Difference In Apnea-hypopnea Index Research Articles

Kairos positive airway pressure (KPAP) equals continuous PAP in effectiveness, and offers superior comfort for obstructive sleep apnea treatment

Study objectivesA recent study challenged the prevailing clinical view that maintaining inspiratory positive airway pressure (IPAP) is necessary for upper airway patency, demonstrating no differences in apnea hypopnea index (AHI) between continuous PAP (CPAP) with and without a resistor to reduce IPAP. In this study, we assessed the effect of Kairos PAP (KPAP), a new algorithm which features multiple drops in IPAP, only returning to therapeutic pressure near the end expiration, on sleep apnea severity and subjective comfort. MethodsTwo randomized clinical trials were conducted. In the Efficacy trial, the effect of KPAP vs. CPAP on AHI in PAP-treated OSA patients was examined using a split-night design, adjusting for period, sequence and fraction of supine sleep (mixed models). Unintentional leak differences between treatments were also examined. Exploratory analyses assessed the effect of KPAP vs. CPAP on key polysomnography outcomes. In the Comfort trial, we tested subjective preference for KPAP vs. CPAP at 9 and 13 cmH2O in PAP-naïve OSA patients. ResultsIn the Efficacy trial (N = 48), KPAP reduced AHI more than CPAP (mean difference [95%CI]: −0.5 [−0.8, −0.2] events/h, P = 0.007). Unintentional leak was also reduced by over 50 % (−2.5 [−3.2, −1.7] L/min, P < 0.001). No significant change was observed in the exploratory variables assessed. In the Comfort trial (N = 150), 69 [61, 77] % and 84 [77, 89] % of participants preferred KPAP over CPAP at 9 and 13 cmH2O, respectively (P < 0.001). ConclusionsKPAP is as effective as CPAP in reducing respiratory events, but is more comfortable and potentially better tolerated.

Age matters: association between age and depression severity at the time of OSA diagnosis and PAP adherence in adult patients.

Numerous studies have shown an association and symptom overlaps between obstructive sleep apnea (OSA) and depression. However, data are limited on the association between age, sex, the severity of depression at the time of OSA diagnosis, and its impact on positive airway pressure (PAP) adherence. The Patient Health Questionnaire (PHQ-9) is a validated depression screening and severity scoring tool recommended by the Diagnostic and Statistical Manual of Mental Disorders (fifth edition). In this retrospective observational study, we evaluate the interrelationship between age at OSA diagnosis, depression severity, and PAP adherence. Patients with new OSA diagnosis, seen at the University of California San Francisco-Fresno Sleep Center between February and October of 2022, were evaluated. PHQ-9 scores for depression severity uses a 1 to 5 scale (1 = none, 2 = mild, 3 = moderate, 4 moderately severe, 5 = severe). The PHQ-9 was administered at the time of OSA diagnosis and follow-up. Average daily PAP usage hours were obtained from PAP devices between 1 to 3 months after therapy initiation. IBM SPSS version 29.0.0 was used to calculate descriptive statistics, Pearson correlation, and Mann-Whitney test. Seventy-seven patients fit the inclusion criteria, of which 28 were women (36.4%). The average baseline apnea-hypopnea index was 34.5 (standard deviation 31.8), with a PHQ-9 mean of 8.3 with standard deviation ± 5.9. A Mann-Whitney comparison between the group with normal PHQ-9 scores and the group with PHQ-9 scores consistent with depression (score of 5 or greater) showed no statistically significant differences in apnea-hypopnea index (P = .470) or average night hour use (P = .195). There was a statistically significant difference in age between both groups (P = .031). Spearman correlation confirmed a negative, statistically significant correlation between PHQ-9 scores and age in patients with OSA. This study showed that PHQ-9 scores at the time of OSA diagnosis are moderately correlated with younger age, with those patients younger than 50 years old having more moderate to severe depression scores than older patients. We did not find a correlation between age and PAP adherence or between PHQ-9 scores and PAP adherence. Our findings can help identify high-risk depression patients early in the diagnosis of OSA and bring awareness that the young adult population can be particularly vulnerable. Niraula R, Singh A, DelRosso LM, Meghpara S, Keenan L. Age matters: association between age and depression severity at the time of OSA diagnosis and PAP adherence in adult patients. J Clin Sleep Med. 2024;20(6):859-862.

