Evaluation of pediatric upper airway

C. GysinORL-Unit

University Children’s Hospital Zurich

SSORL-Ecole d’été – SGORL-Sommerschule 2019

Pediatric airway – anatomy

• large head• short neck• small nares• small mandible• pliable trachea and chest wall• immature alveolae• gastric dilatation, reflux• high metabolic rate• friable mucosa

• high larynx• cricoid cartilage = C4

• long epiglottis• lies against the soft palate

• long uvula• neonate obligate nasal breather

Pediatric airway – anatomy

prominent cuneiform cartilages

short aryepiglottic folds tendency to collapse during inspiration

epiglottis omega-shaped

glottic length 50% ligamentous – 50% cartilaginous (adults 80-20)

Pediatric airway – anatomy

• subglottis:– from conus elasticus to inferior part of

cricoid cartilage– only complete ring of the larynx and trachea– narrowest region of the pediatric airway

• subglottic diameter at birth:– cricoid cartilage: 5.5mm– full-term baby: 4.5-5.5mm– premature baby: 3.5mm

Pediatric airway – anatomy

↓ diameter 1mm = ↓ surface 50%⇒ resistance R = 8µL/πr4

Pediatric airway – anatomy

Newborn Child Adult

Normal

subglottic diameter (mm) 4 8 14

subglottic radius (mm) 2 4 7

subglottic surface (mm2) 12 6 12

1mm edema

subglottic diameter (mm) 2 6 12

subglottic radius (mm) 1 3 6

subglottic surface (mm2) 3 27 108

Diminution of subglottic surface 75% 44% 27%

Pediatric airway – anatomy

Clinical approach

1. age of onset of respiratory symptoms?2. level of obstruction?3. investigations? 4. what is the lesion?

congenital acquired

infection trauma

foreign body

Pediatric airway obstruction

• newborn = congenital• 1-3 years = acquired more likely• >3 years = acquired likely (congenital highly unlikely)

tumor

Diagnosis and age of onset of respiratory symptoms

since birth: bilateral vocal cord paralysis congenital subglottic stenosis bilateral choanal atresia

first 2 weeks of life: laryngomalacia 1-3 months: subglottic hemangioma > 6 months: pseudocroup foreign body epiglottitis

narrowing of the airway

abnormal flow or turbulence

noisy breathing(stridor/stertor)

Pediatric airway – clinic

Clinical evaluation – noisy breathing

• Stertor– nasopharynx, oropharynx– ‘low-pitch’

• Stridor– larynx, trachea (extra-tracheal)– inspiratory vs expiratory!!!– biphasic: subglottis

• Wheezing– trachea (intrathoracic), bronchi

Pediatric airway – evaluation

medical history clinical evaluation radiological examination endoscopic evaluation

Pediatric airway – medical history

Pediatric airway – clinical evaluation

noisy breathing: constant, intermitent dyspnoe, tachypnoe intercostal retraction, tracheal tugging, nasal flaring cyanosis feeding and breathing: aspiration, cough, cyanosis nose, mouth and oropharynx and the examination of larynx?

Pediatric airway - radiology

not routinely!

Rx-Thorax CT-ScanMRI

Pediatric airway – endoscopic evaluation

> 4 years: endoscopy without anesthesia possible, but not below glottis endoscopy under general anesthesia: spontaneous breathing with the flexibel scope to assess the fonction rigid endoscopy to evaluate the anatomy completely, most of the time in

apnea always examine the whole airways!!! There might be a second lesion!!!

Pediatric airway – endoscopic evaluation

good collaboration with the anesthetist always have an iv access before endoscopy always have a bronchoscope in the OR

!!!no coniotomy!!!

