1207 Intercostal Monitoring as a Novel Approach to Polysomnography During Hypoglossal Nerve Stimulator Titration

Introduction Hypoglossal nerve stimulation is an alternative treatment modality for patients with obstructive sleep apnea who are not able to achieve ideal compliance rates with PAP therapy, and is becoming more widespread, with growing numbers of patients considering and undergoing implantation. Protocol for the only commercially available hypoglossal nerve stimulator (HNS) in the US includes a follow up titration polysomnogram (PSG) after implantation for device adjustment. This is typically performed using a standard PSG setup, which does not include leads for monitoring of the intercostals. Following implantation of HNS in our patient, we added intercostal electromyography to the standard PSG during HNS titration study, allowing us to directly monitor activation of the intercostal muscle group responsible for the sensing lead on the HNS. A 2016 study comparing intercostal EMG activity to respiratory inductance plethysmography (RIP) monitoring for differentiating obstructive from central events showed an increase in sensitivity for chest wall EMG in detecting respiratory effort, with 10.4% of events initially detected as central by RIP monitoring being reclassified as obstructive by chest well EMG, and 2.8% noted to be mixed rather than central4 Report of case(s) Our patient is a 46-year-old female with a past medical history May-Thurner syndrome and nutcracker syndrome s/p stenting, Ehlers-Danlos syndrome, mitral valve regurgitation, Barrett’s esophagus, chronic migraines, thyroid cancer s/p radical resection and resultant hypothyroidism, Insomnia, gastroparesis s/p total colectomy, melanoma in situ s/p resection, cholecystectomy, and spinal nerve stimulator implantation. She was initially diagnosed with OSA in 2022 with an AHI 21.8 events per hour, nadir SpO2 87%. She trialed CPAP, but was intolerant to therapy. She underwent HNS implantation on 3/9/23. The device was activated in the clinic and she underwent polysomnography on 7/31/23 for voltage and setting titration. During the study, we monitored electromyography of the intercostals along with a standard PSG montage. Conclusion Intercostal electromyography, in addition to standard polysomnographic montage allowed for direct visualization of the intercostal contraction and subsequent activation of the hypoglossal nerve stimulator. This expanded montage provides more information for the titration study, and may allow for more precise HNS device settings given the increased sensitivity in detecting respiratory effort. Support (if any)