Anesthesia for ENT procedure varies from simple daycare procedure to complex airway reconstruction procedure. Massive bleeding conditions like juvenile nasal angiofibroma (JNA) and carotid body tumors require hypotensive anesthesia as a well multidisciplinary approach. ENT surgeries are versatile in the context of age group, sex, airway, position during operation, bleeding, and need for postoperative ventilation. This chapter will overview the anesthetic considerations for common ENT procedures that include:
Anesthesia for adenoidectomy/tonsillectomy.
Anesthesia for ear surgeries.
Anesthesia for nasal surgeries.
Anesthesia for panendoscopy.
Anesthesia for bronchoscopy.
Anesthesia for obstructive sleep apnea (OSA) surgeries.
Anesthesia for parotid surgeries.
Anesthesia for peritonsillar abscess (PTA) and Ludwig’s angina.
Anesthesia for temporomandibular joint (TMJ) surgeries.
Laser surgeries and airway fire.
Anesthesia for Adenoidectomy/Tonsillectomy
Tonsillectomy is a frequently performed surgical process with or without adenoidectomy. The procedure entails significant surgical as well as anesthetic challenges with substantial morbidity and mortality. Important clinical features are respiratory difficulty due to nasal obstruction, frequent infections, otitis media, decreased hearing (due to Eustachian tube obstruction), and OSA.
Features of upper airway obstruction, dysphagia, and sleep disorders.
PTA not adequately responding to medical management.
Febrile seizures due to tonsillitis.
Tonsillar pathology requiring biopsy for a definitive diagnosis.
Chronic infectious adenotonsillitis.
Obstructive sleep apnea syndrome (OSAS).
Preoperative evaluation should focus on age group, associated comorbidities (such as Downs syndrome), OSA, and upper respiratory tract infection. These are the main factors in stratifying perioperative complications, including postextubation laryngospasm and bronchospasm. Important points of consideration are listed below:
Polysomnography (PSG) is the gold standard to diagnose OSAS in children, but it is not possible in all children.
Electrocardiogram (ECG) in patients with OSA (to exclude right heart involvement secondary to pulmonary artery hypertension).
Hemoglobin and hematocrit should be done to rule out anemia and polycythemia (in patients with OSA), respectively.
Total leucocyte counts and a chest X-ray if respiratory tract infection is present.
Coagulopathy should be excluded, as adenoidectomy/tonsillectomy may lead to massive bleeding during the perioperative period.
Cautious use of premedication because of risk of upper airway obstruction.
The choice of anesthetic technique matters mainly in the presence of upper respiratory tract infections (URTI). Even though the laryngeal mask airway (LMA) is not used frequently for adenotonsillectomy, the evidence suggests that it may have advantages over the tracheal tube.
The endotracheal tube (ETT) is the gold standard of airway management. A preformed south pole-facing tube (oral Ring–Adair–Elwyn [RAE]) is preferable. LMA, especially reinforced one, can be used for airway management but with adequate training and experience.
End-tidal CO2 monitoring is vital to detect early ETT tube kinking, due to placement of mouth gag as well as displacement.
The eye should be well taped and protected from direct pressure and corneal injury. After positioning and Boyle–Davis gag placement, ETT should be examined for obvious kinking and any airway pressure.
Anesthetic medications with lower potency of airway irritation such as propofol, sevoflurane, and halothane are preferred over thiopental and desflurane, which cause airway irritation.
The choice for the neuromuscular blocking agent for intubation is suxamethonium, if not contraindicated.
In a child with URTI, deep extubation is preferable.
Patients must be extubated in lateral and head low position (posttonsillectomy position) after the surgery, and it should also be maintained in the postoperative period.
Before extubation hemostasis, throat free of any secretion or any gauze must be established.
Patients must be shifted to the recovery room in the lateral position and monitored for bleeding as well as any decrease of consciousness.
It is an occult clot of blood left behind the nasopharynx posterior till the soft palate. It usually occurs in surgeries in areas of nasopharynx or trauma, mainly due to adenotonsillectomy. It has the potential to cause fatal airway obstruction following extubation.
The following should be taken into consideration while managing the patient postoperatively:
Keep the child in the recovery position.
Constant monitoring for bleeding.
Pain control with multimodal analgesia.
Postoperative nausea and vomiting (PONV) prophylaxis with dexamethasone and ondansetron.
