Residual Apnea-hypopnea Index Research Articles

Predictors of driving risk in patients with obstructive sleep apnea syndrome treated by continuous positive airway pressure: a French multicenter prospective cohort.

To investigate the predictors of persistent driving risk related to sleepiness in patients with obstructive sleep apnea syndrome treated by continuous positive airway pressure. Longitudinal analysis of a prospective national database including 5,308 patients with obstructive sleep apnea syndrome and an indication of continuous positive airway pressure. Near-misses related to sleepiness, accidents related to sleepiness, and sleepiness at the wheel were assessed before initiation and after ≥ 90 days of treatment. Multivariable associations with the cumulative incidence of near-misses and accidents under treatment were calculated using Cox models adjusted for age, sex, obesity, sleep duration, sleepiness at the wheel, accidents/near-misses history, depressive symptoms, residual apnea-hypopnea index, and adherence to treatment. Residual sleepiness at the wheel under treatment was associated with eight-fold higher incidence of near-misses related to sleepiness (HR=8.63 [6.08-12.2]) and five-fold higher incidence of accidents related to sleepiness (HR=5.24 [2.81-9.78]). Adherence ≤4h/night was also a significant predictor of persistent driving risk (HR=1.74 [1.12-2.71] for near-misses and HR=3.20 [1.37-7.49] for accidents). Residual sleepiness at the wheel and treatment-adherence ≤4h/night are easy-to assess markers to detect persistent driving risk during the follow-up evaluations of patients under treatment. Health professionals, but also policy makers, should be aware of the crucial importance to systematically evaluate these elements during the follow-up evaluations of the patients with obstructive sleep apnea syndrome treated by continuous positive airway pressure to better evaluate their driving risk.

Phenotyping patients treated for obstructive sleep apnea with persistent objective impaired alertness or subjective sleepiness

Background and objectivesSleepiness in patients with obstructive sleep apnea (OSA) is associated with accidental and economic burden, as well as cardiovascular risk. Despite OSA treatment, 10–28 % of patients report residual sleepiness. Its determinants, as well as those of objective impaired alertness remain poorly known. In this study, we investigated factors associated with residual subjective sleepiness and objective impaired alertness in patients treated for OSA. MethodsConsecutive OSA treated patients referred for maintenance of wakefulness tests (MWT) at a tertiary university center were recruited between 2017 and 2020. Clinical data and polysomnography parameters were compared between patients with vs without subjective sleepiness (Epworth Sleepiness Scale, ESS≥11) and those with vs without impaired alertness (at least one trial with sleep onset on MWT). A multivariate logistic model was used to assess explanatory variables of MWT and ESS results. ResultsWe included 141 patients, of whom 12.8 % had both subjective sleepiness and objective impaired alertness, 17.7 % objective impaired alertness only and 9.2 % subjective sleepiness only. Self-reported history of car accident/near miss, smoking history and ESS≥11 were significantly associated with objective impaired alertness whereas residual Apnea-hypopnea Index and CPAP use were not. The only significant variable associated with ESS at the time of MWT evaluation was initial ESS. Patients with objective impaired alertness only were more often smokers (52 % vs 19 %, p = 0.01), had a higher body mass index (BMI) (32 vs 29 kg/m2, p = 0.05), and showed lower initial ESS (11 vs 13, p < 0.01). ConclusionsMore than one third of OSA treated patients referred for MWT have objective impaired alertness and/or subjective sleepiness. Our findings highlight the need for a comprehensive medical assessment including accident history, subjective sleepiness and comorbidities. Particular attention should be paid to smoking patients with high BMI, who are at risk of impaired alertness with no report of subjective sleepiness.

Accuracy of respiratory event indices downloaded from positive airway pressure devices: can they be relied upon when making treatment decisions?

The gold standard for diagnosis and treatment of obstructive sleep apnea (OSA) is attended overnight polysomnography (PSG) in a sleep laboratory. Alternative diagnostic techniques are urgently needed for both diagnosis and treatment control when initiating positive airway pressure (PAP) in the home setting. Current PAP devices compute data such as residual AHI (apnea-hypopnea index) using their proprietary algorithms to provide an automatic event detection (AED). It was suggested that these should be labeled AHIFLOW. The current study situation shows an acceptable agreement with the tendency of mildly overestimating the AHI by the PAP devices. But, the literature is still limited in terms of accuracy, especially when considering the lack of standardization and different detection algorithms. A validation of PAP devices regarding the agreement of AHIFLOW compared to AHIPSG is extremely important, given that the device analysis is exclusively based on the measured flow. There are considerable concerns about assessing the PAP effectiveness in higher risk groups based on the AED function alone. Given these reservations, the use of PAP event detection can be an important addition to the diagnostic spectrum and, in combination with telemonitoring, offers promising potential.

