Intranasal Dexmedetomidine for Sedation During Magnetoencephalography:

Comparing the efficacy of awake and sedated MEG to TMS in mapping hand sensorimotor cortex in a clinical cohort

Non-invasive methods such as Transcranial Magnetic Stimulation (TMS) and magnetoencephalography (MEG) aid in the pre-surgical evaluation of patients with epilepsy or brain tumor to identify sensorimotor cortices. MEG requires sedation in children or patients with developmental delay. However, TMS can be applied to awake patients of all ages with any cognitive abilities. In this study, we compared the efficacy of TMS with MEG (in awake and sedated states) in identifying the hand sensorimotor areas in patients with epilepsy or brain tumors. We identified 153 patients who underwent awake- (n = 98) or sedated-MEG (n = 55), along with awake TMS for hand sensorimotor mapping as part of their pre-surgical evaluation. TMS involved stimulating the precentral gyrus and recording electromyography responses, while MEG identified the somatosensory cortex during median nerve stimulation. Awake-MEG had a success rate of 92.35 % and TMS had 99.49 % (p-value = 0.5517). However, in the sedated-MEG cohort, TMS success rate of 95.61 % was significantly higher compared to MEG's 58.77 % (p-value = 0.0001). Factors affecting mapping success were analyzed. Logistic regression across the entire cohort identified patient sedation as the lone significant predictor, contrary to age, lesion, metal, and number of antiseizure medications (ASMs). A subsequent analysis replaced sedation with anesthetic drug dosage, revealing no significant predictors impacting somatosensory mapping success under sedation. This study yields insights into the utility of TMS and MEG in mapping hand sensorimotor cortices and underscores the importance of considering factors that influence eloquent cortex mapping limitations during sedation.

Innovations in diagnostic and treatment options for pediatric epilepsy and their anesthetic implications

PURPOSE OF REVIEW

To provide an overview of anesthetic techniques for innovative diagnostic and therapeutic epilepsy procedures performed on pediatric patients.

RECENT FINDINGS

Recent studies have been published on the anesthetic consideration for functional MRI, robotic-assisted stereoelectroencephalography, high-intensity focused ultrasound, and magnetoencephalography. These articles describe the anesthesia management, risks, and outcome for these procedures.

SUMMARY

The number of diagnostic and treatment options being used for the management of pediatric epilepsy has increased significantly. In the past few years, a handful of articles have been published, which describe the anesthetic considerations for these procedures. These studies are helpful to anesthesiologists who are planning an upcoming anesthetic or who are developing a 'best practice' model for their institution. Because unlike other diagnostic studies, failure to understand what effects anesthetics have on the brain, may negate the utility of the study. Although these new findings can be used to provide some anesthesia practice recommendations for epilepsy procedures in which the best management is still unclear, additional high-quality studies are needed.

Intranasal dexmedetomidine vs oral triclofos sodium for sedation of children with autism undergoing electroencephalograms

BACKGROUND

Sedation may be necessary for performing electroencephalograms in children with autistic spectrum disorder, however, our sedation success rate using triclofos sodium (TFS) is limited. Intra-nasal dexmedetomidine (IN-DEX) may be a superior sedative for these children.

OBJECTIVE

Compare IN-DEX with TFS for sedation efficacy, resistance to drug delivery and adverse events in children with autism undergoing an electroencephalogram.

STUDY DESIGN

A single center, prospective observational study of children with autism sedated for electroencephalograms using IN-DEX compared to an age matched, historic group of children with autism, sedated for electroencephalograms using TFS.

RESULTS

Characteristics of 41 IN-DEX sedations were compared to 41 TFS sedations in 82 ASD children. Epileptiform discharges were demonstrated in 23/82 (28%) of children in the cohort. Sedation depth by UMSS was significantly deeper in the IN-DEX group (2.49 ± 0.78 vs. 1.41 ± 0.89, p < 0.001). Electroencephalogram quality demonstrated less motion artifact in the IN-DEX group (1.75 ± 0.76 vs. 2.18 ± 0.88, p < 0.001). The rate of very poor or sedation failure was significantly lower in the IN-DEX group (17% vs 56.1%, p < 0.001), RR = 0.3 (95% CI 0.15 to 0.63, p < 0.001). No major adverse events were documented in either group. Bradycardia occurred in 8/41(19.5%) of children in IN-DEX group and none in TFS group (p = 0.003). Hypotension or poor perfusion were not demonstrated in either group.

CONCLUSION

In children with autism undergoing electroencephalograms, IN-DEX was more tolerable than TFS, induced deeper sedation with a greater success rate, and improved electroencephalogram quality. Both sedatives were equally safe in this population.

