Usefulness of transcutaneous capnography to evaluate nocturnal hypoventilation in patients with obesity hypoventilation syndrome treated by non-invasive ventilation at home

Abstract

Background: In patients with obesity hypoventilation syndrome (OHS), current monitoring of domiciliary non-invasive ventilation (NIV) relies on clinical outcomes, daytime arterial blood gases (ABG) and nocturnal pulse oximetry. Aim: To evaluate the usefulness of nocturnal transcutaneous capnography in assessing nocturnal hypoventilation when compared to routine exams. Methods: A monocentric prospective study was conducted from August 2018 to November 2019 in a university hospital centre in France. Thirty-two patients suffering from OHS treated with domiciliary NIV were included. Systematic nocturnal transcutaneous capnography was performed after at least 6 months of home ventilation. Results: Twenty-nine transcutaneous capnographies were analyzed. Main results are displayed in the Table. Eighteen tests showed nocturnal hypoventilation, even though the combination of ABG and nocturnal pulse oximetry revealed nocturnal hypoventilation in 9 cases only. Among the 19 patients with normal ABG and nocturnal pulse oximetry, 11 exhibited nocturnal hypoventilation on transcutaneous capnography. Only one patient reported symptoms. Conclusion: Based on these findings, we suggest that patients with OHS treated by home NIV should be systematically evaluated with additional transcutaneous capnography to detect nocturnal hypoventilation.