Figure 4a. Scatterplots show correlations between radiographic severity grade and catheterization data. Group 1 (radiographic severity grade, 0–2) consisted of normovolemic cases (
) in which the mean stroke volume was 88 mL, and the mean cardiac output was 6.0 L/min. Group 2 (radiographic severity grade, 2–8) consisted of oligemic cases (•) in which the mean stroke volume was 40 mL, and the mean cardiac output was 4.6 L/min. The vertical line indicates the junction between groups. (a) Correlation between radiographic severity and wedge pressure (in millimeters of mercury). For group 1 (n = 4), there was no correlation between wedge pressure and radiographic severity. Significant correlations were found for groups 1 and 2 together (r = 0.81, P = .002; n = 12, with cases 10, 16, and 24 excluded, because no wedge pressure was recorded) and for group 2 alone (r = 0.93, P < .001; n = 8). (b) Correlation between radiographic severity and pulmonary arterial (P.A.) pressure (in millimeters of mercury). For group 1 (n = 4), there was no correlation between pulmonary arterial pressure and radiographic severity. Significant correlations were found for groups 1 and 2 together (r = 0.64, P = .044; n = 10, with cases 10, 16, 17, 20, and 24 excluded, because no pulmonary arterial pressure was recorded) and for group 2 alone (r = 0.93, P = .002; n = 6).