The goal of this project is to develop a small, easily inserted intraesophageal probe containing three pH sensors, two pressure transducers, and a single liquid infusion channel. This probe will be low cost and durable, and safely and easily tolerated by most patients for up to 48 hours at home and at work. It will interface with a small, portable autoinfusion device and a portable, programmable microcomputer with multiple sensor inputs (including a patient event marker), capable of recording continuously for more than I week on a single battery charge.The proposed system will be useful for the evolution and management of gastroesophageal reflux and esophagitis, abnormal esophageal motility, obscure chest pain, pulmonary disease caused by silent esophageal reflux, sudden death syndrome, and obscure nocturnal attacks.Phase 11 will be directed toward clinical testing, validation, and design iterations.Institute Of Arthritis, Diabetes, And Digestive And Kidney Diseases