Table 2.

Comparison of baseline characteristics between the sufentanil and butorphanol groups

	Sufentanil group (n = 55)	Butorphanol group (n = 55)	P value
Age	71.0 ± 5.7	69.6 ± 5.7	0.199
Gender (male/female)	32/23	34/21	0.698
ASA (I/II/III)	0/33/22	0/30/25	0.847
Weight (kg)	63.6 ± 10.3	68.6 ± 11.3	0.058
BMI (kg/m2)	21.1 ± 1.8	20.81 ± 1.7	0.403
Smoking (yes/no)	25/30	26/29	0.703
PONV or motion sickness history (yes/no)	14/41	20/35	0.218
Operation time (h)	3.41 ± 1.30	3.25 ± 1.07	0.484
Intraoperative infusion volume (mL)	1290.9 ± 404.7	1243.6 ± 316.8	0.497
Postoperative 24-h infusion volume (mL)	2380.9 ± 137.6	2342.7 ± 133.8	0.143
Postoperative 48-h infusion volume (mL)	2152.7 ± 128.9	2125.5 ± 117.4	0.249

ASA: American Society of Anesthesiologists; BMI: Body mass index; PONV: Postoperative nausea and vomiting.