obstructive sleep apnea who underwent partial epiglottectomy. These 2 patients used autotitrating positive airway pressure treatment pre- and postoperatively. The present case report will provide insight into the effects of partial epiglottectomy on the use of positive-pressure devices.
| S-EPMC7970606 | biostudies-literature
Project description:PurposeTo evaluate the performance of the NoSAS (neck, obesity, snoring, age, sex) score, the STOP-Bang (snoring, tiredness, observed apneas, blood pressure, body mass index, age, neck circumference, gender) questionnaire, and the Epworth sleepiness score (ESS) as a screening tool for obstructive sleep apnea (OSA) severity based on the apnea-hypopnea index (AHI) and the oxygen desaturation index (ODI).MethodsData from 235 patients who were monitored by ambulant polysomnography (PSG) were retrospectively analyzed. OSA severity was classified based on the AHI; similar classification categories were made based on the ODI. Discrimination was assessed by the area under the curve (AUC), while predictive parameters were calculated by four-grid contingency tables.ResultsThe NoSAS score and the STOP-Bang questionnaire were both equally adequate screening tools for the AHI and the ODI with AUC ranging from 0.695 to 0.767 and 0.684 to 0.767, respectively. Both questionnaires perform better when used as a continuous variable. The ESS did not show adequate discrimination for screening for OSA (AUC ranging from 0.450 to 0.525). Male gender, age, and BMI proved to be the strongest individual predictors in this cohort.ConclusionThis is the first study to evaluate the predictive performance of three different screening instruments with respect to both the AHI and the ODI. This is important, due to increasing evidence that the ODI may have a higher reproducibility in the clinical setting. The NoSAS score and the STOP-Bang questionnaire proved to be equally adequate to predict OSA severity based on both the AHI and the ODI.
| S-EPMC8376723 | biostudies-literature
Project description: Not available
| S-EPMC8606287 | biostudies-literature
Project description:BackgroundOne of the key mechanisms underlying OSA is reduced pharyngeal muscle tone during sleep. Data suggest that pharmacologic augmentation of central serotonergic/adrenergic tone increases pharyngeal muscle tone.Research questionWe hypothesized that venlafaxine, a serotonin-norepinephrine reuptake inhibitor, would improve OSA severity.Study design and methodsIn this mechanistic, randomized, double-blind, placebo-controlled crossover trial, 20 patients with OSA underwent two overnight polysomnograms ≥ 4 days apart, receiving either 50 mg of immediate-release venlafaxine or placebo before bedtime. Primary outcomes were the apnea-hypopnea index (AHI) and peripheral oxygen saturation (Spo2) nadir, and secondary outcomes included sleep parameters and pathophysiologic traits with a view toward understanding the impact of venlafaxine on mechanisms underlying OSA.ResultsOverall, there was no significant difference between venlafaxine and placebo regarding AHI (mean reduction, -5.6 events/h [95% CI, -12.0 to 0.9]; P = .09) or Spo2 nadir (median increase, +1.0% [-0.5 to 5]; P = .11). Venlafaxine reduced total sleep time, sleep efficiency, and rapid eye movement (REM) sleep, while increasing non-REM stage 1 sleep (Pall < .05). On the basis of exploratory post hoc analyses venlafaxine decreased ("improved") the ventilatory response to arousal (-30%; P = .049) and lowered ("worsened") the predicted arousal threshold (-13%; [P = .02]; ie, more arousable), with no effects on other pathophysiologic traits (Pall ≥ .3). Post hoc analyses further suggested effect modification by arousal threshold (P = .002): AHI improved by 19% in patients with a high arousal threshold (-10.9 events/h [-3.9 to -17.9]) but tended to increase in patients with a low arousal threshold (+7 events/h [-2.0 to 16]). Other predictors of response were elevated AHI and less collapsible upper airway anatomy at baseline (|r| > 0.5, P ≤ .02).InterpretationIn unselected patients, venlafaxine simultaneously worsened and improved various pathophysiologic traits, resulting in a zero net effect. Careful patient selection based on pathophysiologic traits, or combination therapy with drugs countering its alerting effects, may produce a more robust response.Trial registryClinicalTrials.gov; No.: NCT02714400; URL: www.clinicaltrials.gov.
| S-EPMC7417375 | biostudies-literature
Project description:Objective/backgroundObstructive sleep apnea is a risk factor for stroke. This study sought to assess the relationship between obstructive sleep apnea (OSA) and wake-up strokes (WUS), that is, stroke symptoms that are first noted upon awakening from sleep.Patients/methodsIn this analysis, 837 Brain Attack Surveillance in Corpus Christi (BASIC) project participants completed an interview to ascertain stroke onset during sleep (WUS) versus wakefulness (non-wake-up stroke, non-WUS). A subset of 316 participants underwent a home sleep apnea test (HSAT) shortly after ischemic stroke to assess for OSA. Regression models were used to test the association between OSA and WUS, stratified by sex.ResultsOf 837 participants who completed the interview, 251 (30%) reported WUS. Among participants who underwent an HSAT, there was no significant difference in OSA severity [respiratory event index (REI)] among participants with WUS [median REI 17, interquartile range (IQR) 10, 29] versus non-WUS (median REI 18, IQR 9, 30; p = 0.73). OSA severity was not associated with increased odds of WUS among men [unadjusted odds ratio (OR) 1.011, 95% confidence interval (95% CI) 0.995, 1.027] or women (unadjusted OR 0.987, 95% CI 0.959, 1.015). These results remained unchanged after adjustment for age, congestive heart failure, body mass index, and pre-stroke depression in men (adjusted OR 1.011, 95% CI 0.994, 1.028) and women (adjusted OR 0.988, 95% CI 0.959, 1.018).ConclusionsAlthough OSA is a risk factor for stroke, the onset of stroke during sleep is not associated with OSA in this large, population-based stroke cohort.
| S-EPMC8563108 | biostudies-literature
Project description:Sleep apnea has been related to brain changes such as atrophy. However, which component of sleep apnea, the apnea-hypopnea index (AHI), nocturnal oxygen desaturation or arousals, can explain this association is unclear. In this large population-based study (n=681, mean age 62.1 years), we investigated the associations of AHI, nocturnal oxygen desaturation and arousals with global and regional gray matter and white matter volumes and with white matter lesion volumes. All participants underwent one night of polysomnography and MRI scanning of their brain. Gray matter, white matter and white matter lesion volumes adjusted for intracranial volume were studied as markers of brain atrophy. Nocturnal oxygen desaturation was related to whole brain white matter atrophy independent of covariates (multivariable adjusted B=-8.3, 95% CI=-16.7; -0.02). This association was most prominently reflected in the association between more oxygen desaturation and a smaller white matter parietal volume (B=-3.95 ml, 95% CI=-6.02; -1.88). Furthermore, oxygen desaturation was related to a smaller hippocampus (B=-0.22 ml, 95% CI=-0.42; -0.01). Although a higher AHI was related to smaller parietal gray (B=-0.05, 95% CI=-0.09; -0.004) and white matter (B=-0.06, 95% CI=-0.12; -0.10) volumes, these associations disappeared when adding oxygen desaturation to the model. We did not find a relation between arousals and gray and white matter brain atrophy and white matter lesion volumes. This suggests that oxygen desaturation mainly explains the association between sleep apnea and brain damage.
| S-EPMC6580891 | biostudies-literature