General Principles
Although much of it is simple and commonplace, ear, nose, and throat surgery has a disproportionately large potential for anesthetic and surgical complications. It demands meticulous attention to all aspects of the child’s perioperative care.
- 1.
Because many of these operations involve the airway, the anesthesiologist must be prepared to provide good surgical access while maintaining a safe ventilatory pathway for the child.
- 2.
The advent of the surgical microscope has permitted development of delicate and precise surgery for the middle ear. Anesthesia for such procedures must provide quiet operating conditions with minimal bleeding, smooth emergence from anesthesia, and minimal disturbance postoperatively.
- 3.
After surgery involving the airway, skilled nursing care in the postanesthesia care unit (PACU) is essential, so that signs of impending complications can be detected early and appropriate therapy instituted.
- 4.
The use of the laser to treat lesions of the larynx creates additional potential problems for anesthesia management.
- 5.
When topical vasoconstrictors are used, the anesthesiologist must be aware of the drugs and doses that will be used because significant systemic absorption may cause dangerous effects. A maximum initial dose of 20 µg/kg of phenylephrine has been recommended for children, but this is considerably less than has been commonly used. Monitor the child carefully when topical vasoconstrictors are applied. Topical phenylephrine may lead to hypertension, which resolves rapidly and requires no treatment. Occasionally, severe hypertension may occur; this should be treated with direct vasodilators (e.g., sodium nitroprusside) or α-adrenergic receptor antagonists (e.g., phentolamine). Do not use β-blockers or calcium channel blockers in the presence of hypertension; these may cause a disastrous decrease in cardiac output and the severe hypertension may cause pulmonary edema.
Suggested Reading
Choanal Atresia
If it is a complete obstruction, as in 90% of cases, choanal atresia (membranous or bony occlusion of the posterior nares) causes respiratory distress immediately after birth. The distress is intermittent; being relieved whenever the infant cries because neonates are primarily nose-breathers. The diagnosis can be easily confirmed by listening for air exchange over each nostril with a stethoscope. Once the diagnosis is established the obstruction can be relieved with an oropharyngeal airway. The passage of an orogastric tube may open the oral airway in some infants and also facilitates feeding of the infant. Early endonasal puncture and stenting may be performed in the neonate, but is usually delayed in the preterm infant. It is now recognized that even incomplete choanal atresia may lead to chronic nasal problems; therefore early repair is common.
Associated Conditions
The “CHARGE” association consists of C oloboma, congenital H eart disease, choanal A tresia, growth and mental R etardation, G enitourinary abnormalities with genital hypoplasia, and E ar anomalies.
Surgical Procedures
- 1.
Endoscopic transnasal puncture may be preferred, especially in preterm infants or in those with associated significant disease (e.g., the CHARGE association).
- 2.
Transpalatal repair if indicated is usually performed at age 1 to 2 days in the healthy, full-term infant. Stents are left in postoperatively for varying periods.
Special Anesthesia Problems
The primary problem is maintenance of the airway until completion of surgery.
Anesthesia Management
Preoperative
- 1.
Adequate ventilation requires continued use of an oropharyngeal airway.
Perioperative
- 1.
Observe all special precautions for neonates (see Chapter 4 ).
- 2.
Leave the oropharyngeal airway in place: give 100% O 2 by mask.
- 3.
Induce anesthesia by inhalation of sevoflurane or halothane. Confirm that manual ventilation via the mask and oropharyngeal airway is successful and, if so, administer a short-acting muscle relaxant; intubate using an oral RAE tube®
- 4.
Maintain anesthesia with N 2 O and small concentrations of sevoflurane or isoflurane with controlled ventilation.
- 5.
Suction the pharynx very carefully at the end of the operation and ensure that the stents are clean and patent.
- 6.
Do not extubate the trachea until the child is fully awake.
Postoperative
- 1.
Order humidified oxygen. The stents must be regularly suctioned with a fine catheter to keep them clear.
- 2.
Constant observation is essential because aspiration during feeding commonly occurs after repair of choanal atresia.
- 3.
Subsequent repairs may be necessary later in childhood for restenosis, but these operations present no other special anesthetic problems.
- 4.
Order appropriate analgesia.
Suggested Reading
Nasopharyngeal Tumors
Teratomas, dermoid cysts, nasal encephaloceles, and other tumors require surgical excision. Juvenile nasal angiofibroma is a rare benign but very vascular tumor that may involve the nose. Biopsy of these tumors may result in extensive bleeding that is very difficult to control; therefore diagnosis is usually made on the basis of imaging studies. An operation to remove the tumor may result in massive blood loss and should be prepared for accordingly. Postoperatively, there may be persistent nasal obstruction and continued bleeding; the endotracheal tube should be left in place until the child is fully awake.
