2.3 Statistical methods
The Kolmogorov-Smirnov method was used to test the normal distribution.
The rank sum test was used to analyze the difference in continuous
variables that are in non-normal distribution. The chi-square test was
used to analyze the difference in classified variables. The variables
with statistical differences were included in multivariate logistics
regression analysis. When P < 0.05, the differences were
considered to be statistically significant. The statistical software was
SPSS24.0.
3 Results
A total of 194 cases of TFBA were included in this study, 120 males and
74 females with a median age of 1.54 years (0.6-12.58 years). The types
of TFBA were inorganic (n = 7), other organic (n = 33), nuts (n = 143)
and legumes (n = 11). Cervicothoracic CT showed TFBA embedded in trachea
and above trachea in 24 cases, in left and right main bronchus in 134
cases (left bronchus 87 cases, right bronchus 47 cases), in segmental
bronchus and below in 36 cases (left segmental bronchus 6 cases, right
segmental bronchus 30 cases). Cervicothoracic CT showed no obvious
abnormality in 60 cases, obstructive emphysema or atelectasis in 77
cases, obstructive pneumonia 50 cases, and the rest 7 cases
(pleural
effusion, mediastinal displacement, subcutaneous emphysema, pneumothorax
and mediastinal emphysema). The general characteristics are showed in
Table 1.
We conducted a univariate
analysis on risk factors mentioned in previous literature and clinically
considered possible. The results showed that there was a significant
difference in cervicothoracic CT diagnosis and the retention time of
TFBA between LRTI group and non-LRTI group. The results of univariate
analysis are showed in Table 2.
.
Cervicothoracic CT diagnosis and the retention time of TFBA were
included in multivariate logistics regression analysis. We found that
there was a correlation between the retention time of TFBA and LRTI,
while no correlation was found between cervicothoracic CT diagnosis and
LRTI. The results of multivariate logistics analysis are showed in Table
3.