Chapter 47 - Acute Pediatric Airway Flashcards by Ben Walters

What causes stridor? (physiologically)

turbulent airflow

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How does pt having a syndrome affect your assessment of their airway?

Syndromic patients w/ mandibular hypoplasia more likely to have multilevel collapse/obstruction

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What condition do you think of when you see respiratory distress with inspiratory or biphasic stridor in setting of strong cry

bilateral TVC paralysis

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How much smaller is infant larynx compared to adult? Average diameter of subglottis in infant

1/3

3.5mm subglottis, adult is 10-14mm

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Cervical level where larynx is located in infant vs adult

Infant: C2-3
Allows supraglottic structures to interdigitate with soft palate to optimize airway for suck-swallow-breathe
Adult: C7

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How does chest wall compliance affect neonatal respiratory distress

Greater compliance –> easier collapse –> quicker O2 desats, higher O2 consumption at baseline, smaller lung capacity

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How poisuelle’s law affects neonatal respiratory distress

resistance inversely proportional to radius^4

1mm obstruction (edema) in infant subglottis (which is 1/2 of the radius) leads to 16-fold increase in resistance, 75% decrease in airway cross-section

1mm obstruction in adult subglottis (r = 6) would decrease cross section area by 30% and increase resistance by 2x

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How to tell if inspiratory stridor is at level of VC or above

at VC: high pitched

above VC: lower pitched (may be stertor)

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Expiratory stridor

distal trachea/bronchi
more prolonged, sonorous sound
prolongs expiratory phase

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Biphasic stridor

fixed lesion, usually subglottis

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Signs of impending respiratory failure

biphasic stridor or quiet breathing after prolonged stridor, suprasternal/subcostal retractions, accessory mm use, nasal flaring, diaphoresis, AMS, neck hyperextension/tripod (lean forward/chin up/mouth open/brace hands), tachypnea, tachycardia, pallor and cyanosis

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What does O2 desaturation tell you about severity of respiratory distress

ominous sign
because tachypnea and tachycardia can compensate and keep O2 up, the O2 going down indicates impending decompensation frequently

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Causes of neonatal airway obstruction at birth: Nose

rhinitis, piriform aperture stenosis, NLD cyst, nasal mass, choanal atresia, encephalocele, midface hypoplasia (Downs, Crouzon)

Nasal obstruction leads to respiratory distress relieved by crying

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Causes of neonatal airway obstruction at birth: OC/OP

Micrognathia (Pierre Robin, Treacher-Collins), macroglossia (Downs), lingual thyroid, mass/cyst

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Causes of neonatal airway obstruction at birth: Larynx

laryngomalacia, VC paralysis, subglottic stenosis, web, atresia, cyst/mass

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Causes of neonatal airway obstruction at birth: trachea

tracheobronchomalacia, stenosis/atresia, extrinsic compression (vascular ring, double aortic arch, pulmonary artery sling), complete tracheal rings

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Until what age are neonates obligate nasal breathers?

4-6 mo

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Choanal atresia: definition, embryology

Posterior nasal cavity doesn’t communicate with NP

Failure of nasobuccal membrane to rupture

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Choanal atresia: Unilateral vs Bilateral

2/3 unilat, usually present later with rhinorrhea, chronic congestion

1/3 bilateral, present neonatal period with cyanosis during feeding relieved by crying, 50-75% have associated congenital anomaly

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Diagnosis of choanal atresia

Failure to pass catheter through nose

confirm with endoscopy, CT

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CHARGE

Coloboma
Heart
Atresia choanae
Retardation
Genitourinary disorder
Ear anomaly/hearing loss

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Robin sequence

Glossoptosis and retrognathia –> BOT obstruction

Micrognathia and glossoptosis –> prevent fusion of palatal shelves at midline –> U-shaped cleft palate

Syndromes with Robin sequence

Treacher Collins, Stickler, velocardiofacial

How to Tx Robin sequence

Evaluate with laryngobronchoscopy/sleep endoscopy/PSG
O2, prone position, nasopharyngeal trumpet, CPAP

If FTT, OSA, respiratory failure –> escalate

Surgery: tongue-lip adhesion, mandibular distraction, tracheostomy

Laryngomalacia: what it is, anatomic causes

collapse of supraglottic larynx --> inspiratory stridor | may result from aryepiglottic fold shortening, redundant supraglottic tissue, hypotonia

Cause of bilateral VC paralysis

Idiopathic 46% | Arnold Chiari, CP, hydrocephalus, spina bifida, birth trauma, hypoxia

