SECTION IV. Head and Neck
A Dacryocystorhinostomy
1. Introduction
Dacryocystorhinostomy is performed for patients who have chronic tearing or obstruction at the level of the nasolacrimal duct. This procedure restores drainage into the nose from the lacrimal sac. The surgeon injects lidocaine 1% with 1:100,000 epinephrine, bupivacaine (Marcaine) 0.75%, and hyaluronidase (Wydase) in the operative site along the lacrimal crest. An additional injection may be given along the medial orbital wall, anesthetizing the ethmoidal nerve. This block may cause a temporary dilated pupil or medial rectus muscle paralysis.
A small incision is made near the medial canthus to allow a subperiosteal dissection to the lacrimal sac. The bone between the lacrimal fossa and middle fossa is broken and cut, making a small canaliculi. The mucosa of the lacrimal sac is anastomosed to the mucosa of the nose. To prevent closure of the newly formed path by scarring, a silicone tube may be placed inside the duct. Muscles and tissues in the area are then closed. The patient is then asked to open the eyelids, and when the proper height is obtained, the incision is closed.
2. Preoperative assessment and patient preparation
a) History and physical examination: This procedure may be done in patients of varying age. The patient’s cardiac history should be determined, because epinephrine is to be used for vasoconstriction. Infections in the surgical area should be treated with antibiotics for several days before surgery. Because of the inaccessibility of the anesthesia provider to the head, patients with obstructive sleep apnea should also be identified and anesthesia planned accordingly.
b) Patient preparation
(1) Laboratory tests: As indicated by the history and physical examination
(2) Diagnostic tests: Electrocardiography as indicated by the history and physical examination
(3) Premedication: Standard
3. Room preparation
a) Monitoring equipment: Standard
b) Additional equipment: An end-tidal carbon dioxide sensing nasal cannula may be used to give additional information about ventilation.
c) An extra-long circuit should be available because of turning of the table 90 to 180 degrees.
d) Drugs: Standard emergency and standard tabletop agents are used.
e) Intravenous fluids: An age-appropriate intravenous line and fluid are used for pediatric patients. One 18-gauge intravenous line is used for adults with normal saline/lactated Ringer’s solution at 2 mL/kg/hr (blood loss should be minimal because of the use of epinephrine).
4. Perioperative management and anesthetic technique
Most of these procedures can be done with local anesthesia with sedation; very rarely is general anesthesia used. The choice depends on the preferences of the surgeon and the patient.
a) Induction is routine for general surgery.
b) For local anesthesia with sedation, short-acting agents are best because these procedures are usually done on an outpatient basis.
c) Maintenance is routine.
d) Emergence: For general anesthesia, the patient should be extubated while awake, unless the condition dictates otherwise (i.e., reactive airway disease).
5. Postoperative implications
As stated earlier, there may be some temporary dilation of the pupil or medial rectus paralysis.
B Cleft Palate and Lip
CLEFT PALATE
1. Introduction
Cleft palate repair is usually performed in stages, depending on the extent of the defect. For the more severe deformities, the initial operation repairs the lip and anterior portion of the hard palate. The soft palate and other deformities are usually corrected later, after 6 months of age. Infants with cleft lip deformities can have difficulty feeding and may be prone to malnutrition and congenital (heart) anomalies and disease.
2. Anesthetic considerations
a) Intubation may sometimes be difficult if the laryngoscope blade slips into the cleft. However, packing the cleft with gauze may prevent this from occurring.
b) An oral RAE tube or flexible connector is used and secured at the midline of the lower lip.
c) A specialized mouth gag is used to hold the mouth open and the endotracheal tube in place during cleft palate surgery.
d) All air bubbles should be carefully removed from IV lines to prevent an air embolus due to the incidence of associated cardiac anomalies, such as an atrial-ventricular defect (AVD), which may lead to air crossing from the venous to the arterial circulation.
e) Congenital heart diseases may influence drugs that are selected for maintenance of anesthesia and for infiltration of the operative site, particularly if epinephrine is selected.
f) Care must be implemented to protect the child’s eyes since accidental damage may occur during the surgical procedure.
g) Before emergence, a suture is often placed through the tip of the tongue and the suture is taped to the cheek. This suture eliminates the need for an oral airway and prevents damage to the palatal repair.
h) If soft tissue obstruction occurs during emergence or recovery, traction on the suture can alleviate the problem. If edema occurs, a more aggressive and immediate airway management technique should be employed.
i) Copious secretions and blood may cause laryngospasm after extubation, and therefore a clear airway is imperative.
