EEG-guided Propofol Sedation Versus Standard Care for Oesophagogastroduodenoscopy and Colonoscopy in Children: A Randomised Controlled Trial to Improve Sedation Safety and Experience

BACKGROUND AND RATIONALE Oesophagogastroduodenoscopy (OGD) and colonoscopy in children are often performed under deep sedation with propofol. Titration of propofol dosage is based solely on cardiorespiratory parameters obtained from standard ASA monitoring. However, this method of propofol titration does not allow visualisation of the patients' brain response and often leads to under- or over-sedation. Under-sedation can lead to undesirable intra-operative movement and potential awareness, while over-sedation is associated with complications such as apnea, hypoxaemia, hypotension, prolonged time to awakening and delay in PACU discharge.(1,2)

Patients are often over-sedated during propofol anaesthesia. A study in adults undergoing colonoscopy using electroencephalography (EEG) monitoring showed that although providers planned for moderate-to-deep sedation, retrospective review of the EEG revealed that many patients were under general anesthesia, often with burst suppression (3) EEG burst suppression has been linked to postoperative deliriumin the elderly (4), and anesthesia titration to minimize burst suppression may decrease the incidence of postoperative delirium. Likewise, over-sedation and EEG isoelectric events are common in children undergoing propofol anesthesia with dosing based solely on population pharmacokinetics and patient haemodynamics. (5)

It was recently proposed that EEG monitoring and guidance during anaesthesia and sedation in children allows direct visualisation of each patient's brain response and complements current standard monitoring to enhance patient safety and experience.(2) EEG-guidance has been shown to reduce sevoflurane requirements in children undergoing general anaesthesia. (9) In particular, the EEG spectrogram, also called density spectral array (DSA), allows easy visualisation of the interactions between brain response, hemodynamic response, and changing procedural stimulation in real time, thus facilitating more precise and nuanced titration of anaesthetic agents. (2)

Processed EEG (pEEG) such as the bispectral index (BIS), Narcotrend index (NI) and patient state index (PSI) are dimensionless numbers derived from the EEG using manufacturers' algorithms to quantify anaesthetic depth (6). However, given the lack of clarity on how different pEEG numbers are computed and how they relate to fundamental neurophysiological properties of the developing brain, it is important to interpret the pEEG number in relation to the raw EEG waveform and spectrogram.

Only two small studies have compared EEG-guided propofol anaesthesia with standard care in children, both using the Narcotrend Index (NI). NI-guidance was shown to result in slightly faster recovery and lower drug consumption.(7)(8). To date, no study has utilised the spectrogram together with the pEEG number to guide anaesthesia. The investigators aim to compare EEG-guidance using Sedline EEG and spectrogram, in addition to the PSI, with standard care in children undergoing propofol TIVA for OGD and colonoscopy. Better visualisation of the brain response using the spectrogram may lead to more precise titration of propofol doses, lower propofol consumption and greater reduction in wake up time.