EFFECT OF ENTERAL FEEDING ON REGIONAL CO2 LEVELS IN NORMAL VOLUNTEERS

本项目的假设是，液体肠内喂养补充剂显着影响正常健康志愿者胃粘膜内二氧化碳水平（PgCO2）的测量。 其具体目的是评估是否可以通过胃张力计将肠内喂养给予胃腔，而不会显著影响胃局部CO2水平的测量。 这是一项初步研究，旨在检查胃肠道喂养对健康志愿者中张力计测量的PgCO2的影响。 将使用空气眼压测量系统，通过鼻胃插管将眼压计置于胃腔中，监测PgCO2水平。 在整个研究期间，将每15分钟自动监测并记录PgCO2水平。将使用Osmolite高氮（HN）进行肠内喂养。胃张力计是测量PgCO2水平的有用工具，这一点已得到充分证明。 研究表明，PgCO2显著增加，诱导内毒素血症和肠系膜血管闭塞，从而确定使用PgCO2作为内脏灌注的准确指标。 PgCO2也被证明是危重患者血流动力学管理的有用指南。 体外研究表明，PgCO2可用作组织氧合的治疗指标，作为疾病严重程度的预后值，并作为脓毒症患者使用多巴酚丁胺的指标。然而，肠内营养对眼压测量PgCO2的准确性的影响还没有系统的研究。 需要回答这个问题，肠内喂养的影响，压力计PgCO2水平的重要性在于准确评估危重病人的血流动力学稳定性与内脏灌注和耐受肠内喂养的能力。在正常志愿者中确定肠内喂养对PgOC 2水平的影响后，将对危重患者进行进一步研究。 一旦确定肠内喂养对正常和危重受试者的PgCO2压力的影响，最后一项研究将尝试利用PgCO2的测量来启动危重患者的早期肠内喂养。

The hypothesis of this project is that liquid enteral feeding supplements significantly affect the measurement of gastric intramucosal carbon dioxide levels (PgCO2) in normal healthy volunteers. The specific aim is to evaluate whether enteral feeding can be given into the stomach lumen via a gastric tonometer without significantly affecting the measurement of gastric regional CO2 levels. This is a pilot study to examine the effect of gastric enteral feeding on tonometrically measured PgCO2 in healthy volunteers. An air tonometry system will be utilized to monitor PgCO2 levels by a tonometer placed in the lumen of the stomach via nasogastric intubation. PgCO2 levels will be automatically monitored and recorded every 15 minutes throughout the study. Osmolite High Nitrogen (HN) will be utilized for enteral feeding. It has been well documented that the gastric tonometer is a useful tool in measurement of PgCO2 levels. Studies have demonstrated significant increases in PgCO2 with induction of endotoxemia and occlusion of the mesenteric vasculature, thus establishing the use of PgCO2 as an accurate indicator of splanchnic perfusion. PgCO2 has also been shown to be a useful guide to hemodynamic management of the critically ill. In vitro studies have demonstrated that PgCO2 can be utilized as a therapeutic index of tissue oxygenation, as a prognostic value for severity of illness, and as an index for the use of dobutamine in septic patients. However, the effect of enteral nutrition on the accuracy of tonometrically measured PgCO2 has not been studied systematically. The need to answer this question regarding the effect of enteral feeding on tonometered PgCO2 levels lies in the importance of accurately assessing the critically ill patient's hemodynamic stability related to splanchnic perfusion and ability to tolerate enteral feeding. After the effect of enteral feeding on the PgOC2 levels is established in normal volunteers, future studies will be conducted on critically ill patients. Once the effect of enteral feeding on tonometered PgCO2 is established for normal and critically ill subjects, the last study will attempt to utilize the measurement of PgCO2 to intiate early enteral feeding in the critically ill patient.