1178 CASE REPORT – USE of WEARABLE OXIMETRY DEVICE to TITRATE HYPOGLOSSAL NERVE STIMULATION SETTINGS

Abstract Introduction Obstructive sleep apnea (OSA) is characterized by repetitive airway narrowing or collapse during sleep. Hypoglossal nerve stimulation (HNS) is one alternative therapy. After device implantation and activation, it is patient-titrated based on symptoms. A sleep study then confirms effective settings based on an apnea-hypopnea index (AHI) below 5. Symptomatic control alone may not entail low AHI. Objective data with overnight oximetry during titration may help bridge this. We describe a patient in whom Wellue pulse oximeter was used during self-titration of the Inspire HNS. Report of case(s) A 63 year-old male presented in June 2022 for HNS evaluation due to gasping and witnessed apneas. AutoPAP trial had failed. In November 2022 diagnostic polysomnography revealed an AHI of 18 and lowest oxygen saturation (OS) of 80%. Sleep endoscopy in February 2023 confirmed no concentric collapse at the level of the velum. He underwent HNS implantation in May 2023 and activation in June. Initial sensation and functional thresholds were 0.6 volts. Amplitude range was 0.6 to 1.6 volts, pulse width 90 microseconds, rate 33 hertz, pause time 15 minutes, electrode configuration [+,-,+], and duration 8 hours. In July, he felt 0.7 volts controlled symptoms. A Watchpat home sleep study revealed an AHI of 46.2 and lowest OS of 82%. He purchased a pulse oximeter and was shown the oxygen desaturation index (ODI) at >3%. On increasing to 1.0 volts, oximetry revealed ODI 8.65 averaged over 4 nights. At 1.1 volts, ODI improved to 0.9-4.14. Since ODI was below 5, he had subsequent in-laboratory titration, revealing at 1.1 volts the residual AHI was 2.5. The lowest OS was 89% with a mean of 95%. Conclusion The post-activation procedure for HNS utilizes symptom-based self-titration. Sleep studies may reveal continued apnea despite self-reported symptom control. We suspect overnight oximetry during self-titration may improve efficacy. In this case, after self-titration with oximetry to decide an amplitude setting, home and in-laboratory sleep studies confirmed effective control. This preliminarily suggests that overnight oximetry used with HNS during the self-titration phase may improve titration outcomes as confirmed by formal polysomnography. Support (if any)