Oxygen overpressure protection system for membrane-type blood oxygenators

Claim 2

In an oxygen and blood delivery system for use in conjunction with a membrane-type blood oxygenator having a blood inlet and outlet and an oxygen inlet and outlet for diffusion therebetween across a porous, hydrophobic membrane, the improvement comprising: blood and oxygen conduit means for operatively communicating with said respective blood and oxygen inlets and outlets of said oxygenator, and for conveying such materials to and from said oxygenator; means for carrying a flexible blood reservoir in a position elevated above the position of said oxygenator, receptacle means, open to the atmosphere, for containing a liquid; an oxygen line having one end thereof disposed within said receptacle means, for immersion in liquid disposed in said receptacle means to create a predetermined pressure head at said one end, said oxygen line communicating with said oxygen conduit means, whereby the oxygen pressure in said conduit means is limited in a manner dependent upon said predetermined pressure head.

Claim 3

The system of claim 3 in which means are provided for assuring a continuous minimum blood pressure comprising the further improvement in said oxygenator.

Claim 4

The system of claim 4 comprising the further improvement in which said oxygen line communicates with said gas conduit means upstream from said oxygenator.

Claim 5

In an extracorporeal oxygenation system in which oxygen and carbon dioxide are transferred across a membranous barrier separating the blood and the oxygen, said oxygenator having a blood inlet, a blood outlet, and an oxygen inlet and outlet; the improvement comprising, in combination: a blood reservoir coupled to said blood outlet downstream therefrom, said blood reservoir being positioned at a higher level than said blood outlet to provide to blood adjacent the membranous barrier a predetermined minimum pressure; and manometer means which comprises a liquid container, open to the atmosphere, being at least partially filled with a liquid; an oxygen supply line coupled to said oxygen inlet, venting conduit means coupled with said oxygen line and communicating with said liquid within said container and having an outlet therein, said liquid having a level that is selected to provide a pressure at said venting conduit means outlet but to permit the venting of the oxygen in order to prevent the pressure of the oxygen from exceeding said minimum pressure of said blood, and further including second manometer means coupled to the blood inlet line, said second manometer means being also operatively connected to said liquid in the container, and responsive to the pressure of the blood in said blood inlet line to automatically adjust the level of said liquid in said container.