End-Tidal-to-Arterial P <sub> CO <sub>2</sub> </sub> Ratio as Signifier for Physiologic Dead-Space Ratio and Oxygenation Dysfunction in Acute Respiratory Distress Syndrome
Richard H Kallet, Michael S. Lipnick
Abstract
BACKGROUND: ([Formula: see text]) was recently suggested for monitoring pulmonary gas exchange in patients with ARDS associated with COVID-19, yet no evidence was offered supporting that claim. Therefore, we evaluated whether [Formula: see text] might be relevant in assessing ARDS not associated with COVID-19. METHODS: ) measured in 561 subjects with ARDS from a previous study in whom [Formula: see text] data were also available. Subjects also were analyzed according to 4 ranges of [Formula: see text] representing increasing illness severity (≥ 0.80, 0.6-0.79, 0.50-0.59, and < 0.50). Correlation was assessed by either Pearson or Spearman tests, grouped comparisons were assessed using either ANOVA or Kruskal-Wallis tests and dichotomous variables assessed by Fisher Exact tests. Normally distributed data are presented as mean and standard deviation(SD) and non-normal data are presented as median and inter-quartile range (IQR). Overall mortality risk was assessed with multivariate logistic regression. Alpha was set at 0.05. RESULTS: < .001) and high hospital mortality (70%). CONCLUSIONS: may be a useful and practical measurement for both management and ongoing research into the nature of ARDS.