DOES GASTRIC TONOMETRY WORK - NO

Gastrointestinal tonometry is supposed to diagnose gut mucosal hypoxia using gastric luminal PCO2 and arterial bicarbonatemia, which are sub stituted in a modified Henderson-Hasselbach equation. This article rev iews some of the problems inherent to the multiple assumptions underly ing this technique. Tonometry is influenced by several local factors a nd by systemic acid-base imbalances that are unrelated to oxygenation. Tonometry is a rather crude and cumbersome method of gut capnometry, a technology that may provide valuable information regarding visceral perfusion, but not necessarily oxygenation.