The role of pulmonary pressure/cardiac index to identify pulmonary hemodynamic responders to acute oxygen breathing pulmonary hypertension COPD patients

We sought to analyze exercise-derived mean pulmonary artery pressure (Mpap) - cardiac index (CI) - relationship to expand the concepts regarding its nature and to better identify pulmonary hemodynamic responders to acute oxygen breathing (AOB - 99.5%) in pulmonary hypertension (PH) - COPD patients. mPAP/CI and extrapolated pressure (Pext) to zero flow were obtained breathing room air (BRA) and under AOB - 99.5% in 40 stable COPD patients with rest and exercise PH. Hemodynamic characteristics were analyzed for the entire cohort and separate for cases those with resting < or > 30 mmHg mPAP (cohort - A and B, respectively). mPAP/CI abnormal location, slope (Sp: 5.77; 95% CI: 5.02 - 6.52 mmHg/L min/m2) and Pext values (15.8 mmHg) were associated with hypoxemia/decreased mixed venous - PO2 and lung mechanics abnormalities. Hemodynamic conditions that did not change for Sp (5.47; 95% CI: 3.64 - 7.3 mmHg/L min/m2, p = 0.4) and Pext (15.7 mmHg, p = 0.2) associated with a mPAP/CI significantly decrease in parallel during AOB - 99.5%. For cohort - A, an averagemPAP decline (12.3 mmHg, p