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R Barthelemy

Publications and source records attributed to R Barthelemy.

At least 19 recordsLinked to original sources

[Heart-lung preservation: historical evolution and current research data].

Over the past decade, combined, heart-lung transplantation has been established as a therapeutic modality for many patients with end stage cardiopulmonary disease. However, the scarcity of suitable donors and the lack of a reliable and simple technique for distant organ procurement have somewhat limited its practice. The normothermic autoperfusion preparation has been utilized in a few satisfactory distant heart-lung preservation and subsequent transplantation, but this method is rather cumbersome. Single cold flush perfusion of the pulmonary artery with infusion of prostaglandin E1, a powerful vasodilator of the pulmonary bed, has been used successfully in heart-lung preservation for transplantation. Donor core-cooling through cardiopulmonary bypass without pulmonary artery flush perfusion appears to provide longer and better graft protection since it improves its function. The production of oxygen radicals after reperfusion of ischemic tissues has important implications in organ preservation and transplantation. Recent studies in the prevention of reperfusion injury indicate that enzymatic scavenger and iron chelator therapy may play an important role in the reduction of reperfusion injury in the clinical setting of heart-lung transplantation.

Cryopreservation

Automatic modules for extracorporeal circulation control.

Maintenance of a constant level in the oxygenator during surgical extracorporeal circulation (ECC) is of paramount importance. We propose a device able to regulate the pump speed accordingly to the level in the oxygenator, and an automatic clamp to control venous return from the patient. The level regulator permits pump speed control and also stops the pump when a prefixed low level is reached (during ECC). Linearization of the level sensor has been made in order to optimize the PI regulator. Simulation results are presented and the regulator is evaluated in a clinical environment. The automatic clamp provides a good solution for reproducible and easy transitions in venous return. When coupled with the level regulator, the pump speed will increase automatically from zero to the correct equilibrium speed, with variable duration (from 30 seconds to 5 minutes) chosen by the operator. The same technique is used for stopping the ECC. These two devices are, in fact, modules, making up part of an evolutive device for ECC automation. The modules can exchange data with a supervising microcomputer.

Automation