CLEFT LIP
1. Anesthetic considerations
a) Management of unilateral cleft lip repair consists of routine induction followed by oral intubation using an oral RAE tube or a flexible connector.
b) Secure the tube to the lower lip and midline via tape.
To decrease tension on the surgical sutures at the end of the procedure, the surgeon may place a Logan bow across the upper lip of the patient.
c) When the Logan bow is placed, mask ventilation during emergence will become impaired or impossible.
d) Extubation must be performed only with the patient fully awake and reflexes intact.
e) The child’s surgical site must also be protected from finger and hand manipulation. Some hospitals recommend the use of hand mittens or taping the extremities onto armboards during the postoperative period.
f) Close monitoring or respiration should proceed into the postoperative period.
C Dental Restoration
1. Introduction
Dental restoration procedures are performed under general anesthesia for a multitude of reasons. These include rampant cavities, history of cerebral palsy or Down syndrome, and an uncooperative patient who is not an appropriate candidate for local anesthetic and an office procedure.
2. Anesthetic considerations
a) Retarded patients develop a close personal relationship with either a family member or their long-term health care worker. It is often suggested that this individual accompany the patient to decrease anxiety and communicate a health history to the anesthesia provider.
b) A thorough airway assessment should be performed before considering induction.
c) Oral midazolam (0.5 mg/kg) or ketamine (3 to 4 mg/kg IM) is most effective in sedating retarded children in the preoperative arena.
d) Since many patients requiring dental restoration have congenital anomalies, it is not uncommon to find a patient with a small oropharynx, enlarged tonsils, a large tongue, and increased secretions.
e) Atlantoaxial instability and congenital heart disease should also be considered in the preoperative preparation and anesthetic management.
f) Preparation and appropriate airway management must be planned and implemented for these patients.
g) Patients who receive phenytoin to control seizures may have gingival hyperplasia. Because the gingiva is highly vascular, any surgical manipulation during restoration may lead to significant blood loss.
h) In patients with normal airways, a standard induction is appropriate and a nasal intubation usually facilitates the dental procedure.
i) The application of a topical vasoconstrictive nasal spray during the preoperative period reduces or prevents bleeding during the insertion of the nasotracheal tube.
j) Following loss of consciousness, lubricated intranasal trumpets may be inserted into the most patent nasal airway. Starting with a smaller nasal trumpet, several are placed in increasing sizes to dilate the airway. When full dilation of the nares has occurred, a well-lubricated endotracheal tube is passed through the nose into the trachea, either blindly or assisted by Magill forceps under direct laryngoscopy.
k) The nasal endotracheal tube is preferably placed on the side opposite where the surgeon will be working. The endotracheal tube is often sewn to the nasal septum by the surgeon.
l) Throat packs may be placed to prevent blood from entering the stomach and causing nausea and vomiting; monitoring their removal is essential to preventing respiratory obstruction following extubation.
D Endoscopy
1. Introduction
a) Endoscopic surgery includes panendoscopy, laryngoscopy, microlaryngoscopy (laryngoscopy aided by an operating microscope), esophagoscopy, and bronchoscopy. All of these procedures can be performed by using a rigid or flexible endoscope. If the rigid laryngoscope is used, the laryngoscope may be suspended from an arching support anchored to the patient’s abdomen/chest or from a Mayo stand over the patient.
b) One of the most common endoscopic procedures performed is endoscopic sinus surgery. Endoscopic sinus surgery is often associated with multiple and seasonal allergies leading to polyps. Patients undergoing surgery are often also being evaluated for such pathology responsible for hoarseness, stridor, or hemoptysis. Other possible reasons for endoscopic examination include foreign-body aspiration, papillomas, trauma, tracheal stenosis, obstructing tumors, or vocal cord dysfunction. Several complications can arise with endoscopic surgery; eye trauma, epistaxis, laryngospasm, bronchospasm, and excessive plasma levels of local anesthesia and epinephrine have been reported.
