Frequency and duration of BIS values outside 40–60 during blinded BIS recording in paediatric anaesthesia: a prospective observational study

This prospective observational study included 104 paediatric patients aged 1–19 years undergoing elective surgery under sevoflurane-based general anaesthesia and combined anaesthesia (general anaesthesia combined with a regional anaesthetic technique) between January 2022 and March 2024. BIS was recorded continuously while anaesthesiologists were blinded to the readings. Episodes of BIS 60 lasting ≥ 30 s were analysed.

Postoperative outcomes included emergence delirium (ED) (PAED score), postoperative nausea and vomiting (PONV), and other complications in patients admitted to the PACU. Overall, 85.6% of patients experienced at least one episode outside the recommended BIS range. The median time spent outside BIS 40–60 was 22 min (35.1% of the duration of surgery).

Episodes of BIS 60 occurred in 51.9% of patients. Blinded BIS monitoring revealed frequent and prolonged deviations from the conventionally recommended anaesthetic depth range in paediatric patients, even when anaesthesia was managed according to conventional physiological and clinical parameters. However, the clinical significance of these findings and their relationship to postoperative outcomes remain uncertain.

Electroencephalography / electroencephalogram Paediatric anaesthesia emergence delirium (scale) We would like to sincerely thank all our colleagues who participated in the study and kindly agreed to perform the measurements. Your willingness and cooperation made this research possible, and we truly appreciate your contribution. We also thank everyone who participated in data collection.

This research was supported by Specific University Research provided by MŠMT (MUNI/A/1781/2025, MUNI/A/1831/2025) and supported by MH CZ – DRO (FNBr, 65269705). Tereza Bönischová and Eva Klabusayová contributed equally to this work. Department of Paediatric Anaesthesiology and Intensive Care Medicine, Faculty of Medicine, University Hospital Brno, Masaryk University, Brno, Czech Republic Tereza Bönischová, Eva Klabusayová, Martina Klincová, Tereza Kramplová, Hana Harazim, Dominik Fabián, Jozef Klučka & Petr Štourač Department of Simulation Medicine, Faculty of Medicine, Masaryk University, Brno, Czech Republic Department of Applied Mathematics, Faculty of Electrical Engineering and Computer Science, VSB – Technical University of Ostrava, Ostrava, Czech Republic Faculty of Medicine, Masaryk University, Brno, Czech Republic Veronika Kašová, Lucie Obermannová & Milka Latinovič The authors declare no competing interests.

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