Category Archives: Emphysema

Pulmonary Vascular Resistance in Emphysema: Terminology

Other sources of increased vascular resistance merit consideration. The range of arterial 02 tension and pHa observed in our subjects (Table 1) is generally accepted as reflecting levels of alveolar 02 tension that are not capable of evoking pulmonary vasoconstriction. Wright and colleagues examined patients with clinical and functional abnormalities similar to those in the present series. Inspiration of 100 percent oxygen had no effect … Continue reading

Pulmonary Vascular Resistance in Emphysema: Sources of Increased Resistance

In our study, values of DcoSB calculated from the single-breath measurement of Va were also closely related to PDG (r = – 0.754, p < 0.025), but the slope of PDG on the inverse of DcoSB calculated from the single-breath measurement of Va was significantly less than the slope calculated from the rebreathing measurement of Va (p < 0.01). This implies a greater loss of … Continue reading

Pulmonary Vascular Resistance in Emphysema: Technical Factors

Although a reduced DcoSB is a useful clinical predictor of the presence of emphysema, morphologic studies do not support a direct correlation between emphysema score and DcoSB. This is particularly true for mild emphysema. The diminution of DcoSB characteristically observed in emphysema has been ascribed to microvascular disruption. The question remains as to how precise a marker of the extent of the pulmonary microcirculation DcoSB … Continue reading

Pulmonary Vascular Resistance in Emphysema: Discussion

In a carefully selected population of patients with emphysema (type A COPD), we observed a mild increase in resistance to pulmonary blood flow that correlated poorly with the severity of airflow obstruction. In none of the patients was vascular resistance sufficiently elevated to produce resting pulmonary hypertension. Statistical evaluation indicated that DcoSB, employed as a marker of extent of the pulmonary microcirculation, was the major … Continue reading

Pulmonary Vascular Resistance in Emphysema: Correlation Analysis

Resistance to pulmonary blood flow in COPD-A was less (p < 0.001) than that in ILD when FVC was less than 50 percent predicted (PDG = 18 ± 6 mm Hg). There were no significant differences in cardiac output heart rate or systemic arterial pressures among the three groups. Conventional calculation of ohmic resistance to blood flow in the pulmonary circulation yielded estimates of PVR … Continue reading

Pulmonary Vascular Resistance in Emphysema: Results

Data are presented as mean ± SD. Significance of difference between sample means was determined by the two-tailed unpaired t test. Linear regression analysis was performed by the least squares method. Partial correlation analysis was performed in order to examine the relationship between two variables independent of their relationship with a third variable. A p value of less than 0.05 was considered significant. Mean pulmonary … Continue reading

Pulmonary Vascular Resistance in Emphysema: Data Analysis

Predicted values for FEV, and FVC are those of Morris and coworkers. Predicted values for RV and functional residual capacity (FRC) are those of Goldman and Becklake. Predicted total lung capacity (TLC) was calculated as the sum of the predicted RV and predicted FVC. Predicted values for Dcocn were those of Gaensler and Wright. Vascular pressures were measured relative to the level of the midright … Continue reading

Pulmonary Vascular Resistance in Emphysema: Protocol

We examined lung function and resting pulmonary hemodynamics in 12 patients with type A COPD. The study protocol, approved by the Institutional Review Board of the Columbia Presbyterian Medical Center, was explained in detail and written, informed consent was secured for all procedures. On the first day, patients underwent complete pulmonary function testing. Immediately after completion of pulmonary function testing, subjects were familiarized with the … Continue reading

Pulmonary Vascular Resistance in Emphysema: Methods

Explorations of the causes of pulmonary hypertension in patients with chronic airways obstruction reported previously from this laboratory emphasized the role of disturbed respiratory gas exchange as the major factor responsible for increased pulmonary vascular resistance in this population. The early demonstration of reversibility of this vasoconstrictive process following correction of hypercapneic respiratory failure became the basis of management in such patients. It was also … Continue reading