What the Anesthesiologist Should Know before the Operative Procedure

Tonsillectomy and adenoidectomy are common procedures performed in the pediatric population. Tonsillectomy is usually for recurrent infection in patients greater than 4 years of age, and adenoidectomy is for sleep apnea in children under 4 years of age. Sometimes children can have both problems. It is important, therefore, to know that the child does not have a bleeding diathesis and how bad the sleep apnea is.

Comorbidities that predispose to postoperative apnea, such as congenital hypotonia, morbid obesity, and central neurologic problems that produce insensitivity to rising carbon dioxide levels or to decreasing arterial oxygen tension, will require postoperative hospitalization.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

There are few issues that would conceivably make tonsillectomy and/or adenoidectomy emergent. Urgency for adenoidectomy is relative, depending on the severity of sleep apnea.

Emergent: The only emergent issue relating to tonsillectomy is either a peritonsillar abscess compromising the ability to breathe, or postoperative bleeding after tonsillectomy. Obviously, the major issues from the anesthetic point of view are controlling the airway without allowing for blood aspiration and establishing intravenous access for adequate fluid and/or blood product resuscitation.

Urgent: The only reason for urgent tonsillectomy or adenoidectomy is active infection spreading into a peritonsillar abscess and/or severe sleep apnea and obstruction.

Elective: Almost all tonsillectomy and adenoidectomy procedures are elective. Issues include: ease of airway management (Syndrome with craniofacial manifestations – Down’s, Beckwith-Wiedemann, Pierre Robin sequence, etc.), potential bleeding diathesis (either inborn or acquired from drugs), and sensitivity to sedatives and narcotics in patients with sleep apnea.

2. Preoperative evaluation

Sleep Apnea

Does the patient snore at night? Stop breathing? Do you ever have to disturb the child to get him/her to breathe again? Did the child have a formal sleep study? Does the child have daytime somnolence, i.e., does s/he fall asleep in class? Does the child sleep on his back, side or stomach? Has the child had a previous anesthetic or narcotics that caused postoperative breathing problems?

Bleeding problems

Does the child bruise easily? Is there a family history of bleeding diathesis? Is the child on any medications that may affect the clotting cascade?

Airway

Are there any craniofacial malformations? Large tongue? Neck extension? Morbid Obesity?

Respiratory

Does the patient have an active respiratory infection or URI?

Medically unstable conditions warranting further evaluation include: all medically unstable conditions that predispose to perioperative complications. This means any evidence of cardiovascular, respiratory or renal conditions which are potentially life threatening or to which anesthetics and perioperative physiological perturbations could adversely affect.

Delaying surgery may be indicated if: there is an active respiratory compromise (asthma) or infection or URI, if there is ongoing evidence of continued easy bruising in a family with known Factor VIII deficiency or other bleeding diathesis, if a patient was not taken off NSAIDS or aspirin prior to surgery, or if there is uncontrolled glucose levels in at Type I diabetic.

Essentially, any physiologically destabilizing process is grounds for delaying surgery in an elective procedure.

Severe sleep apnea is NOT grounds for delaying surgery, since the surgery is often curative.

3. What are the implications of co-existing disease on perioperative care?

Perioperative evaluation: Does the patient have enlarged tonsils and/or adenoids? Is there evidence of sleep apnea? Is there evidence of a bleeding diathesis? Evidence for sleep apnea includes a history of severe snoring, sometimes accompanied by a parental or sibling witness of apnea requiring physical awakening to break.

Polysomnography, i.e., a sleep study, is a more definitive and quantitative aid in the evaluation of the severity of the sleep apnea. While the use of polysomnographic evaluation in children used to be uncommon, centers for the evaluation of sleep disorders in children have been established at major children’s hospitals around the country, and its use in evaluation obstructive sleep apnea is now widely available.

In the absence of a polysomnogram, but in the presence of a clinically significant history of likely sleep apnea, one must be judicious and treat the child as if he had severe obstructive sleep apnea. Bleeding diatheses are most often brought to the attention of the anesthesiologist by parents whose families have a history of the same and have had their children worked up in consultation with Hematology.

Since all genetic diseases may arise spontaneously, in the absence of a family history, it is still important to ask whether the child is prone to easy bruising or has unexplained episodes of bleeding that are difficult to manage. This may alert the anesthesiologist that this child needs further work up before proceeding with surgery.

