860 Variable Sleep Apnea Syndromes Complicated by Neurosurgeries in a Patient with Chiari Malformation Type 1

Introduction Chiari malformations (CM) are congenital conditions defined by craniocervical junction anatomic anomalies with downward displacement of cerebellar structures. Sleep-disordered breathing (SDB) including obstructive sleep apnea (OSA), bradypnea, central sleep apnea (CSA), and hypoventilation are described in CM patients. Report of case(s) 31-year-old male with history of CM type 1 presented to the sleep medicine clinic for management of OSA and CSA diagnosed at age 16. PSG showed an apnea-hypopnea index (AHI) of 14.2, RDI of 29, and no central events. He was started on auto-CPAP with pressures of 5–20 with subsequent visits showing high residual AHI. A subsequent CPAP-titration study resulted in a pressure of 16cm H2O yielding AHI of 0. CPAP pressure was fixed, but a high residual AHI persisted despite excellent compliance. A split-night study resulted in a BiPAP prescription, for which a titration study noted PAP-emergent CSA. He was started on auto Bilevel with IPAP of 30, EPAP of 8 and backup rate of 12bpm. Despite treatment, elevated AHI persisted so he was switched to adaptive servo-ventilation (ASV) with nightly oxygen blended in resulting in controlled complex sleep apnea. SDB management was complicated by multiple neurosurgical decompressions. During the most recent procedure, he was found to have syringomyelia, syringobulbia, and a mass at the brainstem. Surgery, including placement of a 4th ventricle stent and mass excision, initially led to a decrease of residual AHI to a low of 0.7, before progressively increasing to 15. A repeat PSG demonstrated severe OSA (AHI of 35), without evidence of CSA or nocturnal hypoventilation. ASV was resumed and patient’s AHI progressively decreased to an average of 8, with improvement in his sleep apnea symptoms. Conclusion SDM in CM patients can be explained by condition-related anatomical changes and depression of respiratory centers due to possible extrinsic compression leading to complex sleep apnea presentations. While it is unclear why this patient’s sleep apnea improved then worsened after his latest decompression surgery, we believe that CSF recirculation and postoperative inflammation may be responsible. Close monitoring of SDB in patients with CM is important as they may require advanced therapies for proper control. Support (if any):

Gender differences of clinical and polysomnographic findings with obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is underdiagnosed in females and gender differences in clinical and polysomnographic findings have not been widely investigated in China. We examined clinical and polysomnographic differences between males and females with OSAS in order to determine the influence of gender on clinical presentation and polysomnographic features. Data were collected from 303 adult patients diagnosed with OSAS (237 males and 66 females) from 2017 to 2019. All the patients completed physical examination, Epworth sleepiness scale, and whole night polysomnography. AVONA, univariate and multivariate logistic regression analyses were conducted to assess gender differences of clinical and polysomnographic findings with OSAS. P < 0.05 was statistically significant. The average age was 48.4 ± 12.6 years for females and 43.4 ± 12.4 years for males. Compared with female patients with OSAS, male patients were taller and heavier, had higher systolic blood pressure in the morning, shorter duration of slow wave sleep, more micro-arousal events, greater AHI, and more complex sleep apnea events. There are obvious gender differences of clinical and polysomnographic characteristics with OSAS. Understanding gender differences will contribute to better clinical recognition of OSAS in females as well as the provision of proper health care and therapeutic practice.

Help, I Can’t Breathe!

This chapter presents a case of treatment-emergent central sleep apnea (TECSA), which is also known as complex sleep apnea syndrome or continuous positive airway pressure (CPAP)–emergent central sleep apnea. In this disorder, central apnea events emerge in patients with obstructive sleep apnea (OSA) after initiation of CPAP treatment. This phenomenon has been identified in up to 20% of patients with OSA who undergo CPAP titration. Polysomnography in those with TECSA usually shows an elevated residual Apnea–Hypopnea Index and arousal index after PAP initiation and occurs primarily during non–rapid-eye-movement sleep. Several mechanisms that have been postulated will be reviewed. The phenomenon is usually self-limiting, and recommended management includes applying the lowest PAP pressure needed to achieve reasonable control and avoiding modalities that exacerbate hypocapnia.