Studies on Intragastric PCO2 at Rest and During Exercise as a Marker of Intestinal Perfusion in Patients with Chronic Heart Failure

Abstract

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 pCO2 (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%, P<0.001). In CHF, iPCO2 during peak exercise was 25±3% higher than at rest, compared to controls (increase 2±1, P<0.0001). Conclusions: Patients with CHF already at low level exercise develop an increase in iPCO2. This is likely to reflect hypoperfusion of the intestinal mucosa, which may contribute to the development of bacterial translocation.