Effectiveness of remote monitoring in improving CPAP compliance and the impact of preexisting organisation of standard care: a randomised controlled trial

Purpose Continuous positive airway pressure (CPAP) is often the treatment of choice for obstructive sleep apnea (OSA). Short-term adherence and early perceived benefits are the best predictors of long-term adherence. The aim of this study was to determine the effect of telemonitoring in the first period of treatment with CPAP (auto-titrating PAP) on compliance and the long-term outcome.MethodsPatients aged between 18–75 years old with symptomatic severe OSA (apnea–hypopnea index (AHI) ≥ 30) requiring CPAP therapy were included in this single-blind, single-centre, randomised, controlled trial. They were divided into 2 groups (telemonitored standard clinical care versus standard clinical care without telemonitoring).ResultsA total of 230 patients (115 patients/group) were included (mean age 54 ± 16.6 years, BMI 32.6 ± 5.4 kg/m2, ESS 13.1 ± 6.2, AHI 47.5 ± 14.8/hr). At week 10 compliance was similar in both groups (telemonitoring vs control 6:27 and 6:35 h, respectively, p = 0.57), as were AHI (2.4; 2.4/hr, p = 0.89) and ESS (5.8; 4.9, p = 0.22). The number of contacts of a patient with a healthcare professional was significantly higher during the follow-up from week 3 until week 10 (0.25; 0.13, p = 0.03). The number of patients who could be evaluated after 1 year was equally distributed in both groups (104; 104, p = 1.00), as were compliance (6:43; 6:49 h, p = 0.59) and residual AHI (1.9; 2.2/hr, p = 0.41).ConclusionsIn patients with severe OSA with standard intensive follow-up during the initial weeks of CPAP therapy and good compliance, telemonitoring did not improve CPAP compliance nor the clinical outcome in the short or long term. The practical consequences can be highly relevant for patients and healthcare professionals.

Analysis of mandibular jaw movements to assess ventilatory support management of children with obstructive sleep apnea syndrome treated with positive airway pressure therapies.

The polysomnography (PSG) is the gold-standard for obstructive sleep apnea (OSA) syndrome diagnosis and assessment under positive airway pressure (PAP) therapies in children. Recently, an innovative digital medicine solution, including a mandibular jaw movement (MJM) sensor coupled withautomated analysis, has been validated as an alternative to PSG for pediatric application. This study aimed to assess the reliability of MJMautomated analysis for the assessment of residual apnea/hypopnea events during sleep in children with OSA treated with noninvasive ventilation (NIV) or continuous PAP(CPAP). In this open-label prospective non-randomized multicentric trial, we included children aged from 5 to 18 years with a diagnosis of severe OSA. The children underwent in-laboratory PSG with simultaneous MJM monitoring and at-home recording with MJM monitoring 3 months later. Agreement between PSG and MJM analysis in measuring the residual apnea-hypopnea index (AHI) was evaluated by the Bland-Altman method. The treatment effect on residual AHI was estimated for both PSG and MJM analysis. Fifteen (60% males) children were included with a median age of 12 years [interquartile range 8-15]. Two (17%) were ventilated with NIV and 13 (83%) with CPAP. There was a good agreement between MJM-AHI and PSG-AHI with a median bias of -0.25 (95% CI: -3.40 to +2.04) events/h. The reduction in AHI under treatment was consistently significant across the three measurement methods: in-laboratory PSGand MJM recordings in the laboratory and at home. Automated analysis of MJM is a highly reliable alternative method to assess residual events in a small population treated with PAP therapies.

