It appears intuitive that bronchoscopic guidance would make the PDT procedure safer since it would allow visualization of the needle entry into the airway and prevent posterior wall puncture. Kost et al suggested in his 500 PDT experience that continuous bronchoscopic guidance led to a low complication rate with no incidence of pneumothorax, pneumomediastinum, or paratracheal placement.22 However, a study published by Dennis et al in 2013, demonstrated a low complication rate in 3162 patients without the use of bronchoscopy, arguing against mandating bronchoscopic guidance for PDT (complication rate of major airway complications and deaths were 0.38% and 0.16%, respectively).23 The operator’s experience is likely a large contributing factor since Kost et al demonstrated a decline in complication rate once the operator performs over 30 PDTs.22 The decrease in the complication rate occurred even with the percentage of obese and difficult airway patients increasing after the initial 30 patients, suggesting increased comfort level and competency of the operator.
Early Versus Late Tracheostomy
The median tracheostomy timing in United States was reported to be 9 days with interquartile range of 5 to 14 days.24 The definition of early tracheostomy varied based on the study (ranging from 1 to 8 days). Some of the prior retrospective studies suggested the potential benefits of ICU length of stay and duration of mechanical ventilation. However, 3 main randomized trials showed no such benefits. The only benefit of early tracheostomy seems to be potentially using less sedation, meanwhile showing no evidence in reducing ventilator-associated pneumonia, length of ICU stay, or mortality.25,26
Ever increasing popularity of using ultrasound has made its way into PDT. By using linear array high-frequency probe, the neck can be examined prior to tracheostomy to reveal aberrant blood vessels in the path of the needle. In obese patients with difficult anatomy, real-time guidance can be used. There is 1 randomized trial that showed an increased success rate of first time puncture when real-time ultrasound is used compared to the traditional landmark method.27,28,29 However, no statistically significant finding was noted in complication rate. Additionally, a number of feasibility and case series studies showing the potential benefits of the ultrasound guidance especially in obese patients.30 Given the unlikelihood of any adverse effect posed by using the real-time ultrasound, it is possible that this will benefit a subgroup of patients with difficult neck anatomy.27,28,29
One study examined safety and efficiency of PDT performed by physicians trained in either interventional pulmonology or surgery at a tertiary referral center. Of note, all interventional pulmonologists have critical care medicine training background. Almost all procedures were done within 48 hours with no differences in complication rate.31
Specific PDT-Related Complications and Death
A specific type of tracheal stenosis was reported termed “corkscrew stenosis” in 11 patients who underwent PDT, which occurred as a result of tracheal ring fracture. Mean time to occur was 13 months (range 1.5-24 months) with 7 requiring tracheal resection.32 Methods to prevent tracheal ring fracture may be needed to prevent long-term complications like this.
Fatalities that result from PDT arose predominantly from damage to vessels and subsequent bleeding either intraoperatively or up to 22 days after the procedure. Identified factors that led to vessel damage include low placement of tracheostomy below the eighth tracheal ring, prior neck surgery, and radiation therapy. Two fatality cases occurred from loss of airway during the procedure.10,11