The worst complication is bleeding tonsil in this group of patients. It is an emergency and, if not mediated in time, can lead to rapid deterioration of hemodynamics and airway compromise.
At the beginning of the postoperative period, tonsillectomy and adenoidectomy have the highest incidence of laryngospasm (21–26%). Laryngospasm is preventive but can have damaging and life-threatening consequences like negative-pressure pulmonary edema, pulmonary aspiration, bradycardia, oxygen desaturation, and cardiac arrest.
Anesthesia for Ear Surgery
Common surgery of the ear includes otitis media and its related complications. Otitis media is very common in children. The common ear surgery includes:
In this surgical procedure, a small incision is made in the tympanic membrane. Myringotomy and insertion of tympanostomy (grommet tube) are used to improve middle-ear aeration for a prolonged period and to also prevent the accumulation of fluid. It is a daycare procedure of a short duration.
The preoperative examination should be focused to elicit features of URTI and OSA secondary to adenotonsillar enlargement. Due to URTI, the airway becomes hyperreactive, which leads to perioperative airway complications like laryngospasm and bronchospasm.
Anesthesia for myringotomy can be given through facemask or LMA by maintaining spontaneous breathing and with the head rotated to one side.
For analgesia, paracetamol and nonsteroidal anti-inflammatory drug (NSAID) can be given preoperatively.
Mastoidectomy is a surgical procedure that is used for the removal of chronic suppurative middle-ear disease. The most common indication is the treatment of cholesteatoma and the associated infection.
The important anesthetic concerns are the usage of nitrous oxide in middle-ear surgery. The solubility of nitrous oxide in the blood is around 34 times higher than nitrogen. It easily diffuses in the middle-ear cavity, which leads to very high pressure within 30 minutes of use. The raised middle-ear pressures can lead to:
Dislodgment of tympanoplasty grafts.
Deterioration of deafness and rupture of the tympanic membrane.
High incidence of PONV.
During discontinuation, the rapid reabsorption of nitrous oxide gas can result in negative pressure in the middle ear, which can cause dislodgment of the underlay tympanic membrane graft.
For the bloodless surgical field, various methods can be used, such as head-up elevation of around 10 to 15° to reduce venous ooze, vasoconstrictor-like adrenaline infiltration, and maintaining low blood pressure (up to 20% of mean arterial pressure [MAP]).
The use of muscle relaxants should be properly timed if facial nerve monitoring is used.
Total intravenous (IV) anesthesia is an attractive substitute for general anesthesia (GA) with a lesser incidence of PONV.
Anesthesia can be maintained with propofol, short-acting opioids, and inhalational agent like sevoflurane. It also allows maintenance of anesthesia without muscle relaxant and unobstructed facial nerve monitoring.
For airway, ETT and reinforced LMA can be used. The reinforced LMA is a good option for airway management due to less airway stimulation and smooth emergence.
Analgesia and Antiemesis
Multimodal analgesia should be given to minimize opioid dose. Analgesia with paracetamol and NSAIDs can be given through oral, IV, and rectally in the perioperative period.
Opioids like remifentanil, fentanyl, and morphine, providing adequate analgesia, should be given in a low dose with strict postoperative monitoring. A greater auricular nerve block has shown to reduce the postoperative opioid requirement.
For PONV, measures like prevention of long preoperative fasting, good hydration with IV fluids, no nitrous oxide, the practice of total intravenous anesthesia (TIVA), and multimodal analgesia to reduce opioid dose are very helpful.
Anesthesia for Nasal Surgery
The nasal surgeries are performed to relieve upper airway obstruction. The common nasal surgeries are:
Endoscopic sinus surgery.
Rule out OSA by history, examination, and PSG (if needed).
Exclude systemic illness, especially coronary artery disease (CAD) and cardiac arrhythmia; in that case, surgeon should cautiously use local vasoconstriction.
If the patient has a history of chronic use of steroids, they should receive daily maintenance dose perioperatively.
History of the use of anticoagulant and recent nasal bleeding is also important.
For minor procedures or in a patient who cannot tolerate GA, it can be done under local anesthesia (LA).
For complicated surgical procedures, GA is the anesthesia of choice.
