Long-term night-to-night variability of sleep-disordered breathing using a radar-based home sleep apnea test: a prospective cohort study.

STUDY OBJECTIVES: Night-to-night variability of sleep-disordered breathing limits the diagnostic accuracy of a single measurement. Multiple recordings using a reliable, affordable method could reduce the uncertainty and avoid misdiagnosis, which could be possible with radar-based home sleep apnea testing (HSAT). METHODS: We recruited consecutive patients with suspected sleep-disordered breathing and performed contactless radar-based HSAT with automated scoring (Sleepiz One; Sleepiz AG, Zurich, Switzerland) over 10 nights. During the first night, patients were simultaneously measured with peripheral arterial tonometry. RESULTS: Twenty-four of the 28 included patients could achieve a minimum of 4 measurements. The failure rate was 16% (37 of 238 measurements). The apnea-hypopnea index (AHI) and oxygen desaturation index were consistently lower with radar-based HSAT compared with peripheral arterial tonometry. The variability of the AHI was considerable, with a standard error of measurement of 5.2 events/h (95% confidence interval [CI]: 4.6-5.7 events/h) and a minimal detectable difference of 14.4 events/h (95% CI: 12.7-15.9 events/h). Alcohol consumption partially accounted for the variability, with an AHI increase of 1.7 events/h (95% CI: 0.6-2.8 events/h) for each standard drink. Based on a single measurement, 17% of patients were misdiagnosed and 32% were misclassified for sleep-disordered breathing severity. After 5 measurements, the mean AHI of the measured nights stabilized with no evidence of substantial changes with additional measurements. CONCLUSIONS: Night-to-night variability is considerable and stable over 10 nights. HSAT using radar-based methods over multiple nights is feasible and well tolerated by patients. It could offer lower costs and allow for multiple-night testing to increase accuracy. However, validation and reducing the failure rate are necessary for implementation in the clinical routine. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: Recording of Multiple Nights Using a New Contactless Device (Sleepiz One Connect) in Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/study/NCT05134402; Identifier: NCT05134402. CITATION: Tschopp S, Borner U, Caversaccio M, Tschopp K. Long-term night-to-night variability of sleep-disordered breathing using a radar-based home sleep apnea test: a prospective cohort study. J Clin Sleep Med. 2024;20(7):1079-1086.

Treatment of Residual Palatal Collapse in Hypoglossal Nerve Stimulation Using a Palatal Device.

Hypoglossal nerve stimulation (HNS) has increasingly become an alternative therapy for obstructive sleep apnea patients with CPAP intolerance. Stimulation of the hypoglossal nerve during sleep enhances airway patency and alleviates collapse. Suboptimal responses to HNS often stem from insufficient palatal coupling and residual velar collapse. Combining palatal devices, such as Velumount®, with HNS represents a simple and cost-effective strategy to treat residual palatal collapse. Patients desiring conservative treatment for residual palatal obstruction under HNS may consider this combined approach. Laryngoscope, 134:3412-3414, 2024.

Tonsil volume and outcome of radiofrequency uvulopalatoplasty with or without tonsillectomy in adults with sleep-disordered breathing.

PURPOSE: Predictors for the outcome of uvulopalatopharyngoplasty with and without tonsillectomy (UPPP ± TE) in sleep-disordered breathing have not been fully established. This study investigates tonsil grade, volume, and preoperative examination in predicting radiofrequency UPP ± TE outcomes. METHODS: All patients undergoing radiofrequency UPP with tonsillectomy if tonsils were present between 2015 and 2021 were retrospectively analyzed. Patients underwent a standardized clinical examination, including Brodsky palatine tonsil grade from 0 to 4. Preoperatively and 3 months after surgery, sleep apnea testing was performed using respiratory polygraphy. Questionnaires were administered assessing daytime sleepiness using the Epworth Sleepiness Scale (ESS) and snoring intensity on a visual analog scale. Tonsil volume was measured intraoperatively using water displacement. RESULTS: The baseline characteristics of 307 patients and the follow-up data of 228 patients were analyzed. Tonsil volume increased by 2.5 ml (95% CI 2.1-2.9 ml; P < 0.001) per tonsil grade. Higher tonsil volumes were measured in men, younger patients, and patients with higher body mass indices. The preoperative apnea-hypopnea index (AHI) and AHI reduction strongly correlated with tonsil volume and grade, whereas postoperative AHI did not. The responder rate increased from 14% to 83% from tonsil grade 0 to 4 (P < 0.01). ESS and snoring were significantly reduced after surgery (P < 0.01), but the reduction was not influenced by tonsil grade or volume. No other preoperative factor other than tonsil size could predict surgical outcomes. CONCLUSIONS: Tonsil grade and intraoperatively measured volume correlate well and predict the reduction of AHI, while they are not predictive of ESS and snoring response after radiofrequency UPP ± TE.

