Elevated pulmonary artery systolic storage volume associated with redistribution of pulmonary perfusion.

The possibility that an increased pulmonary arterial systolic storage volume (PASSV) correlates with a significant redistribution of pulmonary perfusion was examined in 30 surgical patients. Right ventricular stroke work index (RVSWI) was used as an index of distribution of pulmonary perfusion. The systolic storage volume was calculated from the pulmonary arterial compliance and mean pulmonary arterial distending pressure. Pulmonary arteriolar pressures were computed by Fourier analysis. Pulmonary arterial compliance was derived from the pulmonary arterial time constant and pulmonary arterial resistance. There was a linear relationship between PASSV and RVSWI (r = .81, p less than .001). Also, a direct correlation was found between RVSWI and pulmonary arterial time constant (r = .45, p less than .01). When the patients were divided into three groups according to the severity of pre-existing disease, linear relationships between PASSV and RVSWI were present in all groups, and the slopes were not different among the three groups. The patients were also divided into two groups based on a storage volume fraction of stroke volume index, to evaluate the effect of other hemodynamic data on the PASSV. Comparison of the two groups revealed that pulmonary arterial pressure and pulmonary arterial compliance were significantly higher in the group with a high storage volume fraction (p = .05 and p = .01, respectively). RVSWI and time constant were also significantly different between the groups (p less than .01 and p less than .01, respectively). We conclude that the pressure work generated by the right ventricle improved the distribution of pulmonary perfusion by increasing PASSV.