The importance of controlling PaCO2 throughout long-term noninvasive ventilation

Abstract

BACKGROUND: The significance of changes in PaCO2 during long-term noninvasive ventilation (NIV) on prognosis remains unclear. We aimed to clarify whether stabilizing PaCO2 during NIV had a favorable prognostic effect. METHODS: Data from 190 subjects with restrictive thoracic disease and who received long-term NIV were studied retrospectively. The annual change in PaCO2 during NIV was determined using a simple linear regression method for each subject who had at least 4 6-month intervals of PaCO2 data. Annual changes in PaCO2 during long-term NIV and possible confounders were analyzed with discontinuation of long-term NIV as the main outcome. RESULTS: One hundred and twenty-five subjects who had > 4 6-month intervals of PaCO2 data were included in the study. PaCO2 during long-term NIV decreased in 41 subjects (group 1; < 0 mm Hg/y), increased slightly in 42 subjects (group 2; between 0 and 1.85 mm Hg/y), and increased significantly in 42 subjects (group 3; > 1.85 mm Hg/y). Smaller annual changes in PaCO2 (P