Gastrointestinal Tonometry: Basic Principles and Recent Advances in Monitoring Regional CO₂ Metabolism

Abstract

In the quest to improve outcome in critically ill patients, clinicians have embraced many monitoring modalities in the hope that the sheer quantity of data would assist in the detection and treatment of pathophysiological derangements. Gastrointestinal tonometry has been used increasingly in both the basic science laboratory and the critical care unit, as demonstrated by its mention in more than 800 publications in the medical literature. Tonometric determination of regional PCO₂ is becoming more and more available for clinical use in the intensive care unit (ICU) setting. As reflected by its reluctant acceptance in some circles, however, questions remain surrounding the optimal use of gastrointestinal tonometry and its applications in clinical medicine. This review discusses the physiological basis for using tonometry, as well as many of the studies supporting its role as a monitor of perfusion and local oxidative metabolism.

Key Words:

Gastric tonometry - hypoxia - oxygen transport