Pulmonary Vascular Hemodynamics in Chronic Lung Disease Patients: Results

Pulmonary Vascular Hemodynamics in Chronic Lung Disease Patients: ResultsDifferences in variables between NOD and non-NOD subjects were compared using a Students f-test for unpaired data. Pearson product moment correlations were used to examine parameter interrelations. Mean Ppa and PVR were compared to selected measures of daytime and nocturnal oxygenation using linear regression. The protocol was approved by Human Research Committees at the Houston VAMC and Baylor College of Medicine and all subjects signed informed consents.

Results
Pulmonary Function and Gas Exchange

The two groups did not vary with respect to age, percentage of ideal body weight, RVEF, LVEF (Table 1), or parameters of pulmonary {unction including spirometry, body plethysmographic measurements, and Deo (Table 2). Hemoglobin was significantly higher in the NOD group (15.2 vs 14.4 g/dL). The RBC mass corrected for predicted was normal for both groups. However, when corrected for body weight, the NOD group value was higher.
There were several important differences between the groups with regard to gas exchange (Table 1). The mean resting daytime Pa02 of 70 mm Hg in NOD subjects was lower than that of 82.4 mm Hg in the non-NOD subjects (p<0.0001). This was not due to hypoventilation as PaC02 and Pa02 did not vary significantly between the groups (Table 1). However, measures of gas exchange including the P(A-a)02 and arterial/alveolar oxygen tension ratio (a/A) were more abnormal in the NOD group. The mean resting supine Sa02 measured during the period of collection of hemodynamic data was lower in the NOD vs control group while breathing room air and supplemental oxygen (Fig 1). During hypoxic challenge, there was no difference in oximeter Sa02 between the groups since FIo2 was regulated to achieve a predetermined Sa02 of 80 percent. There were no differences in Sv02 between groups at equivalent FIo2s.
Table 1—Morphometric, Blood Gas, Selected Laboratory, and Sleep Sa02 Data

Group 1 (NOD) N = 36 Group 2 (Non-NOD) N = 13 P
Mean SD Mean SD
Age, yr 62.6 5.7 64.4 4.2 NS
Ideal body weight, % 101.9 21.1 96.7 15.7 NS
PaC02, mm Hg 39.2 5.5 36.4 3.8 NS
Pa02, mm Hg 70.0 7.9 82.4 7.6 <0.0001
Pa02, mm Hg 98.0 6.9 101.6 4.7 NS
P(A-a)02, mm Hg 28.1 9.6 19.1 7.8 <0.004
a/A ratio 0.72 0.08 0.81 0.07 <0.0008
Hemoglobin, g/dL 15.2 1.5 14.4 0.8 <0.02
RBC Mass/Kg, ml/kg 27.51 4.1 25.19 1.7 <0.008
RBC Mass % of predicted 95.3 18.0 93.7 8.5 NS
Plasma Vol/kg 40. 7.6 42.0 5.7 NS
Plasma vol % of predicted 107.4 15.0 91.7 8.8 NS
RVEF, % 42.2 9.0 42.7 9.6 NS
LVEF, % 58.7 8.7 58.3 7.1 NS

Table 2—Pulmonary Function and Carbon Monoxide Diffusion Studies

Group 1 (NOD) N = 36 Group 2 (Non-NOD) N = 13
Mean SD Mean SD P
FEV,, L 1.28 0.51 1.25 0.50 NS
FEV! % predicted 39.5 17.7 37.5 17.3 NS
FVC, L 2.9 0.9 3.2 0.6 NS
FVC % predicted 66.6 18.7 71.2 23.1 NS
FEV,/FVC, % 46.4 16.4 40.0 11.1 NS
TLC, L 7.0 1.4 8.0 1.4 NS
TLC % predicted 110.0 22.9 118.0 19.8 NS
RV.L 4.5 1.3 4.8 1.5 NS
RV % predicted 196.3 69.8 207.1 53.3 NS
Deo, ml/min/mm Hg 11.4 6.5 15.3 6.7 NS
Dco/VA, ml/min/mm Hg/L 2.9 1.9 2.9 1.9 NS
Deo % predicted 37.0 21.9 44.6 19.6 NS

 

Figure 1.

Figure 1.


Category: Lung Disease

Tags: chronic lung disease, Pulmonary function, pulmonary vascular hemodynamics