Preservation of the Ratio of Cerebral Blood Flow/Metabolic Rate for Oxygen during Prolonged Anesthesia with Isoflurane, Sevoflurane, and Halothane in Humans

Abstract

These results demonstrate that CBF/CMRO2 ratio is markedly increased above normal and maintained during prolonged inhalation of volatile anesthetics in humans. It is impossible to determine whether these data indicate a stable CBF or whether CBF and CMRO2 are changing in parallel during the observation period. The unchanging electroencephalographic pattern suggests that the former possibility is more likely and that the increase of CBF produced by volatile anesthetics is maintained over time without decay, which has been reported in several animal studies. It also is suggested that isoflurane possesses greater capability to maintain global CBF relative to CMRO(2) than does halothane or sevoflurane. time.)

Effects of Long-Duration Administration of 1% Isoflurane on Resting Cerebral Blood Flow and Default Mode Network in Macaque Monkeys

“…Isoflurane duration-induced CBF decrease was not observed in prior studies of adults with 1.5 MAC (Kuroda et al, 1996(Kuroda et al, , 1997, children with 1 MAC (Bisonnette and Leon, 1992) (over 3 h), and dogs with 1% isoflurane for 3-4 h (Roald et al, 1989). In particular, increased CBF was seen in the forebrain and hindbrain of cynomolgus monkeys with 1 MAC isoflurane for 4 h reported by McPherson et al (1994), different from the present findings.…”

The effects of Patent Blue dye on peripheral and cerebral oxyhaemoglobin saturations

“…The greater and more prolonged depression For example, the dye may be stored in brain tissues for a long time, and only slowly released into the cerebral venous system. Sevoflurane is a potent cause of cerebral vasodilation [11] that is usually accompanied by increased cerebral blood flow [16]. On the other hand, propofol has no direct effect on cerebral vessels [12] and its administration is usually accompanied by decreased cerebral blood flow [17].…”

Effects of sevoflurane and isoflurane on the ratio of cerebral blood flow/metabolic rate for oxygen in neurosurgery

“…In non-neurosurgical patients, V mca was reported to be decreased by 20% at 1.2 MAC sevoflurane anesthesia [2]. At 1.5 MAC, we previously found that sevoflurane had a significantly smaller CBF equivalent than isoflurane in non-neurosurgical patients [3]. This could be because, in comparison with isoflurane, sevoflurane has a smaller metabolic depressive effect relative to vasodilating effect at 1.5 MAC.…”

“…In patients not undergoing neurosurgery, the mean flow velocity in the middle cerebral artery (V mca ) was decreased under 1.2 MAC sevoflurane [2]. In our previous study [3], performed in non-neurosurgical patients under sevoflurane and isoflurane, we found that the CBF equivalent (CBF divided by CMR o2 ) significantly increased in a dose-dependent manner (0.5, 1.0, and 1.5 MAC), and that the increase in CBF equivalent was maintained with minimal fluctuation for 3 h at 1.5 MAC. In that study at 1.5 MAC, the CBF equivalent in the sevoflurane group was significantly smaller than that in the isoflurane group.…”