Reference Work Entry

Encyclopedia of Otolaryngology, Head and Neck Surgery

pp 2077-2089

Pediatric Anesthesiology

  • Jeffrey SteinerAffiliated withDepartment of Anesthesiology and Pain Management, UT Southwestern Medical Center Dallas, Children’s Medical Center Dallas Email author 
  • , Stephen Q. HoangAffiliated withDepartment of Anesthesiology and Pain Management, UT Southwestern Medical Center Dallas, Children’s Medical Center Dallas
  • , Peter SzmukAffiliated withDepartment of Anesthesiology and Pain Management, UT Southwestern Medical Center Dallas, Children’s Medical Center Dallas

Definition

Pediatric anesthesiology is the study of the subspecialty of anesthesiology that relates to the anesthetic care provided to neonates, infants, and children.

Introduction

Administration of anesthesia for pediatric otorhinolaryngology procedures combines the use of pharmacology, physiology, and good communication skills between the anesthesiologist, surgeon, patient, and the patient’s caretakers. The practice of anesthesiology includes preoperative evaluation, intraoperative anesthetic management, and postoperative care while using different medication classes to produce anxiolysis, amnesia, hypnosis, analgesia, and muscle relaxation (when indicated) – all while maintaining hemodynamic stability.

General Anesthetic Themes

Preoperative Evaluation

Preoperatively, a history and physical is performed, including a detailed airway exam. The anesthetic plan is discussed with the patient and their family, and laboratory or specialty tests are completed prior to going to the operating room, including hematologic considerations if the patient has an underlying bleeding disorder. Baseline vital signs including pulse oximetry are obtained before going to the operating room as well (Davis et al. 2011).

According to the American Society of Anesthesiologists preoperative fasting guidelines, patients should be allowed to have clear liquids, breast milk, a light meal (toast, cereal, low fat), or a heavy meal (high fat/protein) at 2, 4, 6, and 8 h, respectively, before elective surgery.

Since separation from parents is known to be a stressful event for young patients, with serious psychological implications, a way to minimize the stress should be established. Midazolam (0.5–0.7 mg/kg) administered orally is well tolerated by children, has consistent results, and is thus the most frequently used anxiolytic (Davis et al. 2011). In a minority of cases, midazolam administration could result in agitation instead of sedation, as in the case of patient with attention deficient hyperactivity disorder. If the patient is unable or unwilling to take oral medications, alternative options are the following: (1) intranasal anxiolysis with (a) midazolam (0.2 mg/kg) or (b) fentanyl (2 mcg/kg) or (2) intramuscular anxiolysis with (a) ketamine (3–7 mg/kg) or (b) midazolam (0.1 mg/kg).

Another option to reduce anxiety, advocated by some, is the use of parental presence during induction. However, in a review of the subject, this has not been shown to reduce parental or patient anxiety (Chundamala et al. 2009). Some anesthesiologists also choose to add oral analgesics to the premedication, such as hydrocodone/acetaminophen elixir (0.2 mg/kg based off the dose of hydrocodone), in an effort to facilitate intraoperative and postoperative pain control, though the practice is somewhat controversial and not well supported by the literature.

Anesthetic Management

Given that otolaryngologic procedures are associated with a higher incidence of airway complications, it is good practice to have both the otolaryngologist and the anesthesiologist physically present in the OR during the procedure, including induction and emergence.

The majority of patients do not have an intravenous (IV) catheter preoperatively, and thus, a mask anesthesia induction with sevoflurane in an O2/N2O mixture is preferred by most providers. Standard anesthesia monitors (mandated by the American Society of Anesthesiologists) include blood pressure, pulse oximetry, electrocardiography, end tidal CO2 detection, and temperature. Once the patient is under general anesthesia, IV access is established, and the volatile anesthesia can be augmented with propofol (0.5–2 mg/kg), an opioid (fentanyl 1–2 mcg/kg), and/or a nondepolarizing muscle relaxant such as rocuronium (0.6 mg/kg) or vecuronium (0.1 mg/kg) to help in securing the airway. If a patient has an IV prior to arriving in the operative room, then an intravenous induction with propofol (2.5–3.5 mg/kg), lidocaine (1–2 mg/kg) to help with the discomfort of propofol injection, fentanyl (1–2 mcg/kg), and/or a muscle relaxant should be used. If the patient is not hemodynamically stable, or has a contraindication to medications described above, etomidate (0.2–0.4 mg/kg) or ketamine (2 mg/kg) can be used as IV induction agents because they are hypnotic agents with more stable hemodynamic profiles. Some practitioners utilize atropine or glycopyrrolate for anticholinergic effects (tachycardia, dry mucosa), but their effects can mask periods of painful stimulation during anesthesia, and their routine use has decreased in the last decades (Davis et al. 2011). In addition to the premedications, induction agents, inhaled anesthetics, and opioid medications, other adjunct medications are used in the perioperative period. Antiemetic medications such as dexamethasone (0.07–0.15 mg/kg), ondansetron (0.15 mg/kg), metoclopramide (0.15 mg/kg), or a combination of any two or all three can be given intraoperatively in an effort to prevent postoperative nausea and vomiting. Once the patient is anesthetized and IV access established, then securing the airway and maintaining anesthesia depends on the patients’ comorbidities, the surgery, and the preferences of the anesthesiologist and the surgeon. Corticosteroids such as dexamethasone (0.5 mg/kg) are often administered to reduce swelling and scarring at the surgical site and as antiemetic.

