Table 1 Baseline and perioperative data before the study-drug administration

Age, mean ± SD, years

48 ± 11

51 ± 11

0.204

Male, n (%)

15 (50.0)

13 (43.3)

0.605

Body mass index, mean ± SD, kg/m²

23.8 ± 3.8

25.2 ± 4.1

0.165

Education, median (IQR), years

15 (7–16)

12 (7–15)

0.521

Preoperative comorbidity, n (%)

Hypertension

6 (20.0)

6 (20.0)

> 0.999

Coronary heart disease

1 (3.3)

0 (0.0)

> 0.999

Diabetes mellitus

1 (3.3)

2 (6.7)

> 0.999

Ischemic stroke

1 (3.3)

0 (0.0)

> 0.999

History of smoking,* n (%)

10 (33.3)

9 (30.0)

0.781

Alcoholism,† n (%)

4 (13.3)

4 (13.3)

> 0.999

Preoperative ASA classification, n (%)

0.185

I

0 (0.0)

2 (6.7)

II

28 (93.3)

27 (90.0)

III

2 (6.7)

1 (3.3)

Duration of anesthesia, mean ± SD, hours

6.5 ± 1.8

6.5 ± 1.7

0.979

Medication during anesthesia, n (%)

Midazolam

16 (53.3)

20 (66.7)

0.292

Propofol

30 (100.0)

30 (100.0)

> 0.999

Etomidate

13 (43.3)

10 (33.3)

0.426

Dexmedetomidine

4 (13.3)

1 (3.3)

0.353

30 (100.0)

30 (100.0)

> 0.999

Remifentanil

28 (93.3)

27 (90.0)

0.640

26 (86.7)

28 (93.3)

0.389

Desflurane

1 (3.3)

0 (0.0)

> 0.999

Glucocorticoids

1 (3.3)

1 (3.3)

> 0.999

Atropine

8 (26.7)

7 (23.3)

0.766

Penehyclidine Hydrochloride

9 (30.0)

15 (50.0)

0.114

Mannitol

9 (30.0)

12 (40.0)

0.417

Duration of operation, mean ± SD, hours

4.7 ± 1.4

4.9 ± 1.6

0.775

Body position, n (%)

0.190

Supine

15 (50.0)

10 (33.3)

Lateral

15 (50.0)

20 (66.7)

Frontal approach of operation, n (%)

10 (33.3)

9 (30.0)

0.781

Location of the tumor, n (%)

0.289

Supratentorial

14 (46.7)

9 (30.0)

Infratentorial

11 (36.7)

17 (56.7)

Others‡

5 (16.6)

4 (13.3)

Malignant tumor, n (%)

7 (23.3)

6 (20.0)

0.754

Total intraoperative infusion, median (IQR), ml

2600 (2463–3138)

2600 (2250–3513)

0.715

Estimated intraoperative bleeding, median (IQR), ml

200 (200–362)

225 (200–425)

0.464

Blood transfusion during operation, n (%)

4 (13.3)

7 (23.3)

0.317

Episode of intraoperative hypotension, n (%)

6 (20.0)

8 (26.7)

0.761

APACHE II score on ICU admission, median (IQR)

10 (7–12)

10 (8–12)

0.316

GCS on ICU admission, median (IQR)

14 (14–14)

14 (10–14)

0.334

Endotracheal intubation on ICU admission, n (%)

4 (13.3)

8 (26.7)

0.210

Patient-controlled intravenous analgesia, n (%)

12 (40.0)

11 (36.7)

0.791

Emergence delirium before study drug infusion, n (%)

4 (13.3)

0 (0.0)

0.038

Time interval between the end of operation and study drug infusion, mean ± SD, hours

5.5 ± 2.1

5.8 ± 2.0

0.613