Pediatric Airway Series: Part 3 – Time to Intubate!

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December 12, 2017 by Agnes Usoro

Decision has been made to Intubate. What now?

  • There are “7 P’s” for Intubation to help outline a step-wise approach
  • Recall from Part 2 that we discussed the Preparation and Pre-oxygenation steps for a pediatric intubation. Let’s take a look at steps 3-6 here.
    1. Preparation
    2. Pre-oxygenation
    3. Pre-treatment
    4. Paralysis and induction
    5. Protection and Positioning
    6. Placement of the ET tube
    7. Post-intubation management

Pre-Treatment

Blood Pressure

  • Positive pressure ventilation can result in increased intra-thoracic pressure which decreases preload, resulting in hypotension. Pediatric patients are more at risk for hypotension. This can be addressed with pre-intubation fluid resuscitation. Consider a 10-20mL/kg bolus of intravenous fluids prior to intubation.

Heart Rate

  • Vagal tone from the parasympathetic nervous system predominates in children, which can result in marked bradycardia during an intubation. To circumvent this, you can consider pre-treatment with atropine. Keep in mind that this is no longer a favored practice but is still performed by various providers and institutions.

Airway Tone

  • Laryngeal stimulation by either the direct or indirect laryngoscopy blade or the endotracheal tube itself can result in theoretical laryngospasm or bronchospasm. For this reason, you can consider pre-medication with Lidocaine.

Airway Secretions

  • Due to the anatomically smaller sized airway of children,  they are more prone to becoming symptomatic when secretions pull in their airway. This also explains why children are more symptomatic during upper respiratory events. Glycopyrrolate can be used to reduce airway secretions, which can also improve one’s view of the glottis, if secretions are present. 

Intracranial Pressure

  • Pediatric patients with head injuries should be pre-treated with Lidocaine, which has a theoretical benefit of blunting a rapid increase in intracranial pressure in response to endotracheal stimulation. It is interesting to note that the literature shows this benefit when Lidocaine is administered via the endotracheal route although the most common practice is to administer it intravenously. 

Pre-Treatment Medication Doses

Atropine

0.02mg/kg (Max: 0.5mg)

IV, IO, IM

To block vagal tone induced bradycardia during intubation

Glycopyrrolate

0.004mg/kg (Max: 0.1mg)

IV, IO, IM

To reduce upper airway secretions

Lidocaine

1mg/kg (2mg/kg if endotracheal) (Max: 100mg)

IV, IO, Endotracheal

To prevent bronchospasm, and for patient’s at risk for increased ICP

Fentanyl

1-2mcg/kg (Max: 100mcg)

IV, IO

Analgesic. If given too fast (> 1mcg/kg/min), can cause rigid chest. If this occurs, administer a paralytic to relax the chest wall.


Paralysis and Induction

  • Rapid sequence intubation is one of the safest methods for intubating a pediatric patient
  • Dosing for drug agents used in paralysis and induction are noted in the charts below

Induction Medication Doses

Etomidate

0.3mg/kg (normotensive patient) or 0.15mg/kg (hypotensive patient)

(Max: 20mg) IV, IO

Potential risk for adrenal insufficiency

Ketamine

2-4mg/kg (Max: 150mg)

IV, IO

Preferred agent for asthmatics and patients with sepsis

Potential risk for bronchorrhea and laryngospasm

Propofol

2mg/kg

IV, IO

Risk for hypotension

Paralytic Medication Doses

Succinylcholine

1-2 mg/kg IV, IO (Max: 200mg) or 2-4mg/kg IM (Max: 150mg)

Short duration of action (up to 8 min)

Potential risk for bradycardia in children

Potential risk for hyperkalemic cardiac arrest in children with undiagnosed neuromuscular disease, therefore contraindicated in patients with neuromuscular disease and renal failure

Rocuronium

1mg/kg (Max: 100mg)

Longer duration of action (up to 45 min)


Protection and Positioning

Recall that the optimal alignment of the oral, pharyngeal and tracheal axis varies based on the age of the patient. The ideal position is to align the external auditory meatus with the sternal notch. This is called the sniffing position

  • For infants, a shoulder roll can be used
  • For small children, this can be achieved with slight extension of the neck
  • For older children (similar to adults), consider a roll under the head

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Placement of the ET Tube

  • Refer to Part 1 of the series where we discussed age-appropriate equipment sizes for the pediatric intubation
  • Remember the anatomical differences between the pediatric airway compared to the adult
    • Proportionally larger head
    • Unstable teeth
    • Larger tongue
    • Larger and more friable tonsils and adenoids
    • More superior and anterior larynx
    • Shorter and stiffer epiglottis
    • Concave upward-shaped vocal cords

8795.myextj.jpeg

  • Once the vocal cords are visualized, advance the endotracheal tube until the cuff has passed the vocal cords
  • Because of the short distance between the vocal cords and the tracheal carina in children, it is easy to inadvertently intubate the right main-strem bronchus. To prevent this from happening, keep in mind that the depth of insertion of an endotracheal tube is about three times the internal diameter of the endotracheal tube
    • Example: 5.0mm ETT should be advanced to about 15cm at the lips
  • Once the endotracheal tube is placed, confirm endotracheal tube placement with capnography or a colorimetric end-tidal carbon dioxide detector. Auscultating for equal bilateral breath sounds is not as reliable in children given their smaller sized chest which easily transmits breaths sounds making it harder to appreciate diminished lung sounds from a right  main-stem intubation

We will discussing the Difficult Pediatric Airway in Part 4 of the Pediatric Airway Series


References

  • Tintinalli, J.E., et al. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8th Edition.Section 12, Chapter 111
  • Johns Hopkins Children’s Hospital, Hopkins Outreach for Pediatric Education (HOPE) Kids Kard
  • Brucia, J.J., et al. The effects of lidocaine on intracranial hypertension. J Neurosci Nurs. 1992 Aug; 24(4): 205-14
  • Image 1: Luten, R.C. and Godwin, S.A. Anesthesia Key – Pediatric Airway Techniques. Figure 25.2: Clinical determination of optimal airway alignment
  • Image 2: Uptodate.com. Figure: Anatomical differences between the pediatric and adult airway

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