Postoperative Care

At the completion of surgery, the patients are transferred to the postanesthesia care unit (PACU) or pediatric intensive care unit (PICU). Hypoxemia occurs frequently (43%) after general anesthesia in infants and children during transport and in the PACU, (Motoyama and Glazener 1986) and patients should be closely observed for possible obstruction and/or desaturation. Many PACUs utilize the Aldrete score system for evaluating when patients are stable for discharge. The Aldrete score assesses the patient based on five areas: motor activity, respiration, circulation, consciousness, and SpO2. Each area is scored on a point system from 0 to 2, and the total score is calculated with a maximum score of 10 (Davis et al. 2011). At most institutions, a score of 8 or greater is required for discharge.

Anesthesia for Otologic Procedures

As with many ENT procedures, otologic procedures may require short periods of deep planes of anesthesia and no patient movement. While most children who present for otologic procedures are typically healthy, many patients with congenital anomalies and chronic disease (craniofacial malformations, cleft palate, Down syndrome, Turner’s syndrome, and human immunodeficiency virus (HIV) infection) may have a higher incidence of otitis media (Bluestone et al. 2003). In addition, critically ill patients with prolonged nasotracheal intubation have a high incidence of persistent middle ear effusions and sinus infections. Thus, an evaluation of associated medical conditions and comorbidities, as well as an evaluation for airway difficulties, is essential.

Myringotomy and Tympanostomy Tube Insertion

Preoperative Evaluation

These children may present with subacute or chronic upper respiratory tract infection (URI) with or without fever. Perioperative complications and morbidity, in general, are not increased in children undergoing minor surgery who present with acute uncomplicated URI, provided they do not require endotracheal intubation (Tait et al. 1998). Common analgesics used are acetaminophen (10–15 mg/kg PO) and acetaminophen/hydrocodone (500–7.5 mg/15 ml) given as 0.1–0.2 mg/kg of hydrocodone component.

Anesthetic Management

General anesthesia is achieved with mask induction using a volatile anesthetic (sevoflurane), O2/N2O, and maintained via the mask. Since general anesthesia is usually achieved without intravascular access, additional analgesia may be given intranasally, intramuscularly, or rectally. Intranasal fentanyl (1–2 mcg/kg) or butorphanol (25 mcg/kg), intramuscular morphine (0.1–0.2 mg/kg) or ketorolac (1 mg/kg), and/or acetaminophen suppository (30–40 mg/kg) are commonly used analgesics.

Some older children may tolerate the procedure with topical anesthesia, which is completed by instillation of EMLA cream into the ear canal. EMLA cream can produce methemoglobinemia, and patients at risk should be monitored closely. The maximum administration of ELMA is 1 g (0–3 months of age), 2 g (3–12 months of age), 10 g (1–6 years old), and 20 g (7–12 years old).

Postoperative Care

These children should be transferred in the lateral position and supplemental oxygen delivered. They are usually discharged home as same-day surgery patients once they have met discharge criteria.

Mastoid and Middle Ear Surgery

General Anesthetic Principles

Although many of these procedures may be done on an outpatient basis, it is important to recognize that the most common cause of an unscheduled admission to the hospital for children who have undergone tympanomastoidectomy is postoperative nausea and vomiting (PONV) (Megerian et al. 2000). Thus, the facility to perform these procedures should have the availability of inpatient admission, if needed.

Preoperative Evaluation

While this patient population is usually healthy, mastoid and middle ear surgery is sometimes done emergently on critically ill patients due to life-threatening infectious processes. In these situations, care should be taken to evaluate associated comorbidities, particularly risks of sepsis and possible neurologic involvement (meningitis, cranial nerve palsy, cavernous sinus thrombosis).

Anesthetic Management

Both inhalational and intravenous inductions are acceptable choices, followed by placement of an endotracheal tube (ETT). The patient’s head is usually rotated away from the operative side, and careful positioning, without over-rotation, is recommended. Since the surgery is done under the microscope, even minor bleeding can cover the surgical field. Techniques that decrease bleeding and keep the operating field as “clean” include use of reverse Trendelenburg position (10–15°) or controlled hypotension (mean arterial pressure ≤25% below baseline). In pediatric patients, the latter is usually achieved with the use of either higher concentration of inhaled anesthetics and/or increased doses of IV anesthetics.

Facial Nerve Detection

In addition to standard monitoring, electromyography is often used to identify the facial nerve and avoid its injury. Since neuromuscular blocking agents block also the electromyographic response, they should be avoided in these circumstances. In infants and young children, intubation can be easily achieved without the use of neuromuscular blocker by using high concentrations of inhalational agents (sevoflurane) or adding IV agents (propofol 1–2 mg/kg), especially if topical local anesthesia (lidocaine) is sprayed on the vocal cords. If a muscle relaxant must be used to facilitate tracheal intubation, use of a short-acting muscle relaxant (succinylcholine, rocuronium) is recommended. This will assure that muscle function has returned to normal at the time facial nerve identification is performed.

Patient Position

After the trachea has been intubated, the head of the bed is typically turned 180° away from the anesthesia machine. The patient’s head is then rotated so that the operative site is accessible to the surgeon.