SURGERY OF THE NOSE
The most common procedures for nasal surgery are reduction of nasal fractures, septoplasty, rhinoplasty, and excision of nasal polyps.
Special Anesthesia Problems
- 1.
The nasal airway may be blocked. The surgeon may wish to pack the nose with gauze and a vasoconstrictor (e.g., cocaine) preoperatively.
- 2.
Children with nasal polyps usually have cystic fibrosis.
- 3.
Functional endoscopic sinus surgery (FESS) may precipitate special problems (see later discussion).
Anesthesia Management
Preoperative
- 1.
Assess the nasal airway.
- 2.
If the child has cystic fibrosis, order appropriate preoperative care (see Chapter 6, page 177 ).
Perioperative
- 1.
Induce anesthesia by inhalation or intravenously with propofol or thiopental, followed by a muscle relaxant.
- 2.
If the nose is blocked, insert an oropharyngeal airway before attempting mask ventilation.
- 3.
Perform orotracheal intubation, with a cuffed tube.
- 4.
Insert a throat pack to prevent blood pooling in the pharynx and esophagus.
- 5.
Position the child with a slight head-up tilt.
- 6.
Extubate the trachea when the child is fully awake; premature extubation may lead to laryngospasm or airway obstruction.
Postoperative
- 1.
Order analgesics as required.
- 2.
Administer humidified oxygen by mask.
- 3.
Postoperative airway obstruction may occur and may require reintubation. If prolonged, obstruction may predispose to postobstructive pulmonary edema. This requires therapy with oxygen, a diuretic, and morphine. If pulmonary edema is severe, tracheal intubation and positive-pressure ventilation may be required.
FUNCTIONAL ENDOSCOPIC SINUS SURGERY (FESS)
FESS has become a standard surgical treatment for chronic sinus disease. Precise endoscopic resection of diseased tissue and relief of obstruction while preserving normal mucosa is the objective to restore normal sinus function.
Special Anesthesia Problems
- 1.
Many of these children have chronic diseases (e.g., cystic fibrosis).
- 2.
Successful endoscopic surgery requires extensive use of vasoconstrictors. Ensure that maximal permissible doses are not exceeded so as to prevent severe hypertension: 2 to 3 mg/kg cocaine or 10 µg/kg epinephrine. If hypertension ensues, treat it by deepening anesthesia or using vasodilators; do not use β-blockers or calcium channel-blocking agents.
- 3.
Bleeding may be considerable and may require that packing remain in place postoperatively. Because this is likely to cause complete nasal obstruction, have the child fully awake before extubation.
- 4.
Rarely, the surgery may encroach on the orbit or intracranial space. In the latter case intracranial bleeding may occur. There is also a danger of pneumocephalus if positive pressure is applied via a facemask.
TONSILLECTOMY AND ADENOIDECTOMY (T&A)
Chronic inflammation and hypertrophy of lymphoid tissues in the pharynx may necessitate surgery to relieve obstruction or to remove the focus of infection. Repeated middle ear infections may be improved by adenoidectomy. Obstructive sleep apnea (OSA) is now the commonest indication for T&A in North America. Rarely, acute tonsillitis leads to a peritonsillar abscess (quinsy tonsil).
T&A surgery is now often performed in the ambulatory unit; this demands special considerations in the selection of suitable children and in their postoperative evaluation before discharge home. An efficient follow-up service must be provided to deal with unexpected complications. Some children may not be suitable for outpatient T&A.
The following criteria are indications for admission after T&A:
- 1.
Age less than 3 years
- 2.
Those with abnormal coagulation studies or a history suggestive of increased bleeding tendency
- 3.
Those with evidence of significant OSA (see later discussion)
- 4.
Those with other systemic diseases that place them at additional perioperative risk (e.g., congenital heart disease, endocrine or neuromuscular disease, chromosomal abnormalities, obesity)
- 5.
Those with craniofacial or airway abnormalities, including Down syndrome
- 6.
Those with a history of peritonsillar abscess
- 7.
Those who live at an excessive distance from the medical facility or whose home, social, or parental situation might preclude safe postoperative care.
