The Howling Cortex: Seizures and General Anesthetic Drugs

The efficacy and safety of ciprofol and propofol in patients undergoing colonoscopy: A double-blind, randomized, controlled trial

STUDY OBJECTIVE

Propofol is a commonly utilized anesthetic for painless colonoscopy, but its usage is occasionally limited due to its potential side effects, including cardiopulmonary suppression and injection pain. To address this limitation, the novel compound ciprofol has been proposed as a possible alternative for propofol. This study sought to determine whether there are any differences in the safety and efficacy of propofol and ciprofol for painless colonoscopy.

DESIGN

Randomized clinical trial.

SETTING

Single-centre, class A tertiary hospital, November 2021 to November 2022.

PATIENTS

Adult, American Society of Anesthesiologists Physical Status I to II and body mass index of 18 to 30 kg m-2 patients scheduled to undergo colonoscopy.

INTERVENTIONS

Consecutive patients were randomly allocated in a 1:1 ratio to receive sedation for colonoscopy with ciprofol (group C) or propofol (group P).

MEASUREMENTS

The primary outcome was the success rate of colonoscopy. The secondary outcomes were onset time of sedation, operation time, recovery time and discharge time, patients and endoscopists satisfaction, side effects (e.g. injection pain, myoclonus, drowsiness, dizziness, procedure recall, nausea and vomiting) and incidence rate of cardiopulmonary adverse events.

MAIN RESULTS

No significant difference was found in the success rate of colonoscopy between the two groups (ciprofol 96.3% vs. propofol 97.6%; mean difference - 1.2%, 95% CI: -6.5% to 4.0%, P = 0.650). However, group C showed prolonged sedation (63.4 vs. 54.8 s, P < 0.001) and fully alert times (9 vs 8 min, P = 0.013), as well as reduced incidences of injection pain (0 vs. 40.2%, P < 0.001), respiratory depression (2.4% vs. 13.4%, P = 0.021) and hypotension (65.9% vs. 80.5%, P = 0.034). Patients satisfaction was also higher in Group C (10 vs 9, P < 0.001).

CONCLUSIONS

Ciprofol can be used independently for colonoscopy. When comparing the sedation efficacy of ciprofol and propofol, a 0.4 mg kg-1 dose of ciprofol proved to be equal to a 2.0 mg kg-1 dose of propofol, with fewer side effects and greater patient satisfaction during the procedure.

A Case Study and Literature Review of Local Anesthetic Systemic Toxicity During Placement of a Dual-chamber Pacemaker

Local anesthetics are commonly deployed for a variety of medical procedures across many disciplines. Systemic toxicity is rarely seen in clinical practice, and quick recognition and how to manage this syndrome are crucial. The development of systemic toxicity is influenced by the site of administration, the type of anesthetic used, and the total dose administered. Local anesthetic systemic toxicity (LAST) syndrome is used as a diagnosis to encompass the cardiovascular and pulmonary adverse effects associated with the intradermal and subcutaneous use of local anesthetics-in our case, lidocaine. We present a case of a 37-year-old man who experienced dysarthria, bilateral arm shaking, and sinus tachycardia following the administration of 70 mL of lidocaine 2% during surgery for dual-chamber pacemaker placement. While some form of allergic reaction remained a possibility, the strongest clinical correlation and diagnosis were attributed to LAST.

Etomidate versus Propofol for Electroconvulsive Therapy in Patients with Major Depressive Disorders in Terms of Clinical Responses to Treatment: A Retrospective Analysis

General anesthetic agents may be associated with the clinical efficacy of electroconvulsive therapy (ECT), as they may influence seizure quality and duration. Hence, a retrospective study was conducted to compare the clinical effects and seizure variables of etomidate and propofol during ECT. Patients treated with ECT under anesthesia with etomidate (n = 43) or propofol (n = 12) were retrospectively analyzed. Seizure variables (seizure duration, intensity, and threshold) and hemodynamic changes during ECT were assessed and recorded. Clinical responses to treatment were evaluated using the Clinical Global Impression scale and mood at discharge after the course of ECT. Adverse effects were also recorded. The demographic characteristics were similar between the two groups. There were no significant differences in the Clinical Global Impression scale scores, mood at discharge, and adverse effects between the two groups (p > 0.05); however, etomidate was associated with a significantly longer motor (42.0 vs. 23.65 s, p < 0.001) and electroencephalogram (51.8 vs. 33.5 s, p < 0.001) seizure duration than propofol. In conclusion, etomidate showed more favorable seizure profiles than propofol during ECT; however, both agents (etomidate and propofol) were associated with similar clinical efficacy profiles at discharge.

Intraoperative Seizure Under General Anesthesia Not Detected by EEG: A Case Report

Intraoperative seizures under general anesthesia are infrequent. However, seizure activity under general anesthesia confirmed by contemporaneous EEG has been reported. We describe the case of a 39-year-old female undergoing right frontal brain tumor resection who experienced an intraoperative seizure. Intraoperative neuromonitoring was utilized and included four channels of EEG, somatosensory evoked potentials (SSEP), and transcranial motor evoked potentials (MEP). During this operation, characteristic motor manifestations of a seizure occurred. However, the EEG did not demonstrate seizure activity due to limitations in EEG lead placement. Post-operatively in the ICU, motor manifestations of seizure activity continued, and subsequent EEG recordings demonstrated classic seizure activity. Due to the previous hemicraniectomy, corkscrew EEG electrodes were not placed over the right skull defect, thereby failing to detect the intraoperative seizure. Anesthesiologists should be aware that limitations with EEG electrode placement can fail to detect intraoperative seizures, and treatment to extinguish the seizure should proceed in an emergent fashion.

TRPM4 regulates hilar mossy cell loss in temporal lobe epilepsy

BACKGROUND

Mossy cells comprise a large fraction of excitatory neurons in the hippocampal dentate gyrus, and their loss is one of the major hallmarks of temporal lobe epilepsy (TLE). The vulnerability of mossy cells in TLE is well known in animal models as well as in patients; however, the mechanisms leading to cellular death is unclear.

RESULTS

Transient receptor potential melastatin 4 (TRPM4) is a Ca²⁺-activated non-selective cation channel regulating diverse physiological functions of excitable cells. Here, we identified that TRPM4 is present in hilar mossy cells and regulates their intrinsic electrophysiological properties including spontaneous activity and action potential dynamics. Furthermore, we showed that TRPM4 contributes to mossy cells death following status epilepticus and therefore modulates seizure susceptibility and epilepsy-related memory deficits.

CONCLUSIONS

Our results provide evidence for the role of TRPM4 in MC excitability both in physiological and pathological conditions.

Ciprofol: A Novel Alternative to Propofol in Clinical Intravenous Anesthesia?

