Esophageal P CO 2 as a monitor of perfusion failure during hemorrhagic shock

Sato, Yoji, Max Harry Weil, Wanchun Tang, Shijie Sun, Jianlin Xie, Joe Bisera, and Hidehiro Hosaka. Esophageal[Formula: see text] as a monitor of perfusion failure during hemorrhagic shock. J. Appl. Physiol. 82(2): 558–562, 1997.—Measurement of gastric wall [Formula: see text]([Formula: see text]) by tonometric method has emerged as an attractive option for estimating visceral perfusion during circulatory shock. However, gastric acid secretion obfuscates the tonometric measurement. We, therefore, investigated the option of measuring[Formula: see text] in the esophagus to minimize these restraints. Hemorrhagic shock was induced in five Sprague-Dawley rats, and five rats served as sham controls.[Formula: see text] was measured with an ion-sensitive field effect transistor that was surgically implanted into the gastric wall. Esophageal luminal[Formula: see text]([Formula: see text]) was measured by a second ion-sensitive field effect transistor sensor. During hemorrhagic shock, mean aortic pressure declined from 150 to 50 mmHg. Gastric blood flow decreased from 58 to 12 ml ⋅ min −1 ⋅ 100 g −1 (21% of preshock) and esophageal blood flow from 44 to 7 ml ⋅ min −1 ⋅ 100 g −1 (16% of preshock).[Formula: see text]simultaneously increased from 47 to 116 Torr and[Formula: see text] from 47 to 127 Torr. The increases in[Formula: see text] were highly correlated with increases in[Formula: see text]( r = 0.90). Esophageal tonometry may, therefore, serve as a practical alternative to gastric tonometry.