Effect of bispectral index-guided anaesthesia versus standard practice on recovery after general anaesthesia in children: A systematic review and meta-analysis

Abstract

Background and Aims:

Accurate assessment of anaesthesia depth in children is essential for individualised anaesthetic monitoring and remains a considerable challenge in clinical practice. The bispectral index (BIS), a widely used clinical tool for monitoring anaesthesia depth, has been subject to controversy regarding its effectiveness in improving recovery quality in children after anaesthesia. This meta-analysis aimed to compare the impact of BIS-guided anaesthesia versus traditional anaesthesia depth monitoring on postoperative recovery quality in children undergoing general anaesthesia.

Methods:

A comprehensive search of databases, including PubMed, Cochrane Library, Embase, Web of Science, Scopus, and OVID, for articles published up to June 2024, updated in May 2025 was conducted. Randomised controlled trials comparing BIS-guided titration of anaesthetic agents to standard practice using haemodynamic parameters and clinical signs were analysed. Outcomes assessed included surgical duration, anaesthesia duration, end-tidal sevoflurane concentration, propofol consumption, first response time, eye-opening time, extubation time, post-anaesthesia emergence agitation scores, and post-anaesthesia care unit (PACU) stay duration.

Results:

Compared to traditional anaesthesia depth monitoring, children monitored with BIS during anaesthesia maintenance had significantly lower end-tidal sevoflurane concentrations. In addition, BIS monitoring was associated with significantly shorter times for first response, eye-opening, extubation, and PACU stay. Other outcome measures did not show significant differences.

Conclusions:

BIS monitoring in children undergoing general anaesthesia is associated with improved recovery quality, as evidenced by reduced times for first response, eye-opening, extubation, and PACU stay.

INTRODUCTION

Accurate monitoring and regulation of anaesthesia depth in children remains a key challenge for anaesthesiologists. Traditional methods for assessing anaesthesia depth primarily rely on intraoperative haemodynamic indicators, and pharmacokinetic models provide valuable guidance for adjusting anaesthetic drug dosages.[1] However, these approaches do not meet the demand for individualised monitoring. Inaccurate or delayed assessments of anaesthesia depth can lead to adverse events, such as intraoperative awareness or delayed emergence, resulting from insufficient or excessive anaesthesia. With advancements in artificial intelligence, electroencephalography (EEG) and its processed forms (pEEG) have introduced new possibilities for personalised anaesthesia depth monitoring. These methods include bispectral index (BIS), Narcotrend monitoring, and entropy indices.[1] Despite these developments, a dedicated pediatric-specific device for monitoring sedation depth remains unavailable. BIS, recognised as an objective and precise tool for monitoring anaesthesia depth,[2] has become one of the most widely used methods in clinical practice.

In adults, several meta-analyses have shown that BIS-guided anaesthesia can reduce intraoperative anaesthetic drug consumption, shorten extubation time, promote recovery, and decrease the incidence of postoperative adverse events.[3,4,5] However, owing to the immaturity of brain development in children and the substantial inter-individual variability, the effectiveness of BIS in pediatric anaesthesia depth monitoring remains controversial. Several studies suggest that BIS monitoring during paediatric anaesthesia can reduce anaesthetic drug usage and shorten recovery times; however, other findings contradict these conclusions, casting doubt on its reliability as a standard in paediatric anaesthesia monitoring.[6,7,8,9]

The objective of this systematic review and meta-analysis was to comprehensively assess the impact of BIS monitoring versus traditional anaesthesia depth monitoring methods on recovery quality in paediatric patients undergoing general anaesthesia, through comparison of intraoperative parameters and postoperative recovery outcomes.

METHODS

Literature search strategy

This study adhered to the guidelines of the Cochrane Handbook for Systematic Reviews and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol for conducting a systematic review of the impact of BIS monitoring on recovery quality in children after general anaesthesia. The study protocol was registered on the PROSPERO platform (ID: CRD 42024553844, dated 15 June 2024). We conducted a computer-based search of English-language databases, including PubMed, Cochrane Library, Embase and Web of Science, using the following search terms: bispectral index, recovery, children, randomised controlled trial, and others. Each database was searched from its start date to June 2024, and a further updated search was done till May 2025 [Supplementary Table 1].

Supplementary Table 1.

