When endotracheal tubes were first created, the tubes were less flexible than modern tubes with low-volume and highpressure cuffs that resulted in more tracheal trauma than modern endotracheal tubes. However, tracheal trauma and stenosis still occur with modern tubes, and as a result, this leads to one of the indications for timing of the tracheostomy. In order to minimize the risk of tracheal stenosis, most recommend performance of tracheostomy in patients for whom 2 weeks of mechanical ventilation is expected. Pena et al.³ found that 86% of patients requiring laryngotracheal surgery for stenosis had a mean duration of 17 days of mechanical ventilation. So to minimize this risk, tracheostomy is usually recommended for expected duration of 14 days.

Other studies have looked at the timing for when to perform tracheostomies based on outcomes for the patients. Most studies evaluating performance of tracheostomies within the first 10 days of intensive care unit (ICU) course suggest statistically significant improvement in days on ventilator, days in the ICU, need for sedation, costs, and total hospital length of stay.^{4, 5, 6} In busy hospitals, with increased ICU usage, early tracheostomy should be considered.

With respect to timing of the tracheostomy, a final aspect to the history to evaluate is the disease process that required the need for mechanical ventilator support. In patients with severe brain injury,⁷ spinal cord injury associated with ineffective cough, severe multiple system organ failure, or in whom multiple-staged operations are planned, early tracheostomy should be considered.

In the setting of altered anatomy, certainly, the safer option would favor standard surgical tracheostomy with direct exposure of the trachea.

With respect to morbid obesity, Byhahn et al.⁸ reported greater complication rate with PDT over surgical tracheostomy. If an extended length tracheostomy (XLT) is anticipated due to the distance between skin and trachea, then surgical tracheostomy may be a safer approach.

With respect to coagulopathy, PDT can be safely performed in patients with a coagulopathy as long as the risk factors are modified prior to the procedure. If the platelet count is less than 50,000/µL, platelets should be given at the time of the procedure.⁹ If the platelet count is less than 75,000/µL and the patient has other risk factors for platelet dysfunction (i.e., azotemia, antiplatelet therapy) or abnormal coagulation cascade (i.e., elevated prothrombin time or partial thromboplastin time), platelets should be given periprocedural, as well as fresh frozen plasma if the international normalized ratio (INR) is greater than 1.7.

With respect to cervical fixation and cervical fractures, studies have shown that PDT can be safely performed without cervical spine clearance or fixation¹⁰ as long as cervical extension is not needed to gain adequate exposure on physical exam.

In patients with prior tracheostomies, PDT has been shown to be a safe approach to tracheostomy placement.¹¹

The final consideration in preprocedural evaluation is the ventilator settings. High ventilator settings (e.g., positive end-expiratory pressure [PEEP] >14 cm H₂O, vent rate >20 breaths per minute) are a relative contraindication to PDT due to derecruitment issues during bronchoscopy. Depending on the comfort of the surgeon, a PDT can be performed with nonbronchoscopic or a standard open surgical approach.