Effects of dose-dependent levels of isoflurane on cerebral blood flow in healthy subjects studied using positron emission tomography

L. Schlünzen*, G. E. Cold, M. Rasmussen, M. S. Vafaee

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Background: In this study, we tested the hypothesis that escalating drug concentrations of isoflurane are associated with a significant decline in cerebral blood flow (CBF) in regions sub-serving conscious brain activity, including specifically the thalamus. Methods: Nine human volunteers received three escalating drug concentrations: 0.2, 0.4 and 1.0 MAC end-tidal inhalation. During waking, baseline and the three levels of sedation, a H2 15O PET scan was performed. Results: Isoflurane decreased the bispectral index (BIS) values dose-dependently. Cardiovascular and respiratory parameters were maintained constant over time. No significant change in global CBF was observed. Throughout all three MAC levels of sedation, isoflurane caused an increased regional cerebral blood flow (rCBF) in the anterior cingulate and decreased rCBF in the cerebellum. Initially, isoflurane (0 vs. 0.2 MAC) significantly increased relative rCBF in the medial frontal gyrus and in the nucleus accumbens. At the next level (0.2 vs. 0.4 MAC), relative rCBF was significantly increased in the caudate nucleus and decreased in the lingual gyrus and cuneus. At the last level (0.4 vs. 1 MAC), relative rCBF was significantly increased in the insula and decreased in the thalamus, the cuneus and lingual gyrus. Compared with flow distribution in awake volunteers, 1 MAC of isoflurane significantly raised relative activity in the anterior cingulate and insula regions. In contrast, a significant relative flow reduction was identified in the thalamus, the cerebellum and lingual gyrus. Conclusions: Isoflurane, like sevoflurane, induced characteristic flow redistribution at doses of 0.2-1.0 MAC. At 1 MAC of isoflurane, rCBF decreased in the thalamus. Specific areas affected by both isoflurane and sevoflurane included the anterior cingulate, insula regions, cerebellum, lingual gyrus and thalamus.

Original languageEnglish
Book seriesActa Anaesthesiologica Scandinavica
Volume50
Issue number3
Pages (from-to)306-312
Number of pages7
ISSN0001-5172
DOIs
Publication statusPublished - 1. Mar 2006

Fingerprint

Isoflurane
Regional Blood Flow
Gyrus Cinguli
Volunteers
Caudate Nucleus
Nucleus Accumbens
Pharmaceutical Preparations

Keywords

  • Anesthesia
  • Cerebral blood flow
  • Isoflurane
  • PET

Cite this

@article{c8f2f5d7d57a4d8ebcdf9a4cffeed586,
title = "Effects of dose-dependent levels of isoflurane on cerebral blood flow in healthy subjects studied using positron emission tomography",
abstract = "Background: In this study, we tested the hypothesis that escalating drug concentrations of isoflurane are associated with a significant decline in cerebral blood flow (CBF) in regions sub-serving conscious brain activity, including specifically the thalamus. Methods: Nine human volunteers received three escalating drug concentrations: 0.2, 0.4 and 1.0 MAC end-tidal inhalation. During waking, baseline and the three levels of sedation, a H2 15O PET scan was performed. Results: Isoflurane decreased the bispectral index (BIS) values dose-dependently. Cardiovascular and respiratory parameters were maintained constant over time. No significant change in global CBF was observed. Throughout all three MAC levels of sedation, isoflurane caused an increased regional cerebral blood flow (rCBF) in the anterior cingulate and decreased rCBF in the cerebellum. Initially, isoflurane (0 vs. 0.2 MAC) significantly increased relative rCBF in the medial frontal gyrus and in the nucleus accumbens. At the next level (0.2 vs. 0.4 MAC), relative rCBF was significantly increased in the caudate nucleus and decreased in the lingual gyrus and cuneus. At the last level (0.4 vs. 1 MAC), relative rCBF was significantly increased in the insula and decreased in the thalamus, the cuneus and lingual gyrus. Compared with flow distribution in awake volunteers, 1 MAC of isoflurane significantly raised relative activity in the anterior cingulate and insula regions. In contrast, a significant relative flow reduction was identified in the thalamus, the cerebellum and lingual gyrus. Conclusions: Isoflurane, like sevoflurane, induced characteristic flow redistribution at doses of 0.2-1.0 MAC. At 1 MAC of isoflurane, rCBF decreased in the thalamus. Specific areas affected by both isoflurane and sevoflurane included the anterior cingulate, insula regions, cerebellum, lingual gyrus and thalamus.",
keywords = "Anesthesia, Cerebral blood flow, Isoflurane, PET",
author = "L. Schl{\"u}nzen and Cold, {G. E.} and M. Rasmussen and Vafaee, {M. S.}",
year = "2006",
month = "3",
day = "1",
doi = "10.1111/j.1399-6576.2006.00954.x",
language = "English",
volume = "50",
pages = "306--312",
journal = "Acta Anaesthesiologica Scandinavica. Supplementum",
issn = "0515-2720",
publisher = "Wiley-Blackwell Munksgaard",
number = "3",

}

Effects of dose-dependent levels of isoflurane on cerebral blood flow in healthy subjects studied using positron emission tomography. / Schlünzen, L.; Cold, G. E.; Rasmussen, M.; Vafaee, M. S.