Literature Search Strategies

Cochrane Library
ID	Search	Hits
#1	MeSH descriptor: [Consciousness Monitors] explode all trees	241
#2	(Consciousness Monitor):ti,ab,kw or (Monitor, Consciousness):ti,ab,kw or (Monitors, Consciousness):ti,ab,kw or (Bispectral Index Monitor):ti,ab,kw or (Bispectral Index Monitors):ti,ab,kw or (Monitor, Bispectral Index):ti,ab,kw or (Monitors, Bispectral Index):ti,ab,kw or (Index of Consciousness-View Monitor):ti,ab,kw or (Index of Consciousness View Monitor):ti,ab,kw or (Index of ConsciousnessView Monitor):ti,ab,kw or (Cerebral State Index Monitor):ti,ab,kw or (bispectral index):ti,ab,kw or (BIS):ti,ab,kw	6213
#3	#1 or #2	6213
#4	MeSH descriptor: [Anesthesia Recovery Period] explode all trees	2422
#5	(Recovery Period, Anesthesia):ti,ab,kw or (Anesthesia Recovery Periods):ti,ab,kw or (Period, Anesthesia Recovery):ti,ab,kw or (Periods, Anesthesia Recovery):ti,ab,kw or (Recovery Periods, Anesthesia):ti,ab,kw or (Recovery):ti,ab,kw	86079
#6	(child):ti,ab,kw or (pediatric):ti,ab,kw or (children):ti,ab,kw	206002
#7	(randomized controlled trial):ti,ab,kw or (Randomized):ti,ab,kw or (Placebo):ti,ab,kw or (RCT):ti,ab,kw	1353111
#8	#4 or #5	86079
#9	#3 and #6 and #7 and #8	87
Embase
No.	Query	Results
#12	#6 AND #7 AND #10 AND #11	54
#11	“randomized controlled trial’:ab,ti OR ‘randomized’:ab,ti OR ‘placebo’:ab,ti”	1330929
#10	#8 OR #9	790064
#9	“Recovery?Period,? Anesthesia’:ab,ti OR ‘ Anesthesia?Recovery?Periods’:ab,ti OR ‘Period,? Anesthesia?Recovery’:ab,ti OR ‘Periods,? Anesthesia?Recovery’:ab,ti OR ‘Recovery?Periods,? Anesthesia’:ab,ti OR ‘Recovery’:ab,ti”	764433
#8	Anesthesia?recovery?period	14043
#7	#1 OR #2	112733
#6	#3 OR #4 OR #5	4202557
#5	pediatric	1379579
#4	“children’:ab,ti”	1785871
#3	child	3410448
#2	“(((((((((((consciousness AND monitor:ab,ti OR monitor,) AND consciousness:ab,ti OR monitors,) AND consciousness:ab,ti OR bispectral) AND index AND monitor:ab,ti OR bispectral) AND index AND monitors:ab,ti OR monitor,) AND bispectral AND index:ab,ti OR monitors,) AND bispectral AND index:ab,ti OR index) AND of AND ‘consciousness view’ AND monitor:ab,ti OR index) AND of AND consciousness AND view AND monitor:ab,ti OR index) AND of AND consciousnessview AND monitor:ab,ti OR cerebral) AND state AND index AND monitor:ab,ti OR bispectral) AND index:ab,ti OR bis:ab,ti”	111811
#1	(‘consciousness’/exp OR consciousness) AND (‘monitors’/exp OR monitors)	1137
Ovid
No.	Query	Results
#1	(Consciousness Monitors or Consciousness Monitor or Monitor, Consciousness or Monitors, Consciousness or Bispectral Index Monitor or Bispectral Index Monitors or Monitor, Bispectral Index or Monitors, Bispectral Index or Index of Consciousness-View Monitor or Index of Consciousness View Monitor or Index of ConsciousnessView Monitor or Cerebral State Index Monitor or bispectral index or BIS).ti,ab,kw.	111641
#2	(Recovery Period, Anesthesia or Anesthesia Recovery Periods or Period, Anesthesia Recovery or Periods, Anesthesia Recovery or Recovery Periods, Anesthesia or Recovery).ti,ab,kw.	343740
#3	(child or pediatric or children).ti,ab,kw.	1501527
#4	(randomized controlled trial or Randomized or placebo).ti,ab,kw.	787005
#5	#1 and #2 and #3 and #4	28
PubMed
No.	Query	Results
#5	(“consciousness monitors”[Title/Abstract] OR “consciousness monitor”[Title/Abstract] OR “monitor consciousness”[Title/Abstract] OR “monitors consciousness”[Title/Abstract] OR “bispectral index monitor”[Title/Abstract] OR “bispectral index monitors”[Title/Abstract] OR “monitor bispectral index”[Title/Abstract] OR “monitors bispectral index”[Title/Abstract] OR “index of consciousness view monitor”[Title/Abstract] OR “index of consciousness view monitor”[Title/Abstract] OR ((“abstracting and indexing”[MeSH Terms] OR (“abstracting”[All Fields] AND “indexing”[All Fields]) OR “abstracting and indexing”[All Fields] OR “Index”[All Fields] OR “indexed”[All Fields] OR “indexes”[All Fields] OR “indexing”[All Fields] OR “indexation”[All Fields] OR “indexations”[All Fields] OR “indexe”[All Fields] OR “indexer”[All Fields] OR “indexers”[All Fields] OR “indexs”[All Fields]) AND “Monitor”[Title/Abstract]) OR “cerebral state index monitor” [Title/Abstract] OR “bispectral index”[Title/Abstract] OR “BIS”[Title/Abstract]) AND (“anesthesia recovery period”[Title/Abstract] OR “recovery period anesthesia “[Title/Abstract] OR “ anesthesia recovery periods”[Title/Abstract] OR ((“Period”[All Fields] OR “periodic”[All Fields] OR “periodical”[All Fields] OR “periodically”[All Fields] OR “periodicals”[All Fields] OR “periodicity”[MeSH Terms] OR “periodicity”[All Fields] OR “periodicities”[All Fields] OR “Periods”[All Fields]) AND “ anesthesia recovery”[Title/Abstract]) OR ((“Period”[All Fields] OR “periodic”[All Fields] OR “periodical”[All Fields] OR “periodically”[All Fields] OR “periodicals”[All Fields] OR “periodicity”[MeSH Terms] OR “periodicity”[All Fields] OR “periodicities”[All Fields] OR “Periods”[All Fields]) AND “ anesthesia recovery”[Title/Abstract]) OR ((“recoveries”[All Fields] OR “Recovery”[All Fields]) AND “periods anesthesia “[Title/Abstract]) OR “Recovery”[Title/Abstract]) AND (“child”[Title/Abstract] OR “pediatric”[Title/Abstract] OR “children”[Title/Abstract]) AND (“randomized controlled trial”[Title/Abstract] OR “Randomized”[Title/Abstract] OR “Placebo”[Title/Abstract] OR “RCT”[Title/Abstract])	31
#4	“randomized controlled trial”[Title/Abstract] OR “Randomized”[Title/Abstract] OR “Placebo”[Title/Abstract] OR “RCT”[Title/Abstract]	850,463
#3	“child”[Title/Abstract] OR “pediatric”[Title/Abstract] OR “children”[Title/Abstract]	1,735,795
#2	“anesthesia recovery period”[Title/Abstract] OR “recovery period anesthesia “[Title/Abstract] OR “ anesthesia recovery periods”[Title/Abstract] OR ((“Period”[All Fields] OR “periodic”[All Fields] OR “periodical”[All Fields] OR “periodically”[All Fields] OR “periodicals”[All Fields] OR “periodicity”[MeSH Terms] OR “periodicity”[All Fields] OR “periodicities”[All Fields] OR “Periods”[All Fields]) AND “ anesthesia recovery”[Title/Abstract]) OR ((“Period”[All Fields] OR “periodic”[All Fields] OR “periodical”[All Fields] OR “periodically”[All Fields] OR “periodicals”[All Fields] OR “periodicity”[MeSH Terms] OR “periodicity”[All Fields] OR “periodicities”[All Fields] OR “Periods”[All Fields]) AND “ anesthesia recovery”[Title/Abstract]) OR ((“recoveries”[All Fields] OR “Recovery”[All Fields]) AND “periods anesthesia “[Title/Abstract]) OR “Recovery”[Title/Abstract]	579,947
#1	“consciousness monitors”[Title/Abstract] OR “consciousness monitor”[Title/Abstract] OR “monitor consciousness”[Title/Abstract] OR “monitors consciousness”[Title/Abstract] OR “bispectral index monitor”[Title/Abstract] OR “bispectral index monitors”[Title/Abstract] OR “monitor bispectral index”[Title/Abstract] OR “monitors bispectral index”[Title/Abstract] OR “index of consciousness view monitor”[Title/Abstract] OR “index of consciousness view monitor”[Title/Abstract] OR ((“abstracting and indexing”[MeSH Terms] OR (“abstracting”[All Fields] AND “indexing”[All Fields]) OR “abstracting and indexing”[All Fields] OR “Index”[All Fields] OR “indexed”[All Fields] OR “indexes”[All Fields] OR “indexing”[All Fields] OR “indexation”[All Fields] OR “indexations”[All Fields] OR “indexe”[All Fields] OR “indexer”[All Fields] OR “indexers”[All Fields] OR “indexs”[All Fields]) AND “Monitor”[Title/Abstract]) OR “cerebral state index monitor”[Title/Abstract] OR “bispectral index”[Title/Abstract] OR “BIS”[Title/Abstract]	121,550
Scopus
Query		Results
(TITLE-ABS-KEY (“Consciousness Monitors” OR “Consciousness Monitor” OR “Monitor, Consciousness” OR “Monitors, Consciousness” OR “Bispectral Index Monitor” OR “Bispectral Index Monitors” OR “Monitor, Bispectral Index” OR “Monitors, Bispectral Index” OR “Index of Consciousness-View Monitor” OR “Index of Consciousness View Monitor” OR “Index of ConsciousnessView Monitor” OR “Cerebral State Index Monitor” OR “bispectral index” OR “BIS”) AND TITLE-ABS-KEY (“Anesthesia Recovery Period” OR “Recovery Period, Anesthesia” OR “ Anesthesia Recovery Periods” OR “Period, Anesthesia Recovery” OR “Periods, Anesthesia Recovery” OR “Recovery Periods, Anesthesia” OR “Recovery”) AND TITLE-ABS-KEY (“child” OR “pediatric” OR “children”) AND TITLE-ABS-KEY (“randomized controlled trial” OR “Randomized” OR “Placebo” OR “RCT”))		96
Web of Science
No.	Query	Results
#1	randomized controlled trial or Randomized or placebo	3,012,549
#2	child or pediatric or children	3,762,890
#3	Recovery Period, Anesthesia or Anesthesia Recovery Periods or Period, Anesthesia Recovery or Periods, Anesthesia Recovery or Recovery Periods, Anesthesia or Recovery	1,620,848
#4	Consciousness Monitors or Consciousness Monitor or Monitor, Consciousness or Monitors, Consciousness or Bispectral Index Monitor or Bispectral Index Monitors or Monitor, Bispectral Index or Monitors, Bispectral Index or Index of Consciousness-View Monitor or Index of Consciousness View Monitor or Index of ConsciousnessView Monitor or Cerebral State Index Monitor or bispectral index or BIS	704,167
#5	#1 AND #2 AND #3 AND #4	89