Ciprofol is a novel compound that was independently developed in China. According to the Chinese product instructions approved by the China National Medical Products Administration and the information of official website, indications for ciprofol include sedation and anesthesia during the surgical/procedure of nontracheal intubation, induction and maintenance of general anesthesia, and sedation during intensive care. Ciprofol is a short-acting intravenous sedative based on the structural modification of propofol. Ciprofol has high efficacy, good selectivity, and fewer adverse reactions, indicating good clinical application potential. A series of clinical studies have been conducted to evaluate the sedative effect of ciprofol in various procedures and settings, including gastroscopy and colonoscopy, fiber-optic bronchoscopy, general anesthesia in elective surgeries, and mechanical ventilation in intensive care units. This review summarizes the chemical structure, pharmacodynamics, and pharmacokinetic properties of ciprofol. We also assessed the efficacy and safety of ciprofol by synthesizing the relevant clinical trial data.

Flow blockage disrupts cilia-driven fluid transport in the epileptic brain

A carpet of ependymal motile cilia lines the brain ventricular system, forming a network of flow channels and barriers that pattern cerebrospinal fluid (CSF) flow at the surface. This CSF transport system is evolutionary conserved, but its physiological function remains unknown. Here we investigated its potential role in epilepsy with studies focused on CDKL5 deficiency disorder (CDD), a neurodevelopmental disorder with early-onset epilepsy refractory to seizure medications and the most common cause of infant epilepsy. CDKL5 is a highly conserved X-linked gene suggesting its function in regulating cilia length and motion in the green alga Chlamydomonas might have implication in the etiology of CDD. Examination of the structure and function of airway motile cilia revealed both the CDD patients and the Cdkl5 knockout mice exhibit cilia lengthening and abnormal cilia motion. Similar defects were observed for brain ventricular cilia in the Cdkl5 knockout mice. Mapping ependymal cilia generated flow in the ventral third ventricle (v3V), a brain region with important physiological functions showed altered patterning of flow. Tracing of cilia-mediated inflow into v3V with fluorescent dye revealed the appearance of a flow barrier at the inlet of v3V in Cdkl5 knockout mice. Analysis of mice with a mutation in another epilepsy-associated kinase, Yes1, showed the same disturbance of cilia motion and flow patterning. The flow barrier was also observed in the Foxj1^± and FOXJ1Cre^ERT:Cdkl5^y/fl mice, confirming the contribution of ventricular cilia to the flow disturbances. Importantly, mice exhibiting altered cilia-driven flow also showed increased susceptibility to anesthesia-induced seizure-like activity. The cilia-driven flow disturbance arises from altered cilia beating orientation with the disrupted polarity of the cilia anchoring rootlet meshwork. Together these findings indicate motile cilia disturbances have an essential role in CDD-associated seizures and beyond, suggesting cilia regulating kinases may be a therapeutic target for medication-resistant epilepsy.

Comparison of the Effectiveness of Various Drug Interventions to Prevent Etomidate-Induced Myoclonus: A Bayesian Network Meta-Analysis

Background

Myoclonic movement is a very common but undesirable phenomenon during the induction of general anesthesia using etomidate. Such movement may cause unnecessary problems. Currently, there is an increasing number of drugs for preventing etomidate-induced myoclonus (EM). However, direct comparisons of various drugs are lacking, and this interferes with clinical decision-making. Our network meta-analysis (NMA) aimed to compare the efficacy of different drugs for the prevention of moderate-to-severe general myoclonus.

Methods

Using several biomedical databases, randomized controlled trials (RCTs) published in English from inception to August 22, 2021 were searched. Among the various interventions, we selected nine types of intervention drugs (dexmedetomidine, etomidate, lidocaine, NMDA receptor antagonist, κ opioid receptor agonist, μ opioid receptor agonist, muscle relaxant, gabapentin, and midazolam) for comparison, according to the number of studies. Bayesian NMA was performed using STATA16 and R softwares. The relative risk of EM was assessed using risk ratios (RRs) and the corresponding 95% confidence intervals (CI).

Results

A total of 31 RCTs (3209 patients) were included. NMA results showed that, compared with a placebo, etomidate (RR 4.0, 95%CI 2.1–7.8), κ opioid receptor agonist (RR 2.9, 95%CI 1.9–4.6), μ opioid receptor agonist (RR 3.1, 95%CI 2.3–4.3), NMDA receptor antagonist (RR 1.7, 95%CI 1.0–2.8), dexmedetomidine (RR 2.4, 95%CI 1.5–3.9), lidocaine (RR 2.1, 95%CI 1.2–3.9), and midazolam (RR 2.2, 95%CI 1.5–3.2) can significantly reduce the risk of EM. In contrast, the effects of muscle relaxants (RR 2.1, 95%CI 0.81–5.3) and gabapentin (RR 2.8, 95%CI 0.92–9.3) were inconclusive. Further subgroup analyses showed that preoperative low-dose etomidate, μ-opioid receptor agonist, and κ-opioid receptor agonist were significantly better than other interventions in the prevention of moderate to severe EM.

Conclusion

Preoperative use of small doses of etomidate or opioids may be the most effective way to avoid EM, especially moderate and severe EM, which makes anesthesia induction safer, more stable, and aligns better with the requirements of comfortable medicine.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/], [CRD4202127706].

Ketamine in the Past, Present, and Future: Mechanisms, Metabolites, and Toxicity

PURPOSE OF REVIEW

While ketamine's analgesia has mostly been attributed to antagonism of N-methyl-D-aspartate receptors, evidence suggests multiple other pathways are involved in its antidepressant and possibly analgesic activity. These mechanisms and ketamine's role in the nociplastic pain paradigm are discussed. Animal studies demonstrating ketamine's neurotoxicity have unclear human translatability and findings from key rodent and human studies are presented.

RECENT FINDINGS

Ketamine's metabolites, and (2R,6R)-hydroxynorketamine in particular, may play a greater role in its clinical activity than previously believed. The activation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and the mammalian target of rapamycin by ketamine are mechanisms that are still being elucidated. Ketamine might work best in nociplastic pain, which involves altered pain processing. While much is known about ketamine, new studies will continue to define its role in clinical medicine. Evidence supporting ketamine's neurotoxicity in humans is lacking and should not impede future ketamine clinical trials.

Efficacy and safety of ciprofol for the sedation/anesthesia in patients undergoing colonoscopy: Phase IIa and IIb multi-center clinical trials

OBJECTIVE

Ciprofol is a new intravenous anesthetic agent similar to propofol that has the pharmacodynamic characteristics of a rapid rate of onset and recovery in pre-clinical experiments. The aims of the present clinical trials were to compare the efficacy and safety of ciprofol emulsion for sedation or general anesthesia during colonoscopy and to define optimal doses for a subsequent phase III clinical trial.

