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.