Table 1 Inclusion criteria for study selection in this meta-analysis

Number

Inclusion criteria

1

Original prospective cohort studies or randomized controlled trials (RCTs) published in full text and those for which we had full access to all original data and protocols.

2

The studies evaluated the differences of the effect of propofol and sevoflurane on postoperative cognitive functions.

3

Regarding the intervening measures between different groups, the only difference is that the two groups received propofol or sevoflurane, respectively. Other conditions should be the same.

4

Human studies.

5

Predefined outcomes: incidence of postoperative MMSE scores and the plasma protein S100β at various time points.

6

No minimal sample size or dosing regimen was required for inclusion.

Number

Exclusion criteria

1

The study did not have a control group of patients without propofol use or sevoflurane use.

2

They were case studies or case series.

3

The report focused exclusively on other topics or outcomes.

4

No human data were included.

5

Except for the difference of anaesthetic administration, there were other differences between the experimental groups and the control groups.

6

Reviews and duplicated publications.