Use of Nitrous Oxide

Since nitrous oxide significantly changes the pressure in closed spaces, it may displace the tympanic graft and it should be discontinued 5–10 min before placement of the graft. In some cases, its use may actually facilitate the procedure by “tenting” the tympanic membrane and a plan on its use should be discussed with the surgeon.

PONV Prophylaxis

Children undergoing mastoid or middle ear surgery have high incidence of PONV (35–44%) due to surgical stimulation of the vestibular labyrinth, type and duration anesthetic, or both. Prophylactic PONV strategies should be implemented from the beginning of anesthesia and carried out throughout the perioperative period. This calls for administering drugs with different mechanisms of action (Gan et al. 2007). Similarly, the use of anesthetic agents with low PONV potential like propofol, in combination with PONV prophylaxis and avoidance of nitrous oxide, may result in the lowest incidence of all (Barst et al. 1999). Even low infusion rates of propofol (100 mcg/kg/min) as an anesthetic adjunct have been shown to help with PONV (Erdem et al. 2008). The most common PONV prophylaxis drugs used in children are ondansetron (0.15 mg/kg), dexamethasone (0.07–0.15 mg/kg), and metoclopramide (0.15 mg/kg).

Emergence from Anesthesia

In patients whose airway was well maintained during mask induction and who are breathing spontaneously under general anesthesia at the end of the procedure, a “deep” extubation (removal of ETT during a deep plane of anesthesia) should be performed. This will allow for a slow and smooth emergence and will minimize sudden increase in middle ear pressure as with coughing and bucking. Before extubation, deep anesthesia should be confirmed by the absence of any response to suctioning of the oropharynx. An oropharyngeal airway should be placed to avoid upper airway obstruction. Coughing can also be minimized with IV lidocaine (1–1.5 mg/kg) in children older than 1 year old.

Postoperative Care

Preventing PONV and pain are the major objectives in postoperative period. In addition to the PONV prophylaxis mentioned above, maintaining normovolemia and using non-opiate pain medication (ketorolac, acetaminophen, and ibuprofen) should help decrease the incidence of PONV.

Cochlear Implantation

General Anesthetic Principles

Pediatric patients presenting for cochlear implantation can bring with them multiple disabilities. For older children, the patient’s level of hearing dysfunction should be determined and a method of communication with the child should be established throughout the perioperative period. If the patient reads lips, masks should be kept down until after induction. Anesthetic considerations are similar to those for mastoidectomy including facial nerve monitoring, so muscle relaxants should be avoided. In children, intraoperative electrically evoked stapedius reflex threshold (ESRT) and evoked compound action potential (ECAP) are used to guide implant settings. A recent study indicated that even sub-anesthetic concentrations of volatile anesthetics can markedly suppress or completely abolish the stapedius reflex (Crawford et al. 2009), potentially causing an erroneously high maximal comfort level (MCL) that could compromise the outcome of cochlear implantation. In contrast, propofol and nitrous oxide administered during remifentanil infusion had little or no effect on the auditory thresholds and are therefore recommended for the determination of auditory thresholds during pediatric cochlear implant surgery.

Anesthesia for Rhinologic Procedures

Reduction of Nasal Fractures

General Anesthetic Principles

Nasal fractures may be associated with significant bleeding, and some of it may be swallowed. Thus, for emergent reduction of these fractures, full stomach precautions should be considered to prevent aspiration of stomach contents. This implies using a rapid sequence induction and cricoid pressure. The purpose of rapid sequence induction is to minimize the time from loss of protective airway reflexes (after administration of sedatives, hypnotics, and/or muscle relaxants) to the time the airway is protected with an ETT.

In cases in which the patient is NPO and there is no evidence of active bleeding, some authors have been advocating for use of a laryngeal mask airway (LMA).

Nasal Polypectomy

Preoperative Evaluation

As nasal polyps often occur in children with cystic fibrosis (CF), associated lung, pancreas, liver, and gastrointestinal tract comorbidities should be evaluated and optimized. Since the primary causes of morbidity and mortality in patients with CF are bronchiectasis and chronic obstructive pulmonary disease (COPD), management of anesthesia in patients with CF invokes the same principles.

Anesthetic Management

Inhalational or intravenous induction of anesthesia is performed with standard monitoring. A preformed RAE (Ring, Adair, Ellwyn) ETT is routinely inserted and secured midline over the chin to allow head movement with minimal risk of ETT displacement. Anticholinergic drugs may further increase the viscosity of secretions; so they should be avoided or minimized.

Principles of Anesthesia for Patients with Cystic Fibrosis

Excellent pulmonary care is mandatory in CF patients, and frequent lavage and suctioning is often necessary. A deeper plane of volatile anesthetics will decrease airway resistance by decreasing bronchial smooth muscle tone, as well as decreasing the responsiveness of the hyperreactive airways characteristic of cystic fibrosis. Positive end-expiratory pressure (PEEP) can be added to minimize airway closure and atelectasis. Nonsteroidal anti-inflammatory drugs should also be used with caution because of Samter’s triad, which is the association of nasal/ethmoidal polyposis with asthma and aspirin sensitivity.

Emergence

With nasal packing in place at the end of these operations, an oral airway could help avoid obstruction during emergence and extubation.

