Abstracts

Rationale: Intensive care units (ICU) are electrical hostile environments when Electroencephalography (EEG) recordings take place in given patients when these studies are required for the detection of abnormal cerebral activity. As well, these patients are often put through diagnostic and therapeutic procedures that require the use of ultrasound devices. The early identification of potential electrical artifacts in these cases will forbear the misdiagnosis and errors in the interpretation of these recordings and also will prevent unnecessary interventions. We describe a case of a non-physiological electrical EEG artifact occurring during ultrasound-guided central venous catheter placement.  Methods: A patient was admitted to ICU with fever, seizures and progressive functional deterioration and supported with artificial respiration, anticonvulsants, sedation and analgesia. A video-EEG was made to see an electro-clinical correlation and showed a right temporal continuous delta rhythmic activity with anterior temporal spikes and also displayed an evolving bifrontal low amplitude fast activity with maximal in left frontopolar region with increasing amplitude and decreasing frequency with more diffuse slow activity ending with spike-slow wave appearance that show its maximal in right frontocentral electrodes. During review, we observed that this activity was related with switch-on of an ultrasound device for venous central catheterization. When the device was shutdown, the activity ended. Results: Within the literature, there has not been reported any artifact like the mentioned in this article (J Clin Neurophysiol. 1999;16(1):40–5, Am J Electroneurodiagnostic Technol. 2010;50(1):8–25, Artifact: recording EEG in special care units. J Clin Neurophysiol 2011;28(3):264–77, J Clin Neurophysiol. 2015;32(6):481–5). Electronic devices like ultrasound generate alternating current fields and structures that generate static charges and can emit a varied range of frequencies (Crit Care Clin. 2014;30(1):1–24). For the placement of venous central catheters, often patients undergo through ultrasound-guided procedures with transducers using 8-10 Hz frequencies for detect vascular structures (N Engl J Med. 2007;356(21):e21).Every time this kind of activity is seen in a EEG is important to have video registration to have correlation between the activity seen in recordings and procedures that are performed to patients particularly in the ICU (Epileptic Disord. 2014;16(4):439–48, J Clin Neurophysiol. 2018 Sep;35(5):359–64) like physiotherapy (J Clin Neurophysiol 2007 Jun;24(3):252–6), echocardiograms or insertion of devices such an ultrasound-guide central venous catheterization. This finding was reproduced in the same patient during the placement of an ultrasound transducer.  Conclusions: The importance of this finding is that it is easily confused with real electrographic seizures, especially in a hostile environment for EEG recordings. Funding: No funding