Studies on intragastric PCO2 at rest and during exercise as a marker of intestinal perfusion in patients with chronic heart failure

Aims: The aim of this study was to investigate mesenteric ischaemia by determining intragastric PCO₂ (iPCO₂) with gastric tonometry during rest and exercise stress testing in patients with chronic heart failure (CHF). In CHF inflammatory immune activation is hypothesized to result from a chronic endotoxin challenge due to bacterial translocation of hypoperfused intestinal mucosa. Methods and Results: In 10 patients with CHF and ten healthy controls a tonometry catheter was inserted into the stomach. IPCO₂ was measured at rest and during bicycle exercise every 5 min. At rest arterial pCO₂ (aPCO₂), intragastric pCO ₂ (iPCO₂) and the intragastric/arterial gap did not differ between patients and controls. During low level exercise (25 W), patients showed an increase in iPCO₂ compared to resting iPCO₂, whereas controls did not show an increase in iPCO₂ (change in iPCO₂: 12±2% vs. 1±0.4%, P2 during peak exercise was 25±3% higher than at rest, compared to controls (increase 2±1, P2. This is likely to reflect hypoperfusion of the intestinal mucosa, which may contribute to the development of bacterial translocation.