Perioperative risk reduction strategies: If there is a bleeding diathesis such as Factor VIII deficiency, infuse Factor VIII perioperatively in consultations with hematology. Inquire as to the nature of all comorbidities and determine whether the child is at best physical status. If there is severe sleep apnea for whatever reason, we plan for direct postop delivery to the PICU where the patient can be a) extubated and then watched for obstruction, or b) watched for obstruction post-extubation in the OR.

b. Cardiovascular system

Acute/unstable conditions

All congenital heart disease must be evaluated by competent pediatric cardiology services preoperatively.

Baseline coronary artery disease or cardiac dysfunction – Goals of management

Depending on the type of residual congenital heart disease, one must optimize fluid, anesthetic, and sedative therapy so that there is adequate fluid return, forward flow, and reasonable pulmonary pressures to allow forward flow even in cases of cyanotic heart disease. We recommend surgical or invasive transcatheter therapy for all conditions that result in cyanosis and/or hemodynamic instability prior to elective tonsillectomy and/or adenoidectomy.

c. Pulmonary

COPD

In infants and children who are survivors of premature birth and poor pulmonary function (BPD) or cystic fibrosis, one must be sure that the patient is in optimal status, that appropriate pulmonary toilet has been performed, and that all medications have been taken prior to surgery.

Reactive airway disease (Asthma)

Patients with chronic asthma requiring inhaled steroid and/or beta agonist therapy should be up to date with their treatments, and evidence of maximized pulmonary function presented preoperatively.

d. Renal-GI:

N/A

e. Neurologic:

Acute issues

None. If there are acute neurologic issues, surgery is cancelled until the neurologic issues are controlled.

Chronic disease

There are many levels of neurologic disease that may present to the pediatric anesthesiologist in the perioperative period, and the subject is too vast to cover here. Suffice it to say that one’s treatment of the child is geared to his neurologic status, ability to understand, degree of contractures, the degree of vascular instability in the brain, etc.

f. Endocrine:

All endocrine issues must be controlled prior to surgery.

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

See discussion of neurologic issues.

One of the more common syndromes in the pediatric population undergoing tonsillectomy and adenoidectomy is Trisomy 21, or Down’s syndrome. Many of the findings in Down’s syndrome portend a potentially difficult intraoperative and postoperative course, and demand great attention to detail.

In particular:

40% of children with Down’s syndrome have cardiac anomalies and are very sensitive to atropine. One the other hand, these patients tend to get bradycardic with inhalation inductions, which may require treatment with atropine or glycopyrrolate. One must be sure that these children have had a proper cardiac evaluation and be judicious in administering atropine.
All of these children have various airway anomalies, such as micrognathia, large tongue, and subglottic stenosis. The former predisposes one to sleep apnea, which is likely the reason that these patients come for T&A. As such, these anomalies predispose one to increased susceptibility to obstruction during inhalation induction and during the postoperative period, difficulty with visualization of laryngeal structures during direct laryngoscopy, as well as an increased likelihood of post-extubation stridor.
These patients exhibit various degrees of mental retardation and behavioral difficulties, and special attention to the psychological handling of the children is required. The preoperative need for oral sedatives will have to be balanced with the severity of sleep apnea.
All children with Down’s syndrome have various degrees of muscular hypotonia and joint hyperflexibility. This, combined with the potential in these children for a dysplastic odontoid and disastrous atlanto-occipital subluxation during airway manipulation, suggests the need for careful airway evaluation and handling. Many institutions require preoperative radiologic evaluation of the C-spine in Down’s syndrome children to inform the anesthesiologist whether there is an increased risk of subluxation. However, the value of preoperative radiographic evaluation has not been proven to detect individuals at increased risk for subluxation. This reinforces the need for careful airway manipulation in this set of children, whether such evaluation has been performed or not.

4. What are the patient's medications and how should they be managed in the perioperative period?

Generally, we have patients take all of their oral meds, including on the morning of surgery. It is important to ascertain what over-the-counter medications and herbal supplements parents give to the child, especially those that are not prescribed, to avoid potential drug interactions.

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

None.

i. What should be recommended with regard to continuation of medications taken chronically?

Cardiac: Continue.
Pulmonary: Continue.
Renal: Continue.
Neurologic: Continue.
Anti-platelet: Stop for long enough to dissipate the effect.
Psychiatric: Continue.

j. How To modify care for patients with known allergies –

Avoid drugs with crossover allergies.

k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

Avoid latex containing materials.

l. Does the patient have any antibiotic allergies- – Common antibiotic allergies and alternative antibiotics]

Antibiotics are not commonly used for this surgery, unless there is an underlying reason (SBE prophylaxis or ongoing infection).

m. Does the patient have a history of allergy to anesthesia?

