Preliminary studies on the sponge-oxygenator; an improved simple method for extracorporeal blood oxygenation.

Abstract

I N the development of an apparatus for extracorporeal circulation, the blood oxygenating device is the most difficult problem to be solved. Until now many ways have been followed to attain the aim of constructing a safe and efficient oxygenator, and some encouraging and praiseworthy results have been reached in bloodless open heart operations in man. Nevertheless the problem is still open and research for an even more perfect method is being continued. We began our experimental studies on this subject about 10 years ago, and during this time we have constructed and systematically tested on dogs many oxygenators based on the various principles pointed out by other authors and on our ideas.l-14 Recently 2 of us (A. B. and P. L. P.) have devised and realized a new system, the sponge-oxygenator, which proved to be the most safe and efficient we have experimented with to this time, In this report we shall not deal with the blood propelling parts of our apparatus, because the problem of the pumps may be regarded as a separate one. We shall expose only the structural features of the “artificial lung” and the first results experimentally obtained with it. The true oxygenation device is very simple. It is composed of a methyl methacrylate (Lucite; Plexiglas) 13 cm. long tube, with a 4 cm. internal diameter, containing a cylindrical piece of polynrethan spongei with large porosity. This cylinder is 10 cm. long and juts out from one end of the tube leaving a little unoccupied space at the other extremity (Fig. 1). The described device is fixed by simple pressure in the center of a bored support through which the venous blood and the oxygen enter the oxygenating tube by separate ways; the venous blood enters through 2 lateral channels and the oxygen through a long multiperforated needle fixed in a small renewable silicon rubber disc (Fig. 2). All around the central oxygenating tube, a deep circular groove acts as a collecting space for the arterialized blood ; the bottom is inclined toward the outlet hole (Fig. 3). The support