Rationale:
PET CT is an important part of the presurgical evaluation for patients with intractable epilepsy. In the pediatric epilepsy population, obtaining a good PET study often requires sedation with anesthetic agents. As EEG is performed during PET scans to confirm that the study is interictal, EEG pattern changes at the time of anesthesia induction are often captured. Propofol is a common anesthetic agent used for sedation during PET scans at our institution. The EEG changes associated with propofol during status epilepticus management are well documented. However, there are few reports that describe expected findings in pediatric patients being induced with propofol from wakefulness for a short period of sedation. In this case series, we present 21 EEGs from patients who underwent anesthesia induction with propofol to demonstrate expected EEG findings.
Methods:
The charts and EEGs of pediatric patients who underwent sedated PET CT with EEG as part of an epilepsy surgery evaluation at Ann and Robert H. Lurie Children’s Hospital of Chicago between June 1st 2022 and February 28th 2023 were examined. Patients who underwent sedation with propofol during the PET scan were included in the report. Demographic data collected included age at the time of PET and sex. Clinical data collected included epilepsy type, suspected etiology, antiseizure medications, and baseline EEG patterns. EEGs for these patients were obtained from our Natus XLTEK database. EEG patterns before and after induction with propofol were described for each patient. The first pattern change after induction was recorded as well as the progression of patterns until the end of the study.
Results:
Fifty pediatric patients underwent PET CT between June 2022 and February 2023 and 20 underwent sedation with propofol prior to the PET scan. Patient ages ranged from three years to 16 years. At induction, three patients initially had complete background suppression, three had burst suppression, six had discontinuous rhythmic delta activity, and four had continuous rhythmic delta activity. Two patients who had multifocal interictal discharges at baseline appeared to have sleep-activated spike and wave discharges and two patients did not have any change in background activity. EEG patterns tended to evolve as time went on after induction; four became more discontinuous, evolving toward burst suppression and then suppression, and 10 became more continuous as the studies progressed, six of which ended with continuous delta activity. Four did not appear to have evolution to a different pattern. EEG recordings ended an average of 23 minutes (SD four minutes) after the initial pattern change.Conclusions:
In this cohort of 20 pediatric patients undergoing anesthesia induction with propofol, almost all EEGs displayed background slowing and discontinuity, sometimes including a burst suppression. Within an average of 25 minutes of recording, most EEGs became more continuous, though a significant minority became more discontinuous. Pediatric epileptologists must be familiar with these expected EEG changes during induction with propofol so that patients’ EEG findings are not mischaracterized.
Funding: N/A