Table 1.

Preoperative patient characteristics

	PEEP group (n = 31)	ZEEP group (n = 29)
Age (years)	39 ± 9	35 ± 10
Sex
Male	9 (29)	1 (3)
Female	22 (71)	28 (97)
Height (cm)	169 ± 7	166 ± 8
Weight (kg)	113 ± 15	109 ± 12
Body mass index (kg m−2)	39 ± 3.3	40 ± 2.8
35–42.9	27 (87)	25 (86)
43–49.9	4 (13)	4 (14)
Haemoglobin (g l−1)	140 ± 11.1	135 ± 9.6
ASA physical status classification
2	20 (65)	18 (62)
3	11 (35)	11 (38)
Type of surgery
Gastric bypass	25 (81)	23 (79)
Gastric sleeve	6 (19)	6 (21)

Data are presented as mean ± SD or number (%).