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

From: Clamping of chest drain before removal in spontaneous pneumothorax

  All Clamping of chest tube P-value*
No Yes
(n = 122) (n = 54) (n = 68)
Age (year) 59.2 ± 22.9 64.8 ± 20.1 54.8 ± 24.1 0.014
Male sex 112 (91.8) 49 (90.7) 63 (92.6) 0.749
Smokinga        0.284
 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 1.8 ± 2.0 1.7 ± 2.0 1.9 ± 2.1 0.484
Secondary pneumothorax 86 (70.5) 46 (85.2) 40 (58.8) 0.002
Side of pneumothorax        0.570
 Right 47 (38.5) 23 (42.6) 24 (35.3)  
 Left 74 (60.7) 31 (57.4) 43 (63.2)  
 Bilateral 1 (0.8) 0 1 (1.5)  
Size of pneumothoraxb 56.6 ± 24.9 53.0 ± 26.0 59.1 ± 24.2 0.404
No. of previous episodes        0.229
 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)        0.211
 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) 0.466
Type of chest tube        0.456
  ≥ 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) 0  
Clinical setting        0.006
 Medical 116 (95.1) 48 (88.9) 68 (100)  
 Non-medical 6 (4.9) 6 (11.1) 0  
Duration of cessation of air leak before clamping/ removal (hour)d 45.3 ± 33.6 58.3 ± 37.5 35.3 ± 26.5 < 0.001
Duration of drainage (day) 10.5 ± 13.5 12.2 ± 15.7 9.1 ± 11.3 0.228
  1. Data are presented as mean ± SD or count (%)
  2. * Independent t-test, Pearson’s chi-square test or Fisher’s exact test
  3. a n (non-clamping) = 53
  4. b For non-loculated pneumothorax only: n (non-clamping) = 20, n (clamping) = 29
  5. d n (non-clamping) = 52, n (clamping) = 67