Figure 1

Box-whisker plots of (a) alveolar-arterial partial pressureof oxygen [P(A–a)O₂] gradient, (b) arterial partial pressureof oxygen (PaO₂) and (c) arterial partial pressure of carbondioxide (PaCO₂) in patients with and without pulmonary embolism (PE)who had abnormal lung scan or normal/near-normal lung scans. Horizontal line inbox is 50th centile (median); limits of box are 25th and 75th centiles;whiskers are 10th and 90th centiles. *P = 0.001 betweenpatients with and without PE who had abnormal scans, by unpairedt-test; **P = 0.04-0.001 between patients withnormal/near-normal lung scans and patients with or without PE who had abnormalscans, by unpaired t-test.