A device structured to generate an input signal to a monitor (201) to visually indicate a value for one or more physiological state variables measured by one or more transducers (203) associated with a medical patient. Preferred embodiments include a pressure transducer (195) placed in fluid communication with the patient's bladder (177) effective to infer intra-abdominal pressure P2. Embodiments may also include a temperature transducer (143) configured to measure the temperature of fluid in/near the bladder (177) to infer core body temperature. Certain embodiments of the invention may include a second pressure transducer (235) configured to measure arterial blood pressure. In the latter case, signals received from the two pressure transducers (177, 235) may be manipulated to produce a third signal corresponding to abdominal perfusion pressure, which can then be indicated on a numeric display device (233).