Clinical impact of manual scoring of peripheral arterial tonometry in patients with sleep apnea.

PURPOSE: The objective was to analyze the clinical implications of manual scoring of sleep studies using peripheral arterial tonometry (PAT) and to compare the manual and automated scoring algorithms. METHODS: Patients with suspected sleep-disordered breathing underwent sleep studies using PAT. The recordings were analyzed using a validated automated computer-based scoring and a novel manual scoring algorithm. The two methods were compared regarding sleep stages and respiratory events. RESULTS: Recordings of 130 patients were compared. The sleep stages and time were not significantly different between the scoring methods. PAT-derived apnea-hypopnea index (pAHI) was on average 8.4 events/h lower in the manually scored data (27.5±17.4/h vs.19.1±15.2/h, p<0.001). The OSA severity classification decreased in 66 (51%) of 130 recordings. A similar effect was found for the PAT-derived respiratory disturbance index with a reduction from 31.2±16.5/h to 21.7±14.4/h (p<0.001), for automated and manual scoring, respectively. A lower pAHI for manual scoring was found in all body positions and sleep stages and was independent of gender and body mass index. The absolute difference of pAHI increased with sleep apnea severity, while the relative difference decreased. Pearson's correlation coefficient between pAHI and oxygen desaturation index (ODI) significantly improved from 0.89 to 0.94 with manual scoring (p<0.001). CONCLUSIONS: Manual scoring results in a lower pAHI while improving the correlation to ODI. With manual scoring, the OSA category decreases in a clinically relevant proportion of patients. Sleep stages and time do not change significantly with manual scoring. In the authors' opinion, manual oversight is recommended if clinical decisions are likely to change.

Night-to-night variability in obstructive sleep apnea using peripheral arterial tonometry: a case for multiple night testing.

STUDY OBJECTIVES: Night-to-night variability of obstructive sleep apnea severity is considerable and may depend on the diagnostic modality used. We investigated the night-to-night variability using peripheral arterial tonometry (PAT). METHODS: Home sleep apnea testing was performed in 51 patients during 3 consecutive nights using PAT. Patients referred to our sleep clinic were screened and prospectively recruited for this study. All recordings were automatically and manually scored according to the PAT scoring guidelines. RESULTS: No systematic differences in PAT-derived apnea-hypopnea index (pAHI) were found between the nights. The night-to-night variability was comparable between manually and automatically scored data. pAHI varied in 35% of patients more than 10 events/h between the nights. The obstructive sleep apnea severity of 24% of patients was misclassified when using 1 night compared to the average of all nights. On average, pAHI varied by 57% from night to night. The variability of pAHI could partially be explained by the variability of time spent in the supine position with more time supine leading to a higher pAHI. On measuring a subsequent night, 12-14% of patients spontaneously fulfilled the commonly accepted criteria for treatment success without any intervention. CONCLUSIONS: With repeated recordings of PAT, we found no first night effect. However, there is considerable night-to-night variability similar to values found for polysomnography, which can partially be explained by the variability of time spent in the supine position. Obstructive sleep apnea severity was frequently misclassified due to the night-to-night variability. Our findings make a strong case for multiple testing in the diagnostic work-up of obstructive sleep apnea patients. CITATION: Tschopp S, Wimmer W, Caversaccio M, Borner U, Tschopp K. Night-to-night variability in obstructive sleep apnea using peripheral arterial tonometry: a case for multiple night testing. J Clin Sleep Med. 2021;17(9):1751-1758.

