脳外科手術患者におけるエンフルレン，イソフルレン，ジアゼパム-フェンタニール麻酔中の脳皮質血流量のCO₂反応性

Abstract

Background : Effects of the CO₂ reactivity on cortical cerebral blood flow (CBF) have not been investigated by non-invasive, non-radioactive procedure in clinical aneshesia (enflurane, isoflurane and diazepam-fentanyl). The purpose of this study is to evaluate the cortical CBF and CO₂ reactivity under anesthesia with a thermal clearance method. Materials and Methods : The CBF were determined by principle of Peltier's effect (thermal clearance method) in 26 patients who have been anesthetized and undergone neurosurgery. The CO₂ reactivities were measured at the clinical steady state of PaCO₂ levels : 35mmHg, 40mmHg and 45mmHg during enflurane (n=8), isoflurane (n=9) and diazepam-fentanyl (n=9)anesthesia, respectively. Results : The CO₂ reactivities of cortical CBF were well maintained during all anesthesia. The slopes of regression line (ΔCBF vs ΔPaCO₂) were 2.74ml・100g⁻¹・min⁻¹・mmHg⁻¹ (enflurane), 1.17ml・100g⁻¹ ・min⁻¹・mmHg⁻¹ (isoflurane) and 1.01ml・100g⁻¹・min⁻¹・mmHg⁻¹ (diazepam-fentanyl). Conclusion : These results suggest that in neurosurgery under enflurane, isoflurane anesthesia, it should be cared for the great reduction of CBF induced by hypocapnic cerebrovascular reactivity.