Tonsillectomy and Adenoidectomy for Obstructive Sleep Apnea: Anesthetic Considerations, by
Dr. Denise Chan.
Hello, my name is Denise Chan, and I'm a pediatric anesthesiologist at Boston Children's Hospital.
Today, I'll be discussing important aspects of taking care of children with obstructive
sleep apnea syndrome in the perioperative setting.
Introduction.
Now, first let's define what is obstructive sleep apnea syndrome.
Well, it's a disorder of breathing during sleep, and it's characterized by a few different
things, according to the American Thoracic Society.
First of all, these patients have either prolonged upper airway obstruction, which is known as
obstructive hypopnea, or intermittent complete obstruction, known as obstructive sleep apnea.
And this occurs with or without snoring.
Second, the patient exhibits moderate to severe oxygen desaturation.
Third, normal ventilation is disrupted.
And fourth, normal sleep patterns are disrupted.
So these are the components of obstructive sleep apnea syndrome.
Now, in children, obstructive sleep apnea syndrome is oftentimes caused by enlarged
adenoid or tonsillar tissue.
And you can see in this illustration that the hypertrophied tonsils really do get in
the way of normal airflow.
So what do you expect to see in a patient with this syndrome?
First of all, you'll probably see snoring.
They'll have difficulty breathing during sleep, restless sleep, or even nightmares or night
terrors.
You may see excessive sweating.
They may have nocturnal enuresis, or bedwetting, mouth breathing, pauses in breathing, or chronic
rhinorrhea.
More importantly, though, what is the significance of having obstructive sleep apnea, and what
are the consequences for the patient?
Well, there are a number of problems that can occur.
Daytime somnolence-- patients have fallen asleep while driving-- older patients, of
course-- and this can lead to motor vehicle accidents; cognitive dysfunction, which leads
to behavioral problems or problems with work or school performance; metabolic effects,
such as insulin resistance, type 2 diabetes mellitus, or metabolic syndrome; or other
metabolic effects, such as failure to thrive or stunted growth.
Or if obstructive sleep apnea is more severe or left untreated, this could lead to cardiovascular
morbidity, such as pulmonary or systemic hypertension, cor pulmonale, or stroke.
Obstructive sleep apnea syndrome can even lead to death.
And it's been hypothesized to be a factor contributing to SIDS, or Sudden Infant Death
Syndrome.
Diagnosis and Clinical Features.
In order to diagnose whether or not someone has obstructive sleep apnea, you must first
and foremost perform a thorough history and physical exam.
A sleep history screening for snoring should be a part of every child's routine health
care visits.
It's really unlikely that someone's going to have obstructive sleep apnea if they don't
snore.
So if a child does snore, ask the parents more details about the sleep history.
Does your child have difficulty breathing or stop breathing during sleep?
Or are you worried about their breathing at night?
Does your child sweat during sleep?
Does your child have restless sleep?
Does he or she breathe through his mouth while awake?
Has anyone in the family had obstructive sleep apnea or sudden infant death syndrome?
Or does your child have behavioral problems?
When you examine the patient, you may notice certain features that are suggestive of obstructive
sleep apnea, such as a small, triangular chin, retrognathia, a high arched palate or a long
soft palate, a long oval face, or, of course, large tonsils.
There are also certain patients who are at high risk for having obstructive sleep apnea.
And these are patients with obesity; Down syndrome; Prader-Willi syndrome; certain neuromuscular
disorders or other neurologic disorders, like chiari malformation and myelomeningocele;
or craniofacial anomalies that obstruct the upper airway.
Let's just take a moment to compare a few of the features of obstructive sleep apnea
in children versus adults.
Now, you see on this table there's a couple of characteristics of obstructive sleep apnea
in pediatrics versus adults.
And there are a few differences you can note.
In adults, most of these patients are obese; whereas in kids, they can be underweight,
normal weight, or overweight.
Kids with obstructive sleep apnea can be hyperactive; whereas adults with obstructive sleep apnea
are usually somnolent.
You'll see that the treatment also differs between kids and adults.
We use CPAP, Continuous Positive Airway Pressure, in both of these patient populations.
But for surgical treatment, kids usually have a tonsillectomy and adenoidectomy, whereas
adults will have uvulopalatopharyngoplasty.
Now, after you do the history and physical, performing a polysomnography, or sleep study,
can provide even further information.
And this can help you differentiate between primary snoring and obstructive sleep apnea
syndrome.
And a sleep study may help quantitate the severity of disease, as well as correlate
sleep disruption with symptoms.
During the sleep study, we count the number of apneas and hypopneas the patient has each
hour.
This is known as the apnea-hypopnea index.
And the apnea is any pause in respiration for two breaths, while a hypopnea is a reduction
of airflow by 50% for two respiratory cycles, a decrease in oxygen saturation by 3%, or
the patient wakes up from sleep.
And an apnea-hypopnea index of greater than 1 is usually used to identify children with
obstructive sleep apnea.
And this is opposed to an index of 5 or more in adults.
Management.
Once we figure out that a patient has obstructive sleep apnea, what are we going to do for them?
I just mentioned Continuous Positive Airway Pressure, or CPAP, because it has a lot of
great benefits for patients.
It can have local and systemic anti-inflammatory effects.
It can restore disrupted sleep patterns.
It promotes weight loss in patients who have obesity.
It can improve cardiac function and decrease the progression to pulmonary hypertension
or cor pulmonale.
CPAP can decrease airway hyper-responsiveness.
But it's really difficult to get patients, especially kids, to comply with CPAP.
So in children, surgical treatment is often what is needed.