Can polysomnography be replaced by ApneaGraph200 for OSA diagnosis? A protocol for systematic review and meta-analysis.

It is yet unknown if the ApneaGraph200 system can replace the Polysomnography system (PSG), which is now the gold standard for obstructive sleep apnea (OSA) diagnosis. We performed a meta-analysis to evaluate the difference in apnea hypopnea index and lowest oxygen saturation levels between the AG200 system and PSG system. Utilizing PubMed, Elsevier, Wanfang, and China National Knowledge Internet (CNKI), a thorough literature search was carried out. Eligible studies contrasting the AG200 system and the PSG system were found by two separate researchers. Review Manager (version 5.3) was adopted for data synthesis. The meta-analysis A pooled the comparison of AHI between the AG and PSG groups, and included seven studies involving a total of 419 participants, which revealed that there was a significant difference in AHI between the above two diagnostic methods (standard mean difference (SMD) = -0.19, 95% confidence interval (CI) = -0.32 to -0.05, P = 0.008). As a supplementary, meta-analysis B pooled the comparison of lowest oxygen saturation between the AG and PSG groups and included five studies involving a total of 224 participants. It revealed that there was no significant difference between the AG group and the PSG group (SMD = 0.09, 95% CI -0.24 to 0.43, P = 0.58). The ApneaGraph200 system can be used for the initial screening of OSA patients, but it is not a complete alternative to polysomnography for the diagnosis and severity of the OSA condition.

Influence of Lingual Tonsillar Volume in Patients with Obstructive Sleep Apnea.

This study aimed to evaluate the influence of lingual tonsil (LT) volume measured using a three-dimensional (3D) reconstruction volume rendering program on clinical parameters and polysomnography (PSG) results. A total of 100 patients who underwent PSG, computed tomography (CT), and allergy test from April 2016 to April 2020 were randomly selected. LT volume was measured using an imaging software program that enables 3D reconstruction of CT images. PSG parameters were analyzed by dividing the subjects into two groups according to LT volume (each 50 people). Based on the medial volume of 0.863 cm3, the upper half LT volume group and the lower half LT volume group were analyzed. Clinical factors such as body weight, neck circumference, body mass index (BMI), and age showed no difference between the two groups. Among PSG parameters, supine arousal index and non-rapid eye movement (NREM) arousal index were significantly higher in the upper half LT volume group (p = 0.012, 0.037). However, there was no significant difference in apnea-hypopnea index (AHI) between the upper and lower half LT volume groups (p = 0.749). Arousal snoring index and REM arousal index also showed no difference between the two groups. The prevalence of allergic rhinitis was not different in the two groups. High LT volume is associated with NREM arousal and arousal in the supine position, but it is not related to AHI.

Altitude-Induced Sleep Apnea Is Highly Dependent on Ethnic Background (Sherpa Vs. Tamang).

