COCLIA:Neonatal Respiratory Distress

Carolyn NguyenApril 7, 2008

Terminology

• Stridor: abnormal or unwanted noise made by turbulent airflow in the airway excluding stertor

• Stertor: snoring type of noise made by nasopharyngeal and oropharyngeal obstruction

Sites of Obstruction

• Nasal

• Oro/hypopharyngeal

• Supraglottic

• Glottic

• Subglottic

• Tracheobronchial

Nasal Obstruction• Initially obligate nasal breathers so causes

severe respiratory distress• Generally no stridor • Snorting respiration with nasal flaring• Chest retractions common• Cyclical cyanosis: cyanotic episodes frequent

but interrupted with crying• Feeding difficulty because of need for mouth

breathing

Nasal Differential• External

– midline pits or dimples (dermoid) or nasal mass (encephalocele, meningocele, glioma, dermoid, intracranial vascular anomaly)

• Internal – pyriform aperture, turbinate hypertrophy, nasolacrimal duct

cysts, posterior choanae (should pass a 5-6 Fr catheter) and nasopharynx (adenoid, tumor)

• Craniofacial anomalies– Treacher Collins syndrome (narrowed nares, hypoplastic

alar cartilages)– Apert syndrome (midface hypoplasia)

Oro/hypopharynx Obstruction

• Coarse inspiratory stridor, worse with sleep, when supine, feeding or agitated

• Normal cry but may be muffled

• Sternal and intercostal retractions common

• Feeding difficulty because of anatomical obstruction

Oro/hypopharyngeal Differential

• Oral cavity– macroglossia, glossoptosis, micrognathia

• Pharynx– lateral pharyngeal wall collapse– vallecular mass (lingual thyroid, dermoid,

vallecular cyst)

• Pierre Robin sequence– micrognathia, glossoptosis, and cleft palate

Supraglottic Laryngeal Obstruction

• Muffled cry

• Snorting respirations while asleep

• Coarse inspiratory sounds at rest

• Suprasternal and intercostal retractions

• Feeding difficulty if severe obstruction

• Worse with supine position, feeding, and agitation

Supraglottic Differential

• Laryngomalacia

• Arytenoid fixation

Glottic Laryngeal Obstruction

• Hoarse cry or aphonic

• Initially inspiratory stridor becomes biphasic if obstruction increases

• Usually no feeding difficulty (no physical obstruction in pharynx) except hunger for air

Glottic Differential

• Laryngeal cyst

• Laryngeal web

• Laryngeal atresia

• Laryngeal cleft

• Vocal cord palsy

Subglottic Laryngeal Obstruction• Often normal cry

• Initially inspiratory stridor becomes expiratory as obstruction increases (then biphasic if severe)

• Xiphoid retractions

• Barking type cough

• Alar flaring

• Usually feeds normally

Subglottic Differential

• Stenosis

• Cysts

• Hemangiomas

Tracheobronchial Obstruction• Normal cry• Characteristic expiratory stridor• Wheezing component• Retractions uncommon• Nasal flaring• Brassy cough• Normal feeding except air hunger or extrinsic

compression

Tracheobronchial Differential

• Tracheal rings

• Tracheal stenosis or atresia

• Tracheal cysts

• Tracheal hemangioma

• Tracheobronchomalacia

• Tracheoesophageal fistula

• Vascular compression

Physics• Poiseuille’s law: fluid flow through a

tube varies with the fourth power of the radius

• Venturi principle: drop in fluid pressure that results when an incompressible fluid flows through a constricted section of pipe

• Bernoulli’s principle (conservation of energy): an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's gravitational potential energy

Choanal Atresia

• Occurs in 1 in 5,000-8,000 live births• 50% have associated congenital anomalies• 30% pure bony, 70% mixed bony-

membranous• Features: narrow nasal cavity, lateral bony

obstruction by the lateral pterygoid plate & medial obstruction due to vomer thickening (endochondral bone formation), membranous obstruction

Choanal Atresia

• Diagnosis: inability to pass small catheter through the nose into the nasopharynx, rigid or flexible endoscopy

• Imaging: CT• Nonsurgical management: McGovern

nipple, oropharyngeal airway• Surgical management: removing and

shortening posterior bony septum, removal of superior-lateral nasal wall & lateral pterygoid plate, stented 3-6 weeks

Laryngomalacia• Most common cause of neonatal stridor

• Develops within first 2 weeks of life

• Usually resolves by 2 years of age

• Inspiratory stridor results from collapse of the supraglottic larynx

Laryngomalacia• Anterior prolapse of arytenoid

mucosa: laser excision of redundant mucosa

• Short tethered aryepiglottic folds: laser or microscissor supraglottoplasty

• Posterior collapse of the epiglottis: epiglottopexy

Tracheal Vascular Anomalies

• Innominate artery compression

• Double aortic arch

• Right aortic arch

• Pulmonary artery sling

• Pulmonary artery dilation

Innominate Artery Compression

• Most common vascular compression

• Artery arises further to left than usual

• Causes anterior tracheal wall compression particularly during expiration and cough

• Treatment: aortopexy

Double Aortic Arch• “Complete vascular ring”• Second most common• Derived from persistence of the paired

aortic arches• Encircles the trachea and esophagus

and joins to form the descending aorta• Imaging shows posterior esophageal

compression• Treatment: divide the vascular ring

Neonatal “Stridor” Consult• History

– Time of onset, progression– Identify initiating factors– Effects of positioning, feeding, or crying– History of prematurity, difficult labor/delivery, intubation

at birth, cardiac surgery

• Exam– Document quality of stridor and timing with respiration– Characterize cry and presence of cough & dysphagia– Hoarseness – Prolonged exhalation

Congenital Bilateral VC Palsy• Second most common cause of neonatal

stridor• 10% of all congenital laryngeal anomalies• Typically presents within first month of life• Symptoms: stridor, cyanosis, apnea, feeding

difficulty• Slight M>F dominance, bilateral>unilateral• Causes: neurologic disease,

meningomyelocele, trauma, idiopathic

Congenital Bilateral VC Palsy

• Prognosis: spontaneous recovery is unpredictable – Usually within 6 and 36 months– Less likely with associated neurologic problem– Less common when bilateral

• Treatment: vocal cord lateralization, arytenoidopexy, posterior cricoid split

Subglottic Hemangioma• Caucasian

• 2:1 female:male

• 50% affects the head and neck region with subglottis being the most common subsite

• Can be multiple

• Peaks at age 6 weeks, before 6 months

• Most common symptom: initially intermittent stridor, progresses to become constant

Subglottic Hemangioma• Diagnosis: direct laryngoscopy• Smooth, soft, compressible sessile mass

from lateral wall of subglottis• Can be biopsied without hemorrhage• Natural history: rapid proliferation to 1yr

then resolution of airway symptoms 2-3 years (growth of larynx)

• Treatment: laser excision, systemic steroids, interferon alfa-2a

Endotracheal Tubes & Complications

• ID (mm) = [age in years + 16] / 4

• Prevention! Correct technique and size

• Complications: lacerations, cricoarytenoid dislocation, nerve injury (lingual, hypoglossal, superior laryngeal, RLN), vocal cord injury

• Risk of subglottic stenosis from prolonged intubation >7-10 days outweighs the risk of tracheotomy

Cricoid Split• Purpose: to decompress the complete cricoid

ring and temporarily expand the lumen without stenting

• One week period of intubation is required

• Indications: failed extubation from subglottic edema or soft immature stenosis

• Contraindications: less than 1.5 kg, oxygen requirement >35% from BPD