DISTRIBUTION OF PLEURAL INJECTATE - EFFECT OF VOLUME OF INJECTATE ANDANIMAL ROTATION

It is controversial whether rotation is necessary for patients undergo ing pleurodesis. In addition, the optimal volume of the injectate rema ins to be determined. The purpose of this study was to determine the i mportance of rotation and the volume of the agent on the intrapleural dispersion of agents injected into the pleural space of rabbits. Techn etium 99m pertechnetate (Tc-99m) in 0.5, 1.0, or 2.0 ml of saline solu tion was injected into ten lightly anesthetized rabbits, half of whom were rotated for 1 min after the injection. Static images were obtaine d in the anterior projection 1 and 5 min after the injection. After th e second scan, the limits of the lung were defined by obtaining a perf usion scan immediately after the intravenous injection of macroaggrega tes of Tc-99m-labeled serum albumin. The degree of dispersion was sign ificantly greater in the nonrotated groups both at 1 min (F=8.11, p=0. 0085) and at 5 min (F=5.89, p=0.0274). In addition, the homogeneity of the distribution of the injectate was not improved with rotation. Fro m this study, we conclude that rotation of the animal for 1 min after the intrapleural injection does not improve the distribution of the in jectate throughout the pleural space. Furthermore, a volume of 0.5 ml is sufficient for all pleural surfaces to be exposed.