Malignant hyperthermia

Documented

avoid the trigger agents, succinylcholine and inhalational agents:

Proposed general anesthetic plan: preop sedation with oral midazolam (0.5 mg/kg), 70% N2O in oxygen for IV placement, TIVA with propofol/narcotic of choice/dexmedetomidine. Postoperative nausea treated with prophylactic ondansetron (0.05-.1 mg/kg) and dexamethasone (0.5-1 mg/kg). The steroid is given during induction, as it also reduces postoperative edema and the potential for stridor and/or obstruction in the pharynx.

Insure MH cart available: [- MH protocol]

Family history or risk factors for MH

In the absence of a previous episode of MH in the patient or a family history of MH, a positive muscle contracture test in a relative with a direct genealogical line to the child establishes a potential for MH. Myopathic diagnoses with a high concordance for MH include Central Core Disease and its potential variant multiminicore disease, as well as the rare King-Denborough syndrome. There is very poor evidence that any other myopathies predispose to MH.

Local anesthetics/ muscle relaxants

It is rare to need muscle relaxants for intubation in young children. There are no contraindications to the use of any muscle relaxants in children, but there are those who almost never use succinylcholine because of its ability to make MH worse or to induce hyperkalemic cardiac arrest in Duchenne’s muscular dystrophy patients. Some have used local anesthetic infiltration into the peritonsillar bed to decrease postoperative pain, but some surgeons feel this increases the risk of postoperative bleeding. There is not enough literature on this subject to establish a practice guideline.

5. What laboratory tests should be obtained and has everything been reviewed?

Generally speaking, no laboratory tests are required for this surgery, unless a bleeding diathesis is suspected. If sleep apnea is the diagnosis, then one wishes to see a sleep study (polysomnography).

Common laboratory normal values will be same for all procedures, with a difference by age and gender.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

As described above, preoperative sedation with oral midazolam is an option, both for the anxious patient and for the patient who will need IV placement preoperatively. An inhalation induction with sevoflurane is the most common method of induction in children today. Standard ASA recommended monitors are placed pre-induction if possible (not all children will let you put on the monitors before they are anesthetized), or post-induction if necessary.

The IV is then placed, and for tonsillectomy, which is much more painful than an adenoidectomy, my practice is to give fentanyl 2 mcg/kg, dexamethasone 0.1 mg/kg, and propofol 2-3 mg/kg prior to intubation with an appropriate size oral RAE tube, and the tube secured. Others have recommended using an LMA for tonsillectomy, but using this airway device will depend on the comfort of the surgeon, as well as the body habitus of the patient.

Sevoflurane concentrations are reduced to 3-4 vol% in oxygen-air mixtures with the O2 concentrations <30% to decrease the likelihood of airway fires from electrocautery. The head of the bed is then turned 90 degrees to the surgeon, and the table is locked and lowered to its lowest level for the convenience of the surgeon. I then give morphine 0.1 mg/kg IV, adjust fluid administration rates, and maintain sevoflurane levels sufficient to insure hypnosis and non-movement (2-4 vol%).

About ten minutes prior to the end of surgery, I give dexmedetomidine (0.2-0.5 mg IV), as well as ondansetron. Patients with severe sleep apnea have a right-shifted apneic threshold for CO
₂, and are therefore more sensitive to the respiratory depressive effects of narcotics. Hence, reduction of intraoperative narcotics doses by about half in patients with obstructive sleep apnea reduces the risk of postoperative narcotic-induced respiratory depression and is associated with a reduction in severe postoperative airway and respiratory events in these patients.

At the end of surgery, all volatile anesthetics are turned off, oxygen is delivered at 100%, the bed is turned back 90 degrees to the anesthesiologist, and then a decision is made whether to wait to extubate until the patient is wide awake or whether to extubate deep. It is my practice that unless a patient has a bad airway for anatomic reasons (syndromic) or severe sleep apnea, I extubate deep if the tonsilar bed is reasonably dry. Otherwise, I elect to wait for the patient to be awake with intact airway reflexes before extubation.

Monitors are then removed, and the patient is transferred to a bed or crib. It is my practice to place the child in the decubitus position so that any pharyngeal secretions pool not in the hypopharynx but in the cheek so as to reduce the possibility of laryngospasm. The child is then transferred to the PACU with blow-by oxygen or delivery via a face mask.

6. What is the author's preferred method of anesthesia technique and why?

a. Neurologic:

N/A

b. If the patient is intubated, are there any special criteria for extubation?

As mentioned above, extubation criteria should be directed by the degree of sleep apnea prior to surgery and other anatomical considerations. My continuum for extubation: if there is little evidence of sleep apnea, then it is not uncommon to try to extubate the patient deep. If there are any suggestions of potential obstruction while sedated, then extubate awake. In the morbidly obese, or those with severe sleep apnea, keep the patient intubated and bring directly to PICU for extubation when completely awake and possibly 24 hours later when edema has gone down.

c. Postoperative management

What analgesic modalities can I implement?

