Evaluation of pediatric upper airway

C. Gysin ORL-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 Pediatric airway – anatomy

• 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% Clinical approach

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

acquired congenital

tumor foreign body infection trauma

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

narrowing of the airway  abnormal flow or turbulence  noisy breathing (stridor/stertor) 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-Scan . MRI 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: – rigid under 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 Choanal atresia

. 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 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 from the nasopharynx, same symptoms as congenital nasal masses, oft associated cleft 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%) Pediatric airway obstruction – pharynx

. craniofacial malformation: . Pierre-Robin sequence (retrognathia, glossoptosis, cleft palate) . Treacher-Collins . Crouzon . trisomy 21 . vallecular cyst . lingual thyroid/thyroglossal duct cyst Craniofacial malformations

Crouzon Treacher-Collins

complex malformations oft associated with cleft palate/choanal atresia ! multilevel upper airway obstruction oft tracheotomy Pediatric airway obstruction – larynx congenital • laryngomalacia • subglottic stenosis • bilateral vocal cord paralysis • saccular cyst, laryngocele • laryngeal web • laryngeal cleft acquired • lymphangioma • 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 1 Awake /alert, a history of aspiration, no symptoms "silent" foreign body? dislocation, poststenotic complications

Scenario 2 Awake, 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 3 Awake, acute obstruction, danger of asphyxia, effective cough Straight to bronchoscopy Transfer: prepared for intubation

M. Weiss et al, Notfall und Rettungsmed 2012,15:111-116 Priority: according to history and symptoms

Scenario 4 awake, airway obstruction, ineffective/absent/missing cough, danger of asphyxia support cough transfer for bronchoscopy

Scenario 5 unconscious, acute airway obstruction Mask ventilation, intubation Resuscitation Pediatric airway obstruction – trachea

. tracheomalacia . intrinsic, i.e. oesotracheal fistula . extrinsic compression . vascular anomalies . tumors . posterior laryngeal clefts . complete tracheal rings