Desflurane induces more cerebral vasodilation than isoflurane at the same A‐line<sup>®</sup> autoregressive index level

Holmström, Anders; Åkeson, Jonas

doi:10.1111/j.1399-6576.2005.00697.x

Cited by 20 publications

(8 citation statements)

References 22 publications

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“…MAC changes with age, we presumed 1.7% isoflurane and 2.4% sevoflurane in postnatal 14 day rats was about 1.0 MAC according to the results of Orliaquet [32]. Anesthetics cause an intrinsic cerebral vasodilatory effect in a dose-dependent manner [33], [34]. One or 2 MAC of isoflurane and sevoflurane was demonstrated to increase mean cerebral blood flow (CBF) by autoradiography, compared with controls [35].…”

Section: Discussionmentioning

confidence: 98%

Physiological Disturbance May Contribute to Neurodegeneration Induced by Isoflurane or Sevoflurane in 14 Day Old Rats

You

et al. 2014

PLoS ONE

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BackgroundVolatile anesthetics are widely used in pediatric anesthesia but their potential neurotoxicity raise significant concerns regarding sequelae after anesthesia. However, whether physiological disturbance during anesthetic exposure contributes to such side effects remains unknown. The aim of the current study is to compare the neurotoxic effects of isoflurane and sevoflurane in 14 day old rat pups under spontaneous breathing or ventilated conditions.MethodsPostnatal 14 day rats were assigned to one of five groups: 1) spontaneous breathing (SB) + room air (control, n = 17); 2) SB + isoflurane (n = 35); 3) SB + sevoflurane (n = 37); 4) mechanical ventilation (MV) + isoflurane (n = 29); 5) MV + sevoflurane (n = 32). Anesthetized animal received either 1.7% isoflurane or 2.4% seveoflurane for 4 hours. Arterial blood gases and blood pressure were monitored in the anesthetized groups. Neurodegeneration in the CA3 region of hippocampus was assessed with terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling immediately after exposure. Spatial learning and memory were evaluated with the Morris water maze in other cohorts 14 days after experiments.ResultsMost rats in the SB groups developed physiological disturbance whereas ventilated rats did not but become hyperglycemic. Mortality from anesthesia in the SB groups was significantly higher than that in the MV groups. Cell death in the SB but not MV groups was significantly higher than controls. SB + anesthesia groups performed worse on the Morris water maze behavioral test, but no deficits were found in the MV group compared with the controls.ConclusionsThese findings could suggest that physiological disturbance induced by isoflurane or sevoflurane anesthesia may also contribute to their neurotoxicity.

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Section: Discussionmentioning

confidence: 98%

Physiological Disturbance May Contribute to Neurodegeneration Induced by Isoflurane or Sevoflurane in 14 Day Old Rats

You

et al. 2014

PLoS ONE

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“…Anesthesia caused vasodilation. (20–23) Therefore, the animal’s ability to cause vasoconstriction in the post-RF period seemed less probable. Note that the sham heated animals were unable to change the rate of temperature drop due to the vasoconstriction.…”

Section: Discussionmentioning

confidence: 99%

Radio frequency heating at 9.4T (400.2 MHz): In vivo thermoregulatory temperature response in swine

