[Pulmonary impedance plethysmographic features of obliterative pulmonary hypertension]

Pulmonary impedance plethysmography (PIP) has been used for the diagnosis of cor pulmonale secondary to COPD for about ten years. But the PIP features of obliterative pulmonary hypertension (OPH) have not yet been reported. We carried out a comparative study between PIP and hemodynamics determined by catheterization, in which 32 cases of OPH were studied. The results showed that the PIP features of OPH included a delayed delta Zmax peak, and the QZM interval had a positive linear correlation with pulmonary arterial pressure (r = 0.67, P less than 0.0001). According to electric field theory, it was supposed that this phenomenon might be due to narrowed pulmonary arterioles which limit the blood flow.