METHODS

A phase IIa multi-center, open-label, non-randomized, positive control, dose-escalating study was performed to determine a recommended phase IIb dose (RP2D) of ciprofol to induce sedation or anesthesia in patients undergoing colonoscopy. Phase IIb was also a multi-center clinical trial, but the patients were randomized into 3 groups at a ratio of 1:1:1. It was a double-blinded, propofol controlled study that administered ciprofol 0.4 mg/kg (n = 31) and 0.5 mg/kg (n = 32) or propofol at 2.0 mg/kg (n = 31), with the aim of establishing the optimal dose of ciprofol. The primary endpoint was the colonoscopy success rate. Secondary endpoints were the duration of colonoscope insertion, recovery time, number of top-up doses needed, and the total dose of ciprofol or propofol required to maintain adequate sedation or anesthesia. In addition, we evaluated the satisfaction of sedation/anesthesia from the endoscopists, anesthetists and patients' points of view. Safety was assessed according to the incidence of AEs including serious AEs and drug related AEs and the assessment of vital signs, a 12-lead ECG and laboratory tests.

RESULTS

In the phase IIa trial, the colonoscopy success rates in the 0.2-0.5 mg/kg ciprofol and propofol 2.0 mg/kg groups were 100% and all doses were safe and well tolerated. Ciprofol doses of 0.4 mg/kg and 0.5 mg/kg are recommended for subsequent IIb phases. In the phase IIb trial, a 100% success rate was reconfirmed in all the dosage groups. The mean time of colonoscope insertion in the ciprofol 0.4 mg/kg, ciprofol 0.5 mg/kg and propofol 2.0 mg/kg groups were 1.9, 1.5 and 1.5 min, the mean recovery times from colonoscope withdrawal were 6.1, 5.1, and 4.3 min, and the times to discharge were 11.8, 11.2 and 10.6 min, respectively. The satisfaction ratings of anesthetists in the ciprofol 0.5 mg/kg group (9.5 ± 0.8) were higher than in the ciprofol 0.4 mg/kg (9.2 ± 1.0) and propofol 2.0 mg/kg (9.2 ± 0.9) groups. The incidence of sedation and anesthesia-related AEs was highest in the propofol 2.0 mg/kg group (25.8%), followed by the ciprofol 0.5 mg/kg group (21.9%), and was least in the ciprofol 0.4 mg/kg group (16.1%) (P = 0.750).

CONCLUSIONS

Ciprofol was safe and well tolerated at doses ranging from 0.1 mg/kg to 0.5 mg/kg. Ciprofol 0.4-0.5 mg/kg induced equivalent sedation/anesthesia and had a similar safety profile to propofol 2.0 mg/kg during colonoscopy without producing serious AEs.

Rapid-acting antidepressants and the regulation of TrkB neurotrophic signalling-Insights from ketamine, nitrous oxide, seizures and anaesthesia

Increased glutamatergic neurotransmission and synaptic plasticity in the prefrontal cortex have been associated with the rapid antidepressant effects of ketamine. Activation of BDNF (brain-derived neurotrophic factor) receptor TrkB is considered a key molecular event for antidepressant-induced functional and structural synaptic plasticity. Several mechanisms have been proposed to underlie ketamine's effects on TrkB, but much remains unclear. Notably, preliminary studies suggest that besides ketamine, nitrous oxide (N₂ O) can rapidly alleviate depressive symptoms. We have shown nitrous oxide to evoke TrkB signalling preferentially after the acute pharmacological effects have dissipated (ie after receptor disengagement), when slow delta frequency electroencephalogram (EEG) activity is up-regulated. Our findings also demonstrate that various anaesthetics and sedatives activate TrkB signalling, further highlighting the complex mechanisms underlying TrkB activation. We hypothesize that rapid-acting antidepressants share the ability to regulate TrkB signalling during homeostatically evoked slow-wave activity and that this mechanism is important for sustained antidepressant effects. Our observations urge the examination of rapid and sustained antidepressant effects beyond conventional receptor pharmacology by focusing on brain physiology and temporally distributed signalling patterns spanning both wake and sleep. Potential implications of this approach for the improvement of current therapies and discovery of novel antidepressants are discussed.

High Incidence of Epileptiform Potentials During Continuous EEG Monitoring in Critically Ill COVID-19 Patients

Objective: To analyze continuous 1- or 2-channel electroencephalograms (EEGs) of mechanically ventilated patients with coronavirus disease 2019 (COVID-19) with regard to occurrence of epileptiform potentials. Design: Single-center retrospective analysis. Setting: Intensive care unit of Hannover Medical School, Hannover, Germany. Patients: Critically ill COVID-19 patients who underwent continuous routine EEG monitoring (EEG monitor: Narcotrend-Compact M) during sedation. Measurements and Main Results: Data from 15 COVID-19 patients (11 men, four women; age: 19-75 years) were evaluated. Epileptiform potentials occurred in 10 of 15 patients (66.7%). Conclusions: The results of the evaluation regarding the occurrence of epileptiform potentials show that there is an unusually high percentage of cerebral involvement in patients with severe COVID-19. EEG monitoring can be used in COVID-19 patients to detect epileptiform potentials.

Seizure-like movements caused by residual sevoflurane inside the anesthesia machine: A case report

RATIONALE

Sevoflurane-induced seizures are most often caused by high concentrations of sevoflurane during anesthesia induction. However, in this case, we found a rare case of seizure-like movements caused by residual sevoflurane inside the anesthesia machine. Therefore, we propose that the detection of residual anesthesia-inhaled drugs should be included in pre-anesthesia checkout procedures.

PATIENT CONCERNS

An 11-year-old girl with a history of epilepsy was scheduled for emergency appendectomy under general anesthesia. The patient presented with seizure-like movements caused by residual sevoflurane inside the anesthesia machine after pre-oxygenation during rapid sequence induction.

DIAGNOSES

Based on the clinical presentation and previous history of seizures, sevoflurane-induced seizures were diagnosed.

INTERVENTIONS

A washout procedure was performed by turning the oxygen flow up to 10L/min to wash out the residual sevoflurane from the anesthesia machine.

OUTCOMES

The seizures ceased spontaneously, and the vital signs of the patient were stable during the washout procedure. Rapid sequence anesthesia induction and total intravenous anesthesia maintenance were uneventful. Surgery was performed as planned, and there were no postoperative problems. The patient was discharged after 4 days without complications and was well on follow-up.

LESSONS

The check-up procedure of residual anesthesia-inhaled drugs inside the anesthesia machine should be included in the checkout design guidelines, or else the washout procedure should be performed in the pre-anesthesia checkout procedures.

GABAergic neurons are susceptible to BAX-dependent apoptosis following isoflurane exposure in the neonatal period

Exposure to volatile anesthetics during the neonatal period results in acute neuron death. Prior work suggests that apoptosis is the dominant mechanism mediating neuron death. We show that Bax deficiency blocks neuronal death following exposure to isoflurane during the neonatal period. Blocking Bax-mediated neuron death attenuated the neuroinflammatory response of microglia following isoflurane exposure. We find that GABAergic interneurons are disproportionately overrepresented among dying neurons. Despite the increase in neuronal apoptosis induced by isoflurane exposure during the neonatal period, seizure susceptibility, spatial memory retention, and contextual fear memory were unaffected later in life. However, Bax deficiency alone led to mild deficiencies in spatial memory and contextual fear memory, suggesting that normal developmental apoptotic death is important for cognitive function. Collectively, these findings show that while GABAergic neurons in the neonatal brain undergo elevated Bax-dependent apoptotic cell death following exposure to isoflurane, this does not appear to have long-lasting consequences on overall neurological function later in life.

