Hypercapnia Response in Patients with Obesity-Hypoventilation Syndrome Treated with Non-Invasive Ventilation at Home

Introduction: Respiratory center (RC) dysfunction has been implicated in the pathogenesis of obesity-hypoventilation syndrome (OHS), and often requires treatment with home non-invasive ventilation (NIV). Our objective was to measure the effect of NIV on RC function in patients with OHS, and the factors that determine such an effect. Methods: We performed a prospective, repeated measures study to evaluate hypercapnia response (HR) by determining the p01/pEtCO(2) ratio slope at baseline and after 6 months of treatment with NIV in a group of OHS patients. A threshold of 0.22 cmH(2)O/mmHg had previously been established in a control group, in order to differentiate optimal RC response from suboptimal RC response. Results: A total of 36 cases were included, 19 men (52%) aged 65 (SD 9) years, 63% of whom had p01/pEtCO(2) below the reference value. Baseline p01/pEtCO(2) was 0.17 (SD: 0.14) cmH(2)O/mmHg and, after 6 months of NIV, 0.30 (SD: 0.22) cmH(2)O/mmHg (p = 0.011). After 6 months of treatment with NIV, depressed RC function persisted in 12 cases (33%). Conclusion: In total, 63% of OHS patients had RC dysfunction. The application of NIV improves RC function but not in all cases. (C) 2018 SEPAR. Published by Elsevier Espana, S.L.U. All rights reserved.