In: Acta Anaesthesiologica Scandinavica, Vol. 50, No. 3, 01.03.2006, p. 306-312.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Effects of dose-dependent levels of isoflurane on cerebral blood flow in healthy subjects studied using positron emission tomography

AU - Schlünzen, L.

AU - Cold, G. E.

AU - Rasmussen, M.

AU - Vafaee, M. S.

PY - 2006/3/1

Y1 - 2006/3/1

N2 - Background: In this study, we tested the hypothesis that escalating drug concentrations of isoflurane are associated with a significant decline in cerebral blood flow (CBF) in regions sub-serving conscious brain activity, including specifically the thalamus. Methods: Nine human volunteers received three escalating drug concentrations: 0.2, 0.4 and 1.0 MAC end-tidal inhalation. During waking, baseline and the three levels of sedation, a H2 15O PET scan was performed. Results: Isoflurane decreased the bispectral index (BIS) values dose-dependently. Cardiovascular and respiratory parameters were maintained constant over time. No significant change in global CBF was observed. Throughout all three MAC levels of sedation, isoflurane caused an increased regional cerebral blood flow (rCBF) in the anterior cingulate and decreased rCBF in the cerebellum. Initially, isoflurane (0 vs. 0.2 MAC) significantly increased relative rCBF in the medial frontal gyrus and in the nucleus accumbens. At the next level (0.2 vs. 0.4 MAC), relative rCBF was significantly increased in the caudate nucleus and decreased in the lingual gyrus and cuneus. At the last level (0.4 vs. 1 MAC), relative rCBF was significantly increased in the insula and decreased in the thalamus, the cuneus and lingual gyrus. Compared with flow distribution in awake volunteers, 1 MAC of isoflurane significantly raised relative activity in the anterior cingulate and insula regions. In contrast, a significant relative flow reduction was identified in the thalamus, the cerebellum and lingual gyrus. Conclusions: Isoflurane, like sevoflurane, induced characteristic flow redistribution at doses of 0.2-1.0 MAC. At 1 MAC of isoflurane, rCBF decreased in the thalamus. Specific areas affected by both isoflurane and sevoflurane included the anterior cingulate, insula regions, cerebellum, lingual gyrus and thalamus.

AB - Background: In this study, we tested the hypothesis that escalating drug concentrations of isoflurane are associated with a significant decline in cerebral blood flow (CBF) in regions sub-serving conscious brain activity, including specifically the thalamus. Methods: Nine human volunteers received three escalating drug concentrations: 0.2, 0.4 and 1.0 MAC end-tidal inhalation. During waking, baseline and the three levels of sedation, a H2 15O PET scan was performed. Results: Isoflurane decreased the bispectral index (BIS) values dose-dependently. Cardiovascular and respiratory parameters were maintained constant over time. No significant change in global CBF was observed. Throughout all three MAC levels of sedation, isoflurane caused an increased regional cerebral blood flow (rCBF) in the anterior cingulate and decreased rCBF in the cerebellum. Initially, isoflurane (0 vs. 0.2 MAC) significantly increased relative rCBF in the medial frontal gyrus and in the nucleus accumbens. At the next level (0.2 vs. 0.4 MAC), relative rCBF was significantly increased in the caudate nucleus and decreased in the lingual gyrus and cuneus. At the last level (0.4 vs. 1 MAC), relative rCBF was significantly increased in the insula and decreased in the thalamus, the cuneus and lingual gyrus. Compared with flow distribution in awake volunteers, 1 MAC of isoflurane significantly raised relative activity in the anterior cingulate and insula regions. In contrast, a significant relative flow reduction was identified in the thalamus, the cerebellum and lingual gyrus. Conclusions: Isoflurane, like sevoflurane, induced characteristic flow redistribution at doses of 0.2-1.0 MAC. At 1 MAC of isoflurane, rCBF decreased in the thalamus. Specific areas affected by both isoflurane and sevoflurane included the anterior cingulate, insula regions, cerebellum, lingual gyrus and thalamus.

KW - Anesthesia

KW - Cerebral blood flow

KW - Isoflurane

KW - PET

UR - http://www.scopus.com/inward/record.url?scp=33644995387&partnerID=8YFLogxK

U2 - 10.1111/j.1399-6576.2006.00954.x

DO - 10.1111/j.1399-6576.2006.00954.x

M3 - Journal article

C2 - 16480463

AN - SCOPUS:33644995387

VL - 50

SP - 306

EP - 312

JO - Acta Anaesthesiologica Scandinavica. Supplementum

JF - Acta Anaesthesiologica Scandinavica. Supplementum

SN - 0515-2720

IS - 3

ER -