0975 Severe Central Sleep Apnea After Bilateral Lung Transplantation

Abstract

Abstract Introduction Central sleep apnea (CSA) is characterized by repetitive disruptions in airflow during sleep due to impaired central respiratory drive. Multiple studies have described an increased incidence of sleep disordered breathing after lung transplantation. However, these studies implicate obstructive sleep apnea as the primary sleep disturbance related to post-transplant weight gain, increased neck circumference, and fluid retention from immunosuppressive therapy. We report an uncommon presentation of new onset severe central predominant sleep apnea in a bilateral lung transplant recipient. Report of case(s) A 61-year-old female with a history of end stage COPD with chronic hypoxic respiratory failure status post bilateral lung transplantation in 2020 presented to sleep medicine clinic with several months of witnessed apneic episodes, excessive daytime sleepiness, morning headaches, and insomnia. Physical exam was notable for an increased body mass index (BMI) of 35 kg/m² from pre-transplant BMI of 29 kg/m². Epworth Sleepiness Scale was 15, compared to 4 prior to transplant. Polysomnogram showed an apnea hypopnea index (AHI) of 94.5 events/hour with central AHI of 54.6, consistent with severe central predominant sleep apnea. Titration on CPAP at 5 cmH2O and 7 cmH2O improved the AHI to 13.3 and 20.3, respectively, with residual central hypopneas. On follow-up, downloaded therapy data revealed a residual AHI of 23.3 on CPAP at 5 cmH2O and 1.5 L/min O2, suggesting the need for a BiPAP/ASV titration study if control remains suboptimal. Conclusion Common etiologies of CSA include heart failure with Cheyne-Stokes respirations, neurologic disease, high altitude, and the use of centrally acting medications. This patient did not have clearly identifiable risk factors. Pre- and post-transplant echocardiograms showed preserved left ventricular function with no regional wall motion abnormalities. She lacks history of neurologic disease or narcotic use, and her current immunosuppressive regimen has not been linked to worsened sleep apnea. Proposed pathogenesis of CSA in lung transplant recipients include abnormalities in respiratory mechanics due to pulmonary denervation and altered chemoreceptor sensitivity. Prompt diagnosis and treatment of sleep disordered breathing is crucial in organ transplant recipients to prevent adverse cardiovascular outcomes. Thus, further investigation is warranted to better characterize the changes in respiratory parameters that occur after lung transplantation. Support (if any)