ab=abstract; BIS=bispectral index; ID=identity document; kw=keyword; MeSH=Medical Subject Headings; NO=number; RCT=randomized controlled trial; ti=title identification

Inclusion and exclusion criteria

Based on the PICOS framework, the inclusion criteria were: (1) Population: Children aged ≤18 years undergoing general anaesthesia, regardless of gender. (2) Intervention: The experimental group received BIS-guided anaesthesia, with anaesthetic doses titrated to maintain BIS values within the target range. The control group underwent conventional anaesthesia depth monitoring based on minimum alveolar concentration values, haemodynamic parameters, and clinical signs. (3) Outcome Measures: Surgical time, anaesthesia time, first response time, eye-opening time, extubation time, end-tidal sevoflurane concentration, pediatric emergence agitation (PAED) scores, and post-anaesthesia care unit (PACU) stay duration. (4) Study Design: Randomised controlled trials. The exclusion criteria included (1) reviews, meta-analyses, and animal studies; (2) duplicate publications; (3) nonrandomised controlled trials; (4) studies with mismatched population, intervention, or outcome measures; and (5) studies from which valid data could not be obtained.

Literature screening and data extraction

Two researchers independently reviewed and selected studies based on the inclusion and exclusion criteria. Disagreements were resolved by a third researcher. Data extracted from each study included the first author, publication year, country or region, type of surgery, basic characteristics of the study population, sample size, and outcome measures. If data extraction was incomplete, the corresponding author of the study was contacted to obtain the missing data.