Heiniger, Grégory, Simon Walbaum, Claudio Sartori, Alban Lovis, Marco Sazzini, Andrew Wellman, and Raphael Heinzer. Altitude-Induced Sleep Apnea Is Highly Dependent on Ethnic Background (Sherpa Vs. Tamang). High Alt Med Biol. 23:165-172, 2022. Rationale: High altitude-induced hypocapnic alkalosis generates central sleep apnea (CSA). In Nepal, two ethnic groups live at medium-to-high altitude: Tamangs originate from low-altitude Tibeto-Burman populations, whereas Sherpas descend from high-altitude Tibetans. Objective: To compare apnea severity at low and high altitude between Sherpas and Tamangs. Methods: Polygraphy recordings, including airflow and oxygen saturation, were performed in Nepal at "low" (2,030 m) and "high" (4,380 m) altitudes. Resting ventilation () and mixed-exhaled CO2 (FECO2) were also measured at the same altitudes. Differences in apnea-hypopnea index (AHI), oxygen desaturation index (ODI), and % of nocturnal periodic breathing (NPB) at the two altitudes were compared between ethnicities. Measurements and Main Results: Twenty Sherpas and 20 Tamangs were included (males, median [interquartile range] age: 24.5 [21.5-27.8] years vs. 26.0 [21.5-39.8] years, body mass index: 23.9 [22.1-26.1] kg/m2 vs. 25.21 [20.6-27.6] kg/m2). Compared with Tamangs, Sherpas showed a lower increase in AHI (+7.5 [2.6-17.2]/h vs. +31.5 [18.2-57.3]/h, p < 0.001), ODI (+13.8 [5.5-28.2]/h vs. +42.0 [22.6-77.6]/h, p < 0.001), and NPB proportion (+0.9 [0-3.5]% vs. +12.8 [3.1-27.4]%, p < 0.001) from low to high altitude. Resting was higher in Sherpas versus Tamangs at both low (8.45 [6.89-10.70] l/min vs. 6.3 [4.9-8.3] l/min, p = 0.005) and high (9.7 [8.5-11] l/min vs. 8.74 [7.39-9.73] l/min, p = 0.020) altitudes, whereas the mean ± standard deviation FECO2 decrease between low and high altitude was greater in Tamangs versus Sherpas (-0.50% ± 0.44% vs. -0.80% ± 0.33%, p < 0.023). Conclusion: Overall, altitude-adapted Sherpas showed a 3.2-times smaller increase in sleep-disordered breathing between low and high altitude compared with Tamangs, and higher ventilation and a smaller drop in FECO2 at high altitude. These data suggest that genetic differences in breathing control can be protective against CSA.

Postoperative respiratory complications in children with obstructive sleep apnoea syndrome.

SUMMARYObjectiveWe aimed to prospectively assess the effect of comorbidities on the occurrence of postoperative respiratory complications (PoRCs) after adenotonsillectomy in children with obstructive sleep apnoea syndrome (OSA) and whether otherwise healthy children need a higher level of postoperative monitoring.Methods577 children who had OSA and underwent adenotonsillectomy were enrolled. The effects of demographics, comorbidities and OSA on PoRCs were investigated with logistic regression analysis.ResultsThe PoRC rate was 4.3%. Postoperative oxygen desaturations were more marked in patients with comorbidities (p = 0.005). The presence of comorbidity increased the risk of PoRCs (odds ratio 4.234/3.226-5.241, 95% confidence intervals, p < 0.001). There was no difference in apnoea-hypopnoea index (AHI) values between comorbid patients with and without PoRCs [8.2 (3.8-50.2) vs 14.3 (11.7-23.3)]. (p = 0.37). In the group of patients without comorbidities, PoRCs were associated with a higher AHI [14.7 (3.4-51.3) vs 3.9 (2.0-8.0), p < 0.001].ConclusionsComorbidities are more closely linked with PoRCs than OSA severity. In patients without comorbidity, PoRCs are associated with OSA severity and usually occur within the first 2 hours after the intervention.

Effect of One Night of Nocturnal Oxygen Supplementation on Highland Patients With OSA: A Randomized, Crossover Trial

