A pressure sensor, for example, employed by a medical injection system for monitoring blood pressure, is isolated from relatively high pressures by a volume of a compressible medium, preferably air, or other suitable gas. The volume fills an entirety of a cavity of a pressure transducer assembly, and is enclosed between a pressure transmission interface of the assembly and the pressure sensor. The pressure transducer assembly is integrated into a fluid circuit such that the pressure transmission interface is exposed to flow through the fluid circuit. The cavity of the assembly has a configuration that allows transmission of a patients blood pressure from the fluid circuit, via the interface and gas volume, to the pressure sensor, yet prevents transmission of the relatively high pressures, for example, injection pressures. The pressure transducer assembly may be part of a disposable fluid circuit subassembly, for example, packaged as a kit.
