Clinical and Nonclinical Effects on Operative Duration: Evidence from a Database on Thoracic Surgery
Table 2
Regression results for models using only the main effects and without interaction terms. Anaesthetist was excluded because of space.
Predictors
Percentage (%)
Results of model I
Results of model II
Coefficient
95% confidence interval
value
Coefficient
95% confidence interval
value
The day of the week
Sunday
1.22
−0.041
(−0.188, 0.106)
0.582
−0.045
(−0.193, 0.104)
0.556
Monday
1.80
−0.065
(−0.188, 0.058)
0.298
−0.077
(−0.201, 0.048)
0.227
Tuesday
20.77
0.056
(0.004, 0.109)
0.036
0.057
(0.005, 0.11)
0.033
Wednesday
20.03
0.033
(−0.02, 0.086)
0.224
0.035
(−0.018, 0.088)
0.197
Thursday
17.75
0.007
(−0.047, 0.062)
0.790
0.009
(−0.046, 0.063)
0.755
Friday
22.97
0.054
(0.003, 0.106)
0.039
0.053
(0.002, 0.105)
0.042
Number of surgeries in the OR in a day
Less than or equal to 4
−0.066
(−0.089, −0.043)
<0.001
−0.067
(−0.09, −0.044)
<0.001
More than 4
0.103
(0.034, 0.172)
0.003
0.109
(0.04, 0.178)
0.002
Number of surgeries a surgeon performed in a day
−0.061
(−0.08, −0.043)
<0.001
Position
2 surgeries in a day
39.86
2∼1
−0.075
(−0.123, −0.027)
0.002
2∼2
−0.067
(−0.115, −0.019)
0.006
3 surgeries in a day
24.97
3∼1
−0.169
(−0.234, −0.104)
<0.001
3∼2
−0.145
(−0.209, −0.081)
<0.001
3∼3
−0.163
(−0.228, −0.098)
<0.001
4 surgeries in a day
9.06
4∼1
−0.206
(−0.317, −0.095)
<0.001
4∼2
−0.141
(−0.257, −0.026)
0.017
4∼3
−0.129
(−0.238, −0.02)
0.021
4∼4
−0.148
(−0.255, −0.042)
0.006
5 surgeries in a day
1.18
5∼1
−0.287
(−0.601, 0.027)
0.073
5∼2
−0.051
(−0.364, 0.262)
0.749
5∼3
−0.132
(−0.445, 0.182)
0.410
5∼4
−0.443
(−0.784, −0.102)
0.011
5∼5
−0.105
(−0.419, 0.208)
0.510
Surgeons
Surgeon B
20.69
−0.094
(−0.139, −0.048)
<0.001
−0.098
(−0.144, −0.052)
<0.001
Surgeon C
19.75
0.058
(0.015, 0.107)
0.011
0.059
(0.013, 0.104)
0.011
Surgeon D
12.08
−0.006
(−0.058, 0.042)
0.826
−0.008
(−0.061, 0.045)
0.767
Surgeon E
6.94
−0.034
(−0.110, 0.032)
0.329
−0.039
(−0.109, 0.03)
0.271
Surgeon F
3.06
−0.272
(−0.366, 0.178)
<0.001
−0.270
(−0.365, −0.176)
<0.001
Surgery type
1. Lung cancer
4.04
0.155
(0.073, 0.237)
<0.001
0.157
(0.075, 0.239)
<0.001
2. Thoracoscopic pulmonary bullous resection
2.49
−0.369
(−0.476, −0.263)
<0.001
−0.375
(−0.482, −0.267)
<0.001
3. Thoracoscopic partial pulmonary lobectomy
18.07
0.009
(−0.037, 0.054)
0.710
0.009
(−0.036, 0.055)
0.684
4. Total pneumonectomy
1.10
0.388
(0.238, 0.538)
<0.001
0.391
(0.241, 0.541)
<0.001
5. Partial pulmonary lobectomy
11.42
0.110
(0.056, 0.163)
<0.001
0.108
(0.054, 0.161)
<0.001
6. Thoracoscopic exploration
1.31
0.031
(−0.106, 0.168)
0.655
0.033
(−0.104, 0.169)
0.641
7. Pulmonary wedge resection
2.37
−0.077
(−0.182, 0.027)
0.145
−0.077
(−0.181, 0.027)
0.147
8. Esophageal cancer
2.04
0.774
(0.661, 0.887)
<0.001
0.773
(0.660, 0.885)
<0.001
9. Mediastinal tumor resection
5.79
−0.170
(−0.239, −0.101)
<0.001
−0.168
(−0.237, −0.099)
<0.001
10. Pulmonary tumor resection
13.42
−0.043
(−0.093, 0.007)
0.091
−0.043
(−0.093, 0.007)
0.089
Adjusted
0.198
0.203
Significant codes: 0 “”; 0.001 “”; 0.01 “”; 0.05 “”; and 0.1 “”. Categorical variable, the baseline is Saturday. Continuous variables. Categorical variable; the baseline is the fact that a surgery is the only one surgery a surgeon performed in a day. Notation “2∼1” means the first surgery in the day with two surgeries performed by a surgeon in the day. Categorical variable; the baseline is surgeon A who performed most surgeries. Categorical variable; the baseline is a surgery type, named thoracoscopic interior pulmonary lobectomy.
