Late pathophysiologic sequelae after utilization of an intravenacaval oxygenator in experimental animals

The intravenacaval hollow fiber oxygenator (IVOX) has been shown to be remarkably free from acute adverse effects on the venae cavae, right heart, and lungs when indwelling experimentally in sheep and in human clinical trial patients. However, all pathophysiologic assessments reported to date have been carried out during or immediately after IVOX utilization. It is recognized that IVOX indwelling in the venae cavae for up to 3 weeks could produce minor or unrecognized acute injury that could become more evident or more harmful after several weeks had elapsed following removal of the device. Therefore, this current study was designed and carried out to assess any pathophysiologic sequelae that could be recognized on follow-up examination 4 months after removal of an IVOX device that had been indwelling in the venae cavae for from 7 to 13 days. Extensive clinical and physiologic assessments of the blood, hemodynamics, and pulmonary functional status of 8 sheep were carried out 4 months after removal of IVOX devices that had been indwelling for 7 to 13 days. Each animal was then euthanized and complete necropsy examination was conducted looking especially for gross or histologic lesions in the venae cavae, access veins, right heart, and lungs. Findings indicated that all animals were normal, without clinically or pathologically significant pathophysiologic abnormalities or adverse effects from the IVOX utilization. Detailed hematologic, hemodynamic, blood chemistry, pulmonary function, and gross and histopathologic findings, presented in graphic, tabular, and photographic form, document the conclusion that utilization of an IVOX device in normal sheep for from 7 to 13 days produces no significant adverse late pathophysiologic sequelae.