Anesthesia for Tracheal Resection
Tracheal resection is most commonly performed for tracheal stenosis, tumors, or, less commonly, con-genital abnormalities. Tracheal stenosis can result from penetrating or blunt trauma, as well as trachealintubation and tracheostomy. Squamous cell and adenoid cystic carcinomas account for the major-ity of tumors. Compromise of the tracheal lumen results in progressive dyspnea. Wheezing or stridor may be evident only with exertion. The dyspnea may be worse when the patient is lying down, with progressive airway obstruction. Hemoptysis can also complicate tracheal tumors. CT is valuable in localizing the lesion. Measurement of flow–volumeloops confirms the location of the obstruction and aids the clinician in evaluating the severity of the lesion (Figure25–12).
Little premedication is given, as most patients pre-senting for tracheal resection have moderate to severe airway obstruction. Use of an anticholinergic agent to dry secretions is controversial because of the theoretical risk of inspissation. Monitoring should include direct arterial pressure measurements.
An inhalation induction (in 100% oxygen) is carried out in patients with severe obstruction. Sevoflurane is preferred because it is the potent anesthetic that is least irritating to the airway. Spontaneous ventilation is maintained throughout induction. NMBs are generally avoided because of the potential for complete airway obstruction follow-ing neuromuscular blockade. Laryngoscopy is per-formed only when the patient is judged to be under deep anesthesia. Intravenous lidocaine (1–2 mg/kg) can deepen the anesthesia without depressing respi-rations. The surgeon may then perform rigid bron-choscopy to evaluate and possibly dilate the lesion. Following bronchoscopy, the patient is intubated with a tracheal tube small enough to be passed distal to the obstruction whenever possible.
A collar incision is utilized for high tracheal lesions. The surgeon divides the trachea in the neck and advances a sterile armored tube into the distal trachea, passing off a sterile connecting breathing circuit to the anesthesiologist for ventilation during the resection. Following the resection and comple-tion of the posterior part of the reanastomosis, the armored tube is removed, and the original tracheal tube is advanced distally, past the anastomosis (Figure25–13). Alternatively, high-frequency jet ventilation may be employed during the anastomosis
by passing the jet cannula past the obstruction and into the distal trachea ( Figure25–14). Return of spontaneous ventilation and early extubation at the end of the procedure are desirable. Patients should be positioned with the neck flexed immediately after the operation to minimize tension on the suture line (Figure25–15).
Surgical management of low tracheal lesions requires a median sternotomy or right posterior thoracotomy. Anesthetic management is similar, but more regularly requires more complicated tech-niques, such as high-frequency ventilation or even cardiopulmonary bypass (CPB) in complex congen-ital cases.