Postoperative Care

Continued pulmonary care should be carried out in the PACU, as well as hydration to minimize secretion viscosity. If the preoperative pulmonary function is poor, admission for overnight observation on the floor or ICU should be considered.

Sinus Surgery

General Anesthetic Principles

Chronic sinusitis not controlled by medical therapy alone is commonly seen in children with immune deficiency, immotile cilia syndrome (Kartagener’s syndrome), and cystic fibrosis. Since many of these children have chronic disease or upper airway obstruction, the anesthetic considerations are similar to that recommended for nasal polypectomy.

Preoperative Evaluation

Careful assessment of the underlying disease process, including associated medical problems, should be reviewed and assessed. The patient’s medical condition should be optimized, particularly their pulmonary status.

Anesthetic Management

The anesthetic management for sinus surgery is similar to the one for nasal polypectomy. Surgeons often use topical vasoconstrictors such as oxymetazoline (0.25–0.50%), phenylephrine, and less commonly now, cocaine for initial vasoconstriction. It is important that the maximum dosing of vasoconstrictors be established for each patient, as side effects and toxicity can result in severe hypertension, reflex bradycardia, and even cardiac arrest (Murakawa 1998). The maximal dose of epinephrine to be added to lidocaine is 5 mcg/mL or 1:200,000. In addition, lidocaine with epinephrine (maximum 7 mg/kg lidocaine portion) is often injected at the surgical site to provide a bloodless surgical field. It should also be noted that the duration of vasoconstriction usually does not last longer than 1.5 h.

An infraorbital nerve block (cranial nerve V2) can be performed to provide additional intraoperative and postoperative analgesia, but patients should be advised of the side effect of drooling for several hours after the block. The infraorbital nerve can be blocked by using the intraoral approach after the patient is anesthetized and the airway has been secured.

Since blood and irrigation fluids can enter the stomach during the operation, awake extubation is recommended after the stomach and the oropharynx has been suctioned.

Postoperative Care

The nose is often packed with gauze or an absorbable stenting material such as MeroGel at the end of the procedure; thus, the patient becomes an obligate mouth breather. Additionally, airway obstruction can occur if these materials are displaced. The airway patency and oxygen saturation should be closely monitored and airway support should be readily available.

Choanal Atresia

General Anesthetic Considerations

Choanal atresia can occur alone or is associated with Apert’s syndrome, DiGeorge syndrome, trisomy 18 (Edward’s syndrome), Treacher Collins syndrome, campomelic dysplasia, and CHARGE syndrome (i.e., coloboma, heart defects, atresia choanae, retardation of growth and development, genitourinary problems, and ear anomalies).

Preoperative Evaluation

Whether the obstruction is unilateral or bilateral will dictate the severity and acuity of symptoms and the timing of surgery. Evaluation of associated conditions, such as risk of difficult airway, congenital heart defect, and electrolyte disturbances, should be completed.

Anesthetic Management

Unilateral Choanal Atresia

Patients with unilateral atresia are often not diagnosed until months to years later, and typically come for elective repair. In these patients, it is important to have an oral airway available during induction. A preformed oral RAE endotracheal tube is usually used.

Bilateral Choanal Atresia

Since even healthy infants are obligatory nasal breathers up to about 5–6 months old, neonates with bilateral disease usually present with acute respiratory distress. This can be attenuated by keeping the mouth open with an oral airway, or a McGovern nipple (large nipple with a perforated tip). Although rare, bilateral atresia in a syndromic neonate with a potential difficult airway may necessitate emergent tracheostomy.

Anesthetic management is also dictated by the surgical approach. The management of anesthesia for endoscopic transnasal approach is similar with the anesthetic management for sinus and nasal surgeries. The transpalatal surgical approach usually lasts longer and is associated with more blood loss. Bilateral choanal atresia correction might require use of either CO2 or Nd:YAG lasers (see tracheal stenosis section regarding anesthetic management for laser surgery). Awake extubation with full recovery of airway reflexes is recommended.

Postoperative Care

Patients undergoing unilateral repair usually do well in the postoperative period. An oral airway should be either be in place or available during emergence and in the postoperative period. Most patients with bilateral repair will have stents placed in their nasal cavities, which allow for ventilation. Neonates and infants undergoing bilateral repair can experience partial or intermittent upper airway obstruction; thus, they are usually observed in the ICU and sometimes remain intubated postoperatively.

Pharyngeal and Laryngeal Procedures

Pharyngeal and laryngeal procedures can be some of the most challenging procedures for anesthesiologists. Not only can these procedures be relatively short in duration, intensely stimulating, and have the potential for causing edema of the upper airway, but they can also be a challenge due to a surgical field that is shared by both surgeon and anesthesiologist.

Tonsillectomy and Adenoidectomy

General Anesthetic Principles

Tonsillectomy and adenoidectomy (T&A) surgeries are one of the most common surgeries encountered by anesthesiologists (Miller 2010).

Preoperative Evaluation

After any coagulopathies or other comorbidities have been addressed and the patient is cleared for surgery, anesthetic management may proceed, with oral or IV premedication, or parental presence as described above.

Anesthetic Management

The trachea is intubated with a preformed cuffed oral RAE endotracheal tube. Typically, the age-appropriate-sized ETT is downsized 0.5–1.0 mm ID smaller than calculated to accommodate for the size of the cuff (Davis et al. 2011). The ETT is secured in place in the midline first with adhesive tape and then with the Brown-Davis mouth gag. Because T&A surgery tends to be short in duration, most anesthesiologists prefer to avoid muscle relaxants.

