2.1 Characteristics of patients
A total of 251 patients with tracheostomy were involved, of which 29 were excluded [8 cases age < 18 years old, 5 cases with cardiac arrest, and tracheostomy due to severe traumatic brain injury(9 cases), burn(2 case), and (5 cases)], therefore, 222 patients finally met the enrollment criteria.The average age is 50 years old, 160 males (72.1%). The most common injury was traffic accident injuries (156 cases, 70.3%), followed by high fall injuries (41 cases, 18.5%), fall injuries (12 cases, 5.4%), and crush injuries (11 cases, 4.9%) ), unexplained injury (2 cases, 0.9%). Among patients who underwent tracheostomy within 7 days after intubation, 118 cases (53.2%) met the ET, and 104 cases (46.8%) were included in the LT. On account of propensity score matching analysis, There were 87 patients in the ET group and LT group respectively. Hence , a total of 174 patients were sampled for result analysis (Figure 1).
Before propensity score matching, significantly difference in cardiovascular disease, ARDS, VPC, NTRF, and hemothorax between the ET and the LT. After propensity score matching, ARDS, VPC, and NTRF were significantly different; Nevertheless,Age, male, GCS, ISS ,lung disease , TBI , number of fractured ribs, first rib fracture , combined injury (flail chest, maxillofacial, spine, hemothorax, pneumothorax) and initial value of blood lactate were not significantly different; In addition, Timing of tracheostomy for patients in ET and LT were (4.1±1.3) days VS (12.5±3.0) days,which were significantly different (Table 1).
2.2 Outcome of patients
Before propensity score matching, the ratio of closed thoracic drainage and fungal infection in the ET was higher than that of the LT, while no significant difference between after matching. the 28-day mortality of the ET group was lower than that of the LT, and there was a statistical difference (Table 2).
The results of binary logistic regression analysis of multiple factors showed that ARDS, VPC and NTRF were three independent risk factors for patients with multiple rib fractures who underwent early tracheostomy (Figure 2). Pearson correlation analysis of three independent factors showed that: VPC and NTRF are moderately related, R=0.369, P=0.001; ARDS and VPC are lowly related, R=0.179, P=0.018; NTRF and ARDS are not obviously correlation, R=0.132, P =0.110 (Figure 3).
ROC curve analysis showed that the area under the curve of VPC and NTFR were 0.804 and 0.832, respectively, P= 0.001.While that of GCS, ISS and NFR had no significant difference, P-value>0.05 (Figure 4). We calculated the maximum value of the VPC's Youden index [sensitivity - (1-specificity)] is 0.633,corresponding sensitivity=0.828. SPSS statistical software could calculate the corresponding value of VPC is 23.9.As well,we ccould also calculate that the maximum value of the NTFR's Youden index is 0.474, corresponding sensitivity=0.839. SPSS statistical software could also calculate the corresponding value of NTFR is 8.5.
Kaplan-Meier survival analysis showed that the 28-day survival of ET was significantly better than that of LT,P=0.01(Figure 5). In addition, COX survival analysis showed that the timing of tracheostomy(HR=2.51 95%CI 1.12-5.57, P= 0.004) and age(HR= 1.53 95%CI 1.00-2.05, P= 0.042) of patients had a significant impact on the 28-day survival of patients with multiple rib fractures.