In correctly selected patients, a tonsillectomy and/or adenoidectomy can really improve the
symptoms of sleep disordered breathing and quality of life.
Anesthesia and Obstructive Sleep Apnea.
Now, let's say you will be performing the anesthetic for a patient undergoing one of
these procedures.
When you're doing their preoperative evaluation, on these patients having a tonsillectomy and/or
an adenoidectomy, try to elicit any history that would place your patient at a higher
risk for post-operative respiratory complications.
This would include age less than three years; severe obstructive sleep apnea; extremes of
weight-- so failure to thrive or obesity, especially with a body mass index in the 95th
percentile or greater; prematurity; a recent upper respiratory infection-- so in these
cases, you may choose to reschedule or postpone a surgery; reactive airway disease; as well
as some of the factors we discussed earlier, such as neuromuscular disorders; Down syndrome;
and craniofacial abnormalities.
You should also inquire about easy bruising or frequent nosebleeds, because this may indicate
a hematologic abnormality.
And in these patients, or if there's a family history of bleeding problems, consider performing
coagulation studies.
This should be done on a case-by-case basis because not every patient needs coagulation
labs checked.
Now, when you see them immediately preoperatively, really be careful.
Use caution when giving premedication with benzodiazepines or other sedatives, especially
to these patients with obstructive sleep apnea, and especially if they can't be closely monitored
in the preoperative setting, because these are the patients who are going to be at risk
for somnolence and upper airway obstruction.
Intraoperatively, patients are maintained under general anesthesia.
And most patients, because they are pediatric patients, will undergo inhalation induction.
This patient has obstructive sleep apnea and is having an inhalation induction with sevoflurane
and nitrous oxide and oxygen.
And you can see that there is some degree of upper airway obstruction as the pharyngeal
tissues relax and muscle tone decreases.
So what you want to try to do is give some moderate CPAP, maybe about 5-15 centimeters
of water, and jaw thrusts.
And this can help decrease this airway obstruction until the patient is deep enough for oral
airway insertion.
It's really critical for you to watch your patient closely and ensure that you are leaving
their upper airway obstruction so that they can maintain adequate ventilation during this
period.
After an intravenous line is placed, the airway is intubated under a deep plane of anesthesia.
Muscle relaxant is generally not needed.
A volatile anesthetic is used for maintenance, with or without nitrous oxide.
In terms of other medications, antibiotic prophylaxis is usually not needed.
But what is helpful is a single dose of intravenous dexamethasone because this may reduce pain
and swelling and also acts as post-operative nausea and vomiting prophylaxis.
Pain control is achieved by several different methods.
Opioids are given intraoperatively, with lesser amounts given to patients with moderate or
severe obstructive sleep apnea.
Oral acetaminophen, or paracetamol, is given post-operatively.
Oral ibuprofen use is controversial.
But as far as we can tell, it doesn't seem to increase the incidence of post-operative
bleeding, so some people choose to use it.
And always good oral hydration should be encouraged post-operatively because this also helps with
pain control.
In addition, some surgeons also inject local anesthetic directly into the tonsillar fossae
during the case.
At the end of the surgery, deep extubation should not be performed for patients with
obstructive sleep apnea, as they are at risk for airway obstruction as they emerge with
an unprotected airway.
You don't want to be emergently intubating the patient in the recovery room.
After surgery, patients are either discharged home the same day, or they can be admitted
for observation.
Now, make sure that the patients who are discharged the same day have no operative bleeding, no
upper airway obstruction, and have adequate pain control and control of nausea and vomiting.
Here at Boston Children's Hospital, patients are admitted for standard overnight observation
if they meet any of these following criteria-- age between two and three years; weight of
less than 15 kilograms, or below the fifth percentile for their age; and apnea-hypopnea
index of greater than 3 on polysomnography; or conditions such as obesity; any airway
condition or other medical condition that the patient's care team feels would warrant
a standard overnight observation; or if the patients have a known bleeding disorder, or
an immediate family member has a known bleeding disorder.
Patients who are at higher risk are admitted and observed even more closely with continuous
cardiorespiratory monitoring, and even placed in the intensive care unit if necessary.
This is decided on a case-by-case basis.
And these could be patients who are less than two years old; are morbidly obese with a body
mass index of greater than 30 kilograms per meter squared; have severe obstructive sleep
apnea, with an apnea-hypopnea index of greater than 10; or oxygen saturation less than 90%;
or carbon dioxide levels greater than 55 millimeters of mercury; or patients who have a neurologic
or neuromuscular disorder that predisposes them to an upper airway obstruction; patients
who have concurrent cardiac conditions that require electrocardiogram monitoring; patients
who have a concurrent pulmonary disorder predisposing them to respiratory compromise; or again,
those patients who have conditions such as Down syndrome, dwarfism, or other craniofacial
or airway anomalies that predispose them to upper airway obstruction.
Before any of these patients are discharged home from the hospital, they should be cautioned
to avoid sharp foods and vigorous activity, and that's because post-tonsillectomy bleeding
can occur either immediately or 7-10 days post-operatively, as the fibrin clot falls
off the tonsillar bed at this time.
With post-tonsillectomy bleeding, significant amounts of bleeding can occur.
And this may require emergent surgical intervention under general anesthesia.
For you, the anesthetist, this means assessing the patient for hemodynamic stability, as
these patients can be hypotensive or even in shock.
And it means performing a rapid sequence induction, with the airway possibly obscured by blood
and a lot of blood possibly in the stomach.
These can be pretty critical patients.
Today, we've discussed the diagnosis and management of obstructive sleep apnea syndrome in children.
I hope this information has been valuable to you, as you will likely care for many of
these types of patients in your clinical practice.
Thank you.
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