Peds Respiratory Distress

Holly Caretta-Weyer, MD and Jamie Hess, MD

University of Wisconsin School of Medicine and Public Health

 

Objectives:

Upon completion of this self-study module, you should be able to:

  1. Describe the key ways in which the pediatric airway differs from that of an adult
  2. List the life-threatening causes of respiratory distress in a pediatric patient
  3. Be able to differentiate from upper and lower airway obstruction
  4. Describe the initial approach to management of a pediatric patient with respiratory distress

Initial Actions:

The ABCs still apply in children!

First – provide supplemental oxygen! Children may also need some ventilatory assistance depending upon the disease process and there are many ways that this can be delivered.  Options include:

  • Oxygenation:
    • Nasal cannula
      • Provides supplemental oxygen at an FiO2 of ~30% and a rate of 1/8-4 L/min
    • Non-rebreather
      • Provides supplemental oxygen at an FiO2 of 95-100% and a rate of 10-15 L/min
    • High flow nasal cannula
      • Provides supplemental oxygen and a small amount of PEEP with FiO2 of 50-90% and flow of anywhere from 4-50 L/min of flow
    • Ventilatory assistance:
      • Positive pressure ventilation (CPAP or BiPAP)
        • CPAP (Continuous Positive Airway Pressure) can be provided by nasal or full mask and provides a continuous flow with a steady amount of PEEP across inspiration and expiration
        • BiPAP (Bi-level Positive Airway Pressure) provides a level of IPAP (inspiratory positive airway pressure) that assists with filling the lungs and a level of EPAP (expiratory positive airway pressure) to stent open the airways and assist with expiration.
      • Mechanical ventilation
        • Requires endotracheal intubation and allows for a set ventilatory rate and tidal volume.

Suctioning – Given the small airways in children, especially infants, suctioning can be important to clear the airways and decrease resistance of air flow through the passages.  Age/weight specific suction catheter sizes are available for this purpose.

Other airway adjuncts such as oral and/or nasal airways can assist with alleviating obstruction caused by a large tongue and assist with bag-mask ventilation.  These also have age/weight specific sizes.

The approach to the pediatric patient in respiratory distress starts with the ‘A’ and ‘B’ of your ABC’s.

A = Airway:

Key Differences in the Pediatric Airway

Anatomy

Pediatric

Adult

Tongue
Large Normal
Epiglottis
Floppy, omega-shaped Firm, flatter
Epiglottis Level
C3-C4 C5-C6
Trachea
Smaller, shorter Wider, longer
Larynx Shape
Funnel Column
Larynx Position
Angles posteriorly away from glottis Straight up and down
Narrowest Point
Sub-glottic region Level of vocal cords
Lung Volume
250 mL at birth 6 L as an adult

Given that children have a smaller airway diameter and that resistance is related to the radius to the fourth power, any change in radius will cause significant increase in airway resistance and will increase work of breathing in the child.  A good example of this is croup, which increases the airway resistance and work of breathing due to increased sub-glottic swelling.

Indications for Intubation:

  1. Hypoxia
  2. Hypercarbia
  3. Inability to protect the airway – GCS < 8, no cough/gag
  4. Increased work of breathing with signs of tiring or poor cardiac output

How to size an endotracheal tube (ETT):

May use Broselow tape or estimate based on age

For ages 1-12:

Predicted Size Uncuffed Tube = (Age / 4) + 4

Predicted Size Cuffed Tube = (Age / 4) + 3

How to choose a laryngoscope blade for intubation:

  • Miller blades are straight and are to be placed under the epiglottis.
  • McIntosh blades are placed in the vallecula and the epiglottis lifts out of view as the laryngoscope is lifted.