Alternatively, a flexible laryngeal mask airway (fLMA) can be used to secure the airway for T&A. It can be stabilized, much like an oral RAE ETT with tape and the reinforcement of the Brown-Davis mouth gag. Use of fLMA has the advantages that the patient does not have to be as deeply anesthetized as when placing an ETT, the patient can continue to breathe spontaneously. Also, the fLMA is removed while the patient is still deep, eliminating gagging and bucking on an ETT (Mandel 2010). The main concern with the use of fLMA in this setting is the possibility of aspiration of secretions and/or blood accumulated above the fLMA cuff. This concern is perhaps overestimated, and the amount of aspirated material does not tend to be significant (Mandel 2010). Other problems with the use of fLMA are the possibility of dislodgement and need to convert to an endotracheal tube during the procedure and, in some cases, difficulty with the surgical resection due to the size of the fLMA cuff. The use of fLMA for T&A in the USA is uncommon.

Anesthesia is maintained with inhaled anesthetics, most frequently sevoflurane in oxygen/air or N2O. Additionally, supplemental opioids (1–2 mcg/kg of fentanyl, 50–100 mcg/kg of morphine, or 10–20 mcg/kg of hydromorphone) can be added (Davis et al. 2011). The opioids should be administered in small doses and titrated to the respiratory rate if spontaneous ventilation is desired. Routine administration of antibiotics in these cases has fallen out of favor and is not helpful based on current Cochrane review (Dhiwakar et al. 2010).

At the conclusion of surgery, the patient’s pharynx and larynx are suctioned under direct visualization in an effort to prevent disruption of the surgical field (Davis et al. 2011).

Local anesthesia administered either topically or infiltrated in the tonsillar bed is used by some surgeons to provide postoperative pain relief. The efficacy of these methods has not been clearly demonstrated, and close to toxic levels of local anesthetics have been reported in the first minutes after infiltration (Bachmann 1988). A recent meta-analysis demonstrated that topical local anesthesia with either bupivacaine or ropivacaine provides a similar level of analgesia compared to infiltration with lidocaine, bupivacaine, or ropivacaine with/without epinephrine, without the potential side effects (Grainger and Saravanappa 2008).

At the end of the procedure, the patient can either be extubated while deeply anesthetized in an effort to keep the patient from bucking on the ETT, or extubated awake. One of the complications that can occur during emergence of anesthesia (but not restricted to) is laryngospasm. It results in loss of a patent airway and requires immediate airway support and intervention. Prevention of laryngospasm involves reducing stimulation from suctioning and secretions by using IV lidocaine or, more controversially, extubating the patient deep (Alalami et al. 2008).

Postoperative Management

The principles of post T&A care include monitoring, prevention of obstruction and hypoxemia, and effective prevention and treatment of pain and PONV.

Postoperative analgesia is achieved mainly with small doses of opioids (morphine, 50 mcg/kg; fentanyl, 0.5–1 mcg/kg; hydromorphone, 10 mcg/kg) administered intravenously or, if tolerated, PO. Nonsteroidal anti-inflammatory drugs are usually avoided due to their potential to increase risk of bleeding. The newly introduced IV acetaminophen (15 mg/kg) formulation (recently approved for use in the United States) does not interfere with the coagulation and thus could be a valuable analgesic agent in this setting. Patients less than 3 years old should be kept for an overnight observation because of postoperative breathing dysfunction.

Special Patient Considerations for T&A

Management of the Patient with Obstructive Sleep Apnea Syndrome

General Anesthetic Principles

Children can present with a history of sleep-disordered breathing and/or sleep apnea. Patients with obstructive sleep apnea syndrome (OSAS) are at risk for nocturnal hypoxemia, sleep fragmentation, pulmonary hypertension, cor pulmonale, and heart failure (Bandla et al. 2005). They are also more sensitive to the respiratory depressive effects of opioids. It has been recommended that if a patient has a pulse oximetry nadir lower than 85% during their polysomnography, then the postoperative morphine dosing should be reduced by half (Collins and Everett 2010).

Preoperative Evaluation

Polysomnography is the “gold standard” for diagnosing OSAS in children, and the severity of clinical symptoms of OSAS does not correlate with severity of disease (Costa and Mitchell 2009). In patients with signs or symptoms of heart failure, further cardiac testing, such as echocardiogram, EKG, or chest radiograph, might be needed to evaluate the patient. Due to the potential for an exaggerated respiratory depression response to both opioids and benzodiazepines, a reduction in premedication dosing may be appropriate (Bandla et al. 2005).

Anesthetic Management

Either mask or IV is an acceptable choice for induction of anesthesia. If a mask induction is utilized, moderate CPAP (10–15 cmH2O) applied through the anesthesia machine is helpful to maintain the airway before an oral airway can be placed (Davis et al. 2011). Dexmedetomidine, a centrally acting alpha 2 agonist, can be safely used in these patients for its opioid-sparing effects and its ability to not cause respiratory depression. Another newer medication approved for use in the children who are 2 years and older is IV acetaminophen (15 mg/kg for patients less than 50 kg and 1 g for patients greater than 50 kg). In the author’s practice, after the airway is secure, they give a single dose of dexmedetomidine (1 mcg/kg) slowly, then titrate in fentanyl (0.25 mcg/kg) based on the patient’s respiratory rate. Alternatively, if the patient has severe OSAS, the authors use dexmedetomidine in combination with IV ketamine (1 mg/kg) for its analgesic properties.