Changes in measures of consciousness during anaesthesia of one hemisphere (Wada test)

BACKGROUND

In the Wada test, one hemisphere is selectively anaesthetised by unilateral intracarotid injection of a fast-acting anaesthetic agent. This gives a unique opportunity to observe the functions and physiological activity of one hemisphere while anaesthetising the other, allowing direct comparisons between brain states and hemispheres that are not possible in any other setting.

AIM

To test whether potential measures of consciousness would be affected by selective anaesthesia of one hemisphere, and reliably distinguish the states of the anesthetised and non-anesthetised hemispheres.

METHODS

We analysed EEG data from 7 patients undergoing Wada-tests in preparation for neurosurgery and computed several measures reported to correlate with the state of consciousness: power spectral density, functional connectivity, and measures of signal diversity. These measures were compared between conditions (normal rest vs. unilateral anaesthesia) and hemispheres (injected vs. non-injected), and used with a support vector machine to classify the state and site of injection objectively from individual patient's recordings.

RESULTS

Although brain function, assessed behaviourally, appeared to be substantially altered only on the injected side, we found large bilateral changes in power spectral density for all frequency bands tested, and functional connectivity changed significantly both between and within both hemispheres. Surprisingly, we found no statistically significant differences in the measures of signal diversity between hemispheres or states, for the group of 7 patients, although 4 of the individual patients showed a significant decrease in signal diversity on the injected side. Nevertheless, including signal diversity measures improved the classification results, indicating that these measures carry at least some non-redundant information about the condition and injection site. We propose that several of these results may be explained by conduction of activity, via the corpus callosum, from the injected to the contralateral hemisphere and vice versa, without substantially affecting the function of the receiving hemisphere, thus reflecting what we call "cross-state unreceptiveness".

Seizures after percutaneous endoscopic lumbar discectomy: A case report

RATIONALE

Percutaneous endoscopic lumbar discectomy (PELD) is a minimally invasive technique for removing nucleus pulposus and achieving neural decompression via a posterolateral approach. PELD is known to have a very low rate of complications during the perioperative period. Although quite rare, seizures can occur in patients undergoing PELD.

PATIENT CONCERNS

A 58-year-old man with severe low back pain underwent the PELD procedure under general anesthesia. During the recovery phase after general anesthesia, the patient developed a tonic-clonic seizure. Two additional episodes occurred subsequently.

DIAGNOSES

Bilateral disc swelling indirectly supports the diagnosis of intracranial hypertension.

INTERVENTIONS

Midazolam and propofol were administered to control seizures. 1.0 g phenobarbital sodium was administered by intravenous injection. Ten milligrams of furosemide and 250 mL of mannitol (20%) were prescribed sequentially. Two hundred milligrams of hydrocortisone and an ice bag were used to protect the brain. Urapidil, metoprolol, and nicardipine were intermittently used to control his blood pressure. A sustained release of sodium valproate was administered and continued prophylactically for 4 weeks.

OUTCOMES

No further seizures were recorded and the patient recovered well.

LESSONS

We conclude that total volume of fluid used for irrigation was considered a possible cause of seizure. This case illustrates the fact that irrigation should be performed cautiously in PELD procedure. And anesthesiologists should be familiar with the management strategies of perioperative acute seizures.

Toxin-Induced Coma and Central Nervous System Depression

Many medications and toxins may induce central nervous system (CNS) depression. Even when the intention is to induce CNS depression, other nervous system adverse effects may occur, such as with anesthetics. Pain medications produce characteristic CNS toxicities. Sedative hypnotics may induce altered mentation among systemic toxicities. Stimulants may mimic coma when discontinued abruptly. Acute and chronic carbon monoxide poisoning can lead to altered mental status and prolonged cognitive difficulties. Some medications and environmental toxins can mimic brain death. High clinical suspicion and early recognition of these effects is vital to treatment, most of which is supportive.

A Metabolic Mechanism for Anaesthetic Suppression of Cortical Synaptic Function in Mouse Brain Slices-A Pilot Investigation

Regulation of synaptically located ionotropic receptors is thought to be the main mechanism by which anaesthetics cause unconsciousness. An alternative explanation, which has received much less attention, is that of primary anaesthetic disruption of brain metabolism via suppression of mitochondrial proteins. In this pilot study in mouse cortical slices, we investigated the effect of disrupting cellular metabolism on tissue oxygen handling and cortical population seizure-like event (SLE) activity, using the mitochondrial complex I inhibitor rotenone, and compared this to the effects of the general anaesthetics sevoflurane, propofol and ketamine. Rotenone caused an increase in tissue oxygen (98 mmHg to 157 mmHg (p < 0.01)) before any measurable change in SLE activity. Thereafter, tissue oxygen continued to increase and was accompanied by a significant and prolonged reduction in SLE root mean square (RMS) activity (baseline RMS of 1.7 to 0.7 µV, p < 0.001) and SLE frequency (baseline 4.2 to 0.4 events/min, p = 0.001). This temporal sequence of effects was replicated by all three anaesthetic drugs. In conclusion, anaesthetics with differing synaptic receptor mechanisms all effect changes in tissue oxygen handling and cortical network activity, consistent with a common inhibitory effect on mitochondrial function. The temporal sequence suggests that the observed synaptic depression—as seen in anaesthesia—may be secondary to a reduction in cellular metabolic capacity.

Lack of antidepressant effects of burst-suppressing isoflurane anesthesia in adult male Wistar outbred rats subjected to chronic mild stress

Post-ictal emergence of slow wave EEG (electroencephalogram) activity and burst-suppression has been associated with the therapeutic effects of the electroconvulsive therapy (ECT), indicating that mere “cerebral silence” may elicit antidepressant actions. Indeed, brief exposures to burst-suppressing anesthesia has been reported to elicit antidepressant effects in a subset of patients, and produce behavioral and molecular alterations, such as increased expression of brain-derived neurotrophic factor (BDNF), connected with antidepressant responses in rodents. Here, we have further tested the cerebral silence hypothesis by determining whether repeated exposures to isoflurane anesthesia reduce depressive-like symptoms or influence BDNF expression in male Wistar outbred rats (Crl:WI(Han)) subjected to chronic mild stress (CMS), a model which is responsive to repeated electroconvulsive shocks (ECS, a model of ECT). Stress-susceptible, stress-resilient, and unstressed rats were exposed to 5 doses of isoflurane over a 15-day time period, with administrations occurring every third day. Isoflurane dosing is known to reliably produce rapid EEG burst-suppression (4% induction, 2% maintenance; 15 min). Antidepressant and anxiolytic effects of isoflurane were assessed after the first, third, and fifth drug exposure by measuring sucrose consumption, as well as performance on the open field and the elevated plus maze tasks. Tissue samples from the medial prefrontal cortex and hippocampus were collected, and levels of BDNF (brain-derived neurotrophic factor) protein were assessed. We find that isoflurane anesthesia had no impact on the behavior of stress-resilient or anhedonic rats in selected tests; findings which were consistent—perhaps inherently related—with unchanged levels of BDNF.