2. Anesthetic considerations
a) Preoperatively, the patient should be examined for any signs of airway obstruction and proper measures taken to ensure safe and controlled airway management.
Knowledge of the location and size of a mass is important, and discussion with the surgeon about chest roentgenogram, magnetic resonance imaging (MRI), and computed tomography (CT) scan results can be invaluable.
b) Light sedation is suggested for premedication since older children and adults may experience respiratory depression and worsening of airway obstruction.
The airway must be protected from aspiration of gastric contents, especially during prolonged airway manipulation and deeper sedation.
c) Premedication with an antisialagogue to dry secretions and a full regimen of acid aspiration prophylaxis in aspiration-prone patients may be indicated.
d) An awake oral or nasal intubation with minimal sedation and topical anesthesia of the oral cavity, pharynx, larynx, and nasopharynx may be indicated.
e) For shorter ENT procedures, anesthesia should be maintained with short-acting inhalation and intravenous agents to avoid patient movement and vocal cord movement, and to control sympathetic nervous system response to brief periods of extreme stimulation as in laryngoscopy.
f) Good muscle relaxation of the vocal cords is an essential part of anesthesia management for microsurgery of the larynx. A short-acting relaxant or infusion may be considered for brief cases.
g) If the procedure is expected to last 30 minutes or more, use of an intermediate-duration neuromuscular blocking drug such as vecuronium, atracurium, cis-atracurium, or rocuronium for the initial tracheal intubation allows the return of muscle strength and spontaneous respiration to meet extubation criteria at the end of the surgical procedure.
h) Emergence should include adequate oropharyngeal suctioning, humidified oxygenation, and observation in the postanesthesia care unit for laryngeal spasm or postextubation croup.
3. Airway considerations
a) One of the greatest management challenges during endoscopic procedures is to share the airway continuously with the surgeon.
b) Several methods have been used to provide oxygenation and ventilation during the procedures. One method is to control the airway by using a small, cuffed endotracheal tube (5.0 to 6.0 mm for an adult). Since the 5.0-mm and 6.0-mm endotracheal tubes are designed for smaller patients, a better endotracheal tube selection might include the microlaryngeal endotracheal tube (MLT).
c) The MLT in similar sizes (5.0 to 6.0 mm) has a cuff that is larger than the small standard endotracheal tubes (5.0 to 6.0 mm), allowing for a larger cuff distribution across the surface of the trachea, and creates a wider field of pressure on the tracheal surface.
d) There are some distinct advantages of an endotracheal tube; these include a secure airway with easily controlled ventilation, a cuff to protect the lower airway from debris, monitoring of end-tidal CO 2, and the ability to administer inhalational anesthetics.
e) Several drawbacks include the potential for extubation and loss of airway, complications during laser surgery, and interference with the operative field by the endotracheal tube.
f) Intermittent apnea is also used as a technique to ventilate patients in this shared space. The anesthesia provider or the surgeon repeatedly removes the endotracheal tube, operates during a brief period of apnea, and then allows the anesthesia provider to reintubate and ventilate the patient. One advantage of the technique is that no special equipment is needed to ventilate the patient.
g) Many of the patients having these procedures have a long history of heavy smoking and alcohol use, which predisposes them to cardiovascular disease and labile vital signs. Some of the disadvantages of this approach include difficulty in reintubation of the patient and the time allotment between ventilations while preventing desaturations. The procedure must be interrupted frequently to ventilate the patient, and the airway is unprotected while the endotracheal tube is removed. During this technique, the blood pressure and heart rate tend to fluctuate widely. The procedure resembles a series of stress-filled laryngoscopies and intubations, separated by varying periods of minimal surgical stimulation. Intravenous administration or topical application of agents such as lidocaine; small doses of alfentanil, remifentanil, sufentanil, or fentanyl; and/or β-adrenergic receptor blocking drugs such as esmolol may help moderate the sympathetic response.
E Intraocular Procedures
1. Introduction
Intraocular procedures may refer to vitrectomy, glaucoma drainage, corneal transplant, and open eye injury. These procedures involve entry into the vitreous humor. It is crucial to avoid increases in intraocular pressure (IOP) with all intraocular procedures.
