The present invention is a system for monitoring a patient's breath chemistry comprising a plurality of components, including a self-condensing pH sensor distally mounted on a catheter, a transmitter with hydration sensing circuitry for the pH sensor, and, a processing receiver/data recorder. The specifically designed self-condensing pH sensor located on the distal end of the catheter is designed to be inserted into the patient's airway. Monitoring of a patient's breath pH is accomplished by using the miniaturized self-condensing pH sensor, providing for real-time monitoring of patient airway pH values.