4 DISCUSSION
In the present study, we investigated the safety of ST in patients
undergoing CAT and arrived at the following two major results. First, no
significant difference was observed in the incidence of postoperative
complications with or without antithrombotic medication, even though
APTT and PT-INR showed significant differences among these patients.
Second, ST under local anesthesia and airway emergency was a risk factor
for complications after ST.
The literatures contain inconsistent reports regarding the additive risk
of postoperative bleeding with the use of antithrombotic drugs, and this
could presumably be attributed to the differences in surgical
procedures, patient demographics, and degree of antithrombotic
conditions among patients included in the various studies. For instance,
the risk of chronic bleeding after percutaneous dilatational
tracheostomy (PDT) is reportedly higher in the presence of two or more
abnormal coagulation
variables,13 even
though CAT is not considered a risk factor for bleeding after
PDT.14 CAT also
increased the frequency of hemorrhagic complications requiring
intervention after prostate
biopsy.15 In contrast,
a study reported no association between the risk of bleeding after
percutaneous endoscopic gastrostomy and CAT; pulmonary procedures under
CAT did not increase the risk of bleeding
either.16 Various
reports have also concluded that CAT is not a risk factor for bleeding
after minimally invasive surgeries, such as tooth extraction,
percutaneous endoscopic gastrostomy, and endoscopic variceal
ligation.7,11,12The results of the present study support these findings and suggest that
ST can be safely performed even under CAT. However, a bias may exist in
the differences in the intensity of hemostasis between ST with or
without CAT, because surgeons may have performed hemostatic procedures
more carefully in ST under CAT to prevent intraoperative and
postoperative bleeding.
Based on the present results, we recommend that surgeons should pay
careful attention to complications during ST under local anesthesia and
in airway emergencies. Awake tracheostomy is 6.2 times more likely to
result in pneumothorax or pneumomediastinum than general
tracheostomy.5 Patients
undergoing awake tracheostomy often breathe spontaneously after
tracheostomy and are prone to the cough reflex due to the presence of a
tracheal cannula, which may result in subcutaneous emphysema.
Particularly, in airway emergencies, the risk of subcutaneous emphysema
may have been increased because securing the airway is a top priority,
despite the consideration of safety. However, no significant intergroup
differences were observed in the risk of postoperative infection.
Considering that prophylactic administration of antibiotics can prevent
the incidence of PDT-induced wound
infection,17 the use of
antibiotics for the treatment of the primary disease may have reduced
the incidence of infection after ST. Other potential risk factors, such
as DM or albumin level, did not affect the complication rate in the
present study. DM has been reported to be a risk factor for surgical
site infection (SSI) and for postoperative
infection,18 and
compared to a normal albumin level, a low albumin level (<3.5
g/dL) has been associated with an approximately 2.5 times increased risk
of SSI in orthopedic
surgery.19Nevertheless, these factors may not play an important role in minimally
invasive surgeries like ST.
Several limitations of this study should be acknowledged. Retrospective
chart reviews are limited by incomplete or missing documentation.
Patients undergoing ST performed by surgeons at the other departments
were excluded from this analysis, and this might have resulted in the
underestimation of the overall incidence of postoperative complications.
Moreover, patients undergoing PDT, which involves placing a tracheostoma
by dilating the tracheal wall, were excluded from this study. When
bleeding occurs during and after PDT, it might be difficult to identify
the bleeding site, but in ST, the bleeding site can be easily identified
and hemostasis procedures can be performed immediately. Finally,
long-term postoperative complications were not investigated in this
study.
In the clinical setting, ST can be performed relatively safely
regardless of the use of CAT. However, the incidence of complications
can be high in cases of ST performed under local anesthesia or airway
emergencies. Thus, in such cases, ST should be performed carefully.