A catheter insertable into a patient for monitoring pressure having an expandable outer balloon. An expandable inner balloon is positioned within the lumen of the catheter and has having a second outer wall and forms a gas chamber to monitor pressure within the patient. In response to pressure exerted on the outer wall of the outer balloon, fluid within the outer balloon enters an opening in the wall of the catheter lumen to exert a pressure on the outer wall of the expanded inner balloon to deform the inner balloon and compress the gas within the inner balloon. A pressure sensor communicates with the gas containing chamber for measuring pressure based on compression of gas caused by deformation of the expanded inner balloon resulting from deformation of the expanded outer balloon.
