1212 When Everything Else Fails: Volume Assured Pressure Support in a Patient with Chronic Obstructive Pulmonary Disease, Sleep Apnea and Morbid Obesity

Abstract

Introduction: Chronic Obstructive Pulmonary Disease (COPD) and Obstructive Sleep Apnea (OSA) are highly prevalent. Their co-existence "overlap syndrome" carries worse prognosis and ultimately survival. Obesity hypoventilation syndrome (OHS) is a common, yet largely undiagnosed and undertreated condition carrying high mortality. Hypoxemia and hypercapnia can be difficult to treat when the three collide. Despite increased prevalence of this "triple overlap", there is scarce information on its pathophysiology and management. We present a challenging case of COPD, OSA, OHS overlap who failed continuous positive airway pressure (CPAP) and Bi-Level due to persistent nocturnal hypoxia, resolved with initiation of intelligent volume-assured pressure support (iVAPS) therapy. Report of Case: A 55-yo woman with oxygen-dependent COPD, multiple admissions for acute on chronic hypercapnic/hypoxic respiratory failure, morbid obesity (BMI 49.2) and OSA presented for re-evaluation after Bi-Level intolerance. Polysomnography (PSG) showed mild OSA with apnea-hypopnea index (AHI) of 5.9/hour (10.5/hour supine) and severe hypoxia despite additional 2l/min O2 (mean SpO2 <80%). On follow up PSG, Bi-Level and 2 l/min O2 supplementation were titrated from 12/5 to 20/15 cmH2O with 3l/min O2, with AHI 0.7/h but persistence of hypoxia (mean SpO2 81.2%). This triggered therapeutic PSG using iVAPS (S9 VPAP ST-A with iVAPS-ResMed) plus oxygen. Pressure support was set 4-20 cmH2O, EPAP was titrated from 6 to 8 cmH2O to correct obstructive events, target alveolar ventilation was titrated from 3 to 3.3L/min to correct hypoventilation related hypoxemia and rise time adjusted (min 0.3- max 1sec). On the final settings, longer sleep time and REM sleep were achieved; AHI was 1.6/hr with lowest O2 saturation 89% and mean SpO2 of 93.4%. Six-month follow up shows no ED or hospital visits, sleep quality and symptoms resolved. Conclusion(s): Patients with overlap syndrome effectively treated with noninvasive positive pressure ventilation (NPPV) have adequate nocturnal oxygen saturation. In those with additional OHS, supplemental oxygen may not be sufficient and worsen hypoventilation. Combining end expiratory pressure and pressure support variation targeting alveolar ventilation, along with adjustable rise time and set respiratory rate via iVAPS, might be an effective alternative mode for challenging "triple overlap" cases that are not adequately treated with conventional therapy.