Impact of PAP on the gut microbiome in OSA: A pilot study

Objective/backgroundMicrobes within the gastrointestinal tract have emerged as modulators of the host's health. Obstructive sleep apnea (OSA) is characterized by intermittent partial, or complete, airway closure during sleep and is associated with increased risk of non-communicable diseases as well as dysbiosis of the gut microbiome. Thus, we investigated if improving nocturnal airway patency via positive airway pressure (PAP) therapy improves gut microbial diversity in recently diagnosed patients with moderate-to-severe OSA (apnea-hypopnea index ≥15.0 events/hr). Patients/methodsEight subjects (3 F, 56±9yrs, 33.5 ± 7.7 kg/m2, 45.0 ± 38.4 events/hr) provided stool samples before, and two months after, PAP therapy (mean adherence of 95 ± 6%, residual apnea-hypopnea index of 4.7 ± 4.6 events/hr). ResultsWhile the Shannon diversity index tended to increase following PAP (3.96 ± 0.52 to 4.18 ± 0.56, p = 0.08), there were no changes in the Observed (1,088 ± 237 to 1,136 ± 289, p = 0.28) nor Inverse-Simpson (22.4 ± 12.99 to 26.6 ± 18.23, p = 0.28) alpha diversity indices. There were also no changes in beta diversity assessed using the Bray-Curtis (p = 0.98), Jaccard (p = 0.99), WUniFrac (p = 0.98), GUniFrac (p = 0.98), or UniFrac (p = 0.98) methods. No changes in differential abundance taxa were found using a false discovery rate threshold of <0.20. ConclusionsOur data are the first to report that PAP therapy may not offset, or reverse, gut dysbiosis in patients with OSA. Accordingly, interventions which improve gut microbial health should be explored as potential adjunctive treatment options in patients with OSA to reduce their risk of developing non-communicable diseases.

Seasonal changes in positive airway pressure adherence.

Through their effects on sleep duration, bedroom environments, and pollen allergies, seasonal variations may impact positive airway pressure (PAP) adherence. We analyzed daily PAP telemonitoring data from 25,846 adults (median age 64 years, 67.8% male) treated with PAP for at least 4 months [mean (standard deviation, SD) duration of PAP: 5.5 years (SD 4.1)] to examine seasonal changes in PAP adherence, leaks, and residual apnea-hypopnea index. We demonstrate a significant decrease in PAP adherence in June compared to January (mean (SD): 0.37 (1.54) h/night) that achieved the minimal clinically important difference (MCID) of 30 min in 13.9% of adults. Furthermore, we provide novel data supporting the association of rising temperatures with seasonal changes in PAP use. Indeed, the most pronounced decline in PAP adherence was observed during the hottest days, while PAP adherence was only slightly reduced during the coolest days of June. Clinicians should be aware of seasonal changes in PAP adherence that are likely to be exacerbated by climate change.

Effects of mandibular advancement devices on upper airway dimensions in obstructive sleep apnea: responders versus non-responders

Study objectivesTo compare the effects of mandibular advancement device (MAD) therapy on upper airway dimensions between responders and non-responders with mild to moderate obstructive sleep apnea (OSA).MethodsThirty-one participants (21 men and 10 women) with a mean ± SD apnea-hypopnea index (AHI) of 16.6 ± 6.7 events/h, and aged 48.5 ± 13.9 years, were included in this study. Polysomnographic recordings and cone beam computed tomography (CBCT) scans in supine position were performed for every participant at baseline and at 3-month follow-up with their MAD in situ. Responders were defined as having ≥ 50% reduction in baseline AHI with a residual AHI < 10 events/h. The primary outcome variable was the minimal cross-sectional area of the upper airway (CSAmin).ResultsNo significant differences were found between responders (n = 15) and non-responders (n = 16) in age, gender distribution, body mass index, and neck circumference (P = 0.06–0.93), nor in AHI and CSAmin (P = 0.40 and 0.65, respectively) at baseline. The changes of the CSAmin with MAD in situ in the responder group were not significantly different compared to those in the non-responder group (P = 0.06).ConclusionWithin the limitations of this study, we conclude that the changes of the upper airway dimensions induced by MADs are not significantly different between responders and non-responders with mild to moderate OSA.Trial registrationClinicalTrials.gov Identifier: NCT02724865. https://clinicaltrials.gov/ct2/show/NCT02724865

Effect of a digital patient motivation and support tool on CPAP/APAP adherence and daytime sleepiness: a randomized controlled trial

