Walley K R, Friesen B P, Humer M F, Phang P T
Program of Critical Care Medicine, Department of Surgery and Pulmonary Research Laboratory, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada V6Z 1Y6.
J Appl Physiol (1985). 1998 Nov;85(5):1770-7. doi: 10.1152/jappl.1998.85.5.1770.
Gastric tonometer PCO2 measurement may help identify gut ischemia in critically ill patients but is frequently associated with large measurement errors. We tested the hypothesis that small bowel tonometer PCO2 measurement yields more accurate information. In 10 anesthetized, mechanically ventilated pigs subject to progressive hemorrhage, we measured gut oxygen delivery and consumption. We also measured tonometer PCO2 minus arterial PCO2 (DeltaPCO2) and calculated the corresponding intracellular pH from tonometers placed in the stomach and jejunum. We found that the correlation coefficient (r2) for biphasic gut oxygen delivery-DeltaPCO2 relationships was 0.29 +/- 0.52 for the gastric tonometer vs. 0.76 +/- 0.25 for the small bowel tonometer (P < 0.05). In addition, the critical gastric tonometer DeltaPCO2 was excessively high and variable (62.9 +/- 39.6) compared with the critical small bowel tonometer DeltaPCO2 (17.0 +/- 15.0, P < 0.01). Small bowel tonometer PCO2 was closely correlated with superior mesenteric vein PCO2 (r2 = 0.81, P < 0.001), whereas gastric tonometer PCO2 was not (r2 = -0.13, P = not significant). We conclude that measurement of gastric tonometer PCO2 yields excessively noisy and inaccurate data on the onset of gut anaerobic metabolism in hemorrhagic shock. Small bowel tonometer PCO2 is less noisy and, as a result, is superior in detecting gut hypoperfusion and the onset of anaerobic metabolism.
胃张力计测量PCO₂ 可能有助于识别危重症患者的肠道缺血，但常伴有较大的测量误差。我们检验了这样一个假设，即小肠张力计测量PCO₂ 能产生更准确的信息。在10头接受渐进性出血的麻醉、机械通气猪中，我们测量了肠道氧输送和氧消耗。我们还测量了张力计PCO₂ 减去动脉PCO₂（ΔPCO₂），并根据置于胃和空肠的张力计计算了相应的细胞内pH值。我们发现，胃张力计的双相肠道氧输送-ΔPCO₂ 关系的相关系数（r²）为0.29±0.52，而小肠张力计为0.76±0.25（P<0.05）。此外，与关键小肠张力计ΔPCO₂（17.0±15.0，P<0.01）相比，关键胃张力计ΔPCO₂ 过高且变化大（62.9±39.6）。小肠张力计PCO₂ 与肠系膜上静脉PCO₂ 密切相关（r² = 0.81，P<0.001），而胃张力计PCO₂ 则不然（r² = -0.13，P无统计学意义）。我们得出结论，胃张力计测量PCO₂ 关于出血性休克中肠道无氧代谢起始的数据过于嘈杂且不准确。小肠张力计PCO₂ 的噪声较小，因此在检测肠道低灌注和无氧代谢起始方面更具优势。
