2020 Jul 02

Amended

Number of participants for the outcome 'Time to discharge from PACU' corrected in Summary of findings table 2 and Abstract.

2018 Jun 30

Amended

Typo in 'what's new corrected' (the following line: 'the result of our updated review published in 2014 seems contradictory to the result in a recent review published in 2016 by Messina et al' was repeated.

2017 Sep 11

Amended

We made the following corrections to the published review:

• We added a new paragraph to Measures of treatment effect “We used SMD to determine the overall effect of the BIS on requirements of the three volatile anaesthetics (desflurane, isoflurane, and sevoflurane) and expressed it as standardized mean difference of minimal alveolar concentration equivalents (MAC SMD equivalents). We interpreted the SMD as follows: 0.2 represents a small effect, 0.5 a moderate effect, and 0.8 a large effect.”(Higgins 2011)

• We changed paragraph seven, (sub heading Requirement of anaesthetics) Effects of interventions' to read 'The combined results for all volatile anaesthetics from 14 studies with a total of 985 participants demonstrated a significant effect of BIS monitoring in reducing the use of volatile anaesthetics, with an overall decrease of 0.65 MAC SMD equivalents (985 participants; 95% CI ‐1.01 to ‐0.28; I² = 86%) (Analysis 3.2). The requirement for sevoflurane was decreased by 0.52 MAC SMD equivalents (573 participants; 95% CI ‐0.87 to ‐0.18; I² = 74%). The MAC equivalent reduction for sevoflurane was ‐0.15, 95% CI (‐0.25 to ‐0.05).The requirement for desflurane was decreased by 1.02 MAC SMD equivalents (352 participants; 95% CI ‐2.03 to ‐0.10; I² = 94%). The MAC equivalent reduction for desflurane was ‐0.11 to 95% CI (‐0.25 to‐0.03).'

• We added a new reference (Messina 2016)

• We added a new paragraph to Agreements and disagreements with other studies or reviews: the result of our updated review published in 2014 seems contradictory to the result in a recent review published in 2016 by Messina et al (Messina 2016), regarding the effect of BIS‐guided anaesthesia on the risk of intraoperative recall awareness. This could be explained by the differences between the two reviews. Our review focused only on studies which were conducted in surgical patients at a high risk of intraoperative recall awareness. Whereas Messina 2016, included studies with mixed groups of surgical patients (with or without risk of intraoperative recall awareness). Furthermore, our review performed sub‐group analyses based on studies using clinical signs or ETAG as their anaesthetic guide in the standard practice group. While Messina 2016, included all studies regardless as to whether they used clinical signs or ETAG as an anaesthetics guide in the standard practice group. The result favouring BIS monitoring for definite awareness could only be demonstrated in our sub‐group analysis, where clinical signs were used as an anaesthetic guide in the standard practice group.

• In addition we reran the search on 27th February 2017. We identified 14 new studies of interest. These 14 studies of interest are not fully incorporated into the results of the review. There are now 17 studies awaiting classification. They will be dealt with when we update the review.

2010 Sep 03

New search has been performed

• We re‐ran the searches from May 2007 until May 2009. We found 14 new trials (Aime 2006; Akcali 2008; Aksun 2007; Avidan 2008; Chiu 2007; Ibraheim 2008; Mayer 2007; Muralidhar 2008; Zohar 2006; Leslie 2005b; Lindholm 2008; Pavlin 2005; Schulz 2007; Vedtofte 2007). Of those 14 trials we included seven randomized controlled trials in this update (Aime 2006; Avidan 2008; Chiu 2007; Ibraheim 2008; Mayer 2007; Muralidhar 2008; Zohar 2006) and excluded six trials (Akcali 2008; Leslie 2005b; Lindholm 2008; Pavlin 2005; Schulz 2007; Vedtofte 2007); one trial (Aksun 2007) is still awaiting assessment.

• We included four studies (Boztug 2006; Bruhn 2005; Kreuer 2005; Leslie 2005a) awaiting assessment in the first publication in this updated review.

• In total, this review now contains 31 included and 17 excluded studies.

• The additional included studies did not change the conclusions of this review.

• We added five new references to the additional references (Gonsowski 1995; Higgins 2008; Hozo 2005; Liu 2004; RevMan 5.0).

• One previous reference (Leslie 2005) was modified to Leslie 2005a.

• For studies reporting medians and ranges or interquartile ranges (IQR) (Paventi 2001; Struys 2001; Tufano 2000), we recalculated standard deviations (SD) by using the following formulas:

SD = IQR/1.35; SD = range /4 (for n < 70); or SD = range/6 (for n > 70).

• We used the Peto method for computing OR (95% CI) in this updated review.

• These changes did not affect the conclusions of the review.

• We included risk of bias and summary of findings tables in this updated version.

• We included a new plain language summary.

2008 Jan 10

Amended

Converted to new review format.

2017 May 10

Amended

Converted to new review format.