T&A surgery does not always fully resolve OSAS symptoms, and a patient with OSAS is less likely to have adequate respiratory effort and control of upper airway reflexes to maintain their airway. Thus, awake extubation is recommended for these patients (Bandla et al. 2005).

Postoperative Care

The postoperative care is similar as for the T&A. In addition to the potential for respiratory compromise, the potential for cardiac compromise should be considered (Bandla et al. 2005).

If patients are undergoing T&A for OSAS, it is generally recommended that they be admitted to the hospital for at least a 23-h observation following surgery (Davis et al. 2011). The criteria for admission are as follows: all OSAS patients under 3 years old or those with associated craniofacial anomalies and chronic cardiac or pulmonary disease should be admitted. In addition, all patients with moderate to severe OSAS per sleep study should be admitted. Patients older than 3 years with mild OSAS can be discharged home after 2–4 h of PACU stay (Roland et al. 2011).

Those patients that do not have a sleep study or clinical signs of OSAS could be considered for day surgery. If this route is taken, it should include a prolonged PACU stay (minimum 2–4 h). Consideration should be made to give these patients the first dose of home pain medication, allowing them to fall back asleep and observing the patient for problems with upper airway obstruction during this time. While this method has not been studied, this perhaps might be a “low tech” way to evaluate for OSAS while on home/discharge pain medications.

Management of the Patient with a Postoperative Tonsil Bleed

Preoperative Evaluation

Patients with postoperative tonsil bleeding need to (1) have their volume status evaluated, including hemoglobin level; (2) have large-bore IV access established; and (3) have emergency blood available for immediate transfusion. Blood loss is difficult to assess in these patients because the blood loss is swallowed; the patients may be dehydrated, anemic, and agitated (Davis et al. 2011). A hemoglobin level together with type and cross should be obtained. These patients are also at risk of aspiration during induction and emergence from general anesthesia because of the potentially large amount of blood that could have been swallowed.

Anesthetic Management

Anesthesiology equipment for the “bring back” tonsil bleed needs to be prepared prior to the patient’s arrival in the operating room. Along with two well-functioning suction apparatuses, multiple laryngoscope handles and blades, blood and IV fluid for volume resuscitation, and additional qualified personnel should be ready in the OR (Davis et al. 2011).

Induction should begin with preoxygenation with 100% O2 and IV induction with rapid sequence technique utilizing propofol (2 mg/kg) with succinylcholine (2 mg/kg) if the patient is hemodynamically stable. Alternatively, etomidate (0.3–0.4 mg/kg) or ketamine (2 mg/kg) with succinylcholine could be used in unstable patients (Davis et al. 2011). The intubation should take place with the most experienced operator and care should be taken not to disrupt any of the blood clots that have formed. An oral-gastric tube (OGT) should be passed preferably under direct vision. While placing an OGT at the end of the case to empty the stomach seems reasonable, in the author’s experience, the OGT does little to remove the massive clots and copious amount of coagulated blood that has been swallowed by the patient.

At the completion of surgery, the ETT is removed only after the patient is fully awake because the patient is considered to still have a full stomach.

Postoperative Management

Postoperative care for these patients will center on control of PONV, which can be challenging because blood in the stomach causes emesis. Other goals, such as pain control, and hemodynamic stability should also be met.

If there is concern for aspiration, a flexible fiber-optic bronchoscopy and a chest x-ray should be obtained (Davis et al. 2011); however, x-ray findings of aspiration typically manifest themselves several hours after the insult.

Peritonsillar Abscess Incision and Drainage

General Anesthetic Principles

Patients with peritonsillar cellulitis and abscess present with severe throat pain, difficulty swallowing, and potentially a high fever (Davis et al. 2011). Peritonsillar abscesses can lead to airway compromise with obstruction, trismus, dysphagia, and worsening pain as the abscess expands (Miller 2010). These patients can present an airway challenge to both the anesthesiologist and the surgeon. Because of spasm of the pterygoid muscles, these patients may have difficulty opening their mouth (Davis et al. 2011). They can also have distorted upper airway anatomy due to edema and an enlarging pocket puss within the abscess. Should the abscess rupture during intubation or airway manipulation, aspiration of puss and/or blood could occur.

Preoperative Evaluation

An objective airway exam might not be possible due to the presence of trismus and possible lack of patient cooperation. At a minimum, the laterality of the abscess and the amount of edema in the visualized upper airway should be determined and documented. These patients tend to require urgent or emergent treatment and may be considered to have full stomachs depending on last NPO times.

Anesthetic Management

Much like post-tonsillectomy bleeding, two suction apparatuses should be available. General anesthesia can be induced either using spontaneous respirations (if patient is NPO appropriate) or by using a rapid sequence induction to secure the airway (Davis et al. 2011). The airways can be difficult to secure because of distorted anatomy of the abscess. Advanced airway techniques such as fiber-optic intubation, video laryngoscopes, and supraglottic devices, such as LMAs, should be considered.

