Fig. 2.
Relationships between central hemodynamics and hyperinflation and intrathoracic pressure. Relationships between central hemodynamics and hyperinflation, inspiratory intrathoracic pressure, as well as systemic vascular resistance in controls (○) and chronic obstructive pulmonary disease (COPD) patients (●). There was a positive relationship between FEV1 and stroke volume during exercise in COPD patients (A: r = 0.68, P = 0.01). Furthermore, there were positive and negative relationships between ratio of inspiratory capacity to total lung capacity (IC/TLC) and stroke volume (B) and systemic vascular resistance (D) (r = 0.77, P < 0.01 and r = −0.75, P < 0.01) in COPD patients during exercise. Last, inspiratory esophageal pressure time integral (Pes,inspTI) was positively related to cardiac output (C) (r = 0.56, P = 0.047). No significant relationships were present in the controls (all P ≥ 0.43).