The treatment of OSA in highland residents is not established. Does nocturnal oxygen supplementation (NOS) improve sleep-related breathing disturbances, nocturnal oxygenation, and cognitive performance in patients with OSA living at 3,200 m? Forty patients with OSA permanently living in Shangri-La, China at 3,200m (median age [interquartile range], 47.0 [44.0-53.0] years; oxygen desaturation index, 38.4/h [34.2/h-52.3/h]), were randomly assigned to receive nasal NOS and sham oxygen (ambient air), for one night each, at 2 L/min, in a crossover design, separated by a washout period of 2weeks. During treatment nights polysomnography was performed, and further outcomes were evaluated the next morning. The primary outcome was the difference in apnea-hypopnea index (AHI) between nights with NOS and nights with sham oxygen. During nights with sham oxygen, the median (interquartile range) total AHI was 43.4/h (31.1/h-67.5/h), the obstructive AHI was 41.9/h (28.5/h-66.8/h), and the central AHI was 0.6/h (0.1/h-1.3/h); blood oxygenation as determined by pulse oximetry (Spo2) was 87.0%(84.5%-89.0%). In intention-to-treat analysis, NOS decreased the total AHI by a median of 17.9/h (95%CI, 8.0/h-27.1/h; P< .001), through a reduction in obstructive AHI by 16.0/h (95%CI, 6.8/h-26.0/h; P< .001) and central AHI by 0.4/h (95%CI, 0.1/h-0.9/h; P< .001). NOS also increased Spo2 by 7.0%(95%CI, 6.0%-8.0%; P< .001). Heart rate during sleep and pulse rate in the morning after NOS were significantly reduced, but subjective sleep quality and cognitive performance showed no changes. In highland residents with OSA, NOS significantly improved sleep-related breathing disturbances and nocturnal oxygenation. NOS also reduced heart rate during sleep and morning pulse rate. If these beneficial effects are confirmed in longer term studies, NOS may be a treatment option for highland patients with OSA who cannot be treated by CPAP. Chinese Clinical Trial Registry; No.: ChiCTR1800017715; URL: http://www.chictr.org.cn/showproj.aspx?proj=29768.

Children with Down syndrome and mild OSA: treatment with medication versus observation.

Children with Down syndrome (DS) have a high prevalence of obstructive sleep apnea (OSA). Anti-inflammatory medications have been shown to be an effective treatment for mild OSA in otherwise healthy children. However, the efficacy in children with DS and mild OSA has not been investigated. Our aim was to examine the polysomnographic changes of children with DS and mild OSA treated with medication. A retrospective chart review was performed in children with DS (< 18 years) and mild OSA (obstructive apnea-hypopnea index ≤ 5 events/h) diagnosed by polysomnography (PSG) between 2006 and 2018. Patients were included if they were treated with medications (intranasal corticosteroids and/or montelukast) or by observation with a duration of at least 3 months and had baseline and follow-up PSGs. Demographic data, comorbid diagnoses, and PSG data were collected and analyzed. Forty-five children met inclusion criteria. In the medication group, 29 children were identified. The median age was 7.4 years (interquartile range [IQR] 4.9-9.3). In the observation group, 16 children were identified. The median age was 4.0 years (IQR 3.2-5.3). The median time from baseline to follow-up PSG was 14.0 months (IQR 10.0-22.9) for the medication group and 10.5 months (IQR 6.5-33.5) for the observation group. There were no significant changes in the median obstructive apnea-hypopnea index from the baseline to follow-up PSG in either the medication group (2.8 [IQR 2.2-3.6) versus 3.5 [IQR 1.4-4.8) events/h; P = .25) or the observation group (2.3 [IQR 1.3-3.1] versus 2.9 [IQR 1.9-6.8] events/h; P = .12). Similarly, there were no significant differences in apnea-hypopnea index, oxygen nadir or end-tidal carbon dioxide between the groups (P = .07-1). In our cohort, medication therapy did not significantly improve polysomnographic measures in children with DS and mild OSA. Several factors such as hypotonia and relative macroglossia may explain the ineffectiveness of medical therapy for OSA in this population. Further prospective studies are necessary to confirm these results and to evaluate if a subgroup of DS children may benefit from medical therapy.

Global REACH 2018: The Effect of an Expiratory Resistance Mask with Dead Space on Sleep and Acute Mountain Sickness During Acute Exposure to Hypobaric Hypoxia.