If the patient is at risk for a full stomach, fully awake extubation should be planned. In the face of marked edema, the patient might need to remain intubated and transferred to the PICU.

Postoperative Management

As with other patients, attention to control PONV and pain is warranted in the PACU. Careful titration of opioids in the PACU should occur, bearing in mind that once the abscess is drained, the patient may have less pain.

Acute Supraglottitis or Epiglottitis

General Anesthetic Principles

While acute infectious epiglottitis or supraglottitis is uncommon, it is still a truly life-threatening disease in childhood. A partial airway obstruction in these patients can rapidly progress to a complete obstruction (Davis et al. 2011).

Even though this is not a surgical disease, managing the airway of the patient with epiglottitis is bringing together the otolaryngologist and anesthesiologist and represents the typical inter-specialty cooperation in all cases difficult airways. Depending on experience and personal preferences of the anesthesiologist, difficult airway can be managed under general anesthesia (using standard laryngoscope, fiber-optic scope, video laryngoscope, or any other advanced technique) or managed awake with or without sedation. Most pediatric patients will need either general anesthesia or sedation for managing their airway. The difficult airway should be ideally managed in an operating room properly prepared with all the equipment planned to be used, different-sized straight laryngoscope blades, styletted ETT tubes one or two sizes smaller than expected, and equipment for a surgical airway.

Regardless of the airway managing technique planned, care should be taken not to agitate the patient any further, because this could also lead to worsening obstruction.

Anesthetic Management/Postoperative Care

The aim of anesthetic induction is to maintain spontaneous ventilation should intubation prove impossible. These patients can breathe without obstruction only in the sitting position. Consequently, general anesthesia is induced with the patient in the sitting position after standard monitoring is applied and using increasing concentrations of sevoflurane in oxygen (Davis et al. 2011).

Once IV access is established, small boluses of propofol could be added to deepen the anesthesia while spontaneous ventilation is maintained.

A straight Miller blade, as opposed to a curved Macintosh blade should offer the advantage of directly lifting the epiglottis and a possible view of the glottic opening. Should the glottis opening not be visualized with the epiglottis lifted, then the assistant may need to provide forcible manual chest compression in an effort to open the airway and potentially view the opening with bubbles of expired air. Use of video laryngoscopes could also allow for a better view and identification of the anatomical structures, but sometimes even in the presence of a good view, intubating the trachea could be difficult.

Additional airway management includes the use of fiber-optic scope with the patient either awake or under anesthesia and breathing spontaneously. Since the obstruction is at the level of the glottis, a supraglottic device would probably be of no significant help.

If the intubation proves to be impossible or if the patient becomes hypoxic, the primary care of the patient is transitioned to the otolaryngologist for surgical intervention.

Once the airway is secured, then tissue and blood cultures are taken and the patient is given appropriate antibiotics. It is not unusual for the patient to remain intubated for 24–48 h while the infection is treated and the edema subsides.

Endoscopy/Laryngoscopy/Bronchoscopy Procedures

General Anesthetic Principles

The type of anesthesia used for these cases will depend on whether a flexible fiber-optic scope or ridged bronchoscope will be used.

If a flexible fiber-optic scope is to be used, a laryngeal mask is placed or the trachea is intubated with an ETT. The fiberscope is passed through a connection port into the airway device and then into the trachea. This setup allows for maintaining the airway, unobstructed ventilation, providing inhalational anesthetic gases and good endoscopic conditions. If a ridged bronchoscope is to be used, the side port of the device is connected to the anesthesia machine which provides O2 and anesthesia gases.

Having the patient breathing spontaneously is advantageous because this maintains good oxygenation and shortens the overall time of the procedure. If the patient is, or becomes apneic and desaturates, the procedure is paused, the trachea is intubated, and after a short period of ventilation with recovery of saturation to 100%, the procedure restarts. This sequence can repeat itself numerous times depending on the length of the procedure, underlying disease, and pulmonary reserves.

After the patient has been induced under general anesthesia and an IV established, some practitioners spray topical lidocaine to reduce the sensitivity of the vocal cords to instrumentation. General anesthesia with preservation of spontaneous ventilation may be provided by inhaled anesthetics (sevoflurane) supplemented by IV administration of propofol boluses (0.5–1 mg/kg) or infusion (150–300 mcg/kg/min) and/or dexmedetomidine (1 mcg/kg as a bolus over 10 min). Opioids should be used cautiously since they may lead to apnea.

Foreign Body Aspiration

General Anesthetic Principles

There are no conclusive studies to suggest that spontaneous ventilation is better or worse than controlled ventilation for the treatment of patients with a foreign body in the airway. Classic teaching is to maintain the patient with spontaneous respirations so that the foreign body is not further pushed more distally into the lungs. If this technique is used, then the vocal cords should be well topicalized with lidocaine and the patient should be maintained with either a combination of vapor or IV anesthetics. Also, if there is evidence of air trapping, or significant hyperinflation, then N2O should be avoided because of the potential danger of increase in gas volume leading to rupture of the affected lung.

During the retrieval portion of the surgery, ventilation and delivery of volatile anesthetics might be diminished and intermittent boluses of IV medications can be used to maintain anesthesia. While the object is being pulled from the airway, it is possible that it can get lodged in a more proximal part of the airway. If this occurs, and the foreign body cannot be easily removed, and the patient becomes unstable, then the object needs to be once again pushed into one of the main bronchi, so that the patient can be ventilated. After the patient is stabilized, then the retrieval process can once again commence.