Quality assessment

Researchers utilised the Cochrane Risk of Bias tool to evaluate the methodological quality of the selected studies. Any disagreements were resolved by a third researcher. The evaluation criteria were: (1) Was random allocation used? (2) Was allocation concealment implemented? (3) Were the researchers blinded? (4) Was outcome assessment blinded? (5) Were data outcomes complete? (6) Was selective reporting of results observed? (7) Were other sources of bias present? Each item was categorised as “low risk,” “unclear risk,” or “high risk.”

Statistical analysis

Heterogeneity assessment

Statistical analyses were performed using RevMan (version 5.4) and Stata (version 17.0) software packages. Continuous outcome measures were expressed as mean differences (MD) accompanied by 95% confidence intervals (CIs). The I² index and Q-test were used to assess the heterogeneity among the included studies. Heterogeneity was considered present if I² ≥ 50% or the Q-test showed P < 0.1. A random-effects model was applied if heterogeneity persisted; otherwise, a fixed-effects model was used. The alpha level was set at 0.05 for null hypothesis rejection.

Subgroup analysis, meta-regression analysis, and sensitivity analysis

Subgroup and meta-regression analyses were conducted using predefined criteria, including age, types of surgery, and type of anaesthesia. To verify result stability, sensitivity analyses were performed through iterative exclusion of each included study, assessing the consistency of meta-analytic findings. Outcomes with high heterogeneity were prioritised for the analysis above.

Publication bias

Potential publication bias was examined through funnel plot visualisation, with additional quantitative verification via Begg’s and Egger’s statistical tests. A P value < 0.05 indicated potential publication bias.

Trial sequential analysis

Trial sequential analysis (TSA) was implemented to account for potential random errors arising from multiple testing and data sparsity, while simultaneously determining the necessary information size. The required information size (RIS) was computed to adjust for type I error inflation, maintaining an overall α-level of 5% and 80% statistical power. Cumulative Z-curves exceeding monitoring boundaries confirmed evidence sufficiency, whereas boundary noncrossing precluded definitive conclusions. The RIS was computed using TSA software (version 0.9.5.10 Beta).

RESULTS

Study selection and study characteristics

Systematic database screening initially yielded 385 candidate studies. Ultimately, 10 studies[10,11,12,13,14,15,16,17,18,19] met the inclusion criteria, comprising 1,160 patients. After successive screening, two studies by Frelich[19,20] were found to contain identical data; therefore, only one study was included. On an updated search in May 2025, no additional article was found. Figure 1 illustrates the study selection flow, while Table 1 summarises baseline characteristics of included studies, and Figures 2 and 3 present methodological quality assessments.

Figure 1.

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram

Table 1.

