4 Discussion
TFBA is a clinical emergency and a
major cause of death in children13. At present, the
most effective way to remove TFBA is through the rigid bronchoscope as
soon as possible. The most important diagnosis is based on the history
of foreign body choking14.
LRTI is easily caused by TFBA. In this study, most children had purulent
secretions. Previous studies reported that TFBA can cause obstructive
emphysema and pneumonia15 based on preoperative CT.
However, as a LRTI, acute bronchitis with no positive signs in CT is
often ignored. Limited studies reported LRTI caused by TFBA, while they
are mainly focused on bacterial culture7,8.Only one
study reported the risk
factors
for LRTI10. As a result, the situation of LRTI cannot
be fully showed.
In clinical practice, LRTI plays an important role in intraoperative
operation and disease prognosis. A study reported that TFBA with LRTI
have a longer hospital stay10. Therefore, we hope to
find a relevant indicator to predict the occurrence of LRTI for
operators so that they can pay more attention to prepare the operation.
This study collected the children who were applied TFBA extraction and
analyzed the risk factors for LRTI.
We used to have a clinical understanding that organisms are more likely
to cause inflammation and suppuration in tracheobronchial tissues than
non-organisms, especially plants16. In addition, it is
reported that the type of TFBA was an independent risk factor for
LRTI10. However, recent animal experiments found that
there was no difference in tracheal damage between organic and inorganic
foreign bodies9. Similarly, we found that there was no
statistical difference in the incidence of LRTI among legumes, nuts,
other organisms and non-organisms. We also found a correlation between
the retention time of TFBA and LRTI. In our study the incidence of LRTI
was 46.6%, 68.6% and 68.6% respectively with the retention time of
within 24 hours, one week and more than one week,which was consistent
with the results of a previous animal experiment9. In
this animal experiment, it was found that most of the TFBA could cause
tracheal damage within 5 days, and pneumonia more than 5 days. No matter
in animal experiments or clinical findings, LRTI caused by TFBA could be
aggravated with the increase of time.
We speculate that there are three main reasons for the differences
between previous clinical understandings and our study. Firstly, the
family members have a significantly higher understanding of TFBA than
before, and the visiting time is significantly shortened. Secondly, CT
has been more popular which increases the accuracy and timeliness of
diagnosis. Thirdly, it may need time to realize the impact of the type
of TFBA on trachea tissue. This suggests that no matter what type of
TFBA is or where the TFBA is embedded, the longer the time is, the more
serious the LRTI is. Therefore, we suggest that for children with long
retention time of TFBA, the operators should be vigilant and fully
prepared before operation. They should also inform the parents that the
operation can be more difficult and complicated than those with short
retention time.
In a report of LRTI caused by TFBA10, type, shape, the
retention time of TFBA and age were independent risk factors for LRTI.
Analyzed all the related risk factors in our study, except for the shape
of TFBA, there was a correlation between the retention time of TFBA and
LRTI, while there is no correlation between age, the type of TFBA and
LRTI. We speculate that the main reason is that the family members have
different understanding of TFBA, which leads to the difference in
visiting time. In the above study, the median retention time of TFBA is
15 days, while it’s only 1 day in our study. It is controversial whether
there is a difference in the degree of trachea inflammation caused by
the type of TFBA. Although it has been reported that the intratracheal
granulation in TFBA is related to the degree of TFBA oil
release17, no correlation was found in animal
experiments9. As for age, we speculate that the
immunity of younger children is relatively weak so that they are easier
to get LRTI when encounter the same TFBA. However, it needs time to show
this difference.
No indicator of LRTI caused by TFBA was found in clinical symptoms. When
choked by foreign body, the more severe the cough and asthma is, which
indicates that the TFBA is too large, the larynx and trachea spasm
caused by it is obvious and the blockage of foreign body is serious, the
more dangerous the process of choking is. However, tracheal mucosal
inflammation needs time to happen, these clinical symptoms cannot
predict the incidence of LRTI. Despite of this fact, they reflect the
severity of the disease. Operations should be done as soon as possible
for children with obvious symptoms.
There is no specific standard for the subgroup classification of TFBA
complications. According to previous literature, we found that there is
similar classification for obstructive pneumonia and atelectasis in
non-small cell lung cancer, which can be used as a reference. Firstly,
non-small cell lung cancer respectively showed segmental and lobar local
emphysema or atelectasis in incomplete or complete blockage of the
bronchial lumen. Secondly, in the TNM stage of non-small cell lung
cancer18,non-small cell lung cancer with obstructive
pneumonia or partial or whole atelectasis is classified as T2 stage. In
this guideline, atelectasis and emphysema are regarded as the same
element. Furthermore, in previous prognostic studies of non-small cell
lung cancer, preoperative obstructive pneumonia and atelectasis were
also put into one group without discussed separately19when the overall survival rate and recurrence-free survival rate of lung
cancer were compared. To sum up,
we drew lessons from the classification method of non-small cell lung
cancer, and put atelectasis and emphysema into the same group,
considering them as different manifestations of the same type. Based on
this method, we further divided atelectasis or emphysema and pneumonia
into different subgroups. Combined with the clinical criticality, we
classified the mediastinal emphysema, pneumothorax, subcutaneous
emphysema, severe pulmonary inflammation, such as pleural effusion, and
mediastinal displacement as a group. In univariate analysis, we found
that the worse the clinical condition was indicated by cervicothoracic
CT, the higher the incidence of LRTI would be. However, in multivariate
analysis, there was an overlapping relationship between cervicothoracic
CT diagnosis and the retention time of TFBA, suggesting that the longer
the retention time was, the more serious the LRTI would be. The
cervicothoracic CT diagnosis was not related to LRTI.
This study is limited in the following ways. Firstly, the number of
cases included is small, and it is a single center study, which needs to
be supplemented by a larger sample size. Secondly, this study only
includes a single race. It is not clear whether there is a correlation
between race and LRTI. Thirdly, the educational background of the
families and their attention paid to children when they are eating may
be risk factors for LRTI. Due to the lack of these information, this
study is limited in its retrospective way.