Knichwitz G, Brüssel T
Klinik für Anästhesiologie und operative intensivmedizin, Westf. Wilhelms-Universität Münster.
Anasthesiol Intensivmed Notfallmed Schmerzther. 1997 Aug;32(8):479-87. doi: 10.1055/s-2007-995096.
The improvement of tissue perfusion by alterations in global parameters has led to the concept of supranormal oxygen delivery. However, this approach did not cause a significant reduction in the mortality of critical illness. As a consequence, recent research activity concentrates on regional monitoring and on the therapy of especially vulnerable, injury-prone organ systems. Gastric tonometry, a monitoring device of the gastrointestinal region that has produced promising results, can be considered as an area of special attention. The intramucosal pCO2 (piCO2) and the calculated intramucosal pH (pHi) of gastric tonometry can indicate an impairment of the gastrointestinal perfusion and thus point to an immanent injury of the barrier function of the gut mucosa. In clinical practice, however, apart from several technical problems with conventional, discontinuous gastric tonometry, some misconceptions exist in respect of the interpretation of derived pHi data. The technical problems can be overcome by a new fibreoptic piCO2 measurement, an automatic and continuous technique. The analysis of the obtained data must take the physiology of the CO2- and HCO3(-)-metabolism into account. Coupling of the locally derived piCO2 with systemic arterial HCO3- concentration that results in the pHi as the sensitive parameter of the gastrointestinal malperfusion as suggested by Fiddian Green, is not correct. Taking respiratory pCO2 changes into consideration, only the PiCO2 can detect gastrointestinal malperfusion. Therefore, the rather confusing terms "gastric tonometry" and "pHi measurement" should be avoided and the new monitoring technique be defined as "intramucosal pCO2 measurement". Continuous piCO2-measurement is a monitoring technique with high sensitivity in detecting gastrointestinal hypoperfusion based on an intramucosal CO2 accumulation. The clinical significance of the primary parameter piCO2 as well as the suitability of this technique as a monitoring tool for the daily routine must be re-assessed.
通过改变整体参数来改善组织灌注催生了超常氧输送的概念。然而，这种方法并未显著降低危重病的死亡率。因此，近期的研究活动集中在区域监测以及对特别脆弱、易损伤的器官系统的治疗上。胃张力测定法作为一种在胃肠道区域监测中取得了有前景结果的监测手段，可被视为一个特别受关注的领域。胃张力测定法的黏膜内二氧化碳分压（piCO2）和计算得出的黏膜内pH值（pHi）能够表明胃肠道灌注受损，进而提示肠黏膜屏障功能存在潜在损伤。然而在临床实践中，除了传统的间断性胃张力测定法存在的一些技术问题外，对于所导出的pHi数据的解读也存在一些误解。一种新型的光纤piCO2测量技术，即一种自动且连续的技术，可以克服这些技术问题。对所获数据的分析必须考虑二氧化碳和碳酸氢根代谢的生理学原理。按照菲迪安·格林的建议，将局部得出的piCO2与全身动脉血碳酸氢根浓度相结合来得出作为胃肠道灌注不良敏感参数的pHi是不正确的。考虑到呼吸性二氧化碳的变化，只有PiCO2能够检测出胃肠道灌注不良。因此，应避免使用相当令人困惑的术语“胃张力测定法”和“pHi测量”，而将这种新的监测技术定义为“黏膜内pCO2测量”。连续的piCO2测量是一种基于黏膜内二氧化碳蓄积来检测胃肠道灌注不足的高灵敏度监测技术。必须重新评估主要参数piCO2的临床意义以及该技术作为日常监测工具的适用性。