Table 1
Comparison of baseline data of patients before and after propensity score matching
|
Variables
|
Before propensity matching
|
After propensity matching
|
ET(N=118)
|
LT(N=104)
|
P-value
|
ET(N=87)
|
LT(N=87)
|
P-value
|
Age, years, points
|
50.5±15.6
|
47.5±18.2
|
0.196
|
48.2±16.1
|
47.6±20
|
0.818
|
Male sex, n (%)
|
84(71.1)
|
76(73.1)
|
0.754
|
67(77.0)
|
59(67.8)
|
0.175
|
GCS at admission, points
|
9.1±4.3
|
9.0±4.5
|
0.893
|
9.2±4.3
|
8.9±4.6
|
0.660
|
ISS, points
|
38.9±7.2
|
40.1±9.4
|
0.294
|
39.3±7.8
|
40.0±8.8
|
0.580
|
Cardiovascular diseases, n (%)
|
21(17.8)
|
8(7.7)
|
0.026
|
13(14.9)
|
8(9.2)
|
0.245
|
Lung disease, n (%)
|
12(10.2)
|
12(11.5)
|
0.743
|
9(10.3)
|
10(11.5)
|
0.808
|
Traumatic Brain Injury, n (%)
|
84(71.2)
|
72(69.2)
|
0.750
|
60(69.0)
|
62(71.3)
|
0.740
|
Acute Respiratory Distress Syndrome, n (%)
|
76 (64.4)
|
48 (46.2)
|
0.006
|
59(67.8)
|
37(42.5)
|
0.001
|
Volume of pulmonary contusion, points
|
21.1±18.0
|
5.9±8.7
|
0.000
|
33.8±11.4
|
20.1±9.8
|
0.000
|
Number of ribs fractured, points
|
5.8±2.1
|
6.1±2.1
|
0.218
|
5.7±2.1
|
6.2±2.1
|
0.167
|
Number of total rib fractures, points
|
9.1±2.4
|
7.9±2.2
|
0.001
|
10.8±2.7
|
7.9±2.0
|
0.001
|
First rib fractures, n (%)
|
40 (33.9)
|
34 (32.7)
|
0.849
|
30(34.5)
|
29(33.3)
|
0.873
|
Sternum fractures, n (%)
|
37 (31.4)
|
31 (29.8)
|
0.803
|
26(29.9)
|
24(27.6)
|
0.738
|
Flail chest, n (%)
|
20 (16.9)
|
24 (23.1)
|
0.253
|
14(16.1)
|
22(25.3)
|
0.134
|
Spine coinjuries, n (%)
|
12(10.2)
|
4(3.8)
|
0.069
|
10(11.5)
|
4(4.6)
|
0.094
|
Maxillofacial coinjuries, n (%)
|
8(6.9)
|
12(11.5)
|
0.232
|
8(9.4)
|
9(10.3)
|
0.838
|
initial value of blood lactate, points
|
4.0±2.9
|
4.1±2.2
|
0.836
|
4.1±2.9
|
3.8±2.1
|
0.509
|
Hemothorax, n (%)
|
58(49.2)
|
32(32.0)
|
0.010
|
41(47.1)
|
31(35.6)
|
0.124
|
Pneumothorax, n (%)
|
70(59.3)
|
56(53.8)
|
0.411
|
50(57.5)
|
51(58.6)
|
0.878
|
Timing of tracheostomy, day, points
|
4.0±1.3
|
12.6±3.1
|
0.000
|
4.1±1.3
|
12.5±3.0
|
0.001
|
ET, early tracheostomy; LT, late tracheostomy; GCS, glasgow coma scale; ISS, injury severity score.
|
Table 2
Comparison of clinical outcomes of patients before and after propensity score matching
|
Outcomes
|
Before propensity matching
|
After propensity matching
|
ET(N=118)
|
LT(N=104)
|
P-value
|
ET(N=87)
|
LT(N=87)
|
P-value
|
Duration Of mechanical ventilation, days
|
13.5±4.1
|
15.7±5.5
|
0.078
|
13.9±3.0
|
15.9±4.7
|
0.190
|
Duration of tracheostomy, days
|
27.3±6.5
|
35.8±8.2
|
0.180
|
28.4±6.1
|
39.4±7.1
|
0.143
|
Hospital lenght of stay, days
|
18.3±6.0
|
17.7±5.1
|
0.855
|
19.3±6.6
|
17.0±5.8
|
0.521
|
ICU lenght of stay, days
|
7.1±2.7
|
11.5±3.6
|
0.145
|
8.7±2.1
|
11.6±2.7
|
0.412
|
Thoracic close drainage, n (%)
|
66(55.9)
|
44(42.3)
|
0.043
|
46(52.9)
|
39(44.8)
|
0.288
|
Number of fiber bronchoscope use, points
|
2.5±5.4
|
1.7±2.9
|
0.194
|
2.8±5.9
|
1.7±2.8
|
0.129
|
Multidrug resistance bacteria, n (%)
|
36(30.5)
|
34(32.6)
|
0.335
|
29(33.3)
|
28(32.2)
|
0.732
|
Ventilator associated pneumonia, n (%)
|
24(20.3)
|
20(19.2)
|
0.657
|
18(20.7)
|
19(21.8)
|
0.732
|
Antibiotic use, days
|
10.0±3.4
|
9.2±2.6
|
0.722
|
13.5±4.3
|
14.1±4.6
|
0.876
|
Sedatives and analgesics use, days
|
11.4±9.1
|
13.7±8.6
|
0.060
|
11.6±9.2
|
13.5±8.3
|
0.151
|
28-day mortality, n (%)
|
14(11.9)
|
29(27.9)
|
0.003
|
9(10.3)
|
28(32.2)
|
0.001
|
ICU, intensive care unit; ET, early tracheostomy; LT, late tracheostomy.
|