Anesthesia And Sedation

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Ovid: Pediatrics

Editors: Tornetta, Paul; Einhorn, Thomas A.; Cramer, Kathryn E.; Scherl, Susan A.

Title: Pediatrics, 1st Edition

> Table of Contents > Section III: – Specialty Clinics > 34 – Anesthesia And Sedation

Anesthesia And Sedation

Maria Markakis Zestos

Sedation provides a calm, cooperative patient but is not
without risk. Sedation can result in hypoventilation, apnea, airway
obstruction, and cardiac arrest. Safe sedation requires first and
foremost, a skilled and vigilant person who can provide appropriate
patient selection and monitoring.

PATIENT SELECTION, MONITORING, AND DISCHARGE

Patients who are American Society of Anesthesiologist
(ASA) class I or II are considered suitable candidates for sedation by
non-anesthesiologists (Table 34-1). An
independent observer, usually a nurse or another physician, must
continuously monitor the patient and periodically observe and record
vital signs while the orthopaedist performs the procedure. To avoid
adverse events, monitoring, including pulse oximetry, should continue
after the procedure. Many disasters have occurred from airway
obstruction in unmonitored patients after sedation. Children who
receive deep sedation require a level of vigilance equal to that
provided for general anesthesia. This includes recording of vital signs
every 5 minutes and the presence of at least one individual trained in
basic life support. Intravenous (i.v.) access should be readily
available. Finally, appropriate discharge criteria must be followed
before sending the patient home. The criteria recommended by the
American Academy of Pediatrics are as follows:

TABLE 34-1 AMERICAN SOCIETY OF ANESTHESIOLOGISTS’ PHYSICAL STATUS CLASSIFICATION

Class	Description
I	Normally healthy patient
II	Patient with mild systemic disease
III	Patient with severe systemic disease
IV	Patient with severe systemic disease that is a constant threat to life
V	Moribund patient who is not expected to survive without the operation
From American Academy of Pediatrics Committee on Drugs. Guidelines for monitoring and management of pediatric patients during and after sedation for diagnostic and therapeutic procedures. Pediatrics 1992;89:1110-1115.

Cardiovascular function and airway patency are satisfactory and stable.
The patient is easily aroused, and protective reflexes are intact.
The patient can talk (if age-appropriate).
The patient can sit up unaided (if age-appropriate).
For a very young or disabled child,
incapable of the usual expected responses, the presedation level of
responsiveness or a level as close as possible to the normal level for
that child should be achieved.
The state of hydration is adequate.

FASTING GUIDELINES

If the procedure is elective, an appropriate time of
fasting should be allowed. Most physicians consider a 6-hour fast from
solid food acceptable for the majority of children. The intake of clear
liquids has been liberalized in recent years, and only a brief clear
liquid fast is now required. See Table 34-2 for fasting guidelines.

TABLE 34-2 PRESEDATION FASTING GUIDELINES

	Fasting Time (hr)
Age	Milk/Solids	Clear Liquids
<6 mo	4	2
6-36 mo	6	3
>36 mo	8	3
Adapted from Coté CJ. Sedation for the pediatric patient: a review. Pediatr Clin North Am 1994;41:31-58.

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Even with an adequate fasting interval, aspiration can
still occur. Other factors can increase the risk of aspiration,
including obesity, gastrointestinal obstruction, and neurologic
dysfunction. Suction should be readily available for all cases. In some
patients, lighter sedation or no sedation may be desirable to minimize
the risk of aspiration. If the procedure is deemed an emergency, the
need to proceed must be weighed against the risk of aspiration.

MEDICATIONS

Many medications can be used for sedation, including
barbiturates, benzodiazepines, opioids, phencyclidines, and neuroleptic
drugs. There can be an exaggerated effect from the administration of
drugs to small infants and children. The route of administration will
affect both the onset and duration of action of the drug and can extend
the time needed for postprocedure observation. Doses of i.v. drugs
should be titrated to effect. Combinations of drugs are often
discouraged because of the additive or synergistic effects. In general,
a smaller dose of each drug is often given if combinations are to be
used. See Table 34-3 for the doses of drugs commonly used for sedation.