The purpose of this study was to assess the effect of a digital patient support (DPS) tool, complementary to standard care on continuous or automatic positive airway pressure (auto)CPAP adherence and daytime sleepiness after 12 weeks in patients diagnosed with severe obstructive sleep apnea (OSA). All patients with apnea–hypopnea index (AHI) ≥ 30 per hour were prospectively included and randomized to receive standard care (SC) or standard care with personalized DPS via a mobile app prototype version (SC + DPS). Patients in the SC + DPS arm received additionally automated feedback on their therapy, motivational messages and therapy recommendations. 100 patients completed the study (SC: 50, SC + DPS: 50). No differences were found in characteristics of SC vs. SC + DPS (mean ± SD) for age (53.9 ± 10.8 vs. 51.7 ± 12.3 years), initial diagnostic apnea–hypopnea index (51.1 ± 15.5 vs. 50.9 ± 17.7 events/h), BMI (33.8 ± 6.7 vs. 33.5 ± 4.5 kg/m), and Epworth Sleepiness Scale (ESS) baseline score (9.5 ± 4.2 vs. 9.1 ± 5.2). After 12 weeks, mean ESS score was significantly lower (SC: 7.6 ± 4.1 vs. SC + DPS: 5.5 ± 3.9; p = 0.006) in the SC + DPS group vs. standard care group. Therapy adherence was significantly higher (SC: 268.7 ± 122.1 vs. SC + DPS: 338.8 ± 106.8 min; p = 0.002) in the SC + DPS group compared to standard care group. No difference was found in the residual AHI between both groups. However, SC + DPS group showed a trend towards fewer phases with increased leakage compared to SC group. Intention-to-treat analysis (112 (56/56) patients) showed similar results. After 12 weeks, (auto)CPAP adherence and daytime sleepiness improved significantly in patients with severe OSA using the digital patient support tool.Clinical Trial Registration (retrospectively registered): Registry: NCT05440279; Title: Effects of Telemedical Support on Therapeutic Results of CPAP Patients; URL: https://clinicaltrials.gov/ct2/show/NCT05440279; Date of registration: June 30, 2022.

Auto-adjusted versus fixed positive airway pressure in patients with severe OSA: A large randomized controlled trial.

Continuous positive airway pressure (CPAP) in the treatment of severe obstructive sleep apnoea (OSA) can be used in fixed CPAP or auto-adjusted (APAP) mode. The aim of this prospective randomized controlled clinical study was to evaluate the 3 month-efficacy of CPAP used either in fixed CPAP or APAP mode. Eight hundred one patients with severe OSA were included in twenty-two French centres. After 7 days during which all patients were treated with APAP to determine the effective pressure level and its variability, 353 and 351 patients were respectively randomized in the fixed CPAP group and APAP group. After 3 months of treatment, 308 patients in each group were analysed. There was no difference between the two groups in terms of efficacy whatever the level of efficient pressure and pressure variability (p = 0.41). Exactly, 219 of 308 patients (71.1%) in the fixed CPAP group and 212 of 308 (68.8%) in the APAP group (p = 0.49) demonstrated residual apnoea hypopnoea index (AHI) <10/h and Epworth Score <11. Tolerance and adherence were also identical with a similar effect on quality of life and blood pressure evaluation. The two CPAP modes, fixed CPAP and APAP, were equally effective and tolerated in severe OSA patients.

Clinical outcomes of chronic heart failure patients with unsuppressed sleep apnea by positive airway pressure therapy.

Heart failure (HF) is an advanced stage of cardiac disease and is associated with a high rate of mortality. Previous studies have shown that sleep apnea (SA) is associated with a poor prognosis in HF patients. Beneficial effects of PAP therapy that is effective on reducing SA on cardiovascular events, were not yet established. However, a large-scale clinical trial reported that patients with central SA (CSA) which was not effectively suppressed by continuous positive airway pressure (CPAP) revealed poor prognosis. We hypothesize that unsuppressed SA by CPAP is associated with negative consequences in patients with HF and SA, including either obstructive SA (OSA) or CSA. This was a retrospective observational study. Patients with stable HF, defined as left ventricular ejection fraction of ≤50%; New York Heart Association class ≥ II; and SA [apnea-hypopnea index (AHI) of ≥15/h on overnight polysomnography], treated with CPAP therapy for 1 month and performed sleep study with CPAP were enrolled. The patients were classified into two groups according to AHI on CPAP (suppressed group: residual AHI ≥ 15/h; and unsuppressed group: residual AHI < 15/h). The primary endpoint was a composite of all-cause death and hospitalization for HF. Overall, data of 111 patients including 27 patients with unsuppressed SA, were analyzed. The cumulative event-free survival rates were lower in the unsuppressed group during a period of 36.6 months. A multivariate Cox proportional hazard model showed that the unsuppressed group was associated with an increased risk for clinical outcomes (hazard ratio 2.30, 95% confidence interval 1.21-4.38, p = 0.011). Our study suggested that in patients with HF and SA including either OSA or CSA, presence of unsuppressed SA even on CPAP was associated with worse prognosis as compared to those with suppressed SA by CPAP.

Revisiting the maintenance of wakefulness test: from intra-/inter-scorer agreement to normative values in patients treated for obstructive sleep apnea.

