Increased gastric PCO2 during exercise is indicative of gastric ischaemia: a tonometric study

摘要

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 PCO2 during exercise can be used to detect clinically important gastric ischaemia.
Methods—Fourteen patients with unexplained abdominal pain or weight loss were studied. Splanchnic angiography served as the gold standard. Three patients were studied again after a revascularisation procedure. Gastric PCO2 was measured from a nasogastric tonometer, with 10 minute dwell times, and after acid suppression. Gastric and capillary PCO2 were measured before, during, and after submaximal exercise of 10 minutes duration.
Results—Seven patients had normal angiograms; seven had more than 50% stenosis in the coeliac (n=7) or superior mesenteric artery (n=4). Normal subjectsshowed no changes in tonometry. In patients with stenoses, the medianintragastric PCO2(PiCO2) 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 medianintragastric blood PCO2 gradient increased from0.0 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 supernormalvalues at peak exercise. The PCO2 gradientcorrelated with clinical and gastroscopic severity; in patientsreexamined after revascularisation (n=3), exercise tonometry returnedto normal.
Conclusion—Gastric tonometry duringexercise is a promising non-invasive tool for diagnosing and gradinggastrointestinal ischaemia and evaluating the results ofrevascularisation surgery for symptomatic gastric ischaemia.

Keywords:gastric ischaemia; tonometry; carbon dioxide; exercise test