T&A is still one of the most common procedures in children and should be very safe. However, T&A-related deaths still occur: the usual cause is excessive sedation of children with airway compromise, OSA, or mismanagement of postoperative bleeding. Postoperative nausea and vomiting are common after T&A but may be significantly reduced by withholding postoperative oral fluids until the child requests them, rehydration during anesthesia (20 to 25 ml/kg lactated Ringer’s solution or equivalent), and the administration of dexamethasone and a serotonin-receptor antagonist.
Obstructive Sleep Apnea (OSA)
Chronic obstruction due to lymphoid hyperplasia may result in OSA, and this is now a most common indication for T&A. Affected children may be obese (or asthenic), show difficulty arousing in the morning or daytime somnolence, nocturnal enuresis and behavior problems (attention deficit disorder and limited attention span), nocturnal apnea and sweat profusely.
If such a history is obtained preoperatively, ideally a sleep study (polysomnography) should be performed; if the results are significantly abnormal, admission after tonsillectomy is advised. Polysomnographic indications for admission after tonsillectomy for the T&A with a history of OSA include:
- 1.
A baseline value for partial pressure of carbon dioxide (PaCO 2 ) ≥ 50 mm Hg
- 2.
A baseline awake oxygen saturation value ≤ 92%
- 3.
Episodes of oxygen desaturation ≤ 80%
- 4.
Apnea/hypopnea index greater than 1
If polysomnography is unavailable, overnight oxygen saturation monitoring has been suggested as a valuable screening tool; resting saturations less than 90% and episodes less than 80% are strongly predictive of severe OSA. Although the positive predictive value of overnight Sp o 2 monitoring is very high, a negative test is less helpful and should be interpreted cautiously.
Children with OSA have reduced responses to rebreathing CO 2 and may be exceedingly sensitive to opioids, requiring dramatically reduced doses of opioids.
Children with mild OSA are reported to have few complications after T&A. Those with moderate/severe apnea require careful postoperative care.
The child with OSA should be closely monitored before and after surgery; supervised mild sedation (oral midazolam) is safe preoperatively but is often omitted. In all children with diagnosed OSA, spontaneous respiration is indicated after tracheal intubation and small incremental doses of opioid should be administered (i.e., IV fentanyl 0.5 µg/kg or morphine 0.025 mg/kg). Children with upregulated opioid sensitivity may develop apnea after these small opioid doses despite surgical stimulation. In such cases, no further opioids should be administered and postoperative opioid doses should be markedly reduced. Rectal acetaminophen (35 to 45 mg/kg) may be administered after induction of anesthesia, with subsequent rectal doses of 20 mg/kg q6h (maximum daily dose 90 to 100 mg/kg/day). Alternatively oral acetaminophen (10 to 15 mg/kg) may be administered. Posttonsillectomy ketorolac has been criticized because of the risk of bleeding and reoperation, although the data are controversial. There may be roles for diclofenac, tramadol, and ketamine for posttonsillectomy analgesia, although experience with these analgesics in children with OSA is limited. Postoperative sleep studies show that 90% or more improve by 6 months (fewer improve if obesity or moderate/severe OSA is present). Those who do not improve (usually severe OSA), should be investigated for residual soft tissue obstruction and evaluated for uvulopalatopharyngoplasty. Children generally do not tolerate CPAP or BiPAP devices.
Suggested Reading
Cardiorespiratory Syndrome
In very rare instances, severe chronic airway obstruction by adenoidal tissue may lead to pulmonary hypertension and right-sided heart failure (cardiorespiratory syndrome). This condition usually occurs in boys and is more common in African American children. There is usually a history of symptoms lasting 1 year or longer. The child is usually febrile (due to associated adenoid or pulmonary infection) with tachycardia and tachypnea. Chest radiography may reveal cardiomegaly, and the electrocardiogram indicates right ventricular hypertrophy. Children with cardiorespiratory syndrome may be critically ill and may require emergency intubation to relieve the obstruction. Once this is done and the heart failure is controlled with digitalis and diuretics, T&A should be performed. They may need to remain intubated postoperatively and should be admitted to the ICU for further treatment.
Suggested Reading
Special Anesthesia Problems for T&A surgery
- 1.
Sharing the airway with the surgeon
- 2.
Danger of postoperative bleeding
- 3.
A history of bleeding tendency or recent salicylate therapy. Salicylate ingestion during the days before operation increases blood loss during T&A. If such a history is obtained, a test of bleeding time should be performed; if the time is prolonged (more than 10 minutes), the operation is deferred.
- 4.
A history suggestive of OSA; such children may be at risk for perioperative apnea and demonstrated increased sensitivity to opioids (see previous discussion).