The Maintenance of Wakefulness Test is widely used to objectively assess sleepiness and make safety-related decisions, but its interpretation is subjective and normative values remain debated. Our work aimed to determine normative thresholds in non-subjectively sleepy patients with well-treated obstructive sleep apnea, and to assess intra- and inter-scorer variability. We included maintenance of wakefulness tests of 141 consecutive patients with treated obstructive sleep apnea (90% men, mean (SD) age 47.5 (9.2) years, mean (SD) pre-treatment apnea-hypopnea index of 43.8 (20.3) events/h). Sleep onset latencies were independently scored by two experts. Discordant scorings were reviewed to reach a consensus and half of the cohort was double-scored by each scorer. Intra- and inter-scorer variability was assessed using Cohen's kappa for 40, 33, and 19 min mean sleep latency thresholds. Consensual mean sleep latencies were compared between four groups according to subjective sleepiness (Epworth Sleepiness Scale score < versus ≥11) and residual apnea-hypopnea index (< versus ≥15 events/h). In well-treated non-sleepy patients (n = 76), the consensual mean (SD) sleep latency was 38.4 (4.2) min (lower normal limit [mean - 2SD] = 30 min), and 80% of them did not fall asleep. Intra-scorer agreement on mean sleep latency was high but inter-scorer was only fair (Cohen's kappa 0.54 for 33-min threshold, 0.27 for 19-min threshold), resulting in changes in latency category in 4%-12% of patients. A higher sleepiness score but not the residual apnea-hypopnea index was significantly associated with a lower mean sleep latency. Our findings suggest a higher than usually accepted normative threshold (30 min) in this context and emphasise the need for more reproducible scoring approaches.

1009 Surgery: Problem and Solution. Temporomandibular Joint Reconstruction For Treating Obstructive Sleep Apnea After Cosmetic Surgery

Abstract Introduction Orthognathic surgery is often considered for the treatment of obstructive sleep apnea (OSA); however, in some circumstances, specific interventions may precipitate OSA. Report of case(s) A 34 year-old female presented with complaints of snoring and fragmented sleep. She had undergone bimaxillary osteotomy and mandibuloplasty for cosmetic reasons outside of the country in 2019. Prior to the surgery, she was asymptomatic and did not snore. Post operatively, she developed snoring, witnessed apneas, fragmented sleep, and daytime sleepiness. A home sleep apnea test revealed severe obstructive sleep apnea with Respiratory Event Index (REI) 66.4/hr. She was initially treated with Positive Airway Pressure (PAP) while seeking oral surgery consultation. PAP via nasal mask was initially effective with residual Apnea Hypopnea Index (AHI) of 3/hr., but the patient developed difficulty tolerating PAP due to aerophagia, nausea, and eructation, despite limiting pressures to 5-7cm H2O. In 2022, the patient successfully underwent temporomandibular joint (TMJ) reconstruction with total joint prosthesis, TMJ fat grafting, bilateral coronoidectomy, maxillary osteotomy with bone plate and grafting, and partial inferior turbinatectomy. She reported resolution of snoring and significant symptomatic improvement after surgical revision. Repeat home sleep apnea testing 1 month after the surgery revealed REI 0.6/hr. Conclusion This case illustrates the potential for development of OSA following orthognathic surgery. Patients and providers should be aware of this potential complication when pursuing surgical intervention. Support (if any)

0915 Comparison of In-person Versus Telehealth Positive Airway Pressure Set Up for Rural Veterans

Abstract Introduction Traditionally, positive airway pressure (PAP) therapy is initiated in a face-to-face visit. This can be a barrier to accessing care for rural Veterans. The COVID-19 pandemic led to the implementation of telehealth PAP set-ups at two large VA sleep centers providing an opportunity to assess the effectiveness of telehealth versus face-to-face PAP initiation in rural Veterans. Methods We performed a retrospective cohort study of rural Veterans (defined by the Rural-Urban Commuting Areas system) to compare outcomes for those who initiated PAP with in-person visits prior to the COVID-19 pandemic to those who initiated PAP with telehealth during the COVID-19 pandemic. We assessed the days of PAP use, hours of PAP use and residual Apnea Hypopnea Index (AHI) at 30-day and 90-day intervals in these two groups. We excluded individuals who received a replacement device, and those who received PAP on or after June 14, 2021, due to a safety recall of PAP devices that may have affected use. Results PAP initiation data was available for 93 individuals, approximately half of whom were initiated on PAP in-person (n=46) and half by telehealth (n=47). There were no significant differences between the in-person and telehealth groups in terms of age, BMI, and AHI, which were 57.23±16 vs 60.67±14 (mean±SD), 31.81±5 vs 31.99±13, and 27.52±23/hr vs 28.85±22/hr respectively. The average number of days per month with PAP use at 30-day and 90-day intervals for in-person vs telehealth set-up was 17.59±11 vs 15.38±12 (p=0.36) and 15.54±13 vs 14.11±14 (p=0.60) respectively. The average number of hours of PAP use at 30-days and 90-days for in-person vs telehealth set-up was 3.25±3 vs 3.11±3 (p=0.82) and 3.15±3 vs 3.07±3 (p=0.90) respectively. The residual AHI at 30-days and 90-days for in-person vs telehealth set-up was 6.61±8/hr vs 5.25±6/hr (p=0.37) and 6.35±8/hr vs 7.68±11/hr (p=0.60) Conclusion In this cohort of rural Veterans, there were no significant differences in outcomes for those who initiated PAP therapy via telehealth when compared to in-person. This supports the feasibility of more widespread implementation of telehealth services for treatment of OSA in order to improve access without compromising patient outcomes. Support (if any) VA OCC FY21 RFA, VAGLAHS GRECC, K24HL143055