Electroencephalographic Findings and Clinical Behavior During Induction of Anesthesia With Sevoflurane in Human Infants: A Prospective Observational Study

Seizures and interictal epileptiform discharges (IEDs) have been described during sevoflurane. We prospectively estimated their incidence in 54 otherwise neurologically healthy infants by obtaining the full-head video electroencephalogram (EEG). No infants had clinical seizures, but 1 had an electrographic seizure; 3 others had focal IEDs (7.4%; 95% confidence interval [CI], 2.1%-17.9%). We detected no differences in demographic or clinical characteristics between normal and abnormal EEG groups. Diffuse slowing was the most common initial EEG change followed by fast (α, β) activity in all head leads. Larger studies with more statistical power are needed to further investigate the hypotheses generated with this research.

Early postoperative seizures after vocal fold surgery attributed to shigellosis

A 44-year-old previously healthy woman underwent surgery of the vocal folds and developed early postoperative seizures caused by an unusual aetiology. Clinical assessment and laboratory results revealed that the patient suffered from an acute-onset shigellosis infection which was thought to be the cause of her early postoperative seizures. The shigellosis infection was treated with azithromycin which resulted in rapid clinical improvement, and the seizures were successfully managed with benzodiazepines, sodium valproate and levetiracetam. To our knowledge, this is the first reported case of shigellosis-induced seizures in an adult in the peri-operative period. Early detection of the aetiology of seizures is crucial to ensure appropriate management and a safe patient outcome.

The General Anesthetic Isoflurane Bilaterally Modulates Neuronal Excitability

Volatile anesthetics induce hyperactivity during induction while producing anesthesia at higher concentrations. They also bidirectionally modulate many neuronal functions. However, the neuronal mechanism is unclear. The effects of isoflurane on sodium channel currents were analyzed in acute mouse brain slices, including sodium leak (NALCN) currents and voltage-gated sodium channels (Na_v) currents. Isoflurane at sub-anesthetic concentrations increased the spontaneous firing rate of CA3 pyramidal neurons, whereas anesthetic concentrations of isoflurane decreased the firing rate. Isoflurane at sub-anesthetic concentrations enhanced NALCN conductance but minimally inhibited Na_v currents. Isoflurane at anesthetic concentrations depressed Na_v currents and action potential amplitudes. Isoflurane at sub-anesthetic concentrations depolarized resting membrane potential (RMP) of neurons, whereas hyperpolarized the RMP at anesthetic concentrations. Isoflurane at low concentrations induced hyperactivity in vivo, which was diminished in NALCN knockdown mice. In conclusion, enhancement of NALCN by isoflurane contributes to its bidirectional modulation of neuronal excitability and the hyperactivity during induction.

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Volatile anesthetic isoflurane exerts bidirectional modulation of neuronal excitability

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Isoflurane enhances NALCN conductance at sub-anesthetic concentration

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NALCN knockdown diminishes behavioral hyperactivity during isoflurane induction

Neurophysiological Characterization of Thalamic Nuclei in Epileptic Anaesthetized Patients

Deep brain stimulation (DBS) requires precise localization, which is especially difficult at the thalamus, and even more difficult in anesthetized patients. We aimed to characterize the neurophysiological properties of the ventral intermediate (V.im), ventral caudal (V.c), and centromedian parvo (Ce.pc) and the magnocellular (Ce.mc) thalamic nuclei. We obtained microelectrode recordings from five patients with refractory epilepsy under general anesthesia. Somatosensory evoked potentials recorded by microelectrodes were used to identify the V.c nucleus. Trajectories were reconstructed off-line to identify the nucleus recorded, and the amplitude of the action potential (AP) and the tonic (i.e., mean frequency, density, probability of interspike interval) and phasic (i.e., burst index, pause index, and pause ratio) properties of the pattern discharges were analyzed. The Mahalanobis metric was used to evaluate the similarity of the patterns. The mean AP amplitude was higher for the V.im nucleus (172.7 ± 7.6 µV) than for the other nuclei, and the mean frequency was lower for the Ce.pc nucleus (7.2 ± 0.8 Hz) and higher for the V.c nucleus (11.9 ± 0.8 Hz) than for the other nuclei. The phasic properties showed a bursting pattern for the V.c nucleus and a tonic pattern for the centromedian and V.im nuclei. The Mahalanobis distance was the shortest for the V.im/V.c and Ce.mp/Ce.pc pairs. Therefore, the different properties of the thalamic nuclei, even for patients under general anesthesia, can be used to positively define the recorded structure, improving the exactness of electrode placement in DBS.

Febrile convulsions during recovery after anesthesia in an infant with history of MMR vaccination: A case report

RATIONALE

Seizures are rare during the perioperative period; in most cases, there is a previous history of epilepsy or surgery-associated seizures. Febrile convulsions may occur when the body temperature rises above 38°C; this is the most common cause of seizures in children. Febrile convulsions after general anesthesia in the postanesthetic care unit (PACU) without a past or family history are rare. Some reviews suggest that since anesthesia changes immunity, elective surgery should be postponed three weeks after live vaccination.

PATIENT

A 12-month-old female with bilateral hearing loss underwent cochlear implantation under general anesthesia. She did not have any history of convulsions or developmental disorders. However, 1 week before surgery, measles-mumps-rubella (MMR) vaccination was given as a regular immunization.

DIAGNOSES

Forty minutes after arrival at the PACU, sudden generalized tonic-clonic movement occurred during recovery and the patient's measured body temperature exceeded 38.0°C.

INTERVENTIONS

Thiopental sodium was administered intravenously as an anticonvulsant, and the tonic-clonic movement stopped immediately. Endotracheal intubation was performed to secure the airway, and tepid massage and diclofenac β-dimethylaminoethanol administration were performed to lower the patient's body temperature.

OUTCOMES

There was no further fever and no seizures, and no other neurological deficits were observed until discharge.

LESSONS

The anesthesiologist should check the recent vaccination history even if the patient has not developed particular symptoms after vaccination. It is important to know that febrile convulsions may occur in patients who have recently received MMR vaccination.

Propofol-induced refractory status epilepticus at remission age in benign epilepsy with centrotemporal spikes: A case report and literature review

RATIONALE

Benign epilepsy with centrotemporal spikes (BECTS) is one of the most common forms of childhood epilepsy, which is expected to resolve before 16 years of age, with mild effects on the cognitive or behavioral functions in adulthood. This study aims to report the first propofol-induced refractory status epilepticus (SE) in patients with BECTS after 16 years of age, and to review SE in BECTS or induced by propofol.

PATIENT CONCERN

A 16-year-old Chinese girl, who was diagnosed with BECTS at the age of 2 years, developed refractory SE induced by propofol administered during the maintenance stage of general anesthesia during a plastic surgery procedure.