Anesthesia Management
- 1.
For children with a history of chronic infections, anesthesia may be induced intravenously or by inhalation and supplemented with an intermediate relaxant to facilitate intubation. For children with a history of OSA, after induction of anesthesia, we advocate tracheal intubation without the use of a muscle relaxant to assess the respiratory responses to small incremental doses of intravenous opioids during surgery.
- 2.
Perform tracheal intubation with a RAE tube that is positioned under a slotted tongue blade of the mouth gag. Check the airway patency carefully after the gag is positioned. Check for bilateral ventilation because the tip of the RAE tube may become endobronchial after insertion of the mouth gag or if the neck is flexed. Some advocate an LMA in place of a tracheal tube; however, in our opinion the low morbidity and additional security of an endotracheal tube does not justify substituting an LMA.
- 3.
Administer standard antiemetic therapy to all children: ondansetron (0.10 to 0.15 mg/kg) and dexamethasone 0.0625 to 0.15 mg/kg IV (maximum 8 mg), and lactated Ringer’s solution (20 to 25 ml/kg) to reduce nausea and vomiting and improve post- operative comfort.
- 4.
When the indication for surgery is for chronic infection, maintain anesthesia with N 2 O and sevoflurane or isoflurane, assist ventilation (with or without a relaxant) and supplement with opioids. Plan for postoperative analgesia morphine 0.05 to 0.1 mg/kg IV for postoperative analgesia. When the indication is for OSA, an inhalational anesthetic with spontaneous respiration should be supplemented with small incremental doses of opioids while their respiratory responses are monitored. If apnea or hypopnea develops, no further opioids are administered. In addition, some surgeons infiltrate the tonsil fossae with bupivacaine before surgery to reduce postoperative pain, although this is unproven and presents a significant risk for intravascular injection. Ketamine 0.5 mg/kg IV during surgery reduces the need for other analgesics and may be particularly useful in children with OSA.
- 5.
Measure and chart blood losses carefully.
- 6.
Carefully suction the pharynx; the presence of small amounts of blood in the pharynx may lead to laryngospasm. Extubate the trachea when the child is fully awake and airway reflexes are fully restored (especially with OSA). Do not pass suction catheters through the nose because doing so may make the adenoidal area bleed.
Postoperative
- 1.
Order morphine (0.05 to 0.1 mg/kg) IV in the PACU q5-10 min until comfortable in children without OSA. Acetaminophen (10 to 20 mg/kg PO) with or without codeine is often adequate if an opioid has been given and/or bupivacaine has been infiltrated intraoperatively, although early administration of any PO medications may trigger emesis. Children with OSA should be carefully monitored (pulse oximetry) in PACU; morphine in doses 10% to 50% of the usual dose should be titrated to ventilations. Caution: pulse oximetry is a poor measure of adequacy of ventilation if supplemental oxygen is being administered.
- 2.
An intravenous infusion should be maintained until the child is ready for discharge. It is particularly important to ensure that children undergoing T&A on an outpatient basis are well hydrated before discharge.
- 3.
Do not push oral fluids; order fluids by mouth as requested by the child (i.e., cola beverages, Popsicles) when the child is awake. If PONV occurs and further antiemetic therapy is required (e.g., ondansetron), be aware that this might prevent the child who is continuing to bleed from vomiting and thus conceal the hemorrhage.
- 4.
Closely monitor those children with a history of OSA; such children may become apneic with sedation and/or airway obstruction. Constant nursing attention should be provided (i.e., admit to a monitored unit). Some children (especially the obese) may benefit from nasal CPAP therapy or nasal oxygen.
- 5.
Be cautious when ordering opioids for the restless child, especially if there is any evidence of airway compromise. Restlessness may be a symptom of hypoxia secondary to obstruction, and opioids may produce apnea.
- 6.
The outpatient should be evaluated directly by the surgeon for bleeding and the anesthesiologist for adequacy of ventilation before discharge. In general, we recommend observing children for at least 4 hours before discharge.
- 7.
A telephone consultation service should be provided for follow-up of outpatients on the evening after surgery.
- 8.
Complaints of abdominal pain after T&A are suggestive of swallowed blood from ongoing bleeding, especially after potent antiemetic therapy. Suspicion of tonsil/adenoidal bleeding should be raised.
Reoperation for Bleeding After Tonsillectomy
Special Anesthesia Problems
- 1.
The stomach contains blood that may be regurgitated during induction.
- 2.
