[Night-to-night variability of the obstructive sleep apnoea-hypopnoea syndrome]

Validation of a Portable Respiratory Monitoring System for the Diagnosis of Obstructive Sleep Apnea in Patients with Chronic Obstructive Pulmonary Disease: A Crossectional Study

Introduction  Portable respiratory monitoring (PM) has been used to diagnose obstructive sleep apnea (OSA) in the general population. However, its validation in patients with both OSA and chronic obstructive pulmonary disease (COPD), remains unclear. Objective  The aim of the study was to validate PM for the diagnosis of OSA in patients with COPD. Materials and Methods  In this crossectional study, COPD patients were submitted simultaneously to polysomnography (PSG) and PM. Moreover, the risk for OSA was verified by the Berlin, NoSAS, and STOP-BANG questionnaires. Sensitivity, specificity, positive predictive value, and negative predictive value for PM were calculated for the cutoff points of the hypopnea apnea index (AHI) of 5, 15, and 30 events/hour, as well as for the questionnaires. The Bland-Altman test and correlation analyses between the AHI of the PSG and PM were performed. Results  A total of 103 patients were evaluated (age 67.5 ± 9.9 years, 60% men). The STOP-BANG questionnaire had the highest sensitivity for OSA diagnosis, at 94.4% (72.7-99.9%). The sensitivity of PM decreased (87.0, 66.7, and 44.4%), and the specificity increased 40.0, 78.6, and 100.0%) as the AHI cutoff point increased from 5, 15, and 30. The Bland-Altman test indicated good limits of agreement (AHI = 5.5 ± 11.7 events/hour). Therefore, the AHI results of the PM showed a strong and positive correlation with those of the PSG (r = 0.70, p  < 0.0001). Conclusion  The PM test can be a useful tool for OSA diagnosis in patients with COPD.

Evaluation of clinical and genetic factors in obstructive sleep apnoea

Purpose

To evaluate the correlation between several presumed candidate genes for obstructive sleep apnoea (OSA) and clinical OSA phenotypes and propose a predictive comprehensive model for diagnosis of OSA.

Methods

This case-control study compared polysomnographic patterns, clinical data, morbidities, dental factors and genetic data for polymorphisms in PER3, BDNF, NRXN3, APOE, HCRTR2, MC4R between confirmed OSA cases and ethnically matched clinically unaffected controls. A logistic regression model was developed to predict OSA using the combined data.

Results

The cohort consisted of 161 OSA cases and 81 controls. Mean age of cases was 53.5 ± 14.0 years, mostly males (57%) and mean body mass index (BMI) of 27.5 ± 4.3 kg/m2. None of the genotyped markers showed a statistically significant association with OSA after adjusting for age and BMI. A predictive algorithm included the variables gender, age, snoring, hypertension, mouth breathing and number of T alleles of PER3 (rs228729) presenting 76.5% specificity and 71.6% sensitivity.

Conclusions

No genetic variant tested showed a statistically significant association with OSA phenotype. Logistic regression analysis resulted in a predictive model for diagnosing OSA that, if validated by larger prospective studies, could be applied clinically to allow risk stratification for OSA.

Pediatric sleep outcomes after endoscopy-directed simultaneous lingual tonsillectomy and epiglottopexy

Background

The purpose of this study was to evaluate the efficacy of sleep endoscopy-directed simultaneous lingual tonsillectomy and epiglottopexy in patients with sleep disordered breathing (SDB), including polysomnography (PSG) and swallowing outcomes.

Methods

A retrospective review was performed of all patients undergoing simultaneous lingual tonsillectomy and epiglottopexy over the study period. PSG objective measures were recorded pre- and postoperatively, along with demographic data, comorbidities, and descriptive data of swallowing dysfunction in the postoperative setting.

Results

A total of 24 patients met inclusion criteria for consideration, with 13 having valid pre- and postoperative PSG data. Successful surgery was achieved in 84.6% of patients, with no difference based on presence of medical comorbidities including Trisomy 21. Median reduction in obstructive apnea–hypopnea index (oAHI) with the procedure was 69.9%. Four patients (16.7%) had postoperative concern for dysphagia, but all objective swallowing evaluations were normal and no dietary modifications were necessary.

Conclusion

Combination lingual tonsillectomy and epiglottopexy in indicated patients has a high rate of success in this single-institutional study without new dysphagia in this population. These procedures are amenable to a combination surgery in appropriately selected patients determined by sleep state endoscopy in the setting of SDB evaluated with drug-induced sleep endoscopy.