DIAGNOSES

Considering her medical history, EEG, and magnetic resonance images, and brain computed tomography, a diagnosis of refractory SE in BECTS was confirmed.

INTERVENTIONS

The patient had been seizure-free for 3 years from treatment with 2 anti-epileptic drugs (AEDs) valproate acid (VPA) and oxcarbazepine (OXC), and had started monotherapy with OXC for 3 months before the seizure incidence. She had undergone blepharoplasty under local anesthesia prior to receiving general anesthesia. During the maintenance state she developed convulsive SE, which was uncontrolled seizure and lasted for 14 hours. The treatment for which included midazolam, diazepam, propofol, VPA, OXC, and levetiracetam (LEV).

OUTCOMES

The prolonged seizure was controlled by diazepam (4 mg/h), propofol (6 mg/kg/h), VPA (2400 mg/d intravenous injection). Subsequently, she was administered VPA (800 mg/d po), OXC (600 mg/d po), and LEV (1000 mg/d po). Finally, on the 17th day she was discharged, and did not have any seizure recurrence and EEG results were normal as noted during the 3-month follow-up.

LESSONS

This was the first report of an SE in BECTS patient past the remission age. This report implied that interventions of sedation or analgesia in a patient after remission age of BECTS might still be at risk of refractory SE and therefore, should be carefully evaluated and monitored during such procedures, especially when an AED medication has been withdrawn or altered.

Effect of dexmedetomidine on etomidate-induced myoclonus: a randomized, double-blind controlled trial

Background: Etomidate used for the induction of general anesthesia can result in myoclonus. We tested the hypothesis that pretreatment with dexmedetomidine (Dex) reduces the incidence of etomidate-induced myoclonus during the induction of general anesthesia.

Materials and methods: One hundred patients who were scheduled for selective operations under general anesthesia were included in this randomized, double-blind controlled trial. Patients were randomized to receive either Dex 0.5 µg/kg in 20 mL of normal saline or the same volume of normal saline as pretreatment agents 15 mins before the injection of etomidate 0.3 mg/kg. The primary endpoint was the incidence of etomidate-induced myoclonus. Secondary endpoints were the severity of etomidate-induced myoclonus and the incidence of adverse effects from the onset of action of Dex or normal saline to the injection of etomidate, such as dizziness, respiratory depression, bradycardia, hypotension and nausea/vomiting.

Results: All of the 100 patients completed the trial. Dex resulted in a significant 38% reduction in the number of patients who experienced etomidate-induced myoclonus: 13 (26%) vs 32 (64%) (P=0.0001). Additionally, the severity of myoclonus was also reduced in the Dex group than that in the placebo group (P=0.02). Incidence of dizziness, respiratory depression, bradycardia, hypotension and nausea/vomiting was similar in both groups.

Conclusions: Pretreatment with Dex 0.5 µg/kg 15 mins before the induction of general anesthesia not only resulted in a 38% reduction in the incidence of etomidate-induced myoclonus, but also reduced the severity of myoclonus, without inducing any adverse effects.

Effect of butorphanol on etomidate-induced myoclonus: a systematic review and meta-analysis

Objective: To evaluate the effect of butorphanol on the prevention of myoclonus induced by etomidate.

Materials and methods: We searched the PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure databases to collect relevant randomized controlled trials (RCTs) evaluating the effect of butorphanol on etomidate-induced myoclonus in January 2019 without any language restrictions. The primary outcome was the incidence of etomidate-induced myoclonus. Secondary outcomes included the incidence of myoclonus at various degrees and the incidence of adverse effects. Risk ratios (RRs) were calculated for binary outcomes. All statistical analysis were performed by using RevMan 5.3 software.

Results: We identified 6 RCTs involving a total of 608 patients who reported the incidence of etomidate-induced myoclonus. In pooled analyses, the incidence of etomidate-induced myoclonus in the butorphanol group was significantly lower than that in the control group (RR =0.15, 95% CI [0.10, 0.22], P<0.00001). Subgroup analyses showed that butorphanol significantly decreased the numbers of patients with mild myoclonus (RR =0.41, 95% CI [0.25, 0.68], P=0.0005), moderate myoclonus (RR =0.18, 95% CI [0.09, 0.34], P<0.00001), and severe myoclonus (RR =0.04, 95% CI [0.01, 0.10], P<0.00001). Additionally, butorphanol did not increase the incidence of postoperative nausea/vomiting (RR =3.0, 95% CI [0.32, 28.42], P=0.34) or dizziness (RR =6.79, 95% CI [0.84, 54.84], P=0.07) associated with etomidate.

Conclusion: Our findings suggest that butorphanol can effectively prevent the incidence of etomidate-induced myoclonus and alleviate the intensity of etomidate-induced myoclonus, without inducing postoperative nausea/vomiting and dizziness.

Butorphanol effectively prevents etomidate-induced myoclonus: a pooled analysis of 788 patients

Objective

To evaluate the efficacy of pre-injection of butorphanol on etomidate-induced myoclonus during anesthesia induction.

Methods

Randomized controlled trials (RCTs) of the ability of butorphanol to prevent etomidate-induced myoclonus were collected by searching PubMed, Cochrane Library, CNKI, and WanFang databases, from the day of database establishment until May 2017. The literature was screened independently by two evaluators, and the data were then extracted and independently evaluated. Finally, meta-analysis was performed by using RevMan 5.2 software.

Results

Eight RCTs were analyzed. The results of meta-analysis showed that: 1. compared with the control group, butorphanol was effective in preventing etomidate-induced myoclonus [RR = 0.15, 95% CI: 0.11, 0.21]; 2. butorphanol was effective in preventing mild, moderate, and severe etomidate-induced myoclonus [RR = 0.40, 95% CI: 0.25, 0.63; RR = 0.15, 95% CI: 0.08, 0.27; and RR = 0.04, 95% CI: 0.01, 0.09]; 3. butorphanol did not increase the incidence of dizziness and nausea associated with etomidate.

Conclusions

Butorphanol could reduce the incidence and degree of etomidate-induced myoclonus. Notably, it did not increase the incidence of dizziness and nausea associated with etomidate.

Pretreatment with lidocaine reduces both incidence and severity of etomidate-induced myoclonus: a meta-analysis of randomized controlled trials

Objective

One conundrum that frequently occurs during clinical anesthesia is etomidate-induced myoclonus, which results in multiple risks. The aim of the study was to evaluate systematically the effect of pretreatment with lidocaine on preventing etomidate-induced myoclonus.

Materials and methods

The literature search was performed from the inception to April 2018 in PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure. All randomized controlled trials that used lidocaine to prevent etomidate-induced myoclonus were enrolled. The primary outcome included the incidence and severity of etomidate-induced myoclonus. The data were combined to calculate the risk ratio and relevant 95% CI. A meta-analysis was performed following the guidelines of the Cochrane Reviewer’s Handbook and the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement.