Hypovolemia may be present and is easily underestimated. There may be little blood to be seen, but much may have been swallowed.
- 3.
The child may have a bleeding disorder that has been not been identified.
Anesthesia Management
Preoperative
- 1.
Ensure that sufficient fluids have been administered to restore the blood volume, correct severe anemia, and produce normal cardiovascular indices. Bleeding is rarely so brisk that complete restoration of blood volume cannot be achieved before operation.
- 2.
Check that further blood is available in case of need.
- 3.
Check coagulation indices.
- 4.
In some instances, gentle restraint permits examination, insertion of packing, cautery or ligation of bleeding vessels without the need for general anesthesia.
Perioperative
- 1.
Prepare all equipment for a rapid sequence induction (2 suctions, 2 functioning laryngoscope blades, and 2 functioning handles).
- 2.
Check again that the child has been adequately fluid resuscitated.
- 3.
Give 100% O 2 by mask.
- 4.
Rapidly inject propofol (or ketamine or etomidate) with atropine added, followed immediately by succinylcholine (2 mg/kg). If there is a contraindication to succinylcholine, then give high-dose rocuronium (1.2 mg/kg) but anticipate a prolonged recovery from neuromuscular blockade after control of bleeding (∼︀75 minutes).
- 5.
Have an assistant immediately apply cricoid pressure (see page 99 ).
- 6.
Intubate the trachea as rapidly as possible with a styletted tracheal tube.
- 7.
Maintain anesthesia as for T&A (see previous discussion), although surgery for tonsil rebleeding is much less painful compared with the original T&A surgery.
- 8.
Extubate the trachea when any residual neuromuscular blockade has been adequately antagonized and the child is fully awake.
Postoperative
- 1.
Check the hemoglobin level to confirm adequacy of blood replacement.
- 2.
Be alert to the possibility of further bleeding.
- 3.
Monitor oxygen saturation and vital signs closely.
- 4.
Order suitable doses of analgesic as needed (not acetylsalicylic acid).
- a.
Oversedation could result in complete obstruction of the airway.
- b.
Restlessness may indicate hypoxia rather than a need for sedation.
- a.
Peritonsillar Abscess (Quinsy)
Special Considerations
- 1.
Trismus and swollen tissues in the pharynx may make tracheal intubation difficult.
- 2.
There is a danger that the abscess may burst and flood the pharynx with pus that leads to pulmonary aspiration.
Anesthesia Management
Preoperative
- 1.
Children with tonsillar abscess should be closely observed for impending airway obstruction. Check the extent to which the mouth can be opened; significant trismus may be present.
- 2.
Avoid sedative premedications if possible, particularly in children with any degree of airway obstruction.
Perioperative
- 1.
Check that the child can open the mouth. Ensure that strong suction is available. Give atropine 0.02 mg/kg IV.
- 2.
Induce anesthesia by inhalation of N 2 O with sevoflurane or halothane. Maintain spontaneous ventilation. Position the head slightly down and turned to the affected side.
- 3.
Do not give muscle relaxants (airway obstruction may occur).
- 4.
When the child is deeply anesthetized, discontinue N 2 O and continue with sevoflurane in 100% O 2 ; give 1 mg/kg lidocaine IV to reduce the risk of coughing or breath holding during laryngoscopy and endotracheal intubation. Be careful not to rupture the abscess during airway instrumentation.
- 5.
Maintenance is the same as for T&A for chronic infection (see previous discussion).
- 6.
Suction carefully and extubate the fully awake child in a lateral position.
N.B. Sometimes the inflammatory swelling involves the supraglottic structures, and postextubation obstruction may occur. Dexamethasone (0.1 mg/kg up to 8 mg) IV should be considered. Close observation is essential.
Suggested Reading
Otologic Conditions
Surgery for ear conditions ranges from (minor surgery) simple myringotomy and tubes to (major) prolonged surgery for tympanomastoidectomy and cochlear implants. Myringotomy and tube surgery is the briefest surgery performed in the operating room (OR) (as brief as <5 min) but is not without risk because these infants and children often have or had recent URTIs. In contrast, tympanomastoidectomy and cochlear implantation require considerations for prolonged surgery, require tracheal intubation and are associated with PONV.
Special Anesthesia Problems
- 1.
The child may have had repeated procedures and may be very apprehensive.
- 2.
The child’s hearing may be impaired, making communication difficult.
- 3.
