Am. J. Respir. Crit. Care Med.,
Volume 162, Number 6, December 2000, 2073-2078
Pulmonary Blood Flow Distribution in Stage 1 Chronic
Obstructive Pulmonary Disease
ANDRE
CAPDEROU,
ANDRE
AURENGO,
JEAN-PHILIPPE
DERENNE,
THOMAS
SIMILOWSKI,
and
MARC
ZELTER
Services d'Explorations Fonctionnelles Respiratoires, de Pneumologie et de Médecine Nucléaire CHU Pitié-Salpêtrière, UPRES 2397, Université
Pierre et Marie Curie, and Hôpital Marie Lannelongue CHU Kremlin-Bicêtre, Paris, France
We investigated the hypothesis that lung blood flow distribution is
modified in stage 1 chronic obstructive pulmonary disease (COPD).
We compared patients with stage 1 COPD (n = 11) with restrictive patients with comparable blood gases (n = 7), to patients with low cardiac index with normal lungs (n = 11) and to control subjects (n = 11). Distribution of transit time (DTT) was computed by deconvolution from first pass radioactivity curves (albumin 99mTc) reconstructed from right and left ventricular regions of interest. Distribution descriptors, mean transit time (p < 0.05), standard deviation (p < 0.001), relative dispersion (p < 0.001), and kurtosis (p < 0.001) differed between groups (ANOVA). Cardiac index was the same in COPD and low CI groups but lower compared with
normal subjects (p < 0.05). After normalization for cardiac output,
the DTT of patients with COPD remained different from low CI
and restrictive patients (p < 0.001). Therefore changes in DTT in
patients with COPD compared with patients without COPD could
not be explained on the basis of difference in cardiac output. Because PO2, PCO2, and pH were similar in COPD and restrictive
groups, difference in distribution could not be explained either on
the basis of blood gas data. We conclude that changes in DTT occurs in stage 1 COPD and cannot be explained by hypoxemia, hypercapnia, or acidosis alone but must relate to other structural or
regulatory responses.
