Infants <8 months old can often be transported to the operating room without premedication; anesthesia can then be induced by an inhalation technique (see Section VI.C). The vessel-rich organs are proportionately larger, and the muscle and fat groups are smaller in neonates than in adults, affecting uptake and distribution of inhalation agents (see Chapter 11: Administration of General Anesthesia).

Preoperative sedation options for children 8 months to 5 years old (without established IV access) include the following:

1. Often children who are older than 5 to 6 years old are able to proceed to the procedure without sedation (see Section IV.A); however, these techniques are useful in special circumstances where sedation in an older child are required (ie, developmental delay, extreme anxiety, etc.)

2. Oral midazolam, 0.5 to 0.75 mg/kg, dissolved in sweet syrup, usually produces sedation within 20 minutes, although the time to onset of action can be quite variable. Patients often remain awake but sedated, and, generally, they will have no recall of leaving their parents or of induction of anesthesia.

3. Oral ketamine, 5 mg/kg given orally, produces sedation within 10 to 15 minutes and is synergistic with oral midazolam. Emergence time may be prolonged.

4. Intranasal dexmedetomidine (0.5 to 2 μ g/kg) is an effective sedative given 30 to 75 minutes prior to induction with relatively preserved respiratory function. It has also been used to reduce emergence delirium, as an adjunct to postoperative pain management, and for opioid withdrawal. Side effects can include decreased sympathetic activity, including bradycardia and hypotension. Delayed emergence time should also be anticipated.

5. Pulse oximetry is used routinely once a patient is sedated.

Inhalation induction

1. This is the most common approach for pediatric patients, except when a rapid sequence IV induction is indicated.

2. An excitement stage or “stage two” of anesthesia with disconjugate gaze, injected conjunctiva, increased airway obstruction, altered breathing pattern, increased risk for laryngospasm and bronchospasm, muscular jerkiness, as well as sympathetic discharge as reflected by elevated heart rate and blood pressure is often encountered during inhalation induction. This is the critical period during induction of anesthesia; therefore, noise and activity in the operating room should be minimized during this stage. This stage should be explained to parents if they will be present during induction.

3. Techniques

   1. Children 8 months to 5 years old may be anesthetized after premedication. The inhalational induction can begin with nitrous oxide initially (eg, 4 L/min O₂ and 6 L/min nitrous oxide). Once the effect of the nitrous oxide is apparent, characterized by loss of attention and lack of patient response, the concentration of sevoflurane can be gradually increased in 0.5% to 1% increments.

   2. A slow inhalation induction may be used in cooperative toddlers and older children who have not received premedication. Children are shown how to breathe through a clear anesthetic mask. O₂ and N₂O are delivered via facemask, and sevoflurane is gradually added to the mixture. An engaging story incorporating breathing instructions can be very useful.

   3. A “single-breath induction” may be accomplished with a mixture of a volatile anesthetic with nitrous oxide.

      1. Loss of consciousness can be achieved with a single vital capacity breath of 8% sevoflurane and 70% N₂O in O₂. Desflurane and isoflurane are pungent volatile anesthetics that are not recommended for inhalation induction.

      2. The circuit is primed with 70% N₂O–O₂ and 7% to 8% sevoflurane. The end of the circuit should be occluded with a plug or another reservoir bag. Care should be taken to avoid environmental exposure of anesthetic gas to personnel in the room.

      3. Painting the mask with flavor extracts or flavored lip balm may increase acceptance by children.

      4. The child is instructed to take a deep breath approaching vital capacity of room air, blow it all out as a forced expiration, and then hold their breath. At this point, the anesthetist gently places the mask on the patient’s face. The child then takes a deep inspiration of the anesthetic mixture and again holds their breath. This sequence is repeated for four or five breaths.

      5. Most children will be anesthetized with an adequate vital capacity single breath sevoflurane inhalational induction within 60 seconds; a few children will need longer.

   4. Children can become frightened, uncooperative, and even combative during an inhalation induction. Should this occur, it is imperative to have a backup plan, such as an IM injection of a sedative or hypnotic medication.

IM induction. For the extremely uncooperative or developmentally delayed child, anesthesia may be induced with ketamine (4 to 8 mg/kg IM), which takes effect in 3 to 5 minutes. Atropine (0.02 mg/kg IM) or glycopyrrolate (0.01 mg/kg IM) should be mixed with the ketamine to prevent excessive salivation. Midazolam, 0.2 to 0.5 mg/kg IM, may also be given to reduce the chance of emergence delirium.

IV induction

1. For children more than 8 years old. Often, older children may prefer an IV technique rather than a mask. Anesthesia can be induced with propofol (3 to 4 mg/kg). Ketamine (1 to 2 mg/kg) is a useful inductive agent in patients requiring hemodynamic stability upon induction. Etomidate (0.2 to 0.3 mg/kg) can be used in children with major trauma associated with hemodynamic instability or children with cardiomyopathy.

2. IV induction at this age is often preferable to a mask induction because many older children do not like the smell of volatile anesthetics. Local anesthesia before IV placement can be achieved with subcutaneous injection of lidocaine 1%. Alternatively EMLA cream (a eutectic mixture of 2.5% lidocaine and 2.5% prilocaine), LMX cream (lidocaine 4%), or Synera (a heated topical patch with a eutectic mixture of lidocaine and tetracaine) can be applied to the skin approximately 45 minutes before IV placement. EMLA cream is also useful to reduce the pain of accessing a Portacath. The use of the jet injection lidocaine applicator is another method for achieving analgesia for IV placement.

Children with “full stomachs”

1. For rapid sequence induction, in general, the same principles apply to infants and children as for adults.

   1. Atropine (0.02 mg/kg) may be given IV to prevent bradycardia, especially if succinylcholine will be given.

   2. Children often require larger doses propofol (3 to 4 mg/kg) and succinylcholine (1 to 2.0 mg/kg) because of a larger volume of distribution for these drugs.

   3. Infants with gastric distention (eg, pyloric stenosis) should have their stomachs decompressed with an orogastric tube before induction of anesthesia. This gastric tube should be suctioned again before the trachea is extubated.

   4. Ranitidine (2 to 4 mg/kg) can be given to decrease gastric volume and increase gastric pH. Ondansetron (0.1 mg/kg) can be given for postoperative nausea and vomiting prophylaxis.

   5. Metoclopramide should not be given if gastric outlet or bowel obstruction is suspected.

2. An awake laryngoscopy and intubation is an option for the moribund infant or an infant with a grossly abnormal airway (eg, severe craniofacial anomaly) and a “full stomach.”

3. A cuffed endotracheal tube should be considered for a child with a full stomach. This option minimizes the need for replacing an uncuffed tube that proves too small. The cuff volume can be adjusted to ensure an appropriate air leak.