During middle ear procedures, even a small amount of bleeding may interfere with surgery. Position the child carefully and avoid anesthetic causes of bleeding (e.g., hypoventilation, coughing, NSAIDs). However, induced hypotension is not usually warranted for this type of surgery in children.
- 4.
The surgeon may wish to use vasoconstrictor drugs (e.g., epinephrine, cocaine). In such cases the dose should not exceed the maximum (see previous discussion).
- 5.
Otologic procedures can be lengthy; if this is the case, ventilation should be controlled and careful attention should be paid to positioning, padding, and maintenance of body temperature.
- 6.
In rare cases, the child’s cooperation is required during surgery (see Chapter 8, page 258 , Awake Craniotomy).
- 7.
If the surgeon uses a nerve stimulator, relaxants are limited to induction of anesthesia.
- 8.
Postoperative PONV secondary to labyrinthine disturbance is common. Prior therapy with antiemetics (e.g., ondansetron) may be useful.
- 9.
Use of a postauricular nerve block before surgical incision and repeated at the end of surgery has been demonstrated to reduce vomiting compared with opioids.
Minor Otologic Procedures
Minor otologic procedures are usually performed in the outpatient department. N 2 O has been shown to pass into the middle ear cavity if air is present and may modify findings at operation, but in general its use is not contraindicated. N 2 O does not increase the incidence of postoperative vomiting.
Special Anesthesia Problems
- 1.
Some children who require repeated minor otologic procedures have associated congenital deformities of the upper airway that predispose to their ear disease (e.g., cleft palate, Treacher Collins). Check previous anesthetic records carefully for potential airway problems.
- 2.
Many of these children present for anesthesia with signs of an upper respiratory tract infection (URTI). In such instances, the decision to proceed must be based on the urgency of surgery (i.e., acute middle ear infection) compared with the severity of the URTI. If the child’s temperature is normal, behavior and eating habits have been normal and there are no mucopurulent secretions or chest wheezing/rales, then surgery should proceed (see Chapter 6, page 172 ).
Anesthesia Management
Preoperative
- 1.
Sedation is often unnecessary, but oral midazolam is useful for the very upset child, though it delays recovery after very brief surgery. Parental presence at induction of anesthesia may provide adequate anxiolysis.
Perioperative
- 1.
Induce anesthesia by inhalation of sevoflurane or intravenously with propofol or thiopental.
- 2.
Maintain anesthesia with N 2 O and sevoflurane or isoflurane by facemask.
- 3.
Tracheal intubation is not required, but a laryngoscope and suitable endotracheal tubes should be immediately available in case of unexpected difficulties. Likewise an IV infusion is not usually required.
- 4.
Ensure that you can comfortably hold the child’s head very still during the procedure— resting your elbow on the table will help with this.
- 5.
Analgesics are not usually required, especially if the surgeon inserts local analgesic drops. Oral (10-15 mg/kg preoperatively) or rectal acetaminophen (35 to 45 mg/kg intraoperatively) may be administered. A 0.25 injection of 0.125% bupivacaine without epinephrine of the nerve of Arnold (interior surface of the tragus) provides analgesia and reduces the incidence of vomiting. Others have also administered intranasal or IM fentanyl for perioperative pain control.
Postoperative
- 1.
Oral codeine may be administered for ongoing pain.
- 2.
Resume PO fluids when the child is awake.
Major Otologic Procedures
Anesthesia Management
Preoperative
- 1.
Order adequate sedation, especially for children who have had surgery previously.
- 2.
Hearing aids may be worn until induction of anesthesia after which time they should be removed, turned off and stored until the child recovers.
- 3.
If the child communicates by sign language, then either a parent or healthcare professional who can sign should accompany the child to the OR. If the child can lip-read, do not cover your lips until the child is anesthetized.
Perioperative
- 1.
Induce anesthesia by inhalation or intravenously with propofol (or thiopental), followed by a suitable relaxant. If nerve stimulation (usually for facial nerve) is required during surgery, only use a single dose of short (succinylcholine) or intermediate-acting relaxant (rocuronium or cis-atracurium) for intubation.
- 2.
Spray the larynx with lidocaine; then insert an orotracheal (regular or RAE®) tube. Extended breathing circuit tubing is usually required as the anesthetic machine is located at the foot of the OR table. Ensure adequate ventilation for the increased breathing circuit compliance.
- 3.
Maintain anesthesia with N 2 O/O 2 and an inhalational anesthetic; anesthesia must be deep enough to prevent any possibility of bucking on the tube, which increases bleeding. Supplement with opioids as needed, but beware that this may increase PONV (consider remifentanil)
- 4.
