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Effect of BIS-guided anesthesia on emergence delirium following general anesthesia in children

A prospective randomized controlled trial

Anaesthesia Critical Care & Pain Medicine

Submitted February 2024 by Dr Priya Sreedharan

Read by 56 Journal Watch subscribers

This prospective, randomised, double-blinded study was conducted at the University hospital of Ostrava in the Czech Republic. The study hypothesized that optimizing the depth of general anaesthesia using BIS as a guide (BIGA) could reduce the incidence of Emergence Delirium (ED) in the high-risk paediatric population (pre-school children, sevoflurane anaesthesia, otolaryngology procedure) compared with the traditional assessment of anaesthetic depth using MAC value.

165 children with ASA I- II undergoing endoscopic adenoidectomy under general anaesthesia were include in the study over a period of 1 year and were randomised into the BIGA or the non- BIGA group. Preoperative anxiolysis was provided with 0.5 mg/kg of midazolam, and preoperative anxiety was assessed by the modified Yale Preoperative anxiety scale (mYPAS).

All children received volatile induction with sevoflurane 8% in oxygen and air (1:1) mixture. Depth of anaesthesia was monitored with ET sevoflurane and BIS applied in the intervention group as soon as possible. Sufentanil 0.2 ug/kg and paracetamol 15 mg/kg was provided and LMA placed after the intravenous cannula was secured.
The intervention group had the BIS targeted at 40-60 by titrating the sevoflurane whilst the control group had sevoflurane maintained at MAC value 1-1.2. The airway was removed awake in theatre prior to PACU transfer.

The PAED score was used to assess ED in PACU, with scores more than 10 used to quantify significant ED. Only in cases of severe ED, as judged by the PACU physician, pharmacological treatment was provided with propofol 1 mg/kg or dexmedetomedine 0.5 ug/kg.

This study observed an incidence of ED of 35.1% in the control (non BIGA) group and 12.8% in the intervention (BIGA) group, which was statistically significant. Overall, children in the intervention group had lower PAED scores throughout the PACU stay. However, no significant differences between the groups were found in the incidence of pharmacological intervention in the treatment of severe ED or indeed the duration of the PACU stay.

They concluded that BIS guided anaesthesia depth maintenance during volatile anaesthetic in children reduces the incidence of ED and that they had a better overall recovery profile.

Take home message:
Incidence of postoperative ED can vary from 10-80% depending on multiple surgical, anaesthetic and patient factors in children. Multiple studies have shown that intravenous anaesthetic techniques using propofol reduce ED in children. This study joins some of the others to try to answer the question as to whether any intervention is helpful to reduce the incidence of ED with volatile anaesthetic technique. Whilst previous studies have not shown a reduction in volatile consumption in children with BIS guided anaesthesia, Han et al also showed a reduction in ED incidence with EEG-parameter-guided volatile anaesthetic depth.

It has been postulated that reduced ET sevoflurane concentrations both at maintenance and emergence contribute to reduced ED, although the exact mechanism is unclear.

However, the value is of this study is arguable, considering that the need for pharmacological intervention in both groups was the same, i.e. the incidence of severe ED was not different between the two groups. PAED score is a subjective assessment of ED and this can lead to variability in the scoring of individual patients. Furthermore, hypoactive ED, recently described by Lee-Archer et al, cannot be assessed by standard ED scales.

Non- pharmacological interventions remain the mainstay of both prevention and treatment of ED in high-risk children with pharmacological therapy reserved for the severe cases only. Monitoring anaesthetic depth using BIS guided parameters may assist in reducing incidence of ED.

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