Table 1 Baseline patient characteristics before and after IPTW adjustment.

Patient characteristic

 Age (years)

59.6 (14.7)

57.8 (13.7)

0.376

58.7 (1.7)

56.7 (2.7)

0.531

0.131

 Male sex

75 (67%)

61(70%)

0.636

115 (83%)

89 (72%)

0.864

0.031

 BMI (kg/m²)

22.1 (3.9)

22.2 (3.6)

0.876

21.6 (0.5)

22.2 (0.5)

0.342

0.187

 Emergency

28 (25%)

11 (13%)

0.029

25 (16%)

12 (10%)

0.184

0.191

Underlying medical data

 ASA-PS classification (1/2/3/4)

5/25/78/4 (4/22/70/4%)

4/18/63/2 (5/21/72/2%)

0.966

7/28/118/3 (5/18/75/2%)

4/27/91/2 (3/22/74/2%)

0.828

0.136

 Hypertension

48 (43%)

21 (24%)

0.006

60 (39%)

36 (29%)

0.352

0.197

 CAOD

6 (5%)

4 (5%)

 > 0.999

5 (3%)

10 (8%)

0.254

0.191

 CHF

0 (0%)

0 (0%)

N/A

0 (0%)

0 (0%)

N/A

 COPD

10 (9%)

7 (8%)

0.825

19 (12%)

14 (11%)

0.903

0.030

 Previous radiotherapy for head and neck cancer

38 (34%)

28 (32%)

0.795

52 (33%)

31 (25%)

0.365

0.176

 Previous surgery for head and neck cancer

56 (50%)

44 (51%)

0.936

78 (50%)

62 (50%)

0.969

0.008

Pre-procedural data

 Airway bleeding (none/little/severe)

109/0/3 (97/0/3%)

83/1/3 (95/1/3%)

0.648

151/0/6 (96/0/4%)

119/1/4 (96/1/3%)

0.682

0.109

 Oxygen supplementation^a

14 (13%)

6 (7%)

0.192

15 (10%)

7 (6%)

0.333

0.144

 Initial oxygen saturation (%)

98.5 (1.5)

98.8 (1.6)

0.311

98.7 (0.2)

98.9 (0.2)

0.408

0.136