Position the child with a 15° head-up tilt to minimize bleeding.
- 5.
If epinephrine is to be infiltrated, ensure that the dose does not exceed the maximum.
- 6.
Prophylactic antiemetic therapy should be given. IV balanced salt solution should include 20 to 25 ml/kg to decrease postoperative pain and emesis.
- 7.
For tympanoplasty, discontinue N 2 O from the inspired mixture before the graft is positioned. (N 2 O bubbles might float the graft off the desired position.)
- 8.
Smooth tracheal extubation, without coughing, is essential. Therefore, administer intravenous lidocaine 1 mg/kg or propofol 0.5 to 1 mg/kg and remove the tube while the child is still deeply anesthetized and breathing spontaneously. Maintain the airway and allow the child to awaken while administering oxygen by mask.
Postoperative
- 1.
Order analgesics and antiemetics as required.
Awake Ear Surgery
For certain operations (e.g., ossicular reconstruction), the surgeon may wish to assess hearing during the surgical procedure. Most older children cooperate well if such operations are performed under a combination of sedation and local analgesia.
Anesthesia Management
Preoperative
- 1.
Explain in detail what will happen during the operation and reassure the child that there will be no pain.
- 2.
Order PO midazolam in a sufficient dose to ensure adequate sedation preoperatively.
Perioperative
- 1.
Establish an intravenous line using a local analgesic.
- 2.
Titrate propofol ± dexmedetomidine infusions until an adequate degree of sedation is achieved (see Chapter 8, page 258 , Awake Craniotomy, for dosing regimen). Titrate small doses of fentanyl (1 to 2 μg/kg) or a remifentanil infusion until the child is comfortable. Atropine in the usual dosage may reduce any tendency to intraoperative nausea.
- 3.
Ensure that the child is positioned comfortably, and warn the child not to cough or move the head.
- 4.
Talk with the child periodically to assess the effects of the drugs, but allow the child to sleep when cooperation is not required.
- 5.
Monitor ventilation via nasal capnometry, administer supplemental oxygen and, if necessary, remind the child to breathe deeply periodically.
Postoperative
- 1.
Smaller than usual doses of analgesics are effective in most cases.
- 2.
Antiemetic medications may be required.
ENDOSCOPY
Endoscopy is often indicated in infants and children for diagnosis (e.g., stridor) or for therapy (e.g., removal of a foreign body).
Procedures
- 1.
Laryngoscopy
- 2.
Bronchoscopy
- 3.
Esophagoscopy
Special Anesthesia Problems
- 1.
Existing airway problem or tracheotomy
- 2.
Difficulty maintaining optimal ventilation during endoscopy, particularly in a child with a very small airway
- 3.
Possibility of complete airway obstruction during some procedures (i.e., removal of foreign body)
- 4.
Danger of airway fire if cautery or laser is used
- 5.
Danger of postoperative reduction in airway lumen by subglottic edema
N.B. Many conditions for which endoscopy is performed can progress to complete obstruction under anesthesia. Always have a selection of laryngoscopes and endotracheal tubes prepared; from the start of anesthesia, ensure that the endoscopist is at hand in case surgical intervention with either a rigid bronchoscope or tracheotomy become urgently necessary.
General Anesthesia Management
- 1.
Spontaneous ventilation is usually preferred during endoscopy in children. It may be safer than controlled ventilation if there is airway compromise, and it allows the endoscopist to examine the dynamic structure of the airway under normal physiologic conditions. Maintaining spontaneous respirations is particularly important when evaluating the child for airway compression, laryngeal, tracheal, or bronchomalacia. Abnormal airway compression or collapse may not be adequately detected during controlled ventilation.
- 2.
Controlled assisted ventilation is necessary for children who are in respiratory failure and for those who cannot maintain effective ventilation when anesthetized.
Laryngoscopy
Anesthesia Management
Preoperative
- 1.
Do not give heavy sedation to children with airway problems. Oral midazolam is useful for some older children having repeated endoscopy, but beware of sedating any child with a dubious airway. Children with laryngeal papillomata present a particular risk because of the possibility of ball-valve obstruction, airway fire, or embolism of tumor fragments distally. These cases require complete discussion with the surgeon so that the anesthetic prescription needed for that particular child is clear (i.e., spontaneous ventilation with insufflation, intermittent intubation, or paralysis with apneic oxygenation).
Perioperative
- 1.
