We have shown that lung blood flow pulmonary transit time distribution (PTTD) in stage 1 COPD patients (ATS) fits three distinct patterns (patterns A, B, C), depending on the response to hyperoxic challenge. Pattern A distribution is normal and unchanged during hyperoxia, pattern B distribution is significantly enlarged but remains unchanged during hyperoxia, pattern C distribution is enlarged as in pattern B but returns to normal during hyperoxia (Am J Respir Crit Care Med 2002; 165, 8, part 2, A 654).
We studied 17 ATS stage 1, 9 stage 2 and 5 stage 3 COPD patients, non-responsive to salbutamol. A bolus of albumin 99mTc (3.5 MBq/kg) was injected in the external jugular vein in supine position, breathing air, and after administration of 3l/mn O2 with a mask. PTTD was computed by deconvolution from the first pass radioactivity curves reconstructed from the right and left ventricular region of interest. We computed microvascular and cardiopulmonary blood volumes from the global distributions, using the Z transform analysis suggested by Zierler (Ann Biomed Eng. 2000; 28:836-48).
We observed an even repartition of patterns A, B, C in stage 1 patients; 1 A, 6 B and 2 C patterns in stage 2, and 4 B and 2 C patterns in stage 3 patients.
We conclude that the distribution patterns tended to be limited to pattern B and C in stage 2 patients and then to pattern B in stage 3 patients. A longitudinal study is needed to understand the relationship over time between patterns and to determine if pattern B patients are better survivors or it correspond to the normal evolution of the disease.
Distribution patterns may offer a quantitative approach to select COPD patients for oxygen therapy.
A. Capderou, None.