Taking the Fear out of Anesthetizing Children

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Taking the Fear out of Anesthetizing Children

• Jerrold Lerman, M.D.

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What shakes anesthesiologists most when they are
faced with anesthetizing a child?

• A childs cardiorespiratory status is rapidly
  deteriorating
• The Pediatric Perioperative Cardiac Arrest
  Registry
• 1. Substantial changes in the etiology of the
  arrests from the first epoch in 1994-1997 to the
  second, in 1998-2000 including a decrease in the
  role of medication (ie., the shift from
  halothane to sevoflurane) in contributing to the
  arrests.
• 2. Respiratory difficulties during induction of
  anesthesia
• obstructed upper airway, laryngospasm and
  hypoxia
• 3. Substantial incidence of cardiovascular
  factors
• hypovolemia and two causes of ventricular
  tachycardia,
• hyperkalemia and intravascular bupivacaine.
• 4. Congenital heart disease and ASA P/S III
  were more likely to be involved in the arrests.

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Getting the child to the OR. (Separation from
their parents)

• Most children and parents arrive ill-informed and
  ill-prepared for the stress of the situation
• The level of preoperative anxiety in children
  depends, in part, on the childs age.
• 1. Infants younger than 6 months of age usually
  separate easily from their parents.
• 2. Children 6 months to 4 years of age separate
  poorly from their parents and are the audience
  for premedication.
• 3. Children 5 to 12 years of age are less
  concerned about separation.

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Getting the child to the OR. (Separation from
their parents)

• Many strategies have been developed to minimize
  the emotional upheaval and anxiety during this
  stressful period.
• 1. Education, distraction, and familiarity with
  the environment are all effective to some degree.
• 2. The most universally successful technique for
  anxiolysis is parmacologic premedication.

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Getting the child to the OR. (Separation from
their parents)

• In North America, midazolam is the most widely
  used premedcation that is reliable and effective.
  
• Most clinicians administer 0.5 mg/kg to children
  1 to 6 years of age
• -gtgt Only modestly successful
• For healthy children 1-6 years of age
• -gtgt Administer oral midazolam, 0.75 mg/kg
  
• 0.5 mg/kg for children 6 to 8 years of age
• 0.3 mg/kg for those 14 and older with a maximum
  dose of 20 mg

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Getting the child to the OR. (Separation from
their parents)

• Based on current evidence, parental presence at
  induction of anesthesia provides more anxiolysis
  for the parent than it does for the child.
• The cognitively challenged adult-sized teen who
  steadfastly refuses to come to the OR may require
  the parent to accompany them to the OR.
• -gtgt Intramuscular ketamine 3-6 mg/kg (100
  mg/ml
• concentration) may be required for th
  child to
• reach the OR

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Defusing Anxiety at Induction

• Many healthy children 3 to 8 years of age are
  frightened when they arrive in the OR
• First, offer the child a choice of flavors (lip
  balm) for the mask and permit the child to apply
  it to the mask while in the holding area.
• Second, sit the child (2-6 year old) on the OR
  table with the childs back resting against your
  chest, rather than lying him/her down.
• Third, apply the pulse oximeter probe

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Defusing Anxiety at Induction

• Fourth, begin the inhalational induction with 70
  nitrous oxide in oxygen through the scented mask
  until the child stops communicating with you.
• Fifth, as soon as the child ceases to interact
  with you, 8 sevoflurane can be administered and
  he/she will not remember the odor.
• Do not increase the inspired consentration of
  sevoflurane in increments. (It only serves to
  prolong the excitement period)

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Defusing Anxiety at Induction

• Some children have been stigmatized by previous
  bad experiences and refuse to breathe the dreaded
  mask.
• -gtgt Remove the mask from the circuit.

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Inducing anesthesia

• Do not decrease the inspired concentration of
  sevoflurane from 8 or eliminate nitrous oxide
  before respiration diminishes because some have
  demonstrated light levels of anesthesia and/or
  awareness.
• Respiratory depression and apnea are much more
  likely to occur if the child was premedicated.
• When respiration diminishes,
• -gtgt Simply assist ventilation manually.
• To facilitate a return of spontaneous
  ventilation,
• -gtgt Gradually decrease the inspired
  concentration
• of sevoflurane.

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Inducing anesthesia

• Children (neonates in particular) are at risk for
  hypoxia and bradycardia when the airway is lost
  because their metabolic rate is great alveolar
  ventilation to FRC ratio (51) and great oxygen
  requirement.
• In the first US Closed Claims review,
  respiratory events (43) among pediatric claims
  were 50 more common than adult claims.
• In a review of critical incidents after 10,000
  anesthetics at the Childrens Hospital in
  Singapore identified respiratory events in 77 of
  the critical incidents, with laryngospasm
  accounting for 36 of these

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The Airway

• The airway is most commonly lost during or
  immediately after induction of anesthesia.
• -gtgt We require the proper equipment and
  skill set.
• A properly fitting facemask is essential.
• An unsealed mask leads to a dilution of
  the
• anesthetic concentration and prevents the
• administration of positive pressure.

