Gastrointestinal Tonometry: Methodological Considerations with Use of Fluid and Air

Methodological aspects of gastrointestinal tonometry are reviewed. First, we will discuss the relation between ischemia of the gastrointestinal tract and PCO2 and pHi and the influence of acid suppression and food intake on PiCO2. Thereafter we will focus on the sources of error when using fluid filled tonometers for PiCO2 assessment. Blood gas analyzer bias, dead space effects, precision, speed of measurement and the potentially large accidental errors will be discussed. Finally, the potential advantages of air tonometry will be mentioned. Gastrointestinal tonometry - air-tonometry - tonometer fluids - Biasprec…