Results

A total of eight studies were enrolled, and the existing evidence indicated that 1) pretreatment with lidocaine can reduce the incidence of etomidate-induced myoclonus (the incidence of myoclonus: 37.6% in lidocaine vs 73.6% in saline, risk ratio =0.46, with 95% CI [0.34, 0.63], P<0.0001); 2) the pretreatment with lidocaine can reduce the incidence of mild, moderate, and severe myoclonus; 3) a dose of pretreatment with lidocaine cannot significantly decrease the duration of myoclonus compared to placebo; 4) the administration of lidocaine produced no effect on the stable hemodynamic parameters and no more additional adverse effects.

Conclusion

Pretreatment with lidocaine could be served as one effective approach to decrease both the incidence and the severity of etomidate-induced myoclonus, with limited influence on the hemodynamic stability of patients. However, to confirm precise safety and efficacy of such intervention, more high-quality evidence is necessary.

Oxycodone for prevention of etomidate-induced myoclonus: a randomized double-blind controlled trial

Objective

This study was performed compare the effectiveness of oxycodone and fentanyl in reducing the incidence and severity of etomidate-induced myoclonus.

Methods

In total, 162 patients with an American Society of Anesthesiologists physical status of I or II were assigned at random to three groups. Patients assigned to Group O received 0.1 mg/kg of oxycodone (n = 54), those assigned to Group F were given 1 µg/kg of fentanyl (n = 54), and those assigned to Group S were given an equal volume of saline intravenously 2 minutes prior to administration of 0.3 mg/kg of etomidate (n = 54). The incidence and severity of myoclonus was evaluated 2 minutes after etomidate administration. The patients’ vital signs, coughing, nausea, dizziness, and other related adverse reactions were also recorded.

Results

The incidence of myoclonus was significantly lower in Group O (0.0%) than in Group F (31.5%) and Group S (72.2%); the intensity was also lowest in Group O. All patients in each group had stable cardiovascular profiles.

Conclusions

Intravenous injection of 0.1 mg/kg of oxycodone 2 minutes prior to etomidate is more effective in preventing etomidate-induced myoclonus during general anesthesia than is 1 µg/kg of fentanyl.

Comparison of different doses of intravenous lignocaine on etomidate-induced myoclonus: A prospective randomised and placebo-controlled study

Background and Aims

Etomidate-induced myoclonus (EM) is observed in 50%-80% of unpremedicated patients. Low-dose lignocaine has been shown to attenuate but not abolish the EM. The aim of this prospective, randomised controlled study was to compare the different doses of lignocaine on the incidence and severity of EM.

Methods

Two hundred adult patients were randomly assigned into four groups to receive saline placebo (Group I) or IV lignocaine 0.5 mg/kg (Group II), 1 mg/kg (Group III) or 1.5 mg/kg (Group IV) 2 min before injection etomidate 0.3 mg/kg IV. The patients were assessed for the EM using a four-point intensity scoring system. Our primary outcome was the incidence of myoclonus at 2 min (EM2). The incidence of myoclonus at 1 min (EM1) and severity of myoclonus constituted the secondary outcomes. ANOVA and Pearson Chi-square test were used for statistical analysis and P < 0.05 was considered as statistically significant.

Results

The incidence of EM was significantly reduced in Groups III [(EM1: 32% vs. 60%, P = 0.009); (EM2: 42% vs. 76%, P = 0.001)] and IV (EM2: 54% vs. 76%, P = 0.035) compared with Group I. Lignocaine 1 mg/kg and 1.5 mg/kg significantly reduced the incidence of severe myoclonus at 2 min (14% each) compared to Groups I (42%, P = 0.003) and II (32%, P = 0.032).

Conclusion

Lignocaine 1 mg/kg and 1.5 mg/kg IV pretreatment significantly reduces the incidence of EM, with maximum attenuation observed with 1 mg/kg.

Propofol Frenzy: Clinical Spectrum in 3 Patients

Postsedation neuroexcitation is sometimes attributed to intravenous injection of the sedative-hypnotic drug propofol. The movements associated with these events have strongly suggested convulsive activity, but they rarely have been comprehensively evaluated. We present video recordings of 3 healthy young patients who underwent elective surgery under conscious sedation and emerged from sedation with transient but repetitive violent motor activity and impaired consciousness. These manifestations required considerable mobilization of multiple health care workers to protect the patient from inflicting harm. All patients received propofol, and all fully recovered without adverse sequelae. We postulate that these movements are propofol related. Importantly, we found no evidence of seizures clinically or electrographically.

Generalized convulsive seizures are associated with ketamine anesthesia in a rhesus macaque (Macaca mulatta) undergoing urodynamic studies and transcutaneous spinal cord stimulation

A female rhesus macaque developed two episodes of generalized convulsions during transcutaneous spinal cord stimulation (TSCS) and urodynamic studies under ketamine anesthesia. The seizures took place in the absence of active TSCS and bladder pressure elevation. Ketamine anesthesia remains the primary risk factor for the convulsions during these experimental procedures.

Intraoperative Tonic-Clonic Seizure Under General Anesthesia Captured by Electroencephalography: A Case Report

We present the case of a 34-year-old man undergoing craniotomy for arteriovenous malformation resection under general anesthesia who suffered a tonic-clonic seizure captured by intraoperative electroencephalograph. The seizure was extinguished with a propofol bolus. This patient had no previous history of seizures, and no precipitating cause was identified. Intraoperative electroencephalographic seizures under general anesthesia have been recorded previously in the literature, but our observation is the first to demonstrate this with overt motor manifestations. We also discuss the differential diagnosis of an intraoperative seizure under general anesthesia and provide guidance to the anesthesiologist who encounters this event.

Effect of dexmedetomidine in preventing etomidate-induced myoclonus: a meta-analysis

Objective

To investigate the effect of dexmedetomidine in the prevention of etomidate-induced myoclonus.

Methods

We searched for randomized controlled trials (RCTs) regarding the use of dexmedetomidine in preventing etomidate-induced myoclonus in the databases PubMed, EMBASE, the Cochrane Library, and CNKI. We extracted data and assessed the quality of the literature and adopted RevMan 5.2 to conduct meta-analysis on each effective index and employed funnel plot to test publication bias.

Results

The results showed that the incidence of etomidate-induced myoclonus in the dexmedetomidine treated groups was significantly lower than that of the control groups (risk ratio [RR]=0.27, 95% confidence interval [CI] [0.15, 0.47], P<0.00001). With regard to the severity of etomidate-induced myoclonus, incidences of etomidate-induced myoclonus in the dexmedetomidine treated groups resulting in mild myoclonus (RR=0.37, 95% CI [0.19, 0.75], P=0.006), moderate myoclonus (RR=0.21, 95% CI [0.12, 0.37], P<0.00001), or severe myoclonus (RR=0.18, 95% CI [0.08, 0.38], P<0.00001) were significantly lower than those of the control groups. No statistically significant difference was found (RR=0.70, 95% CI [0.47, 1.04], P=0.08) between etomidate-induced myoclonus in the dexmedetomidine treated groups and that of the midazolam treated groups.

