Anesthesia for Otorhinolaryngologic Surgery

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ANESTHESIA FOR OTORHINOLARYNGOLOGIC SURGERY

Endoscopic Otorhinolaryngologic Surgery (Laryngoscopy, Microlaryngoscopy, Esophagoscopy, and Bronchoscopy)

Preoperative evaluation should focus on airway management, particularly given that operative indications include foreign body aspiration, vocal cord dysfunction, tracheal stenosis, obstructing tumors, and other airway difficulties. If there is concern about difficult mask ventilation or intubation via direct laryngoscopy, tracheostomy under local anesthesia and use of fiberoptic bronchoscopy should be considered.

Intraoperative anesthetic management usually requires muscle relaxation, careful planning of oxygenation and ventilation, and specific strategies for cardiovascular stability.

• Muscle relaxation frequently needs to be profound, particularly with microlaryngoscopy, because any vocal cord movement interferes with the surgical procedure. At the same time, patients need to have rapid recovery at the end of the procedure, which dictates careful monitoring of muscle relaxation.

• Oxygenation and ventilation can be achieved by placement of a smaller endotracheal tube (ETT) with conventional positive-pressure ventilation. Occasionally, such as during posterior commissure surgery, an ETT would obstruct the surgical field, and alternative techniques, such as manual jet ventilation, high-frequency jet ventilation, or intermittent apnea, should be used.

• Cardiovascular stability is challenging with varying surgical stimulation. One strategy is to provide supplemental additional anesthetic depth with intermittent boluses as surgical stimulation increases. Another approach is to provide sympathetic antagonists such as esmolol when needed.

Ear Surgery (Stapedectomy, Tympanoplasty, Mastoidectomy, and Myringotomy)

Intraoperative management concerns include avoidance or cautious use of nitrous oxide. Patients with chronic ear problems can have obstructed Eustachian tubes, which can lead to pressure buildup within the middle ear because of rapid diffusion of nitrous oxide into closed spaces. Discontinuation of nitrous oxide can lead to negative pressure within the middle ear if it is opened surgically and then closed.

Hemostasis is critical in microsurgery and can be facilitated by a head-up position, topical or infiltrated epinephrine, and mild controlled hypotension. Deep extubation can prevent coughing that leads to increased venous pressure and postoperative bleeding.

Preservation of the facial nerve can be an important consideration during resection of acoustic neuromas or glomus tumors. Neuromuscular blocking agents should be avoided in these cases and discussed with the surgical team.

Addressing postoperative nausea and vomiting (PONV) prophylaxis adequately can be challenging because middle ear surgery can lead to postoperative dizziness, nausea, and vomiting. Use of dexamethasone, ondansetron, and propofol for induction and maintenance should be considered.

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