Cardiovascular and Respiratory Interactions in Idiopathic Pulmonary Fibrosis by Extended Partial Directed Coherence: Short-term Effects of Supplemental Oxygen.

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease that can lead to chronic arterial hypoxemia, hypercapnia, and dyspnea. To improve clinical symptoms in IPF patients, supplemental oxygen (SupplO2) has been prescribed with the aim to maintain SpO2 level, and consequently to relieve dyspnea, increase physical activity and improve quality of life. In this study, we investigated the effect of disease and short-term SupplO2 on cardiovascular and respiratory autonomic regulation. Linear and nonlinear indices were extracted from the beat-to-beat variability of heart rate (HR), systolic (SYS) blood pressure and respiration (RESP) in IPF patients and healthy subjects spontaneously breathing ambient air (AA) and during SupplO2 at 3 L/min. It was found that the effects on autonomic nervous systems (ANS) regulation were better demonstrated by the Granger causality (GC) method. GC was significantly higher (p<0.01) in patients compared to controls for the interactions RESP→SYS and BBI→SYS.Clinical Relevance-Short-term SupplO2 in IPF could adversely affect systolic blood pressure variability in particular. This study may help in the management of SupplO2 administration.