Shrivastava

Hanson

Kulesa

et al. 2009

Magnetic Resonance in Med

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In vivo thermoregulatory temperature response to radio frequency (RF) heating at 9.4T was studied by measuring temperatures in nine anesthetized swine. Temperatures were measured in the scalp, brain, and rectum. The RF energy was deposited using a four-loop head coil tuned to 400.2 MHz. Sham RF was delivered to three swine to understand the thermal effects of anesthesia (animal weight ‫؍‬ 54.16 kg, SD ‫؍‬ 3.08 kg). Continuous wave (CW) RF energy was delivered to the other six animals for 2. In vivo thermoregulatory temperature responses of mammalian brains to radio frequency (RF) heating are unknown for ultra-high-field magnetic resonance (UHF-MR) systems (i.e., the MR systems with the Larmor water proton resonance frequency Ն128 MHz). Studying these responses are necessary to develop appropriate RF safety guidelines for human MRI at the highest fields.RF heating is a function of an RF coil, head geometry, tissue types, blood flow, and the physiological status of a biological model (i.e., unanesthetized vs. anesthetized, drugged vs. undrugged, fever or no fever, etc.). However, live humans can not be used to study the thermoregulatory temperature responses of RF heating at UHFs. Therefore, animal models with thermoregulatory mechanisms similar to humans are needed to study physiological effects of a temperature change and temperature-time history. Perfused human cadavers are needed to determine RF heating. The results from the animal models and the human cadavers are needed to be interpreted together to improve human RF safety at the highest fields.Experimental data are scarce related to the brain RF heating and related safe temperature and RF power thresholds for MR applications. Studying the brain RF heating at UHFs, Shrivastava et al.(1) measured temperatures in anesthetized swine due to the heating from a 400.2 MHz (9.4T) head volume coil. Spatially unique correlations were reported between the whole-head average specific absorption rate (SAR) (or RF power per unit head weight) and the maximum brain and rectal temperature changes during RF heating (1). Alterations to the thermoregulatory temperature responses due to the RF heating were not studied.Studying thermal effects of RF heating due to volume head coils at lower fields (64 MHz, 1.5T), Barber et al. (2) measured temperatures in anesthetized sheep. Sheep were exposed to the whole-head average SAR of 4 W/kg for an average of 75 min. Skin and eye temperatures increased to about 1.5°C. Jugular vein and rectal temperatures rose by 0.4°C and 0.19°C, respectively. No alterations to the thermoregulatory temperature responses due to the RF heating were reported.Shellock and Crues (3,4) measured forehead skin, corneal, and body (sublingual pocket) temperatures in unanesthetized humans before and after clinical spin echo sequences. Average whole-body SAR of 0.06 W/kg was employed for the maximum of 8.67 min. Statistically significant temperature changes were measured in the skin (0.2°C) and cornea (0.5°C). In another study on humans with similar pulse sequences, ...

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“…A minimal or total lack of effect on anaesthetic depth monitors is seen with opiates and nitrous oxide (12, 13). The reliability of clinical signs such as blood pressure will also vary with different drug agents (14). Recently a meta‐analysis confirmed the overall positive effects of EEG‐monitored anaesthesia (15).…”

Section: Discussionmentioning

confidence: 99%

Cerebral state index response to incision: a clinical study in day‐surgical patients

Anderson

Jakobsson

2006

Acta Anaesthesiol Scand

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Desflurane induces more cerebral vasodilation than isoflurane at the same A‐line^® autoregressive index level

Cited by 20 publications

References 22 publications

Physiological Disturbance May Contribute to Neurodegeneration Induced by Isoflurane or Sevoflurane in 14 Day Old Rats

Physiological Disturbance May Contribute to Neurodegeneration Induced by Isoflurane or Sevoflurane in 14 Day Old Rats

Radio frequency heating at 9.4T (400.2 MHz): In vivo thermoregulatory temperature response in swine

Cerebral state index response to incision: a clinical study in day‐surgical patients

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Desflurane induces more cerebral vasodilation than isoflurane at the same A‐line® autoregressive index level

Cited by 20 publications

References 22 publications

Physiological Disturbance May Contribute to Neurodegeneration Induced by Isoflurane or Sevoflurane in 14 Day Old Rats

Physiological Disturbance May Contribute to Neurodegeneration Induced by Isoflurane or Sevoflurane in 14 Day Old Rats

Radio frequency heating at 9.4T (400.2 MHz): In vivo thermoregulatory temperature response in swine

Cerebral state index response to incision: a clinical study in day‐surgical patients

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Desflurane induces more cerebral vasodilation than isoflurane at the same A‐line^® autoregressive index level