Conclusion

Dexmedetomidine can effectively prevent the incidence of etomidate-induced myoclonus and reduce the severity of etomidate-induced myoclonus. In addition, there were no significant differences between the effects of dexmedetomidine and midazolam in preventing etomidate-induced myoclonus.

Analgesia, sedation, and neuromuscular blockade during targeted temperature management after cardiac arrest

The approach to sedation, analgesia, and neuromuscular blockade during targeted temperature management (TTM) remains largely unstudied, forcing clinicians to adapt previous research from other patient environments. During TTM, very little data guide drug selection, doses, and specific therapeutic goals. Sedation should be deep enough to prevent awareness during neuromuscular blockade, but titration is complex as metabolism and clearance are delayed for almost all drugs during hypothermia. Deeper sedation is associated with prolonged intensive care unit (ICU) and ventilator therapy, increased delirium and infection, and delayed wakening which can confound early critical neurological assessments, potentially resulting in erroneous prognostication and inappropriate withdrawal of life support. We review the potential therapeutic goals for sedation, analgesia, and neuromuscular blockade during TTM; the adverse events associated with that treatment; data suggesting that TTM and organ dysfunction impair drug metabolism; and controversies and potential benefits of specific monitoring. We also highlight the areas needing better research to guide our therapy.

Application of Higuchi's fractal dimension from basic to clinical neurophysiology: A review

BACKGROUND AND OBJECTIVE

For more than 20 years, Higuchi's fractal dimension (HFD), as a nonlinear method, has occupied an important place in the analysis of biological signals. The use of HFD has evolved from EEG and single neuron activity analysis to the most recent application in automated assessments of different clinical conditions. Our objective is to provide an updated review of the HFD method applied in basic and clinical neurophysiological research.

METHODS

This article summarizes and critically reviews a broad literature and major findings concerning the applications of HFD for measuring the complexity of neuronal activity during different neurophysiological conditions. The source of information used in this review comes from the PubMed, Scopus, Google Scholar and IEEE Xplore Digital Library databases.

RESULTS

The review process substantiated the significance, advantages and shortcomings of HFD application within all key areas of basic and clinical neurophysiology. Therefore, the paper discusses HFD application alone, combined with other linear or nonlinear measures, or as a part of automated methods for analyzing neurophysiological signals.

CONCLUSIONS

The speed, accuracy and cost of applying the HFD method for research and medical diagnosis make it stand out from the widely used linear methods. However, only a combination of HFD with other nonlinear methods ensures reliable and accurate analysis of a wide range of neurophysiological signals.

Neurosarcoidosis presenting as status epilepticus: a new bronchoscopic complication

Flexible bronchoscopy is considered a relatively safe procedure. Neurological complications related to bronchoscopy are extremely rare. We report a patient with granulomatous panuveitis due to suspected sarcoidosis manifesting as altered mental status and status epilepticus after an elective diagnostic bronchoscopy. Cerebrospinal fluid and magnetic resonance imaging findings confirmed diffuse leptomeningeal inflammation suggesting neurosarcoidosis. The patient was successfully treated with corticosteroids with complete resolution of central nervous system findings. To the best of our knowledge, this complication has not been reported before in any sarcoidosis patient undergoing bronchoscopy.

Intraoperative seizure and cerebrospinal fluid leak during adult cochlear implant surgery

OBJECTIVE AND IMPORTANCE

To report a rare case of cerebrospinal fluid gusher and subsequent seizure immediately after cochlear implant electrode insertion.

CLINICAL PRESENTATION

After the cochlear implant electrode was inserted, brisk flow of 10 mL of cerebrospinal fluid was seen. The electrode was promptly inserted and the leak was additionally sealed with fascia. Seconds later, the patient had a tonic-clonic seizure lasting 30 seconds. Two additional episodes occurred during the case. Her postoperative course was uneventful with no subsequent seizures. The device has been successfully activated. Intervention & Technique: Postoperative imaging showed correct intracochlear placement of the electrode as well as an incidental enlarged vestibular aqueduct. Neurology consultation including electroencephalogram was unremarkable.

CONCLUSION

To our knowledge, this is the first report of a seizure temporally associated with cochlear implant electrode insertion. The significance and possible casual relationship between these two events is discussed.

Efficacy and Safety of Opioids for the Prevention of Etomidate-Induced Myoclonus: A Meta-Analysis

Etomidate is a widely used hypnotic drug for induction of general anesthesia and sedation, especially in elderly patients and hemodynamically unstable patients. Myoclonus, however, is the most prominent problem during induction of anesthesia with etomidate. Many agents have been used to prevent it and opioid is one of them. This meta-analysis was to evaluate effects of opioids pretreatment for preventing etomidate-induced myoclonus. We searched the PubMed, EMBASE, and the Cochrane Library databases and published studies in English updated to September 2015. Randomized controlled trials of opioids versus placebo/control in patients were included. We evaluated the prophylactic effect of opioids on etomidate-induced myoclonus. All statistical analysis was performed using RevMan 5.2 software. Nine randomized controlled trials involving 604 participants were included. The results indicated that compared with placebo/control, opioids allow more patients to experience no myoclonic movements after etomidate injection [risk ratio (RR) 2.76, 95% confidence interval (CI) 1.75-4.37, P < 0.0001]. The numbers of patients with mild myoclonus [(RR) 0.53, 95% (CI) 0.36-0.78, P = 0.001], moderate myoclonus [(RR) 0.36, 95% (CI) 0.23-0.55, P < 0.00001], and severe myoclonus [(RR) 0.20, 95% (CI) 0.08-0.52, P = 0.0009] after etomidate injection were significantly decreased with the pretreatment of opioids. This meta-analysis suggests that pretreatment with opioids before injecting etomidate was effective for preventing etomidate-induced myoclonus and can reduce the intensity of myoclonus without any adverse effects.

Low-Dose Ketamine Pretreatment Reduces the Incidence and Severity of Myoclonus Induced by Etomidate: A Randomized, Double-Blinded, Controlled Clinical Trial

Myoclonic movement induced by etomidate is a common but undesirable problem during general anesthesia induction. To investigate the influence of pretreatment with low-dose ketamine on the incidence and severity of myoclonus induced by etomidate, 104 patients were randomized allocated to 1 of 2 equally sized groups (n = 52) to receive either intravenous low-dose ketamine 0.5 mg/kg (group K) or an equal volume of normal saline (group S) 1 minute before induction of anesthesia with 0.3-mg/kg etomidate. The incidence and severity of myoclonus were assessed for 2 minutes after administration of etomidate. Here, we found that the incidence and intensity of myoclonus were both significantly reduced in low-dose ketamine-treated group compared with saline-treated group. The incidence of adverse effects was low and similar between groups. These results demonstrate that intravenous infusion of low-dose ketamine 0.5 mg/kg 1 minute prior to etomidate administration is effective in relieving etomidate-induced myoclonic movements during general anesthesia induction.