Table 1 Baseline characteristics of subjects with and without clamping of chest tube before removal

Age (year)

Male sex

112

(91.8)

49

(90.7)

63

(92.6)

Smoking^a

 Never

20

(16.5)

6

(11.3)

14

(20.6)

 Ex-smoker

69

(57.0)

34

(64.2)

35

(51.5)

 Current smoker

32

(26.4)

13

(24.5)

19

(27.9)

Charlson comorbidity index

Secondary pneumothorax

86

(70.5)

46

(85.2)

40

(58.8)

Side of pneumothorax

 Right

47

(38.5)

23

(42.6)

24

(35.3)

 Left

74

(60.7)

31

(57.4)

43

(63.2)

 Bilateral

1

(0.8)

1

(1.5)

Size of pneumothorax^b

No. of previous episodes

 0

75

(61.5)

35

(64.8)

40

(58.8)

 1

29

(23.8)

15

(27.8)

14

(20.6)

 2

10

(8.2)

2

(3.7)

8

(11.8)

  ≥ 3

8

(6.6)

2

(3.7)

6

(8.8)

Total no. of chest tube(s)

 1

106

(86.9)

44

(81.5)

62

(91.2)

 2

11

(9.0)

6

(11.1)

5

(7.4)

  ≥ 3

5

(4.1)

4

(7.4)

1

(1.5)

Prior medical pleurodesis

61

(50)

29

(53.7)

32

(47.1)

Type of chest tube

  ≥ fr 18

70

(57.4)

29

(53.7)

41

(60.3)

 fr 12

51

(41.8)

24

(44.4)

27

(39.7)

 fr 8

1

(0.8)

1

(1.9)

Clinical setting

 Medical

116

(95.1)

48

(88.9)

68

(100)

 Non-medical

6

(4.9)

6

(11.1)

Duration of cessation of air leak before clamping/ removal (hour)^d

Duration of drainage (day)