The most common of these procedures, vitrectomy, is performed by making three openings into the vitreous cavity. One of these openings is used to instill balanced salt solution; another is made for insertion of a fiberoptic light. The third opening is made for the insertion of various instruments used to remove abnormal tissue from the vitreous cavity. Frequently, a gas bubble is introduced during vitrectomy to tamponade retinal tears.
2. Preoperative assessment
a) History and physical examination: Individualized based on patient’s history and medical condition
b) Patient preparation
(1) Laboratory and diagnostic tests: These are as indicated from the history and physical examination.
(2) Medications: Midazolam, 1 to 2 mg, may be given intravenously in divided doses as a premedication. The anesthesia provider must be aware that ocular drugs applied topically can have systemic effects. These include hypertension, arrhythmias, nausea and vomiting, agitation, excitement, disorientation, seizures, hypotension, and metabolic acidosis.
3. Room preparation
a) Monitoring equipment is standard.
b) Additional equipment includes standard emergency drugs, a long breathing circuit (table will be turned), and right-angled endotracheal tubes.
c) Intravenous fluids: One 18-gauge intravenous line with normal saline or lactated Ringer’s solution at 5 to 10 mL/kg/hr is used.
d) A Hudson hood may be used to provide oxygen to the patient if a regional block with sedation is to be used. Care must be taken if there is any electrocautery, because the hood will create an oxygen-rich environment under the drape.
4. Perioperative management and anesthetic technique
a) These procedures can be done with the patient under general anesthesia or under a regional block (retrobulbar or peribulbar block) with sedation.
b) General anesthesia with endotracheal intubation is indicated for the following patients: infants; young children; patients with severe claustrophobia; patients unable to cooperate, communicate, or lie flat for long periods; or patients with a history of acute anxiety attacks.
c) Most adult patients do well with a regional block with sedation, which is the preferred anesthetic technique. If this method of anesthesia is used, it is important to determine the patient’s response to sedatives/narcotics before administration of the block. Once the table is turned and the patient is draped, it can be difficult to maintain an airway if necessary. Care must be taken to avoid oversedation. If oversedated, patients tend to be startled when they arouse and may be confused and move about. A short-acting hypnotic (propofol) may be useful immediately before administration of the block. The surgeon needs to have the patient’s cooperation during the block, because the surgeon may ask the patient to look from side to side.
d) General endotracheal tube anesthesia is also appropriate.
(1) Induction: Standard intravenous induction. Ketamine is not a drug of choice because increased IOP is to be avoided. Care must be taken to avoid pressure on the eyes with the mask. Nondepolarizing muscle relaxants are used for intubation and continued throughout the procedure, titrated to patient response. It is imperative that the patient not move during the procedure. All connections in the breathing circuit should be secured.
(2) Maintenance: Continuous intravenous anesthesia is an option. Another option is the use of inhalational agents. Nitrous oxide may or may not be used. If used, however, and the surgeon performs a gas-fluid exchange, the nitrous oxide should be discontinued 5 to 10 minutes before this exchange. Consider an antiemetic because of the high incidence of postoperative nausea and vomiting.
e) Emergence: Smooth emergence and extubation are important. Coughing, bucking, and straining should be avoided to prevent increasing the IOP. Consider deep extubation, although care must be taken not to place pressure on the operative eye with the face mask.
5. Postoperative implications
Again, coughing, bucking, and straining should be avoided. The patient may be positioned prone or to one side (as ordered by the surgeon) for correct positioning of the gas bubble. The patient’s respiratory status should be ensured before turning the patient postoperatively.
