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

Kuroda, Yasuhiro; Murakami, Masuo; Tsuruta, Junko; Murakawa, T; Shiroyama, Yujiro; Sakabe, Takefumi

doi:10.1007/s005400070019

Cited by 10 publications

(5 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The interpretation of animal data is further complicated by the effects of anesthesia (Sicard et al, 2003). Isoflurane, which was employed in the above studies and many others (Hutchinson et al, 2006;Lu et al, 2009), is vasodilative and may modulate the vascular response in a spatially varying manner depending upon local vascular compositions (Kuroda et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

MRI measurement of the BOLD-specific flow–volume relationship during hypercapnia and hypocapnia in humans

2010

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 99%

MRI measurement of the BOLD-specific flow–volume relationship during hypercapnia and hypocapnia in humans

2010

View full text Add to dashboard Cite

“…Finally, the remarkable SNR in animal hemodynamic studies make them appealing for comparison with human data. However, the involvement of anesthesia can bias baseline hemodynamics in a way that varies with the anesthetic agent (53). The bias is expected to account for significant DCBV and DCBF fluctuations and must be considered before major conclusions regarding human hemodynamics are drawn based solely on evidence from animal studies.…”

Section: Discussionmentioning

confidence: 99%

BOLD‐specific cerebral blood volume and blood flow changes during neuronal activation in humans

2009

View full text Add to dashboard Cite

To understand and predict the blood-oxygenation level-dependent (BOLD) fMRI signal, an accurate knowledge of the relationship between cerebral blood flow (DeltaCBF) and volume (DeltaCBV) changes is critical. Currently, this relationship is widely assumed to be characterized by Grubb's power-law, derived from primate data, where the power coefficient (alpha) was found to be 0.38. The validity of this general formulation has been examined previously, and an alpha of 0.38 has been frequently cited when calculating the cerebral oxygen metabolism change (DeltaCMRo(2)) using calibrated BOLD. However, the direct use of this relationship has been the subject of some debate, since it is well established that the BOLD signal is primarily modulated by changes in 'venous' CBV (DeltaCBV(v), comprising deoxygenated blood in the capillary, venular, and to a lesser extent, in the arteriolar compartments) instead of total CBV, and yet DeltaCBV(v) measurements in humans have been extremely scarce. In this work, we demonstrate reproducible DeltaCBV(v) measurements at 3 T using venous refocusing for the volume estimation (VERVE) technique, and report on steady-state DeltaCBV(v) and DeltaCBF measurements in human subjects undergoing graded visual and sensorimotor stimulation. We found that: (1) a BOLD-specific flow-volume power-law relationship is described by alpha = 0.23 +/- 0.05, significantly lower than Grubb's constant of 0.38 for total CBV; (2) this power-law constant was not found to vary significantly between the visual and sensorimotor areas; and (3) the use of Grubb's value of 0.38 in gradient-echo BOLD modeling results in an underestimation of DeltaCMRo(2).

show abstract

“…It is therefore possible that the cerebrovascular resistance is slightly higher in nonexperimental settings. However, a counteracting effect of doxapram is possible as mild cerebral vasoconstriction has been reported after its use (27)(28)(29).…”

mentioning

confidence: 99%

Cerebral Pressure Autoregulation and Vasoreactivity in the Newborn Rat

et al. 2005

View full text Add to dashboard Cite

Perinatal brain injury has been associated with impaired cerebral blood flow (CBF) pressure autoregulation. The brain of 3-to 5-d-old rat pups is immature and similar to that of a preterm infant, and therefore we tested cerebral vasoreactivity in that animal. CBF pressure autoregulation was tested in 20 Wistar pups during normocapnia and hypercapnia, respectively. Hypotension was induced by hemorrhage and cerebral perfusion was monitored with laser Doppler flowmetry and near-infrared spectroscopy. Systolic blood pressure was measured noninvasively from the tail. During normocapnia, the autoregulatory plateau was narrow. Resting systolic blood pressure (SBP) was 39.2 mm Hg and CBF remained constant until SBP decreased below 36.0 mm Hg (SE 0.8). Below the lower limit, CBF declined by a mean of 2.7% per mm Hg [95% confidence interval (CI), 2.4 -3.0%], and hemoglobin difference (HbD) and total hemoglobin (HbT) changed proportionally to CBF. After inhalation of carbon dioxide, CBF increased significantly by a mean of 17.7% (95% CI, 13.7-22.8%). The CBF-CO 2 reactivity was estimated to 13.4% per kPa (95% CI, 2-24.8%), p ϭ 0.026. Over the range of SBP (6 -54 mm Hg), a linear relationship between CBF and SBP was found during hypercapnia, indicating abolished pressure autoregulation. A linear correlation between CBF and HbD was found (r ϭ 0.80). CBF pressure autoregulation and reactivity to CO 2 operate in the newborn rat. This model may be useful for future investigations concerning perinatal pathophysiology in the immature brain. In very preterm infants, brain injury has been associated with impaired pressure autoregulation of CBF. Accordingly, periventricular hemorrhage may result from abrupt hyperperfusion whereas periventricular leukomalacia has been related to ischemia (1-9).Cerebral pressure autoregulation refers to vascular mechanisms whereby CBF is held within constant levels during variations in perfusion pressure. Perfusion is thus maintained over a range of pressures by appropriate alterations in the diameter of precapillary arterioles. However, the lower limit of autoregulation is reached when the vessels become fully dilated and, beyond that point, any further decrease in pressure results in proportional drops in CBF. Several conditions may affect the autoregulatory plateau and increased CBF as well as complete pressure passiveness secondary to vasodilatation is observed during hypercapnia, hypoglycaemia, hypoxia, and seizure (10 -13).Cerebral pressure autoregulation has been documented in several newborn animals such as piglets, lambs, and puppies (14 -19). Most of these animals have rather mature brains at birth, and to compare vascular physiology with that of a preterm infant, the newborn rat pup served as a model (20,21). Because we could not control ventilation in this immature animal, we evaluated the cerebrovascular response to hemorrhagic hypotension during normocapnia and carbon dioxide inhalation. The hypothesis was that pressure autoregulation operates normally in the healthy immature brain. METH...

show abstract

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

Abstract: Deepening anesthesia from 0.5 to 1.0 MAC was maintained with no difference between the two agents during 4h of neurosurgery.

Cited by 10 publications

References 20 publications

MRI measurement of the BOLD-specific flow–volume relationship during hypercapnia and hypocapnia in humans

MRI measurement of the BOLD-specific flow–volume relationship during hypercapnia and hypocapnia in humans

BOLD‐specific cerebral blood volume and blood flow changes during neuronal activation in humans

Cerebral Pressure Autoregulation and Vasoreactivity in the Newborn Rat

Contact Info

Product

Resources

About