Basic characteristics of included studies

Author	Age (y), mean (SD)	Blinding	Single/ Multicentre	n	Country	Setting	Type of Surgery	Anaesthesia regimen	Intervention (BIS Version)	BIS Range	BIS, mean (SD)	Control	ASA
Bannister 2001(a)	B:0.2 (0.1) C:0.2 (0.1)	Double	Single	60	USA	OT, PACU	Inguinal hernia repair	Induction: sevoflurane 8% in 60% N2O in oxygen Maintenance: sevoflurane in 60% N2O/oxygen, caudal epidural block	BIS, Aspect EEG monitor (Model A-1050, Aspect Medical Systems, Newton, MA, USA)	40–60	Average BIS range during maintenance of anaesthesia: BIS:35.7 (9.6) C:36.2 (11.8)	Blinded BIS	NR
Bannister 2001(b)	B:2.2 (1.0) C:1.9 (1.0)	double	Single	67	USA	OT, PACU	Inguinal hernia repair	Induction:sevoflurane 8% in 60% N2O in oxygen Maintenance: sevoflurane in 60% N2O/oxygen, caudal epidural block, fentanyl 1–2 μg/kg or morphine 0.05–0.1 mg/kg	BIS, Aspect EEG monitor (Model A-1050, Aspect Medical Systems, Newton, MA, USA)	40–60	Average BIS range during maintenance of anaesthesia: BIS:54.8 (9.1) C:50.0 (14.1)	Blinded BIS	NR
Bannister 2001(c)	B:6.7 (2.5) C:6.1 (2.6)	Double	Single	75	USA	OT, PACU	Tonsillectomy/adenoidectomy	Induction:sevoflurane 8% in 60% N2O in oxygen Maintenance: sevoflurane in 60% N2O/oxygen, fentanyl 1–2 μg/kg or morphine 0.05–0.1 mg/kg	BIS, Aspect EEG monitor (Model A-1050, Aspect Medical Systems, Newton, MA, USA)	40–60	Average BIS range during maintenance of anaesthesia: BIS:47.2 (10.1) C:39.6 (11.5)	Blinded BIS	NR
Messieha 2005	B:4 (2) C:4 (2)	Single	Single	29	USA	OT, PACU	Dental rehabilitation	Induction:sevoflurane, fentanyl 1 μg/g, rocuronium 1 mg/kg, ondansetron 0.15 mg/kg Maintenance: sevoflurane	BIS	55–65	BIS values during induction general anaesthesia: BIS:51 (22) C:59 (18)	Blinded BIS	I-II
Bhardwaj 2010	B:6.3 (3.2) C:6 (3)	Single	Single	50	India	OT, PACU	Urogenital surgery	Induction: propofol 3 mg/kg morphine 0.1 mg/kg, and atracurium 0.5 mg/kg Maintenance: Nitrous oxide in oxygen and infuse propofol 150 μg/kg/min	BIS, Model A-2000 IPX2 (Aspect Medical Systems Inc., Newton, MA, USA)	45–60	Median BIS values during surgery: BIS:33–60 C:33–56	Blinded BIS	I
Liao 2011	B:6.0 (2.8) C:6.1 (2.8)	Double	Single	106	Taiwan	OT, PACU	Urologic outpatient surgery	Induction:8 vol% fraction inspired in combination with 50% N2O in oxygen Maintenance: sevoflurane concentration by 0.5% increments and fentanyl 1 mg/kg before incision	BIS, Pediatric BIS Sensor (Philips BIS module, Aspect Medical Systems’XP platform technology, Norwood, MA)	40-60	Mean BIS value during maintenance: BIS:47.6 (11.5) C:35.2 (11.5)	Blinded BIS	I-II
Bresil 2013(a)	B:1-3 C:1-3	Single	Single	24	Denmark	OT	tonsillectomy, adenotomy, myringotomy, laryngoscopy, bronchoscopy and esophagoscopy	Induction: remifentanil 2 μg/kg, 2.5-3.5 mg/kg propofol, infusion of 4 mg/kg/h propofol and further boluses of 0.1–0.2 mg/kg propofol Maintenance: remifentanil 0.5 μg/kg/min and infuse propofol	BIS, IntelliVue Patientmonitor MP70 (Philips Healthcare, Best, the Netherlands)	45–60	Average intraoperative BIS values: BIS:66 (4) C:65 (8)	Blinded BIS	I-II
Bresil 2013(b)	B:4-11 C:4-11	Single	Single	30	Denmark	OT	Tonsillectomy, adenotomy, myringotomy, laryngoscopy, bronchoscopy and esophagoscopy	Induction: remifentanil 2 μg/kg, 2.5–3.5 mg/kg propofol, infusion of 4 mg/kg/h propofol and further boluses of 0.1–0.2 mg/kg propofol Maintenance: remifentanil 0.5 μg/kg/min and infuse propofol	BIS, IntelliVue Patientmonitor MP70 (Philips Healthcare, Best, the Netherlands)	45–60	Average intraoperative BIS values: BIS:63 (43) C:66 (5)	Blinded BIS	I-II
Bresil 2013(c)	B:12-17 C:12-17	Single	Single	33	Denmark	OT	Tonsillectomy, myringo-tympanoplasty	Induction: remifentanil 2 μg/kg, 2.5–3.5 mg/kg propofol, infusion of 4 mg/kg/h propofol and further boluses of 0.1–0.2 mg/kg propofol Maintenance: remifentanil 0.5 μg/kg/min and infuse propofol	BIS, IntelliVue Patientmonitor MP70 (Philips Healthcare, Best, the Netherlands)	45-60	Average intraoperative BIS values: BIS:55 (4) C:58 (5)	Blinded BIS	I-II
Sargin 2015	B:9.75 (0.7) C:11.75 (0.82)	double	Single	40	Turkey	OT, PACU	dental rehabilitation	Induction: sevoflurane 8% in oxygen and rocuronium 0.6 mg/kg Maintenance: sevoflurane, remifentanil 0.25 μg/kg/min and paracetamol 10 mg/kg	BIS (BIS VISTA, Aspect Medical)	45–65	Summarise the BIS values changes at different time points in Group BIS	Standard practice	I–III
Sullivan 2020	B:9.0 (3.42) C:9.9 (3.01)	Single	Single	54	USA	OT, PACU	orthopedic procedures	No standardised regimen, but all patients received general anaesthesia with sevoflurane.	BIS	40–60	Average BIS values during anaesthesia: BIS:43.7 (7.59) C:42.2 (7.84)	Blinded BIS	I-II
Abdelzaam 2020	B:7.4 (2.57) C:7.28 (2.86)	double	Single	54	Egypt	OT, PACU	lower abdominal outpatient surgeries	Induction:7% fraction inspired in combination with 100% oxygen Maintenance: sevoflurane	BIS monitor (A.2000 Aspect Medical System)	40–60	No information	Standard practice	I-II
Liu 2022	B:1-3 C:1-3	Single	Single	375	China	OT, PACU	elective operations	Induction:propofol 2-3 mg/kg, sufentanil 0.2-0.3 μg/kg or fentany 2–3 μg/kg, rocuronium 0.5–0.7 mg/kg Maintenance:propofol 4–12 mg/kg/h and remifentanil 0.2–0.4 μg/kg/min	BIS monitoring instrument (Aspect Medical System, USA, Version 3.0)	45–60	Summarise the BIS values changes at eight time points in the two groups	Blinded BIS	I–II
Frelich 2024	B:4.6 (1.3) C:4.8 (1.3)	Double	Single	163	Czechia	OT, PACU	endoscopic adenoidectomy	Induction: 8% sevoflurane in an O2/air mixture, sufentanil 0.2 mg/kg and paracetamol 15 mg/kg Maintenance: sevoflurane	BIS index (Bispectral Index Monitoring System, MEDTRONIC)	40–60	No information	According to minimal alveolar concentration (MAC)	I–II

ASA=American Society of Anesthesiologists; BIS=bispectral index; C=control; EEG=electroencephalography; MAC=minimum alveolar concentration; N=total number of participants; NR=not reported; OT=operating theater; PACU=postoperative anaesthesia care unit; SD=standard deviation; USA=United States of America; y=year

Figure 2.

Risk of bias bar chart

Figure 3.

Quality assessment of included studies

Meta-analysis results

Intraoperative outcomes

1. Surgical Time: Eight studies[10,11,12,13,14,15,16,19] reported surgical time, and there was no significant difference in surgical time between the BIS-guided group and the control group (MD = 0.35, 95% CI: −2.02, 2.73, P = 0.77, random effects, I² = 58%, P = 0.006) [Figure 4a].