TABLE 34-3 DOSES OF DRUGS COMMONLY USED FOR SEDATION

Drug		Route	Dose (mg/kg)
Barbiturates
	Methohexital	Rectal	20-30
		Intramuscular	10
	Thiopental	Rectal	20-30
		Intramuscular	10
Benzodiazepines
	Diazepam	Oral	0.1-0.3
		Intravenous	0.1-0.3
		Intramuscular	Not recommended
		Rectal	0.2-0.3
	Midazolam	Oral	0.5-0.75
		Intravenous	0.05-0.15
		Intramuscular	0.05-0.15
		Rectal	0.5-0.75
		Nasal	0.2-0.5
		Sublingual	0.2-0.5
	Ketamine	Oral	3-10
		Intravenous	1-3
		Intramuscular	2-10
		Rectal	5-10
		Nasal	3-5
		Sublingual	3-5
Opioids
	Morphine	Intravenous	0.1-0.3
		Intramuscular	0.1-0.3
		Rectal	Not recommended
	Meperidine	Intravenous	1-3
		Intramuscular	1-3
		Rectal	Not recommended
	Fentanyl	Oral transmucosal	0.015-0.020 (15-20 µg/kg)
		Sublingual	0.010-0.015 (10-15 µg/kg)
		Intravenous	0.001-0.005 (1-5 µg/kg in increments of 0.5-1.0 µg/kg)
Chloral hydrate		Oral	20-100 mg/kg (max 1 g)
Adapted from Coté CJ. Sedation for the pediatric patient: a review. Pediatr Clin North Am 1994;41:31-58.

Benzodiazepines

Of any sedative, Midazolam comes the closest to producing a true state of conscious sedation in children.
- □ Water-soluble, short-acting benzodiazepine with a rapid onset.
- □ Most popular sedative in the pediatric age group.
- □ Most children do not fall asleep even with larger doses, but are calm and compliant.
- □ Oral midazolam has a bitter aftertaste that is partially masked by sweeteners.
- □ It has a short half-life (106 ± 29 minutes) and can produce antegrade amnesia.
- □ Onset of action varies with route of
  administration. Can be as short as 2 minutes after i.v. administration
  and as long as 20 minutes after oral administration.
- □ Respiratory depression can occur when used in combination with opioids.

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Diazepam has
a longer duration of action than midazolam and produces significant
pain at the site of i.v. administration, both of which limit its
usefulness for procedural sedation.

Opioids

Opioids provide sedation as well as analgesia for
painful procedures. Because of major side effects including apnea,
pruritis, nausea, vomiting, desaturation, and delayed emergence,
opioids are rarely used solely for sedation. Opioids are useful for
procedures such as fracture reduction in which postprocedure pain is
expected.

Morphine has
a prolonged duration of action of 3 to 4 hours and is often reserved
for longer procedures or those with significant postprocedure pain.
Fentanyl is a
hundred times more potent than morphine. Fentanyl, administered
intravenously, has an onset within 1 to 2 minutes and a short duration
of action of 0.5 to 1 hour, but respiratory depression may last
considerably longer.
- □ Fentanyl should be titrated slowly with several minutes between doses.

Phencyclidines

Ketamine provides excellent analgesia, amnesia, and sedation.
- □ It can be administered by any route (Table 34-3) and is useful to facilitate the cooperation of combative or delayed patients.
- □ Anticholinergic agents are added to dry upper airway secretions.
- □ Absolute contraindications to ketamine include elevated intracranial pressure and elevated intraocular pressure.
- □ Side effects include tachycardia, hypertension, increased intracranial pressure, and increased intraocular pressure.
- □ Reactions such as emergence
  hallucinations, vivid dreams, or frank delirium can occur in up to 10%
  of patients. These reactions are less common in children than in adults
  and can be prevented by pretreatment with a benzodiazepine. Although
  undesirable, they do not contraindicate the use of ketamine.
Emergency medicine physicians recommend
the administration of ketamine 3 mg/kg intramuscularly (i.m.),
midazolam 0.05 mg/kg i.m., and glycopyrrolate 0.005 mg/kg i.m. as a
single bolus injection for children 12 months to 7 years of age who
require sedation for minor surgical procedures.
- □ Onset of action with this cocktail
  occurs within 6 minutes in most patients, and adequate working
  conditions last for 30 minutes.