Comparison of Traditional Upper Airway Surgery and Upper Airway Stimulation for Obstructive Sleep Apnea.

OBJECTIVE: To compare patients with moderate-severe obstructive sleep apnea (OSA) undergoing traditional single and multilevel sleep surgery to those undergoing upper airway stimulation (UAS). STUDY DESIGN: Case control study comparing retrospective cohort of patients undergoing traditional sleep surgery to patients undergoing UAS enrolled in the ADHERE registry. SETTING: 8 multinational academic medical centers. SUBJECTS AND METHODS: 233 patients undergoing prior single or multilevel traditional sleep surgery and meeting study inclusion criteria were compared to 465 patients from the ADHERE registry who underwent UAS. We compared preoperative and postoperative demographic, quality of life, and polysomnographic data. We also evaluated treatment response rates. RESULTS: The pre and postoperative apnea hypopnea index (AHI) was 33.5 and 15 in the traditional sleep surgery group and 32 and 10 in the UAS group. The postoperative AHI in the UAS group was significantly lower. The pre and postoperative Epworth sleepiness scores (ESS) were 12 and 6 in both the traditional sleep surgery and UAS groups. Subgroup analysis evaluated those patients undergoing single level palate and multilevel palate and tongue base traditional sleep surgeries. The UAS group had a significantly lower postoperive AHI than both traditional sleep surgery subgroups. The UAS group had a higher percentage of patients reaching surgical success, defined as a postoperative AHI <20 with a 50% reduction from preoperative severity. CONCLUSION: UAS offers significantly better control of AHI severity than traditional sleep surgery. Quality life improvements were similar between groups.

Tonsil size and outcome of uvulopalatopharyngoplasty with tonsillectomy in obstructive sleep apnea.

OBJECTIVES/HYPOTHESIS: To investigate the relationship of tonsil volume and grade on outcomes of uvulopalatopharyngoplasty (UPPP) with tonsillectomy in patients with obstructive sleep apnea (OSA). STUDY DESIGN: Retrospective cohort analysis. METHODS: Data of 70 consecutive patients undergoing UPPP with tonsillectomy between 2015 and 2018 were analyzed. Patients with an apnea-hypopnea index (AHI) <10/hr or concomitant surgery other than nasal surgery were excluded. Tonsil volume was measured intraoperatively. Preoperatively and 3 months after surgery we assessed the AHI using respiratory polygraphy, daytime sleepiness using the Epworth Sleepiness Scale (ESS), and a visual analog scale for the snoring index (SI). RESULTS: Tonsil grade and volume both showed a significant correlation with preoperative AHI. Postoperative AHI was not significantly different between grades and volume. The AHI reduction after surgery increased significantly with larger volume and higher tonsil grade. For all grades, the postoperative ESS was significantly reduced compared to the preoperative value, but was not significantly correlated with tonsil volume. Preoperative and postoperative SI was not significantly correlated between tonsil grade or volume. In all grades, SI was significantly reduced after surgery. CONCLUSIONS: In our study, we found that large tonsils are responsible for higher preoperative AHI values, and their removal leads to greater reduction of initial AHI. However, the postoperative effect on daytime sleepiness and snoring reduction is not significantly correlated with tonsil size and volume, indicating that these parameters are mainly influenced by other factors. The knowledge of the significance of tonsil size and volume is important for ear, nose, and throat physicians when counseling OSA patients. LEVEL OF EVIDENCE: 2c Laryngoscope, 129:E449-E454, 2019.

Low-Volume Cardioplegia and Myocardial Protection in Coronary Artery Bypass Graft Surgery.

We studied myocardial protection during coronary artery bypass graft surgery using low-volume cardioplegia (Cardioplexol) and minimal extracorporeal circulation (MECC) for different types of coronary artery diseases. In total, 426 consecutive patients were included and divided into four groups: those with left main stem stenosis (n = 45), those with three-vessel disease (n = 200), those with both (n = 141), and those with neither (n = 40). The peak postoperative myocardial markers and 30-day mortality were analyzed. Both myocardial markers and 30-day mortality were significantly elevated in patients with isolated main stem stenosis. We conclude that the use of low-volume cardioplegia and MECC is safe. However, patients with underlying isolated left main stem stenosis might be less protected.