1119 Nocturnal Non-Invasive Ventilation (NNIV) for Treating Hypercapnic Respiratory Failure

Abstract

Introduction: NNIV is a widely accepted treatment for sleep-related hypoventilation. We report two cases with disparate medical conditions in which NNIV treatment was effective in treating acute-on-chronic hypercapnic respiratory failure. Report: A 73-year-old woman with severe kyphoscoliosis presented to the emergency department with worsening dyspnea. ABG on supplemental oxygen showed pH 7.37, pCO2 63 mmol/L, pO2 89 mmol/L, HCO3 36 mmol/L. Chest imaging was negative for pulmonary embolism and suggestive of pulmonary hypertension. Frequent nocturnal awakenings due to headaches prompted polysomnography, which revealed poor sleep efficiency, AHI 0/hour and oxygen nadir of 81%. Introduction of nocturnal BIPAP S/T titrated to 14/8 cm H2O, with a back-up rate of 10/hour and supplemental oxygen led to improvement in sleep efficiency and gas exchange. ABG on room air after 60 days of NNIV revealed pH 7.41, pCO2 50 mmol/L pO2 51 mmol/L, HCO3 31 mmol/L. The patient reported greatly improved sleep with fewer nocturnal awakenings, and increase in daytime energy and function. A 48-year-old woman with lymphoma was hospitalized for somnolence and hypoxia with ambulatory O2 saturation 89%. Chest imaging excluded pulmonary embolism. ABG on supplemental oxygen showed pH 7.22, pCO2 97 mmol/L, pO2 129 mmol/L, HCO3 39 mmol/L. BIPAP S/T was started in the emergency department, and eventually titrated to 12/5 cm H2O with a back-up rate of 12/hour. Brain MRI showed diffuse leptomeningeal involvement. A portable sleep study revealed REI 0.6/ hour, oxygen nadir of 62%, and Biot's respiration suggestive of CNS etiology. She was continued on NNIV with supplemental oxygen. ABG, 20 days later, revealed pH 7.46, pCO2 51 mmol/L, pO2 62 mmol/L, HCO3 36 mmol/L. She reported improved daytime energy and function. Conclusion: In these two patients with unrelated medical conditions, acute-on-chronic hypercapnic respiratory failure responded to NNIV with improvement of gas exchange, symptoms, and quality of life.