Factor

n

Air (+)

%

ERCP + sphincterotomy

49

7

14.3

Procedure duration < 30 min

36

4

11.1

CBD stones removal

26

3

11.5

Use of biliary baskets

22

3

13.6

Juxtapapillary diverticulum

20

1

5.0

Procedure duration > 30 min

14

3

21.4

Large stones removal

12

2

16.7

Precut

10

1

10.0

Use of balloon

4

0

0