F Jet Ventilation
1. Introduction
Jet ventilation has been used extensively for laryngeal surgery. When the trachea is not intubated, a metal needle mounted in the operating laryngoscope or passed through the cords can be used for jet ventilation. Jet ventilation may be performed manually, using a simple hand valve attached to an appropriate oxygen source, or with the use of various mechanical devices that allow for adjustment of rate and oxygen concentration. Because oxygen can support combustion, the anesthesia provider should consider as low a concentration of oxygen as is possible. Many patients will tolerate an Fi o2 of 30% or less; however, oxygen requirements for each patient should be considered for their individual needs. Using lower levels of oxygen will be less likely to create a fire.
a) High-frequency jet ventilation
High-frequency jet ventilation (HFJV) was originally used as a technique to provide adequate oxygenation and alveolar ventilation for rigid bronchoscopy and laryngeal surgery. HFJV is typically ventilation at low tidal volumes with high respiratory rates. A needle connected to a high-pressure hose with a regulator to adjust rate and volume is used to deliver the ventilation. With the tip of the needle either above or below the glottis, the anesthesia provider directs a high-velocity jet stream of oxygen into the airway lumen. The lungs are ventilated as the mixture of oxygen forces air into the lumen. Introduction of high-pressure (up to 60 psi) jet-injected oxygen entrains room air into the lung, allowing the jet stream of gases into the airway for ventilation. While inspiration is accomplished by HFJV pressurizing gas into the airway, the expiration is passive. Therefore, some pauses in ventilation may be necessary to provide adequate time for expiration, particularly in patients with severe respiratory disease.
If an airway mass lies above the level of delivery of the gas jet, it may be easy to force the gas down the trachea during inspiration. But the gases will be trapped during expiration. This air trapping can lead to increased airway pressure, subcutaneous emphysema, and pneumothorax, particularly in patients with bullae. The anesthesia provider or surgeon may also find it difficult to aim the jet into the airway lumen, leading to hypoxia. If the jet is not accurately aimed, gastric distention, subcutaneous emphysema, or barotrauma may result. Patients with decreased pulmonary compliance or increased airway resistance from bronchospasm, obesity, or chronic obstructive pulmonary disease (COPD) are at high risk for hypoventilation with jet techniques. Jet ventilation is contraindicated in any situation in which an unprotected airway is a concern (e.g., full stomach, hiatal hernia, or trauma).
Adequacy of ventilation is assessed by observing chest movement, auscultation with the precordial stethoscope, and a pulse oximeter. Total intravenous anesthesia (TIVA) is the primary anesthesia technique used with HFJV, since volatile agents cannot be delivered and environmental contamination is a concern. TIVA with short-acting agents such as propofol, alfentanil, fentanyl, and remifentanil provide an excellent anesthetic for these procedures.
G Foreign Body Aspiration
1. Introduction
Aspiration of foreign bodies is a common problem. There is a high morbidity and mortality, particularly in children, who aspirate foreign objects. Some common aspirants include peanuts, popcorn, jelly beans, coins, and bites of meat and hot dogs. The majority of aspirated items are food particles; however, beads, pins, and small toys are not unusual. A common site of foreign body aspiration is the right bronchus. If the patient is supine when the aspiration occurs, the object will most likely be found in the right upper lobe. If the patient is standing, the right lower lobe is most likely to be affected. Signs of aspiration include wheezing, choking, coughing, tachycardia, aphonia, and cyanosis. These signs indicate an obstructive severe irritation and swelling in the airway. As a result of the swelling, air may be trapped in the lungs, not allowing adequate expiration.
2. Anesthetic management
a) The anesthetic management depends on the location of the airway obstruction, the size and location of the object, and the severity of the obstruction. If it is located at the level of the larynx, a simple laryngoscopy with Magill forceps should allow for easy removal of the object.
b) Care must be taken not to dislodge the object and allow the object to fall deeper into the airway. If the foreign body is located in the distal larynx or the trachea, the patient should have an inhalation induction performed in the operating room, maintaining spontaneous respiration. With the patient spontaneously breathing, the surgeon will most likely use a rigid bronchoscope for extraction of the foreign body.
c) A gentle mask induction without cricoid pressure or positive pressure ventilation is the preferred induction technique. The anesthesia provider should not assist with respirations because this may cause the object to move further into the airway and compromise ventilation with occlusion. Patients should be placed in the sitting position because it is known to produce the least adverse effect on airway symptoms.
d) An antisialagogue, H 2 antagonist, and metoclopramide are often administered intravenously to decrease secretions and promote gastric emptying; the secretions may obscure the view through the bronchoscope.
e) Patients with full stomachs who are induced with a rapid sequence must be prepared for complete occlusion of the airway.
