Effects of Supplemental Oxygen on Cardiovascular and Respiratory Interactions by Extended Partial Directed Coherence in Idiopathic Pulmonary Fibrosis

Abstract

Idiopathic pulmonary fibrosis (IPF) is a chronic and restrictive disease characterized by fibrosis and inflammatory changes in lung tissue producing a reduction in diffusion capacity and leading to exertional chronic arterial hypoxemia and dyspnea. Furthermore, clinically, supplemental oxygen (SupplO2) has been prescribed to IPF patients to improve symptoms. However, the evidence about the benefits or disadvantages of oxygen supplementation is not conclusive. In addition, the impact of SupplO2 on the autonomic nervous system (ANS) regulation in respiratory diseases needs to be evaluated. In this study the interactions between cardiovascular and respiratory systems in IPF patients, during ambient air (AA) and SupplO2 breathing, are compared to those from a matched healthy group. Interactions were estimated by time series of successive beat-to-beat intervals (BBI), respiratory amplitude (RESP) at BBI onset, arterial systolic (SYS) and diastolic (DIA) blood pressures. The paper explores the Granger causality (GC) between systems in the frequency domain by the extended partial directed coherence (ePDC), considering instantaneous effects. Also, traditional linear and nonlinear markers as power in low (LF) and high frequency (HF) bands, symbolic dynamic indices as well as arterial baroreflex, were calculated. The results showed that for IPF during AA phase: 1) mean BBI and power of BBI-HF band, as well as mean respiratory frequency were significantly lower (p < 0.05) and higher (p < 0.001), respectively, indicating a strong sympathetic influence, and 2) the RESP → SYS interaction was characterized by Mayer waves and diminished RESP → BBI, i.e., decreased respiratory sinus arrhythmia. In contrast, during short-term SupplO2 phase: 1) oxygen might produce a negative influence on the systolic blood pressure variability, 2) the arterial baroreflex reduced significantly (p < 0.01) and 3) reduction of RSA reflected by RESP → BBI with simultaneous increase of Traube-Hering waves in RESP → SYS (p < 0.001), reflected increased sympathetic modulation to the vessels. The results gathered in this study may be helpful in the management of the administration of SupplO2.

Assessing High-Order Links in Cardiovascular and Respiratory Networks via Static and Dynamic Information Measures

“…Then, a dynamic system with the same causal connections is simulated (Fig. 2b) defining a trivariate VAR process fed by independent Gaussian innovations as in (6), where M = 3, p = 1 and the time-lagged effects are determined by the coefficient matrix A 1 .…”

“…2) Gaussian variables: The second simulation reproduces a network comprising M = 6 nodes, whose activity is mapped by a multivariate random process defined by the VAR model (6) implemented with Σ U = I, p = 2, and time lagged coefficients reported in Fig. 4a,b.…”

“…In turn, biomedical signal processing methods are shifting towards the multivariate analysis of several parameters, which naturally leads to representing physiological systems as interconnected networks whose nodes and links are associated respectively to the parameters and to the interactions between them. This representation is very popular in the field of Network Physiology [2] where cardiovascular, cardiorespiratory interactions and others are studied in a wide range of healthy and diseased states [3]- [6].…”

Wearable Multisensor Ring-Shaped Probe for Assessing Stress and Blood Oxygenation: Design and Preliminary Measurements

“…Therefore, small and lightweight PPG probes can be integrated within portable biosensing devices to measure cardiovascular parameters, providing useful information to monitor an individual’s heart health status. Furthermore, the concurrent utilization of dual-wavelength PPG sensors and appropriate signal processing algorithms enables the extraction of oxygen saturation level of hemoglobin in the arterial blood, providing valuable information for monitoring individuals affected by respiratory-related pathologies, such as sleep apnea or COVID-19 [ 17 , 18 , 19 , 20 , 21 ]. These conditions can lead to low oxygenation levels that pose a potentially life-threatening risk.…”

Induced Relaxation Enhances the Cardiorespiratory Dynamics in COVID-19 Survivors

“…Several signs and symptoms associated with this autonomic impairment have been reported, with chronic fatigue, chest pain, dyspnea, sleep disturbances, anxiety, depression, and post-traumatic stress syndrome being the most common among post-COVID patients [ 15 , 16 , 17 , 18 ]. Recent research on the dynamics of the autonomic nervous system (ANS) in pathological conditions has demonstrated the existence of an autonomic imbalance in orthostatic syndrome [ 19 ], respiratory disease [ 20 ], and cardiovascular pathologies [ 21 ] by mathematical modeling of physiological interactions related to system coupling and causality. However, scarce studies have addressed the study of ANS dynamics in COVID survivors.…”