1023 A Case of Stridor in the Sleep Clinic

Abstract Introduction Multisystem atrophy (MSA) is a neurological degenerative progressive disease affecting multiple systems. These patients are frequently seen in the sleep clinic at specialty centers by sleep neurologists for co-management of sleep disordered breathing and nocturnal respiratory issues. Stridor is a life-threatening condition seen in these patients and requires emergent action. We present a case of MSA with worsening stridor that was missed in the era of virtual telemedicine. Report of case(s) A 53-year-old female with a history of obstructive sleep apnea (OSA) on BiPAP S and multiple system atrophy with parkinsonian subtype presented virtually to sleep clinic for follow up evaluation of her sleep disordered breathing. Six months prior to her visit she was noted to have bilateral vocal fold hypomobility without stridor. At that time, she had a residual apnea-hypopnea index (AHI) of 1.4 with BiPAP-S 16/13 cm H2O and no nocturnal stridor. She was wheelchair bound. She had routine follow up visits with various providers however these were telemedicine visits with her husband doing most of the talking due to weakness. Over the next 5 months she had worsening fatigue and was using BiPAP S during the day intermittently and was referred to the sleep medicine clinic for consideration of supplemental oxygen at night. A repeat overnight oximetry revealed residual oxygen desaturation index (ODI) of 2.5/hr while on BiPAP S. Repeat pulmonary function testing was ordered and patient was recommended to return for immediate in person follow up. When seen in person, patient was noted to have significant stridor which had been ongoing and worsening over last few months including being appreciated while on PAP therapy. Emergent same-day ENT consultation was arranged by sleep providers. Posterior cordectomy was performed shortly thereafter. The patient was scheduled for an AVAPS titration study. Conclusion In cases with progressive neuromuscular disease, stridor may be missed during virtual appointments for a variety of reasons including technical difficulties, or the virtual medium not being sensitive enough to convey stridor. This case highlights the importance of having a high index of suspicion for stridor and impending respiratory failure requiring emergent intervention in patients with neuromuscular disease. Support (if any)

0999 A dramatic response to sleeve gastrectomy in a patient with severe obstructive sleep apnea

Abstract Introduction Obesity is a well-established major, yet modifiable risk factor for the development of obstructive sleep apnea (OSA). Weight loss has consistently been associated with improvement in OSA severity. Here, we present a case of a patient with morbid obesity and severe OSA who underwent bariatric surgery, which resulted in complete resolution of sleep apnea. Report of case(s) A 31-year-old woman with a history of morbid obesity (body mass index (BMI) 54kg/m²) and diabetes mellitus was seen in the sleep disorders clinic with symptoms of loud snoring, gasp awakenings, fragmented sleep, and excessive daytime sleepiness with an Epworth sleepiness score (ESS) of 18. Polysomnography (PSG) demonstrated severe OSA with an apnea-hypopnea index (AHI) of 129/hr, mean arterial oxygen saturation (SaO2) of 85%, and nadir SaO2 of 52%. Continuous positive airway pressure (CPAP) was prescribed but never started. One year later, she returned requesting treatment for OSA as part of evaluation for bariatric surgery. A split-night PSG re-demonstrated severe OSA with AHI 60/hr and nadir SaO2 of 51% with 54% of total sleep time spent with SaO2 less than 88%, and a good response to CPAP 14cmH2O with residual AHI 4/hr. CPAP was started and she demonstrated excellent adherence on follow up. Three years lapsed before she returned to the sleep clinic. During this time, she had undergone a sleeve gastrectomy and was successful at losing 156lbs (achieving BMI 31kg/m²). She reported resolution of snoring and daytime sleepiness with ESS of 1. She stopped using CPAP six months after surgery and wished to be re-evaluated for OSA. Repeat PSG showed no evidence of OSA with AHI 1/hr and SaO2 nadir of 91%. Conclusion Bariatric surgery is considered the most effective treatment for obesity and is indicated for patients with BMI 35kg/m² or greater with comorbid OSA. Although observational and randomized studies of weight reduction surgery have shown improvement in OSA severity post-operatively and even cure in some cases, few patients exhibit the extreme reduction in AHI seen here, with complete resolution of OSA. This case serves as an important reminder that weight loss should be a priority when managing patients with OSA and excess body weight. Support (if any)