f) Direct and sometimes rigid laryngoscopy is typically performed. A rigid bronchoscope is also used and passed through the vocal cords into the trachea. Ventilation is accomplished through a side port of the laryngoscope or bronchoscope that can be attached to the anesthesia circuit.
g) If a foreign body is present, the telescope eyepiece within the bronchoscope is removed and optical forceps are inserted through the bronchoscope for retrieval of the item. While the telescopic eyepiece is being changed, a leak is present in the ventilation system and protracted periods can lead to hypoxia.
h) When an anesthesia gas machine circuit is used, high fresh gas flow rates, large tidal volumes, and high concentrations of inspired volatile anesthetic agents are often necessary to compensate for leaks around the ventilating bronchoscope.
i) Coughing, bucking, or straining during instrumentation with the rigid bronchoscope may cause difficulty for the surgeon and result in damage to the patient’s airway; these must be avoided.
j) The best anesthesia technique for rigid laryngoscopy and bronchoscopy is TIVA, allowing greater control of cardiovascular stability and relaxation for short periods, as well as ventilation with 100% oxygen, allowing longer periods of hypoventilation without hypoxia.
k) A rigid bronchoscopy can lead to several complications including damage to dentition, gums, and upper lips, and chipped or damaged teeth, all of which can be prevented to some degree with the use of a mouth guard and vigilance.
l) Vagal stimulation may be noted from the extreme head extension, and tracheal tears can occur with the introduction of the bronchoscope. Inadequate ventilation manifests as hypoxemia, hypercarbia, barotrauma, and dysrhythmias.
m) The surgeon must be prepared to perform an emergency tracheostomy or cricothyrotomy if partial obstruction suddenly becomes complete.
n) At the conclusion of the procedure, patients can be intubated to provide ventilation until returning to consciousness. Allow the patient to return to consciousness as quickly as possible with airway reflexes intact prior to extubation.
o) Laryngeal and subglottic edema may occur for 24 hours after removal of a foreign body. To check for airway edema, the cuff of the endotracheal tube can be deflated if not contraindicated, and the lumen of the endotracheal tube should be occluded for one or two breaths during inspiration and expiration while listening for air movement around the tube. If there is no air escaping around the endotracheal tube, postoperative sedation and ventilation might be considered.
p) Close observation and use of humidified oxygen are suggested during the recovery period. Some additional supportive measures that can alleviate some of the postoperative complications that occur include racemic epinephrine, bronchodilators, and steroids.
H Laryngectomy
1. Introduction
Most cancers of the upper respiratory tract are squamous cell carcinomas. When the laryngeal musculature or cartilage is invaded, total laryngectomy is performed. Intractable aspiration, with resultant pneumonia that has been unresponsive to other treatments, is another indication for laryngectomy.
2. Surgical procedures
Total laryngectomy involves removal of the vallecula and includes the posterior third of the tongue if necessary. Surgical exposure is from the hyoid bone to the clavicle. A tracheostomy is performed, and an anode tube is placed. The larynx is usually transected just above the hyoid bone. The trachea is brought out to the skin as a tracheostomy without the need for an endotracheal tube or tracheostomy tube as the pharynx is closed.
Supraglottic laryngectomy leaves the true vocal cords by resection of the larynx from the ventricle to the base of the tongue. Surgical exposure is similar to that for total laryngectomy. The specimen includes the epiglottis, the false vocal cords, the supraglottic lesions, and a portion of the base of the tongue. The thyroid perichondrium is approximated to the base of the tongue along with the strap muscles for closure. A temporary tracheostomy is required.
Hemilaryngectomy or vertical partial laryngectomy retains the epiglottis but involves removal of a unilateral true and false vocal cord. Surgical exposure is similar to that of supraglottic laryngectomy, and a tracheostomy is required.
Near-total laryngectomy involves removal of the entire larynx. One arytenoid is used to construct a phonatory shunt for speaking. A permanent or temporary tracheostomy is created, and the procedure may be combined with neck dissection and pharyngectomy with flap reconstruction.
The table on p. 322 describes the structures removed, structures remaining, and postoperative conditions for the types of surgical procedures.
