1167 Chasing Centrals

Abstract Introduction Distinguishing between obstructive and central hypopneas raises a clinical challenge when evaluating sleep apnea. Currently, absence of snoring, inspiratory flow limitation, and paradoxical thoraco-abdominal excursions can aid in identifying a central hypopnea. Defining these events is imperative as it affects options for therapy. This case highlights the importance of appropriate classification of central hypopneas. Report of case(s) A 57 YO F with PMH of HTN presents for snoring, frequent awakenings, and suffocation disrupting sleep. Her BMI is 35.5. Epworth Sleepiness Scale is 15. She has a family history of sleep apnea. Her STOP-BANG score is 4. In conjunction with sleep disordered breathing evaluation, she was undergoing neurologic evaluation of oropharyngeal dysphagia resulting in ILD from aspiration, weakness and numbness in bilateral hands, and worsening balance. Imaging showed a Chiari 1 Malformation. She underwent PSG to evaluate SBD and split for CPAP titration due to frequent apnea and hypopnea events. Despite titration, events worsened. Upon further review of the study, it was noted the hypopnea events were majority central in nature. The diagnostic portion showed 32 central apneas, 2 obstructive apneas, 0 mixed apneas, 49 central hypopneas and 4 obstructive hypopneas. The total AHI was 44/h with a central index of 42/h and O2 nadir of 71% with O2 less than 88% for 70 minutes. She returned for ASV versus Bipap ST titration. Again, pressures were increased due to presence of hypopneas and at the termination of the study, apnea was poorly controlled. The residual AHI of 50/h on BIPAP 18/8 rate 16. Review of PSG found optimal settings to be BIPAP 15/6 rate16. AHI on these settings was 8.9/h, nadir SPO2 82%. She is currently scheduled for chiari decompression. Conclusion This case demonstrates that detection of central hypopneas affects ability to titrate PAP therapy and determine best treatment options. This case is further complicated by a clinical history concerning for obstructive sleep apnea. Support (if any) Javaheri S, Rapoport DM, Schwartz AR. Distinguishing central from obstructive hypopneas on a clinical polysomnogram. J Clin Sleep Med. 2023 Apr 1;19(4):823-834. doi: 10.5664/jcsm.10420. PMID: 36661093; PMCID: PMC10071374.