0975 Severe Central Sleep Apnea After Bilateral Lung Transplantation

Abstract Introduction Central sleep apnea (CSA) is characterized by repetitive disruptions in airflow during sleep due to impaired central respiratory drive. Multiple studies have described an increased incidence of sleep disordered breathing after lung transplantation. However, these studies implicate obstructive sleep apnea as the primary sleep disturbance related to post-transplant weight gain, increased neck circumference, and fluid retention from immunosuppressive therapy. We report an uncommon presentation of new onset severe central predominant sleep apnea in a bilateral lung transplant recipient. Report of case(s) A 61-year-old female with a history of end stage COPD with chronic hypoxic respiratory failure status post bilateral lung transplantation in 2020 presented to sleep medicine clinic with several months of witnessed apneic episodes, excessive daytime sleepiness, morning headaches, and insomnia. Physical exam was notable for an increased body mass index (BMI) of 35 kg/m² from pre-transplant BMI of 29 kg/m². Epworth Sleepiness Scale was 15, compared to 4 prior to transplant. Polysomnogram showed an apnea hypopnea index (AHI) of 94.5 events/hour with central AHI of 54.6, consistent with severe central predominant sleep apnea. Titration on CPAP at 5 cmH2O and 7 cmH2O improved the AHI to 13.3 and 20.3, respectively, with residual central hypopneas. On follow-up, downloaded therapy data revealed a residual AHI of 23.3 on CPAP at 5 cmH2O and 1.5 L/min O2, suggesting the need for a BiPAP/ASV titration study if control remains suboptimal. Conclusion Common etiologies of CSA include heart failure with Cheyne-Stokes respirations, neurologic disease, high altitude, and the use of centrally acting medications. This patient did not have clearly identifiable risk factors. Pre- and post-transplant echocardiograms showed preserved left ventricular function with no regional wall motion abnormalities. She lacks history of neurologic disease or narcotic use, and her current immunosuppressive regimen has not been linked to worsened sleep apnea. Proposed pathogenesis of CSA in lung transplant recipients include abnormalities in respiratory mechanics due to pulmonary denervation and altered chemoreceptor sensitivity. Prompt diagnosis and treatment of sleep disordered breathing is crucial in organ transplant recipients to prevent adverse cardiovascular outcomes. Thus, further investigation is warranted to better characterize the changes in respiratory parameters that occur after lung transplantation. Support (if any)

1004 A novel use of adaptive servo ventilation for VNS-induced central sleep apnea in an adolescent with refractory epilepsy

Abstract Introduction Epilepsy is frequently encountered in the pediatric population and some patients are treated by stimulation of the vagus nerve to reduce their seizure frequency. Vagus nerve stimulation (VNS) may induce central sleep apnea. Adaptive servo ventilation is a known treatment option for central sleep apnea in certain adult patients with heart failure and Cheyne-Stokes respiration but is infrequently utilized in the pediatric population. Report of case(s) A 17-year-old male with a history of intractable generalized epilepsy, VNS placement, obstructive sleep apnea (OSA) and central sleep apnea (CSA) presented to our tertiary care center for management of his sleep disordered breathing. Initial management of sleep disordered breathing included CPAP for OSA. After VNS placement, the patient began to have a high residual apnea-hypopnea index on data card download of his CPAP. Polysomnography (PSG) was performed on CPAP and CSA events were noted that correlated with VNS firing. BiPAP was titrated and was unsuccessful in treating the CSA. VNS adjustment did not impact the sleep disordered breathing. Repeat titration with adaptive servo ventilation successfully treated the OSA and CSA. In follow up, the patient is tolerating ASV with improvement in his nocturnal sleep disordered breathing events and his daytime functioning. Conclusion Central sleep apnea can be induced by vagus nerve stimulation. This unique case documents successful treatment of vagus nerve stimulation induced central sleep apnea by adaptive servo ventilation in an adolescent patient. Support (if any)