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The Airway

• As anesthesia is induced in the child, the
  internal dimensions of upper airway decrease
  further.
• may be complicated by the presence of
  large
• tonsils and adenoids.
• Airway obstruction
• suprasternal and supraclavicular
  retractions, chest wall indrawing and extreme
  diaphragmatic excursions -gtgt inspiratory noises
  (crowing) d/t a partially closed glottis

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The Airway

• A tight-fitting mask with a breathing circuit
  that was primed with 100 oxygen and 8
  sevoflurane should be applied.
• Close the pop-off valve to pressurize the
  breathing circuit and maintain 5-10 cm H2O
  pressure.
• Do not attempt to ventilate against a closed
  glottis This will only inflate the stomach with
  gas and increase the risk of regurgitation and
  aspiration.

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The Airway

• Jaw thrust maneuver

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The Airway

• If the laryngospasm does not abate, respiratory
  chest movement continues without vocalization and
  the capnogram is undetectable,
• -gtgt atropine 20 µg/kg
• keep the heart beating and delay or
  prevent
• bradycardia
• -gtgt propofol 1-2 mg/kg
• prevent laryngospasm if given
  prophylactically
• or relieve it if given
  therapeutically
• At this point, the pulmonary system is in
  difficulty, but the cardiovascular system remains
  functioning.

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The Airway

• If the lungs cannot be manually ventilated after
  these maneuvers -gtgt complete laryngospasm or an
  obstruction to the airway distal to the larynx.
• Remember, the tone and numerical display of the
  pulse oximeter generally underestimates the true
  oxygen saturation when the saturation is
  decreasing rapidly and when it reads less than
  60.
• If complete laryngospasm has occurred, then
  promptly administer succinylcholine, 0.5-1.0
  mg/kg IV or IM.
• Suggamadex (which may reverse rocuronium within 3
  minutes)

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Alveolar recruitment

• The pulse oximeter display begin to decrease in a
  healthy child whose airway was intubated?
• In the absence of endobronchial intubation,
  secretion, or bronchospasm, the most common cause
  of a gradual desaturation in a healthy child is a
  right-to-left shunt due to segmental atelectasis.
• In fact, a sustained single manual lung inflation
  to 20 to 30 cm H20 for 20 to 30 sec (depending on
  their cardiorespiratory status even with 70
  nitrous oxide in oxygen as the fresh gas) will
  rapidly restore the oxygen saturation to normal
  values.

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The difficult pediatric airway

• What you see is what you get
• History, physical examination and the syndrome.
• Physical examination of the head and neck should
  provide a clear picture of how difficult the
  airway may be.
• The lateral profile of the head and neck will
  provide a sense of bony proportions (looking for
  micrognathia as in Pierre Robin sequence), the
  extent of mouth opening (looking at microstomia
  as in Freeman-Sheldon synd), extension/flexion of
  the neck(as in Klippel-Feil synd) and any
  intraoral masses.

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Emergence

• During emergence from anesthesia, the saturation
  often decreases precipitously suddenly, even with
  the tracheal remains intubated.
• This usually occurs after the child has coughed,
  breath-held or strained, all of which reduce the
  FRC and increase V/Q mismatch.
• The solution for this problem is simple
  ventilate the lungs with 100 oxygen, use
  positive end-expiratory pressure as needed to
  recruit alveoli and be patient.

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Emergence

• Rarely, children bite and occlude th tracheal
  lumen
• -gtgt bite block, oral airway
• Opening the mouth by inducing a gag reflex,
  deepening th level of anesthesia(with propofol),
  or paralysis

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Emergence

• Emergence from inhalational anesthesia
• 1. arousal with bucking and coughing
• 2. a quiet period of straining, apnea or shallow
  breathing
• 3. A reprise of bucking, coughing, but this time
• accompanied by mouth opening and purposeful
• movements.
• To avoid laryngospasm, remove the tube during the
  third and final stage of emergence.

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Do children experience Awareness?

• The very first anesthetic administered in the
  Ether dome at the Massachusetts General Hospital
  was a case of awareness.
• In adults, the incidence of awareness during
  general anesthesia is 0.0065 - 0.3
• In children, Davidson et al reported 0.8
  incidence of awareness after general anesthesia.
• In my practice, an incidence of 112,500 or 0.008

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Do children experience Awareness?

• Routinely administer a dose of intravenous
  propofol after induction of anesthesia with
  sevoflurane and before laryngoscopy and tracheal
  intubation.
• Although awareness is a potential risk with
  general anesthesia in children, care must be
  taken to maintain an adequate depth of anesthesia
  in children at all times because depth of
  anesthesia may change rapidly with these
  relatively insoluble anesthetics.

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Conclusion

• Learn how to deal with the struggling,
  uncooperative child, learn how to induce
  anesthesia sensitively, develop the skills to
  manage the obstructed airway and laryngospasm,
  and how to ensure that the children in our care
  remain asleep throughout their surgeries.
• Once familiar with these strategies,
  anesthetizing children will become much more
  enjoyable and less fearsome.