Colaco, Brendon

Abstract Introduction Hypoglossal nerve stimulators (HGNS) are used in patients with moderate-to-severe obstructive sleep apnea (OSA) who are unable to tolerate or do not respond to continuous positive airway pressure (CPAP) therapy. However, a subgroup of patients fail to achieve resolution of OSA with HGNS alone. Previous studies have shown that lower BMI, lower nadir oxygenation, decreased sleep latency, and higher VOTE score on drug-induced sleep endoscopy (DISE) predict better treatment outcome. We hypothesize that baseline diagnostic polysomnography (PSG) may further predict which patients will achieve successful therapeutic outcome with HGNS therapy. Methods We conducted a retrospective analysis of all adult patients who underwent HGNS implantation at Mayo Clinic Arizona between 2019-2025 and had a pre-implantation diagnostic PSG available for review. Treatment success was defined by Sher Criteria: >50% reduction in post-treatment apnea hypopnea index (AHI) to a final AHI of < 20/hr. Responders met Sher criteria and non-responders did not meet Sher criteria. Demographics, sleep questionnaire results, PSG variables, and VOTE score on DISE were collected and analyzed using Spearman’s rank correlation of reduction in AHI. Results Twenty-three patients (11M/12F, median age: 69[IQR:64,75] years) met inclusion criteria. Median baseline AHI was 24[IQR:19,37]/hr. Median post-implant AHI was 8 [IQR:3, 14]/hr. Responders (n=15, 65%) and non-responders (n=8, 35%) demonstrated median post-implant AHI of 4.5[IQR:2.3,7.3]/hr and 15.7[IQR:12.3,28.5]/hr, respectively. Treatment response was associated with less time with SpO2 < 88% (T88%) (21min [IQR:3,64] vs. 73[IQR:36,105mins]; p=0.023) and higher central apnea index (CAI) (1[IQR:0.1,3] vs. 0[IQR:0,1], p=0.03) on pre-implantation PSG. Conclusion In this small cohort of OSA patients, less nocturnal hypoxemia as defined by T88% and higher baseline central apnea index were predictors of better treatment response to HGNS therapy as measured by Sher criteria. We hypothesize that greater nocturnal hypoxemia likely reflects more severe airway obstruction during sleep. Our analysis also showed that responders had higher baseline CAI than non-responders, however we believe this association is not clinically significant and likely driven by one outlier (CAI 13/hr). Further analysis in a larger HGNS cohort is needed to confirm these findings. Data enrichment efforts and more sophisticated analyses are underway. Support (if any)

Abstract Introduction Patients presenting with daytime somnolence need to be evaluated for common etiologies including sleep-related breathing disorders, shift work disorder, insufficient sleep, insomnia and disorders of hypersomnolence. Sleep disordered breathing (SDB) is one of the most common causes of daytime sleepiness. We postulate that treatment of SDB may actually worsen symptoms, if associated with poor sleep due to positive airway pressure (PAP) therapy. Methods N/A Results A 49-year-old female presented to our clinic with increased daytime somnolence. She was diagnosed with obstructive sleep apnea (OSA) at an outside center 3 years ago and was started on auto PAP therapy with pressure settings at 6-10 cmH2O. She had 100% usage, 95th percentile pressure of 9 cm H2O, and a residual Apnea Hypopnea Index (AHI) of 1.1. The patient reported excessive daytime sleepiness, with an Epworth Sleepiness Scale of 16, requiring a daily 3-hour nap. Further sleep history revealed that she had multiple nocturnal awakenings due to discomfort with PAP therapy, including mask related issues causing sleep disruption. Several mask adjustments did not result in any sleep improvement. We decided to re-evaluate her with an in-lab polysomnography. Diagnostic data revealed an overall AHI of 1.6, supine AHI of 12.0, and lateral AHI of 1.5. Mean oxygen saturation was 94.6% with a nadir of 89.0%. The patient was advised to discontinue PAP therapy, and to sleep on her sides, which led to improvement in her sleep quality and daytime sleepiness. Conclusion Positional OSA, defined by greater than 50% increase in AHI in supine position compared to non-supine position, with or without AHI less than 5 in non-supine position, is seen in up to 50-60% of patients with OSA. In addition, intolerance to CPAP has been noted in 29-83% of patients. We need to be clinically aware of the potential effect of PAP devices, or oral appliances, on sleep disruption among intolerant patients. Among this group, conservative therapies like positional therapy or weight loss may be more effective for symptom management, especially for mild SDB. Support (if any)

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)

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)