Given the floppy nature of the epiglottis in infants and young children, a Miller, or straight, blade is often used for intubation in the youngest children to lift the epiglottis out of the way and visualize the vocal cords. A Miller 0 should be used for premature infants and neonates. A Miller 1 blade should be used from 1 month to 2 years of age. A Miller 2 should be used for children 3-6 years of age. After 6 years, one may use either a Miller 2 or McIntosh 2. Over age 12, you may refer to adult sized blades.

B = Breathing:

Normal respiratory rate varies by age:

  • Age < 1 year: 30-60 breaths/min
  • Age 1-2 years: 24-40 breaths/min
  • Age 2-5 years: 22-34 breaths/min
  • Age 6-12 years: 18-30 breaths/min
  • Age > 12 years: Refer to adult rates

Certain physical exam findings will make you think about certain diagnoses, maneuvers, and medications.

Stridor:

Inspiratory stridor should make you think of an obstructive process above the level of the larynx. Biphasic stridor should make you think of an obstruction at the level of the vocal cords and/or trachea. Expiratory stridor should make you think of an obstructive process below the level of the larynx. Stridor is most often heard with upper airway obstructive processes. Other findings often associated with obstructive processes of the upper airway include muffled or hoarse voice, drooling, and tripoding or leaning forward in an attempt to open the airway.

Wheezing:

Often indicates swelling and constriction of the bronchioles; however, all that wheezes is not asthma! Cardiac processes, foreign bodies, infectious processes, and obstructive processes below the level of the larynx can all also cause wheezing.

Specific treatments are targeted at specific diseases and will be covered in more detail in separate sections, such as albuterol and ipratropium nebulizers and steroids for asthma, racemic epinephrine and oral steroids for croup, IM epinephrine for anaphylaxis, and IV antibiotics for epiglottitis.

Differential Diagnosis

Upper airway processes (often hear stridor and/or muffled or hoarse voice):

  • Foreign body
  • Epiglottitis
  • Croup
  • Bacterial tracheitis
  • Severe tonsillitis
  • Diphtheria
  • Peritonsillar abscess
  • Retropharyngeal abscess
  • Anaphylaxis
  • Angioedema
  • Upper airway burns
  • Caustic ingestions
  • Congenital anomalies such as Pierre Robin, choanal atresia, laryngeal tumors, neck cysts, congenital vocal cord paralysis, larnygnomalacia
  • Obstructive sleep apnea

Lower airway processes (often hear wheezing, rales, and/or rhonchi):

  • Asthma
  • Bronchiolitis
  • Pneumonia
  • Foreign body
  • Anaphylaxis
  • Transient tachypnea of the newborn
  • Pneumothorax, hemothorax
  • Diaphragmatic hernia
  • Empyema
  • Effusion

Cardiac causes (may hear cardiac wheezing, crackles):

  • CHF secondary to congenital anomaly, myocarditis, cardiomyopathy
  • PE
  • Cardiac tamponade

Toxic/Metabolic (often see hyper- or hypoventilation):

  • DKA
  • Aspirin ingestion
  • Carbon monoxide exposure
  • Cyanide
  • Methemoglobinemia
  • Smoke inhalation
  • Opioid ingestion

Neurologic causes (can see changes in respiratory rate and/or mental status):

  • Subarachnoid hemorrhage or other intracranial bleed
  • Non-accidental trauma
  • Tumor
  • Meningitis
  • Increased ICP
  • Anxiety

 

References:

  1. American Academy of Pediatrics, American College of Emergency Physicians. APLS: The Pediatric Emergency Medicine Resource, 5th, Fuchs S, Yamamoto L, Jones and Bartlett Learning, Sudbury 2012.
  2. Berg MD, Schexnayder SM, Chameides L, et al. Part 13: pediatric basic life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010; 122:S862.
  3. Pediatric Advanced Life Support Provider Manual. Hazinski MF, Samson RA, Schexnayder SM. American Heart Association, Dallas, 2012.
  4. Todres ID. Pediatric airway control and ventilation. Annals of Emergency Medicine 1993; 22:440.

 

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