Evaluation of a new catheter for esophageal pH monitoring.

A new catheter, provided with an Ion Sensitive Field Effect Transistor as a pH sensor and incorporating a reference electrode, was evaluated for esophageal pH recording. The pH-sensitivity was 54 mV/pH in vitro, with a linear response between pH 2 and pH 9. Clinical semi-ambulatory 24-hour esophageal pH recordings were carried out in 6 adults and 15 infants. System drift after 24-hour in vivo recording was 0.14 pH units +/- 0.10 pH units, and -0.01 pH units +/- 0.10 pH units, in pH 4.0 and pH 7.0 calibration solution, respectively, in the pediatric group (n = 15). It is concluded that the reusable catheter combines accurate esophageal pH monitoring with optimum patient comfort.