2. Anaesthesia Time: Seven studies[12,13,14,15,16,18,19] reported anaesthesia time. There was no statistically significant difference in anaesthesia time between the BIS-guided group and the control group (MD = 0.49, 95% CI: −0.53, 1.52, P = 0.35, fixed effects, I² = 35%, P = 0.14) [Figure 4b].

3. End-tidal Sevoflurane Concentration: Five studies[10,13,16,17,19] demonstrated significantly lower sevoflurane concentrations in the BIS-guided group (MD = −0.50, 95% CI: −0.69, −0.31, P < 0.01, random effects, I² = 81%, P < 0.01) [Figure 4c].

4. Propofol Consumption: Two studies[12,18] found no significant difference in propofol dosage (MD = 20.36, 95% CI: −0.43, 41.16, P = 0.05, fixed effects, I² = 20%, P = 0.26) [Figure 4d].

Figure 4.

Forest plots of intraoperative outcomes. (a) Time for surgical procedures (min). (b) Time for anaesthesia procedures (min). (c) End-tidal sevoflurane concentration (%). (d) Propofol dosage (mg). BIS = bispectral index; CI = confidence interval; df = degrees of freedom; I² = I-squared IV = inverse variance; SD = standard deviation

Post-anaesthesia recovery outcomes

1. First Response Time: Three studies[10,13,16] showed shorter first response time in the BIS-guided group (MD = −1.91, 95% CI: −3.07, −0.75, P = 0.001, random effects, I² = 60%, P = 0.04) [Figure 5a].

2. Eye-Opening Time: Four studies[12,13,14,15] found no significant difference in eye-opening time between the two groups (MD = −0.96, 95% CI: −3.39, 1.46, P = 0.44, random-effects model, I² = 75%, P = 0.001). [Figure 5b].

3. Extubation Time: Eight studies[10,13,15,16,18,19] demonstrated significantly shorter extubation time with BIS monitoring (MD = −1.54, 95% CI: −2.36, −0.72, P = 0.0002, random effects, I² = 72%, P = 0.0002) [Figure 5c].

4. PAED Scores: Three studies[16,17,19] compared emergence agitation scores between the two groups. The PAED scale was used in all studies, with a maximum score of 20. The results showed no significant difference in PAED scores (MD = −1.16, 95% CI: −2.88, 0.56, P = 0.19, random effects, I² = 74%, P = 0.02) [Figure 5d].

5. PACU Stay Time: Seven studies[10,11,13,15,16,17,18] reported reduced PACU stay in the BIS-guided group (MD = −7.62, 95% CI: −12.67, −2.57, P = 0.003, random effects, I² = 92%, P < 0.01) [Figure 5e].

Figure 5.

Forest plots of post-anaesthesia recovery outcomes. (a) Time for first response (min). (b) Time for eye-opening (min). (c) Time to extubation (min). (d) PAED scores (points) in PACU. (e) Time for discharge from PACU (min). BIS = bispectral index; CI = confidence interval; df = degrees of freedom; I² = I-squared; IV = inverse variance; PACU = postoperative anaesthesia care unit; PAED = pediatric anaesthesia emergence delirium; SD = standard deviation

Subgroup analysis, meta-regression analysis, and sensitivity analysis

Subgroup analysis

Subgroup analysis with age adjustment demonstrated a significantly shorter eye-opening time in the BIS-guided group compared to controls, specifically for children aged 4–11 years (MD = −3.26, 95% CI: −4.52, −2.01, P < 0.01, fixed effects, I² = 0%, P = 0.45) [Figure 5b].

Meta-regression analysis

Regression analysis revealed that the anaesthesia regimen and type of surgery had no significant effect on end-tidal sevoflurane concentration, first response time, eye-opening time, extubation time, and PACU stay time, indicating that these factors were not sources of heterogeneity [Supplementary Tables 2-6].

Supplementary Table 2.

Meta-regression analysis of end-tidal sevoflurane concentration

Subgroup	n	MD(95% CI)	I 2	P 1	P 2
Anaesthesia protocol					0.566
Inhalation anaesthesia with caudal epidural block	3	−0.59(−1.12, −0.07)	91.3%	<0.001
Inhalation anaesthesia	5	−0.46(−0.66, −0.27)	70.8%	0.008
Overall	8	−0.50(−0.69, −0.31)	81.0%	<0.001

CI: confidence interval; I²=I-squared; MD=mean differences; N=denotes the number of studies; P¹=heterogeneity within each subgroup; P²=heterogeneity between subgroups

Supplementary Table 6.

Meta-regression analysis of PACU stay time

Subgroup	n	MD(95%CI)	I2	P 1	P 2
Anaesthesia protocol					0.554
Inhalation anaesthesia with caudal epidural block	3	−4.55 (−8.97, −0.13)	51.9%	0.125
Inhalation anaesthesia	5	−10.82 (−18.89, −2.66)	92.0%	<0.001
Intravenous anaesthesia	1	−2.00 (−4.57, 0.57)	-	-
Type of surgery					0.221
Lower abdominal surgeries	3	−6.98 (−15.23, 1.27)	90.7%	<0.001
Otorhinolaryngology surgeries	2	−1.01 (−17.08, 15.05)	61.6%	0.106
Urological surgeries	1	−2.30 (−5.95, 1.35)	-	-
Dental rehabilitation	2	−21.94 (−28.00, −15.87)	17.2%	0.272
Elective surgeries	1	−2.00 (−4.57, 0.57)	-	-
Overall	9	−7.62 (−12.67, −2.57)	92%	<0.001

CI=confidence interval; I²=I-squared; PACU=postoperative anaesthesia care unit; MD=mean differences; N=denotes the number of studies; P¹=heterogeneity within each subgroup; P²=heterogeneity between subgroups

Supplementary Table 3.

