Respiratory noninvasive venous waveform analysis investigated in chronic pulmonary conditions

ABSTRACT

INTRODUCTION: Respiratory disease, acute and chronic, can be difficult to diagnose and monitor. To date, there are only two standard non-invasive monitoring approaches for assessing respiratory distress respiratory rate and SpO2. The Respiratory non-Invasive Venous waveform Analysis (RIVA) was first described in COVID-19 patients as a promising, novel physiological measurement that predicted a COVID-19+ patient's need for oxygen support therapy. The aim of this study was to investigate if this RIVA signal was present in chronic pulmonary conditions. METHODS: Secondary analysis of a venous waveform dataset of human subjects that had pulmonary function tests (PFT) were analyzed to assess how their chronic respiratory illnesses affected the magnitude of their respiratory signal. Data was captured via a non-invasive piezoelectric sensor and analyzed on LabChart 8. Using spectral analysis in 8K windows, the respiratory peak of the signal (low frequency ~0.2 Hz) was measured for magnitude relative to their cardiac peak (higher frequency ~1.0 Hz) to calculate RIVA-RI (respiratory peak/cardiac peak). These values were grouped according to their pulmonary disease and an ANOVA with multiple comparisons was conducted to determine the significance between groups. RESULTS: Healthy control subjects displayed significantly lower RIVA-RI values compared to patients reporting the PFT lab with asthma or idiopathic pulmonary fibrosis (IPF;p < 0.05). Patients with chronic obstructive pulmonary disease, pulmonary hypertension, and/or obstructive sleep apnea did not have significant RIVA-RI values compared to healthy controls. CONCLUSIONS: This novel signal, first discovered in COVID-19+ patients that required oxygen support therapy, is also present in asthmatic and IPF patients. More research is needed to better understand the respiratory venous signal and how it could be used to monitor respiratory disease.