Abstract

BACKGROUND: The aim of our research was to evaluate the influence of generalanesthesia with controlled nitroglycerin-induced hypotension on splanchnic mucosal perfusion using gastrictonometry. MATERIAL/METHODS: In six patients (1 female, 5 males, median age 46 years, range 32-62) undergoingelective resection of meningiomas, measurements of gastric mucosal perfusion were taken by nasogastrictonometry. Controlled hypotension was initiated after craniotomy and terminated prior to hemostasis procedures.The mean arterial blood pressure (MAP) was maintained 25-30% below initial parameters during controlledhypotension. The adequacy of perfusion was defined by the intramucosal pH (pHi) and the difference betweenarterial and intramucosal pH (pHGAP). All parameters were analyzed before the induction of controlledhypotension, after the 1st, 2nd, and 3rd hour, and 1 hour after the termination of controlled hypotension.RESULTS: The MAP decreased during controlled hypotension by ca. 26.5% (min. 21.1%; max 31.6%). The lowerMAP was accompanied by a statistically significant increase in heart rate. A significant increase frombaseline in regional prCO2 was seen after the 1st, 2nd, and 3rd hour of controlled hypotension. IntramucosalpH values decreased significantly during the same period, from 7.428+/-0.032 to 7.372+/-0.015. Despitethese statistically significant differences during controlled hypotension, the pHi values were alwaysgreater than 7.35, and the pHGAP values were lower than 0.05, which were recognized as being within thenormal range. CONCLUSIONS: Controlled hypotension allows accurate evaluation of the blood flow qualityat the level of microcirculation. Mild controlled hypotension slightly alters splanchnic mucosal perfusion,but does not lead to ischemia and hypoxia in tissues.

Keywords: Anesthetics, Anoxia, Blood Pressure, Hydrogen-Ion Concentration, Hypotension, Ischemia, Oxygen, Perfusion, Splanchnic Circulation, Stomach, Tonometry, Ocular