1024 A Challenging Inspire Case: All Roads Do Not Necessarily Lead to Rome

Abstract Introduction Hypoglossal nerve stimulation (HNS) for the treatment of obstructive sleep apnea (OSA) in patients who have failed positive airway pressure (PAP) therapy for one reason or the other is now standard of care. Once the device is implanted and activated, voltage to stimulate the nerve has to be titrated over time, ultimately leading to an HNS titration study. There are 4 possible electrode configurations to stimulate different fibers in the nerve that can be employed for treatment. We present a case of a patient who was a challenge with worsening of OSA with Inspire. Report of case(s) A 65-year-old woman with hypertension, and severe OSA, intolerant of positive airway pressure or oral appliances was implanted with Inspire. Post activation, there was symptomatic improvement with reduction of overall apnea-hypopnea index (AHI) from 34 per hour of sleep to 6.3 per hour. However, patient slept exclusively on the sides with evidence of significant residual disease in REM sleep. During subsequent weeks, patent reported inability to restrict position and discomfort and anxiety associated with up titration. Both awake endoscopy and advanced overnight HNS titration were pursued. All 4 electrode configurations were tested during both procedures. With the exception of (minus-plus-minus) configuration, there was worsening of sleep disordered breathing and higher residual AHI of 60 per hour on polysomnography and evidence of poor tongue motion and collapsed velopharynx on awake endoscopy. Inspire settings were readjusted to (minus-plus-minus) configuration with instructions for very slow outpatient uptitration and co-management of anxiety and discomfort with anxiolytics and sleep aids. Conclusion We make two important conclusions from this case. Firstly, although there are established criteria for patient selection for hypoglossal nerve stimulation therapy, certain other factors that impact success which are not as easily defined include the patients’ expectations, tolerance of discomfort, propensity to anxiety and personality type which impact the ability to successfully titrate voltage with the Inspire device over time. Secondly, as the tongue is a complex muscle, both under titration and over titration may be counterproductive and additionally, electrode configuration may also have varying effects on tongue protrusion and impact success. Support (if any)

0988 Vagal Nerve Stimulation and OSA

Abstract Introduction We present a case of obstructive sleep apnea (OSA) worsened by implantation of a vagal nerve stimulator (VNS). A 22-year-old M with PMH of autism and refractory epilepsy s/p VNS implantation was diagnosed with moderate OSA. His parents noted that his sleep-disordered breathing worsened after VNS implantation. He was started on APAP 4-12 cm H2O. Review of adherence data revealed an elevated residual apnea-hypopnea index (AHI) despite nightly usage. PAP titration study was obtained with improvement of AHI on 16 cm H2O. Despite consequent use of determined pressure settings, residual AHI remained elevated. In consultation with the patient’s neurologist, VNS settings were gradually down titrated. Residual AHI improved and remained low as CPAP settings were subsequently weaned. Report of case(s) The vagus nerve is part of the parasympathetic nervous system. Afferent fibers project to cortical regions involved in seizure activity. Vagal nerve activation leads to desynchrony, thereby decreasing seizure activity.3 VNS, an adjunctive non-pharmacologic treatment of refractory epilepsy, consists of a generator with multiple adjustable settings and a lead connected to the left vagus nerve.1 VNS activation, in conjuction with medical therapy, can lead to decreased seizures. However, VNS may cause complications such as vocal cord dysfunction, laryngeal spasm, and dyspnea.2 In this case, VNS was noted to cause OSA due to increased airway obstruction, though the pathophysiological mechanism behind this has not been clearly delineated. 3 Conclusion Based on current evidence of precipitation or worsening OSA with VNS activation, screening and diagnostic testing for OSA in patients under evaluation for VNS placement should be considered. A multidisciplinary approach between Sleep Medicine and Neurology in conjunction with patient goals can lead to a balanced optimization of both epilepsy and OSA management via adjustments of VNS settings, anti-epileptics, and CPAP. Support (if any) 1. VNS therapy epilepsy. Epilepsy Foundation. https://www.epilepsy.com/sites/default/files/atoms/files/516VNS_VNS_FINAL.pdf. December 20, 2022. 2. Ebben MR, Sethi NK, Conte M, Pollak CP, Labar D. Vagus nerve stimulation, sleep apnea, and CPAP titration. J ClinSleepMed. 2008 Oct 15;4(5):471-3. PMID: 18853706. 3. Parhizgar F, Nugent K, Raj R. Obstructive sleep apnea and respiratory complications associated with vagus nerve stimulators. J ClinSleepMed. 2011 Aug 15;7(4):401-7. doi: 10.5664/JCSM.1204. PMID: 21897779.