Background Diagnosis of gastric ischaemia is difficult and angiography is an invasive procedure. Angiographic findings may not correlate with clinical importance.

Aims To investigate whether tonometric measurement of intragastric Pco ₂during exercise can be used to detect clinically important gastric ischaemia.

Results Seven patients had normal angiograms; seven had more than 50% stenosis in the coeliac (n=7) or superior mesenteric artery (n=4). Normal subjects showed no changes in tonometry. In patients with stenoses, the median intragastric Pco ₂(Pico ₂) at rest was 5.2 kPa (range 4.8–11.2) and rose to 6.4 kPa (range 5.7–15.7) at peak exercise; the median intragastric blood Pco ₂ gradient increased from 0.0 kPa (range −0.8 to 5.9) to 1.7 kPa (range 0.9 to 10.3; p<0.01). Only two subjects had abnormal tonometry at rest; all had supernormal values at peak exercise. The Pco ₂ gradient correlated with clinical and gastroscopic severity; in patients reexamined after revascularisation (n=3), exercise tonometry returned to normal.

Conclusion Gastric tonometry during exercise is a promising non-invasive tool for diagnosing and grading gastrointestinal ischaemia and evaluating the results of revascularisation surgery for symptomatic gastric ischaemia.