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Examination of candidates
ОглавлениеThe ideal patient for PDT has a well‐defined anatomy – a long thin neck, with palpable tracheal spaces that can be hyperextended safely. The first criterion safeguards the anatomy for this essentially blind procedure: namely that the tracheotomy is done between the third and fourth tracheal cartilage. The splaying of the cartilage rings is key in the proper positioning of the patient for PDT. In general, patients with recent neck injuries, morbidly obese necks, and previous tracheostomy or neck irradiation are contraindicated for bedside PDT. Anterior infection or burns of the neck, as well as goiter or masses, are also contraindications. Such patients are better relegated to an open surgical procedure.
If cervical spinal injury is present, PDT is contraindicated, and if in question, neurosurgical or neurological clearance for hyperextension would be necessary. Patients whose neck cannot be hyperextended such as patients with cervical osteoarthritis are also better treated in the OR. Note: PDT is not meant for acute emergency tracheotomies where the more cephalad cricothyroid membrane is the anatomy of choice for the tracheotomy.
The physical exam concentrates on identifying adenopathy, burns, infection, masses, scars (previous surgery or old tracheostomy scar), trauma, and thyromegaly (goiter). Review the skin surface for small veins to avoid lacerating during the procedure. If available, US examination can assist in identifying any aberrant vasculature or other anomalies that may defer PDT to an operative procedure.
Assess the extent of neck hyperextension. Is the neck short and thick? Is extension not possible due to cervical arthritic changes? Inability to palpate the tracheal anatomy due to obesity or short neck length, and/or inability to hyperextend allowing at least two finger breaths above the sternal notch would contraindicate the procedure.
Patients with obese necks may have successful PDT although they may require bronchoscopic assistance, cut down, and longer tracheostomy tubes. The patient must be hemodynamically stable as significant sedation and/or paralysis may be needed for the procedure. The most common reason to prolong the PDT procedure is sedation‐related hypotension necessitating intravenous fluids or vasopressors. Assessing the degree of hyperextension earlier will require full sedation, indicating the need for fluid resuscitation prior to the procedure. Also be aware that bradycardia due to vagal effects may worse.
The patient should have satisfactory gas exchange, not requiring high PEEP.