Carr, Jay, Rachel Stone, Courtney Tymko, Kaitlyn Tymko, Geoff B. Coombs, Ryan L. Hoiland, Connor A. Howe, Michael M. Tymko, Philip N. Ainslie, and Alexander Patrician. Global REACH 2018: the effect of an expiratory resistance mask with dead space on sleep and acute mountain sickness during acute exposure to hypobaric hypoxia. High Alt Med Biol. 21:297-302, 2020. We hypothesized that an expiratory resistance and dead space (ER/DS) mask, a version of which was previously shown to partially alleviate sleep-disordered breathing and headache severity during acute normobaric hypoxia (Patrician et al.), would exhibit similar results in conditions of hypobaric hypoxia. In a randomized, single-blinded, sham-controlled, and sex-matched design, 31 healthy lowlanders rapidly (6-8 hours) ascended from sea level to 4300 m (Cerro de Pasco, Peru) and slept with either an ER/DS mask (n = 15) or sham mask (n = 16). Sleep was assessed (via WatchPAT) and questionnaires collected before sleep and upon waking the morning after. There was no difference in apnea-hypopnea index (AHI) between the ER/DS (77 ± 20 events/h) or sham mask (84 ± 27 events/h; p = 0.57). In addition, there was no alleviation of headache scores, improvement in sleep quality, or acute mountain sickness symptom severity. Both the sham and ER/DS masks were poorly tolerated (∼50% subject noncompliance in both groups). These findings highlight the importance and necessity of field-testing and demonstrate that more testing is needed before ER/DS devices, such as these, can be recommended for prophylactic benefits at high altitude.

Design and Evaluation of a Non-ContactBed-Mounted Sensing Device for AutomatedIn-Home Detection of Obstructive Sleep Apnea:A Pilot Study.

We conducted a pilot study to evaluate the accuracy of a custom built non-contact pressure-sensitive device in diagnosing obstructive sleep apnea (OSA) severity as an alternative to in-laboratory polysomnography (PSG) and a Type 3 in-home sleep apnea test (HSAT). Fourteen patients completed PSG sleep studies for one night with simultaneous recording from our load-cell-based sensing device in the bed. Subjects subsequently installed pressure sensors in their bed at home and recorded signals for up to four nights. Machine learning models were optimized to classify sleep apnea severity using a standardized American Academy of Sleep Medicine (AASM) scoring of the gold standard studies as reference. On a per-night basis, our model reached a correct OSA detection rate of 82.9% (sensitivity = 88.9%, specificity = 76.5%), and OSA severity classification accuracy of 74.3% (61.5% and 81.8% correctly classified in-clinic and in-home tests, respectively). There was no difference in Apnea Hypopnea Index (AHI) estimation when subjects wore HSAT sensors versus load cells (LCs) only (p-value = 0.62). Our in-home diagnostic system provides an unobtrusive method for detecting OSA with high sensitivity and may potentially be used for long-term monitoring of breathing during sleep. Further research is needed to address the lower specificity resulting from using the highest AHI from repeated samples.

The Effect of Patient-Facing Applications on Positive Airway Pressure Therapy Adherence: A Systematic Review.

Many patients struggle with adherence to positive airway pressure (PAP) therapy for sleep apnea. In this systematic review we examined the effect that patient-facing applications (PFA)-web-based applications that interact directly with the patient-have on PAP adherence. A comprehensive search of PubMed, CINAHL, MEDLINE, and SCOPUS databases was performed. We looked for studies where: (1) patients were adults with sleep apnea initiating PAP therapy for the first time; (2) the intervention was a PFA that incorporated individual PAP use data; (3) the comparison was usual and/or telemedicine care, and (4) outcomes of objective PAP adherence data were recorded. Seven studies were identified (two randomized trials, one prospective cohort trial, four retrospective cohort studies). Cumulatively the studies enrolled 304,328 patients, with individual enrollment ranging between 61 and 172,678 patients. Six studies showed that PFA use was associated with using PAP for significantly more hours per night (range 0.7-1.3 hours more). PFA cohorts used PAP a greater proportion of nights and had a lower rate of mask leak. There was no difference in apnea-hypopnea index and self-reported measures of symptoms between study groups. PFA use was associated with improved adherence to PAP therapy. Although this conclusion is based on only two small trials and predominantly observational studies and therefore should be tested in large prospective trials, the PAFs are inexpensive, do not draw on health care resources, and show promise in improving PAP therapy for OSA.

