An animal model for the study of regional lung function.

An animal model for the study of regional lung function is described. In sheep, the bronchus to the right apical lobe (RAL) of the lung arises directly from the trachea. A tracheal divider, inserted under local anesthesia via a permanent tracheostomy, was used to separate the ventilation of the RAL from that of the rest of the lung. Lobar blood flow was estimated from the RAL contribution to the pulmonary clearance of an intravenous bolus of 85Kr. Gas exchange was measured by conventional methods. Expressed as a percentage of the value obtained for the whole lung, lobar expired volume was 14.7 +/- 4.3%, capillary perfusion was 12.3 +/- 4.2%, oxygen uptake was 14.7 +/- 4.9%, and carbon dioxide production was 13.4 +/- 5.5% (mean +/- SD of 25 studies in 11 animals breathing air). The model permits the study of experimental conditions confined to a single lobe of the lung and offers the advantages of an intact chest wall, spontaneous ventilation and an unanesthetized animal.