Decreases in mesenteric blood flow associated with increases in sublingualPCO2 during hemorrhagic shock

We investigated relationships between visceral blood flow, intestinal wall carbon dioxide tension (PCO2), and sublingual PCO2 during hemorrhagic shock . In five pigs, cardiac output declined 81% and superior mesenteric blood f low 77% during hemorrhage. Duodenal PCO2 increased from an average of 50 to 121 mmHg and sublingual PCO2 concurrently increased from an average of 46 to 101 mmHg. Within 60 min after reinfusion of shed blood, duodenal and sub lingual PCO2 returned to baseline values. Decreases in mesenteric blood flo w were correlated with increases in sublingual (r= 0.91; P < 0.001) and duo denal (r = 0.89; P < 0.001) tissue PCO2. In five randomized "sham hemorrhag e" control animals, neither decreases in cardiac output or mesenteric blood flow nor increases in duodenal or sublingual PCO2 were observed. Decreases in mesenteric blood flow during hemorrhage were therefore associated with early and comparable increases in tissue PCO2 in both visceral and sublingu al sites.