Workup of bilateral VC paralysis

MRI genetics laryngoscopy and palpate cricoarytenoid joint (delineate VC paralysis from joint fixation)

Treatment and prognosis of bilateral VC paralysis

tracheotomy | recovery in time usually with idiopathic cases

Epiglottitis: age, onset, prodrome, temp, sx, pathogens, xr

``` 2-7 yo Rapid onset No prodrome or mild URI High fever Muffled voice, speech limited (pain) Late inspiratory stridor, none at first No cough Odynophagia/drool Toxic appearing H Flu B, GABHS (S Pyogenes) Thumb print sign lateral XR (thick/round epiglottis, lose normal vallecula air space ```

Laryngitis

Any age, slow onset, URI prodrome, no fever hoarse, no stridor, variable cough, no odynophagia/drool Non-toxic virus

Croup

``` 6mo-3yr Slow onset, URI progrome No fever or low grade Hoarse, inspiratory stridor (progress to biphasic if severe), barky cough, no odynophagia/drool Non-toxic PIV RSV Steeple sign (narrow subglottis) ```

Tracheitis (bacterial)

6mo-8yr Rapid onset, URI progrome High fever Hoarse, biphasic stridor, barky cough, no odynophagia/drool Toxic appearance S Aureus, M Catarrhalis XR- normal epiglottis, tracheal lumen obscured by sloughed mucosa...called "pseudomembranes"

How to differentiate epiglottitis from tracheitis: age, sx

``` Epiglottitis younger (6mo-3yr), tracheitis 6mo-8yr Epi has no prodrome, no hoarseness, no stridor, no cough Trach has prodrome, hoarseness, biphasic stridor, barky cough Both are rapid onset, high fever, toxic-appearing ```

Why is the name epiglottitis not really correct?

Typically involves entire supraglottis

When did HIB vaccine get implemented?

1988

Management of supraglottitis

If stridor/respiratory distress --> may have impending need for surgery Close airway surveillance, ABx IV, 10-14d course If operation necessary: DL w/ ET tube or trach Usually extubate within 48 hr when edema improves and air leak present around ETT

Management of croup

Supportive care 85-99% outpatient Steroids if significant sx (1 dose dex), race epi If inpatient --> repeated dex/race epi until resolve 1-5% require intubation

When to DL patients with croup

very young | severe or recurrent to r/o underlying pathology (subglottic stenosis, hemangioma, subglottic cyst)

Tx bacterial tracheitis

``` not as severe as epiglottitis usually rigid bronch, debridement 60-80% require intubation extubation after fever resolves, secretions diminish, air leak present IV ABx, 10-14d course ```

Presentation of PTA vs RPA/PPA

PTA: hot potato voice, stertor, milder airway sx (obst at OP) RPA/PPA: fever, sore throat, dysphagia, decreased neck mobility, more likely to have airway obstruction (es with RPA)

Why are 1-3 yo more prone to FB aspiration?

``` explore with mouths poor swallowing coordination lack posterior dentition necessary for chewing properly lack appreciation of what is edible likely to be playing when eating ```

Items most likely to be aspirated

incompletely chewed food - nuts, seeds, beans | toys

Most common esophageal FB

coins

Sx of FB aspiration: Larynx

cough, hoarse, obstruction --> edema

Sx of FB aspiration: trachea

stridor, wheeze, dyspnea, coughing | No hoarseness!

Sx of FB aspiration: bronchi

most common location 80-90% | cough, wheeze, decreased unilateral breath sounds

Sx of FB: esophagus

dysphagia, odynophagia, drool, vomit more common than airway FB cricopharyngeus, where esophagus crosses aortic arch

x-ray to get for FB

inspiratory and expiratory XR FB may allow air to enter but not escape --> trapping/hyperinflation exaggerated by expiratory phase atelectasis, pneumonia

How many FB pts have NL XRs?

25-50%

How to manage FB aspiration

DL, bronch to remove | steroids if severe obst, mucosal damage, or significant edema

How to manage coin ingestion

Allow pass if in distal esphagus or if older child if no signs of airway compromise

When you need acute intervention for FB

acute or potential airway obstruction esophageal injury disc/button battery

Image findings with button battery, and complications

double halo or double ring sign on AP, or step off on lateral may be mistaken for coin caustic injury within 1 hr perf within 6 hr If >20mm, 12% of young kids swallowing will have major complication (perf, TEF, major vessel injury, stricture, VC paralysis, C-spine injury)