The effects of zolpidem in obstructive sleep apnea - An open-label pilot study.

New knowledge on hypnotics and their effects on the phenotypic causes of obstructive sleep apnea indicate that zolpidem has therapeutic potential for certain patients. Specifically, zolpidem increases the threshold for arousal threshold and pharyngeal dilator muscle responsiveness. However, the effects of a standard dose of zolpidem (10 mg) on obstructive sleep apnea severity and symptoms have not been investigated. In an open-label pilot study, 12 unselected people with obstructive sleep apnea were recruited following a diagnostic in-laboratory sleep study. Participants then returned for a single-night sleep study in which 10 mg of zolpidem was given just prior to sleep. Tolerability, next-day sleepiness and the effects of zolpidem on polysomnography variables were assessed. Zolpidem was well tolerated and significantly improved the sleep efficiency compared with the no-drug night (77 ± 12% versus 84 ± 9%, p = 0.005). Individual responses on obstructive sleep apnea severity to zolpidem in this unselected obstructive sleep apnea patient population were variable with no overall systematic difference in apnea-hypopnea index (29 ± 18.2 events per hr versus 33 ± 28 events per hr, p = 0.45) or other key respiratory parameters (e.g. event duration or hypoxemia). Next-day sleepiness assessed via the Karolinska Sleepiness Scale was not different between visits (4 ± 1 versus 4 ± 2, p = 0.85). These findings provide the first insight into the effects of a standard dose of zolpidem in obstructive sleep apnea, and highlight its tolerability and potential to improve sleep quality. The variable effects on obstructive sleep apnea severity observed in this pilot also underscore the need for larger trials that incorporate phenotypic characterisation (e.g. arousal threshold, Pcrit and muscle responsiveness) to understand inter-individual heterogeneity and the therapeutic potential of zolpidem for certain people with obstructive sleep apnea.

Medium Increased Risk for Central Sleep Apnea but Not Obstructive Sleep Apnea in Long-Term Opioid Users: A Systematic Review and Meta-Analysis.

Opioids are associated with higher risk for ataxic breathing and sleep apnea. We conducted a systematic literature review and meta-analysis to assess the influence of long-term opioid use on the apnea-hypopnea and central apnea indices (AHI and CAI, respectively). A systematic review protocol (Cochrane Handbook guidelines) was developed for the search and analysis. We searched Embase, Medline, ACP Journal Club, and Cochrane Database up to November 2014 for three topics: (1) narcotics, (2) sleep apnea, and (3) apnea-hypopnea index. The outcome of interest was the variation in AHI and CAI in opioid users versus non-users. Two reviewers performed the data search and extraction, and disagreements were resolved by discussion. Results were combined by standardized mean difference using a random effect model, and heterogeneity was tested by χ(2) and presented as I(2) statistics. Seven studies met the inclusion criteria, for a total of 803 patients with obstructive sleep apnea (OSA). We compared 2 outcomes: AHI (320 opioid users and 483 non-users) and 790 patients with CAI (315 opioid users and 475 non-users). The absolute effect size for opioid use was a small increased in apnea measured by AHI = 0.25 (95% CI: 0.02-0.49) and a medium for CAI = 0.45 (95% CI: 0.27-0.63). Effect consistency across studies was calculated, showing moderate heterogeneity at I(2) = 59% and 29% for AHI and CAI, respectively. The meta-analysis results suggest that long-term opioid use in OSA patients has a medium effect on central sleep apnea.

