Arousal Effect of Afferent Discharges From Muscle Spindles Uron Electroencephalograms in Cats

Motokizawa, Fumiaki; Fujimori, Bunichi

doi:10.2170/jjphysiol.14.344

Cited by 26 publications

(17 citation statements)

References 18 publications

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“…Secondly, neuraxial block reduces the anesthetic requirement to suppress movement in response to a noxious stimulus above the level of sensory block. The afferentation theory proposes that tonic sensory and muscle-spindle activity modulate cerebral activity and maintain a state of wakefulness, and decreased afferent input to the brain could lessen the excitatory descending modulation of the spinal cord motoneurons and suppress motor function [19-21]. Through these mechanisms, caudal block could reduce the sevoflurane requirement for LMA removal despite the fact that caudal block does not have a direct analgesic effect on the upper airway.…”

Section: Discussionmentioning

confidence: 99%

Caudal analgesia reduces the sevoflurane requirement for LMA removal in anesthetized children

Kim

Park

Lee

et al. 2010

Korean J Anesthesiol

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BackgroundAn anesthetic state can reduce adverse airway reaction during laryngeal mask airway (LMA) removal in children. However, the anesthetic state has risks of upper airway obstruction or delayed emergence; so possibly less anesthetic depth is advisable. Caudal analgesia reduces the requirement of anesthetic agents for sedation or anesthesia; it is expected to reduce the sevoflurane requirement for LMA removal. Therefore, we determined the EC50 of sevoflurane for LMA removal with caudal analgesia and compared that to the EC50 without caudal analgesia.MethodsForty-three unpremedicated children aged 1 to 6 yr were enrolled. They were allocated to receive or not to receive caudal block according to their parents' consent. General anesthesia were induced and maintained with sevoflurane and oxygen in air. EC50 of sevoflurane for a smooth LMA removal with and without caudal analgesia were estimated by the Dixon up-and-down method. The LMA was removed when predetermined end-tidal sevoflurane concentration was achieved, and the sevoflurane concentration of a subsequent patient was determined by the success or failure of the previous patient with 0.2% as the step size; success was defined by the absence of an adverse airway reaction during and after LMA removal. EC50 of sevoflurane with caudal block, and that without caudal block, were compared by a rank-sum test.ResultsThe EC50 of sevoflurane to achieve successful LMA removal in children with caudal block was 1.47%; 1.81% without caudal block. The EC50 were significantly different between the two groups (P < 0.001).ConclusionsCaudal analgesia significantly reduced the sevoflurane concentration for a smooth LMA removal in anesthetized children.

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Section: Discussionmentioning

confidence: 99%

Caudal analgesia reduces the sevoflurane requirement for LMA removal in anesthetized children

Kim

Park

Lee

et al. 2010

Korean J Anesthesiol

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“…Depolarizing neuromuscular blocking drugs administered i.v. do not cross the blood-brain barrier, but may activate the electroencephalogram (EEG) in humans [1,2] and laboratory animals [3,4]. This indirect CNS effect is induced by increased proprioceptive afferent activity from intrafusal muscle fibres stimulated by the blocker [5], by pain arising from muscle damage induced by fasciculation, or by both [2].…”

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confidence: 99%

Nitrous Oxide Antagonizes CNS Stimulation by Laudanosine in Mice

Avramov¹,

Mori²

1990

British Journal of Anaesthesia

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We have investigated whether nitrous oxide antagonizes or augments the CNS stimulant action of laudanosine in mice by comparing the mean convulsive doses (CD50 (SE] of a control group and those following pretreatment with 65% nitrous oxide in oxygen for 20 and 180 min. Nitrous oxide significantly increased CD50 from 46.8 (1.4) mg kg-1 of control to 57.3 (1.3) mg kg-1 at 20 min and 53.5 (1.7) mg kg-1 at 180 min. The attenuation of the effect of nitrous oxide at 180 min, suggestive of possible partial drug tolerance, was not statistically significant. These findings indicate that nitrous oxide antagonizes the CNS stimulating action of laudanosine.

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“…In particular, we would suggest that spasticity in these patients, combined with a compromised gating system at the spinal level, might lead to a flooding of altered afferent proprioceptive impulses which would interfere with the patient's ability to maintain awareness [77]. There is evidence from experimental studies that tonic sensory and muscle spindle activity may play a role in modulating brain activity and wakefulness [108]. Spinal cord stimulation (SCS), sometimes used to control spasticity, has also been seen to improve consciousness in a number of cases of VS, and although the dynamics behind this remain unclear the observed clinical improvement lends further support to the overload hypothesis [109,110].…”

Section: Overflow Hypothesismentioning

confidence: 99%

Silencing The Brain May Be Better Than Stimulating it. The GABA Effect

Pistoia¹,

Sarà²,

Sacco³

et al. 2013

CPD

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Cases of recovery from vegetative and minimally conscious state after the administration of various pharmacological agents have been recently reported. These agents include CNS depressants (zolpidem, baclofen, lamotrigine) and CNS stimulants (tricyclic antidepressants, selective serotonin reuptake inhibitors, dopaminergic agents, methylphenidate). The action of CNS depressants as awakening agents sounds paradoxical, as they are commonly prescribed to slow down brain activity in the management of anxiety, muscle tension, pain, insomnia and seizures. How these drugs may improve the level of consciousness in some brain-injured patients is the subject of intense debate. Here we hypothesize that CNS depressants may promote consciousness recovery by reversing a condition of GABA impairment in the injured brain, restoring the normal ratio between synaptic excitation and inhibition, which is the prerequisite for any transition from a resting state to goal-oriented activities (GABA impairment hypothesis). Alternative or complementary mechanisms underlying the improvement of consciousness may include the reversal of a neurodormant state within areas affected by diaschisis (diaschisis hypothesis) and the modulation of an informative overload to the cortex as a consequence of filter failure in the injured brain (informative overload hypothesis). A better understanding of how single agents act on neural networks, whose functioning is critical for recovery, may help to advance a tailored pharmacological approach in the treatment of severely brain injured patients.

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Arousal Effect of Afferent Discharges From Muscle Spindles Uron Electroencephalograms in Cats

Cited by 26 publications

References 18 publications

Caudal analgesia reduces the sevoflurane requirement for LMA removal in anesthetized children

Caudal analgesia reduces the sevoflurane requirement for LMA removal in anesthetized children

Nitrous Oxide Antagonizes CNS Stimulation by Laudanosine in Mice

Silencing The Brain May Be Better Than Stimulating it. The GABA Effect

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