Dexamethasone (0.4–1.0 mg/kg, up to 20 mg/kg) is frequently used to help with laryngeal edema, and inhaled racemic epinephrine (0.5 ml of 2.25% solution diluted to 3 mL of saline solution) is used for postoperative croup treatment (Davis et al. 2011).

Laser Surgery

General Anesthetic Principles

Laser safety is of utmost importance for both patient and operating room personnel. Not only can the mishandling of a laser cause unintentional eye injury, even with proper use, it can be a source of ignition in an airway fire.

Prevention of an airway fire is the first line of defense in safely using a laser in otolaryngology surgery. Operating room windows should be covered to prevent inadvertent laser beams from straying outside the operating room, and the room should be clearly marked as having a laser surgery being conducted within the room. Eye protection for all operating room personal should be adhered to, as well as protection for the patient with their eyes taped closed, and the face should be covered with saline-soaked eye pads, metal shields, or both (Davis et al. 2011).

Most ETTs utilized in the delivery of anesthesia gases are susceptible to ignition by the laser, including the different materials used for ETTs, with the exception of special metallic tubes. Metal tubes are seldom used though, and although some prepare standard ETT by covering them with aluminum foil, they still can prove to be a source of ignition. If a cuffed ETT is used, the cuff should be filled with water and dye (methylene blue) in order to alert the surgeon to inadvertent cuff perforation by the laser beam. Both O2 and N2O support combustion. As so, the inspired concentration of O2 should be minimized (<30%) and N2O should be avoided (Miller 2010). If the patient cannot maintain their oxygenation, then the laser should be paused and 100% oxygen should be given to the patient to raise their saturation.

Tracheal Surgery

General Anesthetic Principles

There are multiple indications for tracheal surgery including those that are elective (such as laryngotracheal reconstruction for stridor and tracheotomy for syndromes such as Treacher Collins) and those that are more urgent, such as massive facial injuries or facial edema mandating a definitive airway. Before the procedure begins, the surgeon and the anesthesiologist should plan out if the airway needs to be secured and how (such as in the case of a potential difficult airway) should the failed airway require quick surgical intervention.

Tracheotomy While Under GA

Many times an elective tracheotomy is performed after the airway has been secured with an ETT. If the patient is not intubated prior to arriving in the operating room, then the airway will need to be secured prior to the start of surgery. Should intubation become impossible, then an LMA can be placed to help maintain the airway, ventilate if necessary, and provide inhaled anesthetics to maintain anesthesia (Davis et al. 2011). Anesthesia is maintained with a combination of inhaled anesthesia, opioids, and a hypnotic such as propofol.

The most critical part of the surgery is when the trachea is opened, the ETT is retrieved, and the tracheostomy tube inserted. Also, it can sometimes be difficult to tell if the patient is still intubated based off of end tidal CO2 which can escape through the tracheotomy opening.

If the patient has a difficult airway, a fiber-optic scope or a bougie can be placed by the anesthesiologist through the ETT so that the ETT can be easily returned to the trachea should an accidental extubation occur. The bougie can be left than in place for the next 24 h and serve as a conduit for reintubation in case the fresh tracheostomy airway is lost.

Anterior Cricothyroidotomy

The patient positioning for an anterior cricothyroidotomy is very similar to a tracheotomy position with regard to neck extension and the elevation of the patient’s shoulders. General anesthesia with muscle relaxation is used to facilitate care of this patient (Davis et al. 2011).

Laryngotracheal Reconstruction

This procedure can be done in stages; however, a single-stage laryngotracheal reconstruction technique is also widely used. With this technique, an anterior cartilage graft with/without a posterior cartilage graft is used. The stoma site may need reconstruction, and stenting may or may not be used in any combination with these procedures (Davis et al. 2011).

Airway management and care of the ETT during and at the end of the surgery deserve special attention. After the patient is induced through either an IV or the tracheotomy site, the tracheostomy tube is replaced with a sterile cuffed armored ETT which is sutured to the chest and covered with adhesive tape. After the repair has been completed, the armored ETT is removed and the airway is secured with a nasotracheal ETT and sutured in place at the nasal septum (Davis et al. 2011). Since the graft can be dislodged with movement, the patient will need to be sedated and paralyzed for 1–2 days postoperatively. Care for these patients following surgery includes leaving the patient intubated and sedated from 7–14 days, depending on the type of grafting used.

Conclusion

Administration of anesthesia for pediatric otorhinolaryngology procedures combines the common elements of pediatric anesthesia (anxiolysis, amnesia, hypnosis, analgesia, and muscle relaxation) with increased reliance on good communication skills between anesthesiologist and surgeon because of having to share the airway. Preoperative evaluation, intraoperative anesthetic management, and postoperative care need to be tailored to each individual patient; these are based on the patient’s past medical history, the proposed surgery, and operating room resources. Through the coordinated effort of the anesthesiologist and surgeon, the best perioperative plan can be designed and implemented for care of the pediatric otorhinolaryngology patient.

Cross-References

Chronic Sinusitis

Sleep Apnea

Tonsillectomy

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© Springer-Verlag Berlin Heidelberg 2013
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