Long-Term Effect of Weight Loss on Obstructive Sleep Apnea Severity in Obese Patients with Type 2 Diabetes

To examine whether the initial benefit of weight loss on obstructive sleep apnea (OSA) severity at 1 year is maintained at 4 years. Randomized controlled trial with follow-up at 1, 2, and 4 years. 4 Look AHEAD clinical centers. Two hundred sixty-four obese adults with type 2 diabetes and OSA. Intensive lifestyle intervention with a behavioral weight loss program or diabetes support and education. Change in apnea-hypopnea index on polysomnogram. The intensive lifestyle intervention group's mean weight loss was 10.7 ± 0.7 (standard error), 7.4 ± 0.7, and 5.2 ± 0.7 kg at 1, 2, and 4 years respectively, compared to a less than 1-kg weight loss for the control group at each time (P < 0.001). Apnea-hypopnea index difference between groups was 9.7 ± 2.0, 8.0 ± 2.0, and 7.7 ± 2.3 events/h at 1, 2 and 4 years respectively (P < 0.001). Change in apnea-hypopnea index over time was related to the amount of weight loss (P < 0.0001) and intervention, independent of weight loss (P = 0.001). Remission of OSA at 4 years was 5 times more common with intensive lifestyle intervention (20.7%) than diabetes support and education (3.6%). Among obese adults with type 2 diabetes and OSA, intensive lifestyle intervention produced greater reductions in weight and apnea-hypopnea index over a 4 year period than did diabetes support and education. Beneficial effects of intensive lifestyle intervention on apneahypopnea index at 1 year persisted at 4 years, despite an almost 50% weight regain. Effect of intensive lifestyle intervention on apnea-hypopnea index was largely, but not entirely, due to weight loss.

A comparison of inspiratory airflow dynamics during sleep between upper airway resistance syndrome patients and healthy controls

A test of the hypothesis that upper airway resistance syndrome (UARS) patients have an increased prevalence of inspiratory airflow limitation (IFL) during sleep compared to healthy controls. We compared inspiratory airflow dynamics during sleep between 12 UARS patients (nine females and three males) and 12 healthy controls matched for age, gender and obesity with maximal age limited at 45years. A standard clinical polysomnogram (airflow measured with a nasal/oral pressure catheter) was performed to assess the impact of SDB on the participants' natural sleep. A second full-night polysomnogram with a pneumotachograph and a supraglottic pressure catheter to measure airflow and effort was performed to compare the maximal inspiratory airflow and effort and the percentage of flow-limited breaths during supine, continuous stage 2 sleep between groups. During clinical polysomnography, UARS participants did not differ significantly from controls in sleep architecture or fragmentation. We observed a small difference in apnea hypopnea index between UARS participants and controls (1.6 ± 1.9 vs. 0.4 ± 0.3, respectively; p = 0.035). During supine, continuous stage 2 sleep, 64.2% (35.8; mean (SD)) of UARS participants' breaths were flow-limited compared with 34.0% (39.3) of controls' breaths (p = 0.06). The groups did not differ in maximal inspiratory airflow or inspiratory effort. Our findings indicate a less-than-robust difference in respiratory parameters during sleep between UARS patients and healthy controls and no difference in standard sleep parameters or sleep fragmentation. We consider a pathophysiology of UARS that incorporates these findings.

Year in review 2010: Interstitial lung diseases, acute lung injury, sleep, physiology, imaging, bronchoscopic intervention and lung cancer

Year in review 2010: Interstitial lung diseases, acute lung injury, sleep, physiology, imaging, bronchoscopic intervention and lung cancer

Evaluation of auto bi-level algorithm to treat pressure intolerance in obstructive sleep apnea

The objective of this study was to evaluate whether a new auto-adjusting bi-level algorithm was comparable to a standard method for prescribing bi-level therapy. This study was a prospective randomized, double-blinded crossover evaluation of the equivalency of the auto-adjusting bi-level mode (VAuto™) compared to standard bi-level mode, using a pre-determined difference in Apnea-Hypopnea Index (AHI) of five events per hour. Data were obtained during sleep studies performed on two separate nights. Twenty-two subjects met the entry criteria and were enrolled in the study at four investigational sites in the USA. Mean AHI for the auto-adjusting bi-level mode was 6.2 ± 5.4 events per hour and for the standard bi-level mode 8.3 ± 5.8 events per hour. The AHI for the two modes were clinically equivalent. The difference in median pressure between these two modes was -3.8 cm H(2)O ± 3.6 (p = 0.0008) in favor of the auto-adjusting bi-level mode. In addition, the maximum pressure was significantly higher in the auto-adjusting bi-level mode (16.0 cm H(2)O vs. 14.1 cm H(2)O, p = 0.02). Our results demonstrated that the auto-adjusting bi-level mode normalized AHI comparable to the standard bi-level mode. The results of this study have several significant implications for the clinical management of sleep apnea. Obstructive sleep apnea (OSA) is a common condition and is associated with untoward complications. Non-compliance with positive airway pressure (PAP) limits the efficacy of the PAP therapy. The auto-adjusting bi-level mode provides a potentially reliable alternative for sleep clinicians faced with prescribing bi-level PAP for non-compliant patients. This study documents that this type of auto-adjusting device provides effective treatment of OSA.