Meta-regression analysis of first response time

Subgroup	n	MD(95%CI)	I 2	P 1	P 2
Anaesthesia protocol					0.276
Inhalation anaesthesia with caudal epidural block	3	−1.40(−2.87, 0.08)	64.3%	0.061
Inhalation anaesthesia	2	−2.78(−4.09, -1.48)	0.0%	0.605
Type of surgery					0.710
Lower abdominal surgeries	3	−1.46(−3.08, 0.15)	66.3%	0.051
Otorhinolaryngology surgeries	1	−2.80(−4.53, -1.07)	-	-
Urological surgeries	1	−2.50(−4.19, -0.81)	-	-
Overall	5	−1.91(−3.07, −0.75)	60.0%	0.040

CI=confidence interval; I²=I-squared; MD=mean differences; N=denotes the number of studies; P¹=heterogeneity within each subgroup; P²=heterogeneity between subgroups

Supplementary Table 4.

Meta-regression analysis of eye-opening time

Subgroup	n	MD(95%CI)	I 2	P 1	P 2
Anaesthesia protocol					0.243
Intravenous anaesthesia	4	−0.01(−2.63, 2.62)	63.6%	0.041
Inhalation anaesthesia	2	−3.74(−5.28, -2.19)	0.7%	0.316
Type of surgery					0.413
Dental rehabilitation	1	−3.97(−5.55, -2.39)	-	-
Otorhinolaryngology surgeries	3	0.51(−3.00, 4.01)	73.6%	0.023
Urological surgeries	2	−2.50(−4.19, –0.81)	0.0%	0.927
Overall	6	−0.96(−3.39, 1.46)	75.0%	0.001

CI=confidence interval; I²=I-squared; MD=mean differences; N=denotes the number of studies; P¹=heterogeneity within each subgroup; P²=heterogeneity between subgroups

Supplementary Table 5.

Meta-regression analysis of extubation time

Subgroup	n	MD(95%CI)	I2	P 1	P 2
Anaesthesia protocol					0.486
Inhalation anaesthesia with caudal epidural block	3	−2.97 (−5.30, −0.64)	65.0%	0.057
Inhalation anaesthesia	5	−1.29 (−2.26, −0.32)	76.4%	0.002
Intravenous anaesthesia	2	−0.90 (−3.77, 1.98)	66.4%	0.085
Type of surgery					0.541
Lower abdominal surgeries	3	−1.31 (−2.47, 0.16)	46.1%	0.156
Otorhinolaryngology surgeries	2	−2.04 (−6.25, 2.18)	86.1%	0.007
Urological surgeries	2	−1.03 (−3.19, 1.13)	55.2%	0.135
Dental rehabilitation	2	−3.36 (−4.69, −2.03)	0.0%	0.367
Elective surgeries	1	0.30 (−1.22, 1.82)	-	-
Overall	10	−1.91 (−3.07, −0.75)	72%	<0.001

N=denotes the number of studies; MD=mean differences; CI=confidence interval; I²=I-squared; P¹=heterogeneity within each subgroup; P²=heterogeneity between subgroups

Sensitivity analysis

Sensitivity analyses were conducted for outcomes with higher heterogeneity, such as end-tidal sevoflurane concentration, first response time, extubation time, PAED scores, and PACU stay time [Supplementary Figure 1 ^{(3.4MB, tif)} ]. Sensitivity analysis confirmed the robustness of conclusions, as the exclusion of individual studies did not significantly alter pooled effect sizes.

Publication bias

Funnel plots, complemented by Begg’s and Egger’s tests, assessed publication bias. Despite funnel plot asymmetry for multiple outcomes (anaesthesia time, end-tidal sevoflurane, eye-opening/extubation times, PAED scores, PACU stay), Begg’s and Egger’s tests showed no significant publication bias. Egger’s test suggested some publication bias for the outcome indicators of surgical time and first response time. In contrast, Begg’s test showed no clear evidence of publication bias [Table 2 and Supplementary Figure 2 ^{(3.7MB, tif)} ].

Table 2.

Outcomes of publication bias

Domains	Outcomes	Egger test	Begg test	Publication bias
Intraoperative outcomes	Surgical time	0.016	0.304	Yes
	Anaesthesia time	0.423	0.602	No
	End-tidal sevoflurane concentration	0.599	0.536	No
Post-anaesthesia recovery outcomes	First response time	0.028	0.221	Yes
	Eye-opening time	0.210	0.452	No
	Extubation time	0.212	0.152	No
	PAED scores	0.849	1.000	No
	PACU stay time	0.886	0.466	No

PACU=postoperative anaesthesia care unit; PAED=pediatric anaesthesia emergence delirium

Trial sequential analysis

TSA indicated inconclusive evidence for eye-opening time and PAED scores, with cumulative Z-curves remaining within monitoring boundaries. For end-tidal sevoflurane, first response, extubation, and PACU parameters, TSA confirmed robust evidence through Z-curves surpassing monitoring boundaries and accrued data exceeding RIS [Supplementary Figure 3 ^{(3.2MB, tif)} ].

DISCUSSION

Our study systematically assessed the application of BIS monitoring in pediatric anaesthesia in a comparative analysis with traditional anaesthesia depth measurement methods. This study comprehensively analysed the clinical outcomes of using BIS monitoring during anaesthesia, including its effect on an aesthetic dose and an aesthetic recovery period. The results showed that the BIS-guided group had shorter first response times, extubation times, and PACU stay times. In addition, BIS monitoring was associated with lower end-tidal sevoflurane concentrations, suggesting optimised anaesthetic titration.

