摘要 |
Type-A (operational) and type-B (non-operational) syringes (2A, 2B), used for double-blind clinical tests, are constructed so the type-B syringe mimics the operation of the type-A syringe while avoiding the delivery of anything into the patient. Each syringe includes an injector (4), a fluid connector (12) coupling the exit port (10) of the injector to a discharge port (14) to which a catheter or needle cannula is connected, a valve (18) positioned along the fluid connector, and a dumping reservoir (24) mounted to the valve. The type-A valve fluidly couples the exit port to the discharge port in both purging and infusion positions. The type-B valve couples the exit port to the discharge port in the purging position, but couples the exit port to the dumping reservoir in the infusion position. The infusate is directed through the catheter and into the patient when in the infusion position with the type-A valve but is directed into the dumping reservoir with the type-B valve.
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