Neuroleptic Drugs

Droperidol is a butyrophenone that acts centrally to produce a dissociative state.
- □ The usual dose is 25 to 75 µg/kg.
- □ Its duration of action is 6 to 12 hours.
- □ It is generally not used except for antiemetic effects.
- □ Its use has recently been discouraged because of a significant incidence of arrhythmias.

Chloral Hydrate

Traditionally used for sedating young
infants and children for nonpainful procedures, it remains one of the
most popular sedatives used by non-anesthesiologists.
The peak effect after oral administration can occur as late as 1 hour after administration.
Although this drug is said to have a
minimal effect on respiration, respiratory depression, airway
obstruction and even death have occurred, especially when used in
combination with other sedatives or narcotics.
Children should be observed after sedation, particularly for airway patency.

Demerol Phenergan Thorazine

Often referred to as a “lytic cocktail.”
This mixture of meperidine (25 mg/mL), promethazine (12.5 mg/mL), and chlorpromazine (12.5 mg/mL), is given intramuscularly.
Sedation lasts about 5 hours, often outlasting many procedures.
The dose is 0.1 to 0.2 mL/kg in a healthy
child. The maximal dose should not exceed 2 mL. Life-threatening
seizures have been reported with its use in children.

Propofol

Sedative hypnotic with a fast onset, a short duration of action, and some antiemetic effect.
Sedation has been achieved with a continuous infusion titrated to the response of the child (50 to 200 µg/kg/min).
Propofol is a general anesthetic, and its use is limited to specialists skilled in airway management.

Nonsteroidal Antiinflammatory Drugs

Provide analgesia while decreasing opioid requirements and side effects.
- □ Opioid use has been decreased as much as 25% when these are used.
- □ There is no evidence that one nonsteroidal antiinflammatory drug (NSAID) is more efficacious than the others.
Ketorolac is an NSAID that has been studied extensively in the pediatric population.
- □ Its i.v. formulation has increased its popularity over other NSAIDs.
- □ Its dose varies with route of administration, with a maximum daily dose of 2 mg/kg/day for 5 consecutive days.
- □ Its side effects include renal failure,
  bradycardia, anaphylaxis, gastrointestinal injury, platelet
  dysfunction, and perioperative bleeding.

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TABLE 34-4 MAXIMUM RECOMMENDED DOSE OF COMMONLY USED LOCAL ANESTHETICS

Local Anesthetic	Maximum Dose (mg/kg)
Lidocaine^a	7.0
Bupivacaine^b	3.0
Tetracaine	1.5
Procaine	10.0
Mepivacaine	7.0
2-Chloroprocaine	20.0
^aLidocaine is short-acting—approximately 90 min. ^bBupivacaine is long-acting—approximately 180-600 min.
Adapted from Coté CJ. Sedation for the pediatric patient: a review.
Pediatr Clin North Am 1994;41:31-58.

Local Anesthetics

Useful in the treatment of pain by both subcutaneous injection and by regional blocks.
Can anesthetize the affected area and reduce or eliminate pain during manipulation.
Local anesthetic overdose can result in
tinnitus, seizures, vasodilation, arrhythmias, and cardiac arrest.
Overdose is more likely in smaller patients who communicate poorly and
have delayed drug metabolism and elimination.
The maximum dose of each commonly used local anesthetic is listed in Table 34-4.

GENERAL ANESTHESIA

Many procedures that are routinely performed in sedated
adults are performed under general anesthesia in children. There are a
few differences in the preoperative preparation in children when
compared with adults:

Preoperative laboratory studies
- □ No laboratory studies are routinely obtained in healthy children for elective surgery.
- □ When significant blood loss is expected, a starting hematocrit can be obtained after induction of anesthesia.
Mask inductions
- □ Many children are anesthetized with inhalation anesthetic gases, such as sevoflurane, before an i.v. is placed.
Parental presence
- □ Many operating rooms allow parents to stay with their children during induction of mask anesthesia.
- □ This is most useful in children ages 1 to 6 years of age when separation anxiety is a major issue.
- □ Parental presence is usually not needed if premedication can be given and if an i.v. is present.
Preoperative medication
- □ Many institutions prefer to premedicate
  children before induction of anesthesia even if parents are allowed to
  be present for induction.
- □ The most common pediatric premedicant
  used in the majority of children is midazolam 0.5 mg/kg p.o. (maximum
  single dose of 25 mg).