As a prevalent pediatric inhalational anaesthetic, sevoflurane demonstrates a significant association with postoperative agitation.[21] Therefore, it is essential to minimise sevoflurane exposure while ensuring that children do not experience intraoperative awareness. The results of this meta-analysis indicated that the BIS-guided group had significantly lower end-tidal sevoflurane concentrations during anaesthesia than the control group, consistent with the findings of previous studies.[22,23,24] This demonstrated that EEG-guided anaesthesia can lower the sevoflurane needs in children undergoing general anaesthesia. Propofol, a frequently used intravenous anaesthetic, has a good correlation with BIS values.[25,26] However, our study found that BIS monitoring did not significantly reduce propofol consumption during anaesthesia, which contradicts the results of a meta-analysis by Park et al.[27] that included only adults but aligns with the findings of Gu et al.[4] in a study involving all age groups. This discrepancy may be owing to the cautious administration of propofol in pediatric patients under traditional anaesthetic depth monitoring to maintain hemodynamic stability and avoid adverse reactions, such as propofol infusion syndrome.[28]

Regarding recovery parameters, our findings indicate that, compared to traditional monitoring, children who received BIS-guided anaesthesia had significantly shorter first response times, eye-opening times, extubation times, and PACU stay times. These findings are consistent with previous meta-analyses conducted in adults.[3,4,5,29] This effect may be attributed to BIS enabling more precise titration of anaesthetic dosage, thereby facilitating faster postoperative recovery. Regarding eye-opening time, Bresil et al.[14] conducted a study stratifying patients by age. Our subgroup analysis of children within the inclusion criteria revealed that age was a source of heterogeneity. This could be due to differences in brain development across different age groups, suggesting that age-related differences in brain maturation may contribute to variations in recovery. Therefore, studies on perioperative EEG monitoring in children are continuously increasing, laying the foundation for the development of individualised anaesthetic depth prediction models for children in the future.[30,31,32,33] The PAED scale, widely used in clinical settings as a standardised tool for diagnosing postoperative delirium in children[34] was employed in this study. PAED scores showed no significant intergroup difference, aligning with Long et al.’s findings.[24] Recent meta-analyses in elderly patients have suggested that EEG-guided anaesthesia does not reduce the incidence of postoperative delirium.[35,36] Notably, in this meta-analysis, only the study by Frelich et al.[19] utilised the PAED scale to assess postoperative delirium, reporting a significantly lower incidence of emergence agitation in the BIS-guided group (12.8% vs. 35.1%). Future studies should investigate the impact of BIS monitoring on the emergence of agitation across different age groups, surgical types, and anaesthetic agents.

This study has certain limitations. First, it included various surgical types. Although no significant differences were observed in surgical and anaesthetic durations between the two groups, different surgical types and anaesthetic protocols may influence postoperative recovery, potentially affecting the accuracy of the results. Second, some studies in the BIS monitoring group had actual BIS values that were not maintained within the target range, and some outcome indicators lacked clear definitions, which may introduce bias. Third, this meta-analysis included a study of a heterogeneous patient population.[15] These patients may exhibit distinct neurophysiological responses to anaesthesia, potentially influencing BIS values or recovery parameters. While subgroup analyses based on neurodevelopmental status were not feasible due to limited data, future studies should stratify outcomes by developmental profiles to enhance generalizability. Finally, most included studies exhibited limited sample sizes and failed to assess critical postoperative adverse events such as agitation, delirium, nausea, and pain. To verify the effectiveness of BIS monitoring in pediatric populations, large-scale, multicenter, randomised controlled trials are required.

CONCLUSION

As the first systematic comparison of BIS monitoring versus standard an aesthetic depth monitoring in relation to postoperative recovery quality in children, this study shows that, compared to traditional an aesthetic depth monitoring, BIS monitoring during pediatric general anaesthesia helps shorten first response time, eye-opening time, extubation time, and PACU stay time, thereby improving the quality of recovery. BIS monitoring is a convenient and effective method for monitoring an aesthetic depth in children; however, large-scale clinical studies are necessary to establish its efficacy further in guiding anaesthetic depth management in children.

Presentation at conferences/CMEs and abstract publication

None.

Data availability

The data for this systematic review and/or meta-analysis may be requested with reasonable justification from the authors (via email to the corresponding author) and will be shared upon request.

Disclosure of use of artificial intelligence (AI)-assistive or generative tools

The AI tools or language models (LLM) have not been utilised in the manuscript, except that software has been used for grammar corrections.

Declaration of Use of Permitted Tools

The scales, and scores are freely available and not copyrighted.

Author contributions

All authors were involved in all steps of this systematic review and meta-analysis.

Conflicts of interest

There are no conflicts of interest.

Supplementary material

This article has supplementary material and can be accessed at this link. Supplementary Material at http://links.lww.com/IJOA/A34.

Supplementary Figure 1

Sensitivity analysis of outcomes (a) End-tidal sevoflurane concentration. (b) First response time. (c) Extubation time. (d) PAED scores. (e) PACU stay time. CI = confidence interval; PACU = postoperative anaesthesia care unit; PAED = pediatric anaesthesia emergence delirium

Supplementary Figure 2

Funnel plots of publication bias (a) Surgical time. (b) Anaesthesia time. (c) End-tidal sevoflurane concentration. (d) First response time. (e) Eye-opening time. (f) Extubation time. (g) PAED scores. (h) PACU stay time. PACU = postoperative anaesthesia care unit; PAED = pediatric anaesthesia emergence delirium

Supplementary Figure 3

Trial sequential analysis of outcomes (a) End-tidal sevoflurane concentration. (b) First response time. (c) Eye-opening time. (d) Extubation time. (e) PAED scores. (f) PACU stay time. PACU = postoperative anaesthesia care unit; PAED = pediatric anaesthesia emergence delirium; RIS = required information size

Funding Statement

Nil.