Patent ID: 6953453

Claim:
A method for supplying a contrast medium to a patient's vascular system comprising: (a) providing a flexible bag filled with contrast medium at essentially atmospheric pressure; (b) operatively connecting said flexible bag to the patient's vascular system via a gas transfer system, said gas transfer system including: a dual check valve adapted to be connected to a lower pressure source of contrast medium, said dual check valve having a first inlet port, a first outlet port and a first inlet-outlet port, said dual check valve containing a first one-way valve at said first inlet port automatically responsive to the relatively low pressure at said first inlet-outlet port to permit downstream fluid flow and to prevent upstream fluid flow, said dual check valve containing a second one-way valve at said first outlet port automatically responsive to the relatively high pressure at said first inlet-outlet port to permit downstream fluid flow and to prevent upstream fluid flow, said first inlet-outlet port in communication with said first and second one-way valves and adapted to be connected to a pump, and a connecting tubular member having an upstream and a downstream end, said upstream end in communication with said first outlet port of said dual check valve; (c) purging said gas transfer system of air; and (d) delivering said contrast medium from said flexible bag through said gas transfer system to the patient's vascular system, the delivering step including: suctioning at said first inlet-outlet port by the pump to cause said first one-way valve to automatically open, allowing flow of contrast medium from said bag into the pump, and to cause said second one-way valve to automatically close, preventing fluid flow upstream from said connecting tubular member into the pump, and exerting positive pressure at said first inlet-outlet port from the pump to cause said second one-way valve to automatically open, allowing fluid flow from said pump into said tubular member, and to cause said first one-way valve to automatically close, preventing upstream fluid flow to the source; wherein said gas transfer system further comprises a first stopcock upstream of said first inlet port of said dual check valve to turn flow from the source on and off; wherein said gas transfer system further comprises a second stopcock on said downstream end of said tubular member to turn flow into the catheter on and off.