Pediatric airway – endoscopic evaluation

• nasopharyngolaryngoscopy– flexibel

spontaneous breathing (dynamic)• laryngotracheoscopy:

– rigidunder relaxation (anatomy)

• microlaryngoscopy• bronchoscopy

Positioning of the patient for the endoscopy (rigid)

Instruments rigid bronchoscopy

Size of the rigid bronchoscope

Size of bronchoscope Outer diameter (mm) Age

2.5 4.0 premature – newborn

3.0 5.0 newborn – 6 months

3.5 5.7 6-18 months

4.0 7.0 18-36 months

5.0 7.8 3-8 years

6.0 8.2 > 8 years

Telescopes 0°/30° 20 or 30 cm length

Pediatric airway obstruction – nose

choanal atresia/ choanal stenosis piriforme aperture stenosis cleft lip and palate craniofacial malformations Treacher-Collins, Crouzon

arrhinie (agenesia of the nose) proboscis lateralis congenital cysts midline deficiency Encephalocele, Meningoencephalocele

chordoma, hamartoma

Bilateral congenital nasal obstruction

acute respiratory distress ⇒ emergency intermittent cyanosis relieved by crying clinical evaluation: nose

external aspect of the nose 5Fr/6Fr suction catheter via nostrils laryngeal mirror test

stethoscope

oral cavity other malformations

feeding difficulties

definition: anatomical closure of the posterior choanae incidence: 1:5000 - 1:8000 births “2:1 rule”: 2w : 1m 2unilateral : 1bilateral 2rights : 1left

associated syndromes: CHARGE, Treacher-Collins, Apert-Crouzon, Pfeiffer… diagnosis: 5-6 Fr catheter via nostrils: obstruction 3-3.5 cm, nasal endoscopy, CT-scan treatment: transnasal endoscopic opening of choanae

Choanal atresia

Pyriform apertura stenosis

definition: bony overgrowth of the nasal process of the maxilla (anterior nasal stenosis) incidence: 1:50’000 births diagnosis: CT associated anomalies: megamaxillary incisor,

holoprosencephaly treatment: milder forms: conservative therapy, otherwise

surgery

Congenital nasal tumors

teratomas hamartomas rhabdomyosarcoma …

teratomas/hamartomas may arise fromthe nasopharynx, same symptoms as congenital nasal masses, oft associatedcleft palate

Bilateral congenital nasal obstruction – summary

diagnosis: endoscopy examination of the oral cavity radiological evaluation before any surgery! CT MRI

acute management depending on the etiology and severity of obstruction: special pacifier (dummy): McGovern nipple, with an opening oroendotracheal Intubation tracheotomy in complex syndromal malformations

Cleft lift and palate

1:800 births 85% isolated >200 syndromes associated with cleft lip and palate significant upper airway obstruction at birth mostly

with associated malformations /syndrome Pierre Robin sequence: retrognathia glossoptosis cleft palate + other malformations = syndrome (50%)

craniofacial malformation: Pierre-Robin sequence (retrognathia, glossoptosis, cleft

palate) Treacher-Collins Crouzon trisomy 21

vallecular cyst lingual thyroid/thyroglossal duct cyst

Pediatric airway obstruction – pharynx

Craniofacial malformations

Crouzon Treacher-Collins

complex malformationsoft associated with cleft palate/choanal atresia! multilevel upper airway obstructionoft tracheotomy

congenital• laryngomalacia• subglottic stenosis• bilateral vocal cord paralysis• saccular cyst, laryngocele• laryngeal web• laryngeal cleft• lymphangioma

Pediatric airway obstruction – larynx

acquired• subglottic stenosis• subglottic hemangioma• laryngeal papillomatosis• granuloma• angioedema• epiglottitis• foreign body• trauma

Laryngomalacia

incidence: most common cause of newborn stridor (35-75%) clinical signs: inspiratory stridor that worsens with feeding, agitation, crying,

and supine positioning natural history: symptoms worsen at 4-8 months, improve between 8 and

