Abstract
Patients who have undergone surgical or radiation therapy for laryngeal cancer frequently present for direct laryngoscopy (MDL) in the operating room to evaluate new lesions found on surveillance positron emission tomography (PET) scanning. Loss of airway is the most feared complication. Airway management may be complicated by altered anatomy and radiation-induced changes to the larynx, which include edema and fibrosis. A team approach to airway assessment and anesthetic planning is important. Consideration may be given to preinduction nasopharyngolaryngoscopy, awake look with videolaryngoscopy, or awake tracheostomy. The immediate presence of the ear, nose, and throat (ENT) specialist and surgical airway equipment in the room at the time of airway management or induction of anesthesia is prudent. Jet ventilation is an excellent strategy for oxygenation during MDL. When used with a subglottic catheter under direct vision and an automated jet ventilator with pressure shutoff function, the risks of barotrauma and pneumothorax are minimized. Laser surgery of the larynx warrants careful attention to reducing the risks of airway fire with the use of jet ventilation or fire retardant materials and lowered inspired oxygen concentrations. Postoperative monitoring of the MDL patient for airway complications is important. The known difficult airway details related to intraoperative management and a written plan for unplanned emergent airway management should be documented in the record and patients identified systematically.
Keywords
difficult airway, direct laryngoscopy, jet ventilation, laryngeal cancer, radiation
Case Synopsis
A 62-year-old obese man (body mass index 41) with a history of laryngeal cancer presents for microdirect laryngoscopy, esophagoscopy, and bronchoscopy to evaluate a positron emission tomography (PET)–positive lesion on recent surveillance scanning. He has a history of chronic obstructive pulmonary disease on 2 L home oxygen, hypertension, hyperlipidemia, 35 pack-year smoking, and laryngeal cancer for which he underwent transoral robotic surgery and subsequent radiation. He underwent nasopharyngolaryngoscopy in the surgical clinic, which demonstrated no overt mass and significant laryngeal edema and scarring. After induction of general anesthesia with propofol and remifentanil, mask ventilation is difficult but adequate to maintain oxygen saturation greater than 90%. The airway is immediately turned over to the ear, nose, and throat (ENT) specialist. Surgical laryngoscopy with a Jackson laryngoscope provides no view of the larynx. Mask ventilation is resumed and subsequent exposure with an anterior commissure scope is sufficient to introduce a 4% lidocaine laryngeal tracheal applicator and a metal suction catheter through the glottic opening. High-frequency jet ventilation is initiated through the metal suction catheter (frequency 120, driving pressure 22 psi, inspiratory time 40%, Fio 2 100%). Hypotension (blood pressure 90/50 mm Hg) and bradycardia (heart rate 48 beats per minute) are treated with 10 mg of intravenous ephedrine, and the procedure is completed with no biopsies or bleeding. A 6.0 endotracheal tube is placed through the anterior commissure scope by the surgeon, and the patient is extubated after fully awake. A difficult airway bracelet is applied, and the patient is taken to the recovery area.
Problem Analysis
Preoperative Considerations
Patients presenting for microdirect laryngoscopy (MDL) and related procedures often have significant comorbidities. Life expectancy has improved with advanced diagnostic and therapeutic interventions for laryngeal and related cancers. Airway-related complications, especially loss of airway, are the most concerning for the perioperative team. More patients who have undergone prior airway surgery, radiation, or a combination of surgery and radiation are presenting to the operating room (OR) for surveillance biopsy or evaluation for PET-positive recurrence. Laryngeal masses can occlude the airway after induction, obstruct glottic view and impede direct passage of the endotracheal tube through the glottic opening, or bleed due to trauma during laryngoscopy. Radiation causes fibrosis, edema, and reduced tissue mobility that may be critical for glottic exposure. Surveillance frequently includes esophagoscopy and flexible fiberoptic bronchoscopy in addition to laryngoscopy. Abnormal airway anatomy, especially when due to reduced laryngeal mobility after radiation therapy, may also make tracheostomy or emergency cricothyroidotomy difficult.
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