Intrapleural distribution of a liquid bolus let in the costophrenic sinus

ntrapleural distribution of a dye bolus (0.4-0.6 ml, once 1 ml) let in through a cannula in the 10th right intercostal space (ics) was studied in anesthetised, breathing (N = 6) and apneic (N = 5) dogs in the left lateral posture. Rapid movements of the dye were detected through «windows» of endothoracic fascia in the 8th and 6th ics; overall distribution of the dye was assessed at autopsy 12 to 25 min after its entrance. In all dogs dye moved first to the caudal border of the lung following the direction of the diaphragmatic fibers, rather than the shortest route. Then dye moved along the caudal border of the lung mainly ventrally, reaching occasionally the ventral tip of the middle lobe. In some breathing dogs dye reached the «window» in 8th ics within few sec. In all but one breathing dogs dye reached also the margin between the middle and caudal lobe. No other parts of the visceral and corresponding parietal pleura were stained. Distribution pattern was not systematically different after 12 or 25 min. These findings validate the hypothesis that a small liquid bolus let in the pleural space is drawn to the lobar edges (Agostoni and D'Angelo, 1969).