Intramucosal–arterial PCO₂ gap does reflect tissue dysoxia

Excerpt

In their recent paper, Dubin and coworkers [1] subjected anaesthetized, paralyzed sheep to decreases in oxygen delivery either by progressive bleeding (ischaemic hypoxia [IH] group) or by decreasing oxygen saturation (hypoxic hypoxia [HH] group). They found substantial increases in mesenteric venous–arterial blood partial carbon dioxide tension (PCO₂) gradient (ΔPCO₂) in the IH group, whereas ΔPCO₂ remained unchanged both in the HH and in a sham operated control group. The authors concluded that intestinal tonometry has limited value in detecting the presence of anaerobic metabolism in tissues. Dubin and colleagues should be congratulated on the soundness and quality of their experiments, but in our opinion the conclusion of the study may be at odds with the data presented. …