Clinical Characteristics in Two Subgroups of Obstructive Sleep Apnea Syndrome in the Elderly: Comparison Between Cases With Elderly and Middle-Age Onset

Morbidity due to obstructive sleep apnea syndrome (OSAS) is increased in the elderly population. However, the clinical characteristics of OSAS in elderly patients have not been characterized conclusively. The aim of this study was to clarify differences in clinical characteristics of OSAS between patients with middle-age onset and elderly onset of OSAS. Patients with OSAS aged > or = 65 years were classified into groups according to age at first identification of respiratory pauses during sleep: a middle-age onset group (n = 32) where onset was at age < 50 years and an elderly onset group (n = 31) where onset was at age > or = 60 years. We compared demographic variables; polysomnographic variables; daytime sleepiness measures, including the multiple sleep latency test (MSLT) and the Epworth sleepiness scale (ESS); and adequate level of nasal continuous positive airway pressure (CPAP) between groups. BMI and frequency of underlying cardiovascular disorder were lower in the elderly onset group than in the middle-age onset group. No significant differences in apnea-hypopnea index or percentage of the period showing O(2) desaturation were seen between groups. However, arousal index, maximal negative esophageal pressure value, and adequate nasal CPAP level were significantly smaller in the elderly onset group. Mean sleep latency on MSLT was longer, and ESS score was lower in the elderly onset group. Compared with the middle-age onset group, the clinical significance of OSAS in the elderly onset group seemed to remain milder. This finding is possibly because of the smaller physiologic response to respiratory events.

Inspiratory airflow dynamics during sleep in irritable bowel syndrome: a pilot study

This study is a preliminary test of the hypothesis that the pathophysiology of irritable bowel syndrome (IBS) derives from pharyngeal collapse during sleep. We studied inspiratory airflow dynamics during sleep in 12 lean females with IBS and 12 healthy female controls matched for age and obesity. A standard clinical polysomnogram (airflow measured with a nasal/oral pressure catheter) was performed to assess the impact of pharyngeal collapse on the participants' natural sleep. A second polysomnogram with a pneumotachograph and a supraglottic pressure catheter to measure airflow and effort was performed to compare the maximal inspiratory airflow and effort and the prevalence of inspiratory airflow limitation (IFL) during supine stage 2 sleep between groups. During clinical polysomnography, IBS participants did not differ significantly from controls in sleep architecture or respiration. The difference in apnea-hypopnea index between IBS participants and controls, however, approached statistical significance (2.8 +/- 2.7 vs 1.1 +/- 1.5, respectively; p = 0.079). Although nine of the 12 IBS participants had a prevalence of IFL of at least 33% during supine stage 2 sleep, they did not differ from controls in maximal inspiratory airflow, inspiratory effort, or the prevalence of IFL. Controls, however, differed from IBS participants in having their prevalence of IFL during stage 2 sleep positively correlated with age (r = 0.86; p = 0.0003) while IBS participants demonstrated no relationship between the prevalence of IFL and age. Our findings, while less than definitive, suggest a prevalence pattern of pharyngeal collapse during sleep among females with IBS that differs from that of healthy females, providing necessary background to inform further work on the relationship of pharyngeal collapse during sleep to IBS.