Graphical abstract

Night-to-night variability of respiratory events in obstructive sleep apnoea: a systematic review and meta-analysis

Background

It is current practice to use a single diagnostic sleep study in the diagnostic workup of obstructive sleep apnoea (OSA). However, a relevant night-to-night variability (NtNV) of respiratory events has been reported.

Methods

We evaluated the NtNV of respiratory events in adults with suspected or already diagnosed OSA who underwent more than one diagnostic sleep study. Data sources were PubMed, Cochrane and Embase up to 23 January 2019. Random-effects models were used for evidence synthesis. For moderator analysis, mixed-effects regression analysis was performed. The study was registered with PROSPERO (CRD42019135277).

Results

Of 2143 identified papers, 24 studies, comprising 3250 participants, were included. The mean Apnoea-Hypopnoea Index (AHI) difference between the first and second night was −1.70/hour (95% CI −3.61 to 0.02). REM time differences (first to second night) were significantly positive associated with differences in mean AHI (β coefficient 0.262 (95% CI 0.096 to 0.428). On average, 41% (95% CI 27% to 57%) of all participants showed changes of respiratory events >10/hour from night to night. Furthermore, 49% (95% CI 32% to 65%) of participants changed OSA severity class (severity thresholds at 5/hour, 15/hour and 30/hour) at least once in sequential sleep studies. Depending on the diagnostic threshold (5/hour, 10/hour or 15/hour), on average 12% (95% CI 9% to 15%), 12% (95% CI 8% to 19%) and 10% (95% CI 8% to 13%) of patients would have been missed during the first night due to single night testing.

Conclusion

While there was no significant difference between mean AHI in two sequential study nights on a group level, there was a remarkable intraindividual NtNV of respiratory events, leading to misdiagnosis and misclassification of patients with suspected OSA.

The effects of threshold inspiratory muscle training in patients with obstructive sleep apnea: a randomized experimental study

OBJECTIVES

Patients with obstructive sleep apnea (OSA) (an obstructed airway and intermittent hypoxia) negatively affect their respiratory muscles. We evaluated the effects of a 12-week threshold inspiratory muscle training (TIMT) program on OSA severity, daytime sleepiness, and pulmonary function in newly diagnosed OSA.

METHODS

Sixteen patients with moderate-to-severe OSA were randomly assigned to a TIMT group and 6 to a control group. The home-based TIMT program was 30-45 min/day, 5 days/week, for 12 weeks using a TIMT training device. Their apnea-hypopnea index (AHI), Epworth sleepiness scale (ESS), and forced vital capacity (FVC) scores were evaluated pre- and post-treatment. Polysomnographic (PSG) analysis showed that 9 TIMT-group patients had positively responded (TIMT-responder group: post-treatment AHI < pre-treatment) and that 7 had not (TIMT non-responder group: post-treatment AHI > pre-treatment).

RESULTS

Post-treatment AHI and ESS scores were significantly (both P < 0.05) lower 6% and 20.2%, respectively. A baseline AHI ≤ 29.0/h predicted TIMT-responder group patients (sensitivity 77.8%; specificity 85.7%). FVC was also significantly (P < 0.05) higher 7.2%. Baseline AHI and FEV_6.0 were significant predictors of successful TIMT-responder group intervention. OSA severity and daytime sleepiness were also significantly attenuated.

CONCLUSIONS

Home-based TIMT training is simple, efficacious, and cost-effective.

Apnea-hypopnea index in sleep studies and the risk of over-simplification

According to recent reports, sleep disorders affect 30% of the adult population and 5-10% of children. Obstructive Sleep Apnea Hypopnea Syndrome (OSA) has a considerable epidemiological impact and demand for consultation is growing in our community. Therefore, it is necessary to know the principles of interpretation of diagnostic methods. A suspicion of OSA requires confirmation. According to the guidelines of the Argentine Association of Respiratory Medicine, polysomnography (PSG) is the gold standard for OSA diagnosis, while home sleep testing (HST) can be accepted as a comparatively effective method depending on the clinical situation of the patient. This article questions the use of AHI (apnea-hypopnea index) as the only measurement needed to diagnose OSA and assess its severity. In fact, it is surprising that, despite the large mass of data analyzed during sleep studies, current practices only focus on AHI. More than four decades have passed since OSA was first described. Our tendency to oversimplify complex conditions may prevent us from gaining a deeper and more thorough understanding of OSA. The development and validation of OSA severity scoring systems based on multiple parameters is still a pending issue.