ETT seems to be the prime option for endoscopic sinus surgeries, because of its superior protection against aspiration compared to supraglottic airway (SGA) devices. Blood can still sip through the outer surface of the ETT to vocal cord and trachea. Therefore, throat pack is necessary in case of ETT too, in order to prevent blood aspiration.
The oral RAE tube is better due to its preformed shape, and due to that, less kinking intraoperatively. Fixation of ETT should be done in midline.
Patient head (airway) is away from anesthesiologists; hence, EtCO2 and airway pressure monitoring is prudent to diagnose any kinking or disconnection.
Throat pack should be removed before extubation, and for that, checklist should be followed, because if left, then catastrophic consequences can occur.
Throat pack removal should be followed by a careful examination of the oral cavity and nasopharynx for any clot.
For maintenance, TIVA is an ideal anesthetic technique. It has certain advantages like less bleeding due to low blood pressure, better surgical field, and reduction in the incidence of PONV.
The position of the patient in reverse Trendelenburg with 15° head up helps in decreasing blood loss. This positioning should be done slowly to avoid hypotension.
The patients who are on steroids preoperatively should continue perioperatively to reduce edema and inflammation.
Vasoconstrictor (epinephrine, phenylephrine) topical and injection applied on nasal mucosa helps to decrease congestion and hemostasis. Vasoconstrictor should be used with caution, especially in a patient with a history of CAD, cardiac arrhythmia, or myocardial infarction (MI).
There are certain advantages of awake extubation like less chance of aspiration of blood or secretion due to the full return of laryngeal reflex. Drawbacks of this technique are coughing, bucking, and laryngospasm.
Additional suctioning and laryngoscopy should be done to reduce chances of aspiration of blood or secretions during deep extubation.
Multimodal analgesia for pain control.
PONV can be prevented by:
Use of TIVA.
Liberal IV fluid.
Use of dexamethasone, ondansetron.
Judicious use of opioid.
Anesthesia for Panendoscopy
Panendoscopy is also called “triple endoscopy,” which includes rigid laryngoscopy, bronchoscopy, and esophagoscopy.
Evaluation of head and neck cancer for documentation of the extent of tumor.
Biopsy for tissue diagnosis.
Search for primary tumor and any recurrence after treatment.
Evaluation of vocal cord lesions and pathology involving the pharynx, larynx, or tongue.
Panendoscopy is a short but highly stimulating procedure requiring deep anesthesia, obtunded hemodynamic reflexes, immobile surgical field, and rapid emergence with early return of protective airway reflexes. An antisialogogue (i.e., glycopyrrolate 0.2 mg IV or intramuscular [IM]) can be given to minimize secretions prior to induction. Usually, a routine IV anesthetic induction is preferred along with the application of LA (i.e., lidocaine 4%) to the vocal cords prior to further airway manipulation. It should be corroborated with the surgeon whether LA will interfere with their planned procedure.
A proper evaluation of pathology and its impact on ventilation, intubation, and cricothyroid access is essential.
The surgeon’s preference for airway management should be given consideration.
The cardiovascular and pulmonary comorbidities must be evaluated and optimized before the surgery.
Reflux history and potential for aspiration should be noted carefully.
Prior detailed discussion and close communication with the surgeon and sharing the airway during the procedure.
The eyes should be covered and well-padded. Upper dentition should be protected with a mouth guard or folded gauze.
The regular ETT, which is used for GA, is not suitable for this procedure as it will compromise vision due to its bigger size. LMA/tubeless technique/microlaryngeal surgery (MLS) tube is used to secure the airway for this procedure.
LMA: It is used at the beginning of the procedure and also at the end to secure the airway for sedated patients and for smooth emergence.
Tubeless technique: The technique involves either apnea bag-mask ventilation or ventilation through rigid bronchoscope.
For known or suspected difficult airway, the procedure can be done either by awake intubation, prophylactic placement of a cricothyroid cannula, or awake tracheostomy. A discussion with the ENT surgeon and a preoperative nasal endoscopic examination of the upper airway may aid in the decision-making.
For maintenance, TIVA is useful in this procedure and decrease the chances of OT pollution.
The emergence phase can be managed by many techniques. At the completion of panendoscopy, the muscle relaxation is reversed if nondepolarizing agents are used, and the IV or volatile anesthetic is stopped. The patient management can be done with bag/mask ventilation or by insertion of a SGA device until spontaneous ventilation is resumed.