ACUTE IN-VIVO STUDIES OF THE PITTSBURGH INTRAVENOUS MEMBRANE-OXYGENATOR

The efficacy of an innovative intravenous membrane oxygenator (IMO) wa s tested acutely (6-8 hrs) in seven calves. The IMO prototypes consist ed of a central polyurethane balloon within a bundle of hollow fibers with a membrane surface area of 0.14 m(2). The IMO devices were insert ed through the external jugular vein into the inferior vena cava of an esthetized calves (68.9 +/- 2.3 kg). Rhythmic balloon pulsation (60-12 0 bpm) was controlled with an intra-aortic balloon pump console. Oxyge n sweep gas was delivered through the device at 3.0 L/min. Cas concent rations were monitored continuously by mass spectroscopy. The principa l results were as follows: 1) oxygen and carbon dioxide exchange range d from 125 to 150 ml/min/m(2) and 150 to 200 ml/min/m(2), respectively ; 2) there was at least a 30-50% augmentation of gas exchange with bal loon pulsation; 3) maximum exchange occurred with 60-90 bpm balloon pu lsations; and 4) hemodynamic parameters remained unchanged. There were no device related complications, and the feasibility of insertion of the device by a cervical cut-down was established. These acute in vivo experiments show that the Pittsburgh IMO device can exchange oxygen a nd carbon dioxide gases in vivo at levels consistent with this current prototype design, and that intravenous balloon pulsation significantl y enhances gas exchange without causing any end-organ damage.