A multi-lumen catheter for monitoring intra-abdominal pressure, the catheter including an expandable outer balloon and an expandable inner balloon positioned within the outer balloon. A first lumen communicates with the inner balloon and the inner balloon and first lumen are filled with gas to form a gas filled chamber to monitor pressure within the bladder to thereby monitor pressure within an abdomen of the patient. A second lumen communicates with the bladder to remove fluid from the bladder. The catheter is configured for attachment of an external pressure transducer communicating with the gas filled chamber for measuring bladder pressure based on gas compression caused by deformation of the expanded inner balloon deformed by the expanded outer balloon.
