THE GASTRIC TONOMETER - A VALUABLE MONITOR OF SPLANCHNIC PERFUSION

Minimally invasive assessment of the adequacy of perfusion of the gast rointestinal tract has become clinically feasible with the availabilit y of the gastric tonometer. This modified nasogastric tube permits cal culation of the pH of the gut mucosal cells; a low tissue pH may indic ate tissue hypoxia due to regional hypoperfusion. Such regional hypope rfusion is often undetected by other monitors and, if it occurs intra- operatively, may result in a poor outcome following major surgery. In critical illness, the splanchnic area seems to be particularly vulnera ble to hypoperfusion and such a regional oxygen deficit is implicated in the causation of organ dysfunction/failure. Recent studies have beg un to define the circumstances in which splanchnic tissue acidosis dev elops and several therapies have been proposed to reverse the regional oxygen deficit. This review seeks to clarify whether or not the tonom eter is a valuable addition to our current monitoring aids.