Intravenous narcotics are the most efficacious ways of managing pain. Morphine, even hydromorphone, has been used successfully.

What level bed acuity is appropriate?

PACU is appropriate to the vast majority of patients post T&A. Patients with severe or significant obstructive sleep apnea will require overnight admission to a monitored bed even if extubated. Anyone requiring postoperative intubation will require admission to the PICU.

What are common postoperative complications, and ways to prevent and treat them?

Postoperative pain and delirium is the most common complication, and these are relatively easily treated with a combination of narcotics and dexmedetomidine. Secondary edema and respiratory arrest is the most feared complication of T&A. If you suspect this, treatment with racemic epinephrine and more intravenous steroids is of benefit. If this does not help, then nasal BiPAP is often of help if the child will cooperate with the mask. Otherwise, it is likely that reintubation will be required, with a postoperative stay in the PICU. Another feared complication of tonsillectomy is postoperative bleeding, whether primary (postoperative, in hospital), or secondary (10 days to 2 weeks postoperatively). Risk of primary postoperative bleeding is in the range of 1%, and secondary bleeds in the range of 2-4%. Much of the literature on this topic is confusing, since most are single center, retrospective studies that do not control for surgical technique, which has been evolving in different directions, depending on the surgeon and institution. The largest retrospective study of postoperative bleeding comes from the Swedish National Registry, and during the seven years of review, the post-tonsillectomy bleed rate has decreased from 2% to 0.96% for reasons that have yet to be deciphered. There is little in anesthetic care that is known to lessen the likelihood of this complication, but we must be prepared to take care of this surgical emergency as soon as it appears.

What's the Evidence?

Collins, C.E.. “Anesthesia for pediatric airway surgery: recommendations and review from a pediatric referral center”. Anesthesiology Clin. vol. 28. 2010. pp. 505-517. (One of the more recent reviews on how to handle anesthesia for pediatric airway surgery.)

Litman, R.S., Samadi, D.S., Tobias, J.D.. “Anesthesia for Pediatric ENT surgery”. Pediatric Anesthesia: The Requisites in Anesthesiology. 2004. pp. 238-241. (A short review of the subject – what you need to know, what you need to do. Good for medical students or beginning anesthesia residents.)

Raghavendran, S., Bagry, H., Detheux, G., Zhang, X., Brouillette, R.T., Brown, K.A.. “An anesthetic management protocol to decrease respiratory complications after adenotonsillectomy in children with severe sleep apnea”. Anesth. Analg. vol. 110. 2010. pp. 1093-1101. (A report of a protocol designed to reduce post-T&A airway complications in patients with a pre-operative history of obstructive sleep apnea.)

Grainger, J, Saravanappa, N. “Local anesthetic infiltration for post-tonsillectomy pain: a systematic review and meta-analysis”. Clin. Otolaryngol. vol. 33. 2008. pp. 411-19. (A meta-analysis of the efficacy of local anesthetic infiltration in the control of post-tonsillectomy pain.)

Mandel, J.E.. “Laryngeal mask airways in ear, nose and throat procedures”. Anesthesiology Clin. vol. 28. 2010. pp. 469-483. (A review of ENT procedures that can now be accomplished with use of LMA in the airway.)

Landsman, IS, Werkhaven, JA, Motoyama, EK, Davis, PJ, Cladis, PF, Motoyama, EK. “Anesthesia for pediatric otorhinolaryngologic surgery”. Smith's Anesthesia for Infants and Children. 2011. pp. 786-820. (An outstanding, in depth chapter describing anesthesia for ENT surgery in children.)

Martich, V, Ben-Ami, T, Yousefzadeh, DK, Roizen, NJ. “Hypoplastic posterior arch of C-1 in children with Down syndrome: a double jeopardy”. Radiology. vol. 183. (1992). pp. 125-8. (The radiologic description of C-1 anomalies in children with Down Syndrome.)

Hessén Söderman, AC, Ericsson, E, Hemlin, C, Hultcrantz, E, Månsson, I, Roos, K, Stalfors. “Reduced risk of primary postoperative hemorrhage after tonsil surgery in Sweden: results from the National Tonsil Surgery Register in Sweden covering more than 10 years and 54,696 operations”. J. Laryngoscope.. vol. 121. 2011. pp. 2322-6. (Article about the reduced risk of postoperative hemorrhage after tonsil surgery.)

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