The Role of Magnetoencephalography and Single-Photon Emission Computed Tomography in Evaluation of Children With Drug-Resistant Epilepsy

Surgery holds the best outcomes for drug-resistant epilepsy in children, making localization of a seizure focus essential. However, there is limited research on the contribution of magnetoencephalography and single-photon emission computed tomography (SPECT) to the presurgical evaluation of lesional and nonlesional pediatric patients. This study proposed to evaluate the concordance of SPECT and magnetoencephalography (MEG) to scalp electroencephalography (EEG) to determine their effective contribution to the presurgical evaluation. On review, MEG and SPECT studies for 28 drug-resistant epilepsy cases were completed at Children's Hospital of Pittsburgh from May 2012 to August 2018. Although not reaching statistical significance, MEG had increased lobar concordance with EEG compared with SPECT (68% vs 46%). MEG or SPECT results effectively provided localization data leading to 6 surgical evaluations and 3 resections with outcomes of Engel class I or II at 12 months. This study suggests MEG and SPECT provide valuable localizing information for presurgical epilepsy evaluation of children with drug-resistant epilepsy.

A review of magnetoencephalography use in pediatric epilepsy: an update on best practice

Introduction: Magnetoencephalography (MEG) is a noninvasive technique that is used for presurgical evaluation of children with drug-resistant epilepsy (DRE).Areas covered: The contributions of MEG for localizing the epileptogenic zone are discussed, in particular in extra-temporal lobe epilepsy and focal cortical dysplasia, which are common in children, as well as in difficult to localize epilepsy such as operculo-insular epilepsy. Further, the authors review current evidence on MEG for mapping eloquent cortex, its performance, application in clinical practice, and potential challenges.Expert opinion: MEG could change the clinical management of children with DRE by directing placement of intracranial electrodes thereby enhancing their yield. With improved identification of a circumscribed epileptogenic zone, MEG could render more patients as suitable candidates for epilepsy surgery and increase utilization of surgery.

Dexmedetomidine: What's New for Pediatrics? A Narrative Review

Over the past few years, despite the lack of approved pediatric labelling, dexmedetomidine’s (DEX) use has become more prevalent in pediatric clinical practice as well as in research trials. Its respiratory-sparing effects and bioavailability by various routes are only some of the valued features of DEX. In recent years the potential organ-protective effects of DEX, with the possibility for preserving neurocognitive function, has put it in the forefront of clinical and bench research. This comprehensive review focused on the pediatric literature but presents relevant, supporting adult and animal studies in order to detail the recent growing body of literature around the pharmacology, end-organ effects, organ-protective effects, alternative routes of administration, synergetic effects, and clinical applications, with considerations for the future.

Pediatric Anesthesia Outside the Operating Room: Case Management

Anesthesiology teams care for children in diverse locations, including diagnostic and interventional radiology, gastroenterology and pulmonary endoscopy suites, radiation oncology units, and cardiac catheterization laboratories. To provide safe, high-quality care, anesthesiologists working in these environments must understand the unique environmental and perioperative considerations and risks involved with each remote location and patient population. Once these variables are addressed, anesthesia and procedural teams can coordinate to ensure that patients and families receive the same high-quality care that they have come to expect in the operating room. This article also describes some of the considerations for anesthetic care in outfield locations.

Intravenous dexmedetomidine sedation for magnetoencephalography: A retrospective study

BACKGROUND

Magnetoencephalography (MEG) plays a preponderant role in the preoperative assessment of patients with drug-resistant epilepsy (DRE). However, the magnetoencephalography of patients with drug-resistant epilepsy can be difficult without sedation and/or general anesthesia. Our objective is to describe our experience with intravenous dexmedetomidine as sedation for magnetoencephalography and its effect, if any, on the ability to recognize epileptic spikes.

METHODS

In this retrospective study, we reviewed the records of 89 children who presented for Magnetoencephalography/electroencephalography (EEG) scans between August of 2008 and May of 2015. Data analyzed included demographics and the frequency of epileptic spikes. Sedated magnetoencephalography recordings were compared to nonsedated video-electroencephalography (vEEG) recordings in the same patients to determine the impact of dexmedetomidine.

RESULTS

Spike frequency between magnetoencephalography with sedation and video-electroencephalography without sedation was compared in 85 patients. Magnetoencephalography and video-electroencephalography were considered clinically concordant in 80 patients (94.1%) and discordant in 5 patients (5.9%), all with less spikes during Magnetoencephalography. The median (range) bolus dose of dexmedetomidine was 2 (1-2) mcg/kg. The median (range) infusion rate of dexmedetomidine was 2 (0.5-4) mcg/kg/h. All patients experienced reductions in heart rate after administration of dexmedetomidine; these reductions were statistically, but not clinically, significant.

CONCLUSIONS

Our results suggest that dexmedetomidine-based protocol provides reliable sedation in children undergoing MEG scanning because of the high success rate, limited interictal artifacts, and minimal impacts on spike frequency.