12 months, and usually resolve by 12-18 months of age classification: mild (40%): conservative management moderate (40%): complicated with regurgitation, coughing, and choking

episodes with feeding. severe: (20%) failure to thrive, feeding problems, aspiration, apnea, hypoxia,

recurrent cyanosis, cor-pulmonale, will require surgery

Laryngomalacia

etiology: theory of neuromuscular alteration in laryngeal tone and resultant prolapse of supra-arytenoid tissue and supraglottic collapse causing airway obstruction diagnosis clinical history endoscopy: supra-arytenoid tissue prolapse during inhalation, omega-shaped

epiglottis, retroflexed epiglottis, short aryepiglottic folds, poor visualization of the vocal folds, and edema of the posterior glottis

management: conservative proton pump inhibitors supraglottoplasty

Subglottic stenosis

congenital: more likely to be associated with a syndrome (Down!) acquired: < 1% of neonates with a history of prolonged intubation clinical signs: biphasic stridor, associated symptoms depending on the

severity of the symptoms grading-system nach Cotton-Myer: grade I: up to 50% stenosis grade II: 51% to 70% stenosis grade III: 71% to 99% stenosis grade IV: no lumen

Subglottic stenosis

management: grad I: conservative (recurrent croups!) more severe forms: endoscopic: laser, balloon dilatation, anterior split, posterior split external approach: laryngotracheoplasty, cricotracheal resection tracheotomy

"prevention": Down patients should be intubated with an endotracheal tube 1 full size smaller tube than the age-appropriate as a result of a smaller airway diameter and higher incidence of congenital subglottic stenosis

Subglottic hemangioma

hemangioma: most common congenital vascular, can be seen everywhere in the airway, predilection for subglottis 2 f : 1m beginn of symptoms between 4-6 weeks of age clinical signs: 50% of patients have also cutaneous hemangiomas biphasic stridor hoarse voice airway obstruction

! recurrent croups < 6 months of age! diagnosis: endoscopy management: beta-blocker (propranolol)

Epiglottitis

definition: acute inflammation and edema of the epiglottis and surrounding tissues leading to progressive airway and a potentially life-threatening condition peak incidence: 2-4 years old Haemophilus influenza type B (Hib), but since vaccination other strains observed

(group A beta-hemolytic streptococcus, Streptococcus pneumonia, Klebsiella sp, and Staphyloccocus aureus incidence: 1.3 cases per 100’000 since vaccination against Haemophilus

influenza type B (Hib) abrupt onset of symptoms: high fever, sore throat, irritability, drooling, muffled

voice, and progressive respiratory distress

Epiglottitis

clinical signs: children appear toxic respiratory symptoms contribute to a high level of anxiety patients prefer resting in the tripod position (leaning forward with jaw

protrusion) management: avoid procedures that increase the child’s anxiety until after their airway is

secured observation in ICU or direct laryngoscopy and intubation antibiotic treatment steroids

Foreign body

epidemiology: mostly < 4 years, peak incidence 1-2 years clinical presentation: be alert! 50% of cases occur without a choking event

having been witnessed clinical signs: vary based on the location of the foreign body and the degree of

obstruction may change over time as the foreign body might move within the

respiratory tract ! oesophageal foreign body and airway obstruction

thorax X-ray including posteroanterior (PA) and lateral views secondary signs of FBA such as overinflation, opacification, or atelectasis of

the distal lung

Priority: according to history and symptoms

Scenario 1Awake /alert, a history of aspiration, no symptoms

"silent" foreign body?dislocation, poststenotic complications

Scenario 2Awake, acute airway obstruction, coughing w/ or w/o dyspnea

Bronchoscopy asap, observation in ICU until then,Transfer: prepared for intubation

M. Weiss et al, Notfall und Rettungsmed 2012,15:111-116

Priority: according to history and symptoms

Scenario 3Awake, acute obstruction, danger of asphyxia, effective cough

Straight to bronchoscopyTransfer: prepared for intubation

M. Weiss et al, Notfall und Rettungsmed 2012,15:111-116

Priority: according to history and symptoms

Scenario 4awake, airway obstruction, ineffective/absent/missing cough, danger of asphyxia

support coughtransfer for bronchoscopy

Scenario 5unconscious, acute airway obstruction

Mask ventilation, intubationResuscitation

tracheomalacia intrinsic, i.e. oesotracheal fistula extrinsic compression vascular anomalies tumors

posterior laryngeal clefts complete tracheal rings

Pediatric airway obstruction – trachea