3. Preoperative assessment
Most patients are older and have a long history of tobacco and alcohol abuse. Associated medical problems may include chronic obstructive pulmonary disease, hypertension, coronary artery disease, and alcohol withdrawal.
a) History and physical examination: Individualized
(1) Respiratory: Smoking (more than 40 packs/year) is associated with bronchitis, pulmonary emphysema, and chronic obstructive pulmonary disease, which impair respiratory function. Arterial blood gases may reveal carbon dioxide retention and hypoxemia. Pulmonary function tests demonstrate decreased forced expiratory volume, forced vital capacity, and the ratio of forced expiratory volume to forced vital capacity. Preoperative airway assessment is imperative because edema may distort airway anatomy, and tumor and edema may cause airway compromise. Tracheal deviation must be considered. Fibrosis, edema, and scarring from prior radiation therapy may distort the airway as well.
(2) Assess for signs of alcohol withdrawal (altered mental status, tremulousness, and increased sympathetic activity).
(3) Gastrointestinal: Weight loss, malnutrition, dehydration, and electrolyte imbalance can be significant.
(4) Hematologic: Anemias or coagulopathies may be present.
4. Patient preparation
a) Laboratory tests: Baseline arterial blood gases, electrolytes, hemoglobin, hematocrit, prothrombin time, partial thromboplastin time, and, if indicated from the history and physical examination, hepatic function tests are obtained.
b) Diagnostic tests: Chest radiography, electrocardiography, pulmonary function testing, echocardiography, and stress tests are as indicated from the history and physical examination. Indirect and direct laryngoscopies preoperatively and review of computed tomography may help in planning intubation.
c) Medications: Treatment with a long-acting hypnotic, such as chlordiazepoxide or diazepam, as a precaution for delirium tremens can be considered, unless sedation would be contraindicated because of concerns of airway compromise. An intravenous antisialagogue (glycopyrrolate, 0.2 mg) facilitates endoscopy by the surgeon.
5. Room preparation
a) Monitoring equipment
(1) Standard
(2) Foley catheter
(3) Arterial line: Useful for serial laboratory and arterial blood gas studies
(4) Central venous pressure catheter: If indicated by coexisting disease (prefer basilic/cephalic vein)
b) Additional equipment
(1) Regular operating table: May be turned 180 degrees
(2) Extension tubes
(3) Fluid warmer and humidifier
(4) Fiberoptic laryngoscope with anticipated difficult airway or potential for airway obstruction
(5) Tracheostomy under local anesthesia occasionally necessary for severe airway management.
c) Drugs
(1) Standard emergency drugs
(2) Standard tabletop
(3) Intravenous fluids
(4) Two 16- to 18-gauge or larger intravenous lines with normal saline/lactated Ringer’s solution at 3 to 5 mL/kg/hr
(5) No sudden large blood losses; transfusion usually not necessary
6. Perioperative management and anesthetic technique
General endotracheal anesthesia is used.
a) Induction: Standard intravenous induction is appropriate with a normal airway. The choice of an induction drug should be based on the patient’s medical condition. If airway difficulty is possible, direct laryngoscopy can be performed while the patient is breathing spontaneously, and a muscle relaxant may be administered once the glottis is visualized. In more difficult cases, awake intubation or fiberoptic laryngoscopy may be required.
b) Maintenance: The patient is in the supine position, with the head elevated 30 degrees; standard maintenance is used, considering the patient’s preexisting medical problems. An inhalation agent and supplemental narcotics will benefit patients with reactive airway disease. Use of nondepolarizing muscle relaxants should be discussed with the surgeon because nerve stimulation for facial nerve localization may be performed.
c) Emergence: Many patients undergo tracheostomy. If no tracheostomy is performed, the amount of airway edema and distortion needs to be discussed with the surgeon before determining extubation. Gradual emergence with stable hemodynamic parameters is an important consideration in the patient with coronary artery disease.
7. Postoperative implications
a) Injury to the facial nerve can cause facial droop. Recurrent laryngeal nerve injury can result in vocal cord dysfunction; diaphragmatic paralysis may result from phrenic nerve injury.
b) Pneumothorax may occur with low neck dissection.
c) Airway impingement results from restrictive neck dressings or hematoma development.
d) Communication difficulties occur following laryngectomy.
I Laser Surgery
1. Introduction
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