AUTOMATED GAS DELIVERY SYSTEM FOR BLOOD GAS EXCHANGE DEVICES

A system for delivering oxygen to a gas permeable membrane oxygenator is disclosed. The system may include an integral source of gas under pressure and a source of vacuum. A first mass flow controller is connected to the source of gas upstream in the gas flow from the gas exchange device. A pressure valve is positioned in the gas flow between the first mass flow controller and the membrane oxygenator. An atmospheric vent is positioned between the pressure valve and the first mass flow controller. A second mass flow controller is positioned downstream from the gas exchange device and is connected to the source of vacuum. A central controller commands the pressure valve to maintain the pressure at the inlet of the gas exchange device at a subatmospheric pressure. The second mass flow controller is commanded to maintain a rate of flow which is desired through the gas exchange device. The first mass flow controller is commanded to maintain a rate of flow higher than the second mass flow controller to ensure that a sufficient flow of gas is available through the pressure valve and the gas exchange device. The excess gas is exhausted through the vent. The present invention ensures sufficient gas flow at the gas permeable membrane to provide transfer of gases with the blood. Also, the pressure of the gas within the membrane oxygenator is low enough that outgassing through the membrane of bubbles into the blood is avoided.