Apply monitors, including pulse oximeter, and induce anesthesia by inhalation of N 2 O and O 2 with sevoflurane and insert an appropriate size intravenous catheter.
- 2.
Hydration with 20 ml/kg of lactated Ringer’s solution will support the circulation during deep inhalation anesthesia.
- 3.
When the child is deeply anesthetized, discontinue the N 2 O, continue with sevoflurane in O 2 , perform laryngoscopy and spray the larynx and supraglottic structures with lidocaine (maximum dose, 4.5 mg/kg).
- 4.
Replace the mask until the lidocaine becomes effective (2 to 3 minutes). The duration of the procedure may be brief in some cases but prolonged in others. Anesthesia may be continued with an infusion of propofol (± remifentanil).
- 5.
Monitor ventilation visually, with a precordial stethoscope and by capnometry.
Postoperative
- 1.
Observe the child closely until awake.
- 2.
Order humidified oxygen postoperatively.
- 3.
Maintain NPO status until 2 hours after application of the lidocaine spray.
N.B. The previous method of anesthesia, employing topical analgesia and propofol with spontaneous ventilation is considered overall the safest and most satisfactory method. Endotracheal tubes get into the surgeon’s field of vision, and all other methods are cumbersome and complicated and therefore may fail. “Jet ventilation” methods can be dangerous in children, especially if the high pressure jet migrates distal to an obstructing lesion; fatal pneumothorax and pneumomediastinum may occur.
Special Considerations
Laryngomalacia
A common cause of inspiratory stridor in the neonate, laryngomalacia can be diagnosed during laryngoscopy while the infant is awake or is awakening from anesthesia. The stridor usually disappears during deeper levels of anesthesia and with small amounts of positive end expiratory pressure (PEEP); PEEP is especially useful in maintaining a patent airway during the initial phases of induction. In this condition, there is incomplete maturation of the cartilages of the larynx and a tendency for the epiglottis or one of the arytenoid cartilages to prolapse into the glottis during inspiration, causing marked inspiratory stridor. The condition is self-limited and disappears as the child ages; no special therapy is usually required. However, laryngoscopy is indicated to rule out other causes of stridor (e.g., cysts).
Congenital Cysts
Congenital cysts may occur in the region of the epiglottis and aryepiglottic folds. There may be inspiratory and expiratory stridor and a poor cry. The diagnosis is usually confirmed by radiologic imaging. Therapy is by excision or marsupialization.
Congenital Webs
Subglottic webs reduce the cross-sectional diameter of the upper airway lumen to 2 to 4 mm in neonates. These webs usually have a single central perforation through which the neonate ventilates. Because of the limited diameter of the perforation and the oxygen requirements of the neonate, respiratory distress often occurs soon after birth. Laryngoscopy may reveal the presence of a web, otherwise, an appropriate sized tracheal tube may not pass below the vocal cords. When the diagnosis is confirmed by bronchoscopy, laser resection of these webs effectively restores the lumen of the upper airway.
Subglottic Hemangioma
Subglottic hemangioma may manifest with crouplike symptoms and a barking cough, usually commencing at a few months of age. The child frequently has other visible hemangiomas, especially on the face. The symptoms persist or recur, and diagnosis is confirmed with endoscopy. Commonly therapy is by laser ablation; however, this is sometimes followed by subglottic stenosis. Open resection of the hemangioma is now advocated by some.
Anesthesia Management
For laser resection:
- 1.
Manage as for laryngeal papillomata (see later discussion)
- 2.
Humidified oxygen should be administered postoperatively after laser therapy
For open excision:
- 1.
An initial laryngoscopy and bronchoscopy will be performed to assess the lesion. This may be managed with inhalational anesthesia plus topical lidocaine (see later discussion).
- 2.
Following the endoscopic examination, an oral endotracheal tube is inserted and general anesthesia continued.
- 3.
An anterior incision in the neck is made to display and open the larynx.
- 4.
At this stage the oral endotracheal tube is withdrawn and a second sterile tracheal tube passed by the surgical team via the lower end of the incision into the trachea.
- 5.
The hemangioma on the posterior aspect of the larynx is now resected.
- 6.
On completion of the operation a nasotracheal tube is passed through the
glottis and larynx into the trachea and left in situ.
- 7.
The child is returned to the ICU for continued ventilation, sedation, and paralysis for the initial postoperative days. Immobility of the laryngeal structures is important during the early healing period.
- 8.
The child is returned to the OR for examination before extubation several days later. Dexamethasone is administered before removing the tube. Close observation is required for a further period of 2 to 3 days.
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