Phenobarbital versus valproate for generalized convulsive status epilepticus in adults (2): A multicenter prospective randomized controlled trial in China (China 2-P vs. V)

Review of Noninvasive Neuromonitoring Modalities in Children II: EEG, qEEG

Critically ill children with acute neurologic dysfunction are at risk for a variety of complications that can be detected by noninvasive bedside neuromonitoring. Continuous electroencephalography (cEEG) is the most widely available and utilized form of neuromonitoring in the pediatric intensive care unit. In this article, we review the role of cEEG and the emerging role of quantitative EEG (qEEG) in this patient population. cEEG has long been established as the gold standard for detecting seizures in critically ill children and assessing treatment response, and its role in background assessment and neuroprognostication after brain injury is also discussed. We explore the emerging utility of both cEEG and qEEG as biomarkers of degree of cerebral dysfunction after specific injuries and their ability to detect both neurologic deterioration and improvement.

Phenobarbital in Status epilepticus - Rediscovery of an effective drug

Phenobarbital (PB) is one of the oldest Antiseizure Medicines (ASMs), which is in clinical use since 1912. Its value in the treatment of Status epilepticus is currently discussed controversially. Phenobarbital has fallen out of favor in many countries across Europe because of reports of hypotension, arrhythmias, and hypopnea. Phenobarbital has a strong antiseizure effect with remarkably little sedation. It exerts its clinical effects, through the increase of GABE-ergic inhibition and decrease of glutamatergic excitation by inhibition of AMPA receptors. Despite good preclinical evidence, there are remarkably few randomized controlled studies on humans in SE, which suggest, that it is at least as good as lorazepam in first-line treatment in early SE, and significantly better than valproic acid in benzodiazepine-resistant SE. Data from randomized trials and large non-randomized prospective and retrospective studies suggest, that Phenobarbital is well tolerated even if used in very high dose protocols. Thus, despite its decline in its popularity at least in Europe and North America, it should be considered a highly cost-effective treatment for early and established SE, not only in resource-limited settings. This paper was presented at the 8th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures held in September 2022.

Effective Perturbations by Phenobarbital on INa, IK(erg), IK(M) and IK(DR) during Pulse Train Stimulation in Neuroblastoma Neuro-2a Cells

Phenobarbital (PHB, Luminal Sodium^®) is a medication of the barbiturate and has long been recognized to be an anticonvulsant and a hypnotic because it can facilitate synaptic inhibition in the central nervous system through acting on the γ-aminobutyric acid (GABA) type A (GABA_A) receptors. However, to what extent PHB could directly perturb the magnitude and gating of different plasmalemmal ionic currents is not thoroughly explored. In neuroblastoma Neuro-2a cells, we found that PHB effectively suppressed the magnitude of voltage-gated Na⁺ current (I_Na) in a concentration-dependent fashion, with an effective IC₅₀ value of 83 µM. The cumulative inhibition of I_Na, evoked by pulse train stimulation, was enhanced by PHB. However, tefluthrin, an activator of I_Na, could attenuate PHB-induced reduction in the decaying time constant of I_Na inhibition evoked by pulse train stimuli. In addition, the erg (ether-à-go-go-related gene)-mediated K⁺ current (I_K(erg)) was also blocked by PHB. The PHB-mediated inhibition on I_K(erg) could not be overcome by flumazenil (GABA antagonist) or chlorotoxin (chloride channel blocker). The PHB reduced the recovery of I_K(erg) by a two-step voltage protocol with a geometrics-based progression, but it increased the decaying rate of I_K(erg), evoked by the envelope-of-tail method. About the M-type K⁺ currents (I_K(M)), PHB caused a reduction of its amplitude, which could not be counteracted by flumazenil or chlorotoxin, and PHB could enhance its cumulative inhibition during pulse train stimulation. Moreover, the magnitude of delayed-rectifier K⁺ current (I_K(DR)) was inhibited by PHB, while the cumulative inhibition of I_K(DR) during 10 s of repetitive stimulation was enhanced. Multiple ionic currents during pulse train stimulation were subject to PHB, and neither GABA antagonist nor chloride channel blocker could counteract these PHB-induced reductions. It suggests that these actions might conceivably participate in different functional activities of excitable cells and be independent of GABA_A receptors.