Acute Stridor in Children

Dr James PeerlessJanuary 2015

Objectives

• Anatomy and Physiology• Assessment• Common Causes– Viral croup– Epiglottitis– Bacterial tracheitis– Retropharyngeal or tonsillar abscess– Foreign body

• Management

RCoA SyllabusAnnex B• PA_BK_08 Describes the management of acute airway obstruction including

croup, epiglottitis and inhaled foreign body• AN_BK_01 Mouth, nose, pharynx, larynx, trachea, main bronchi, segmental

bronchi, structure of the bronchial tree; age-related changes from the neonate to the adult

Annex C• PA_IK_15 Explains the principles of stabilisation and safe transport of critically ill

children and babies • EN_IK_17 Recalls/explains the principles underlying the use of helium • EN_IK_11 Explains the principles of the recognition and appropriate

management of acute ENT emergencies, including bleeding tonsils, epiglottis, croup, and inhaled foreign body

Anatomy & Physiology of the Normal Airway in Children

Stridor

“Stridor is the harsh, vibratory sound produced when the airway becomes partially obstructed.”

Stridor Level of ObstructionInspiratory Above cords/extrathoracic;

croup, epiglottitis

Expiratory Below cords/intrathoracic; FB

Biphasic At or below cords; FB, bact. tracheitis

The Infant Airway

• Upper and lower airways are small• Prone to occlusion– Secretions– Oedema

• H-P equation– Laminar flow rate most affected by changes to

vessel callibre– Reduced callibre reduced flow, increased WoB

The Infant Airway

• Upper and lower airways are small• Prone to occlusion– Secretions– Oedema

• H-P equation– Laminar flow rate most affected by changes to

vessel callibre– Reduced callibre reduced flow, increased WoB

The Infant Airway

• Thoracic cavity underdeveloped and compliant– Cartilaginous ribs– Perpendicular to vertebrae– Immature intercostal/accessory muscles– Diaphragm-dependent• Higher ratio of fatigable muscle fibres

• Increased WoB recession

The Infant Airway

• High metabolic rate• Increased O2 demand• Smaller FRC

• All these factors predisposes the infant to rapid deterioration

Assessment

• Disturb as little as possible– Crying and agitation increased effort– Don’t examine the airway– Don’t cannulate

• Allow to adopt comfortable position• Assess degree of compromise– Inspection– Gentle examination– SpO2

– Lab. tests and radiology

Increased Work of BreathingVentilatory frequency Infant >50

Child >30

Effort Infant: head-bobbing, nasal flaringChild: see-saw chest and abdomen, recession (subcostal, intercostal, sternal, tracheal tug), nasal flaring

Posture Infant: Arching backwardsChild: Tripod

Noise Grunting (to generate auto-PEEP)WheezingStridor

Ineffective breathing Hypoxia & hypercarbia tachcardia, sweating, agitation, confusion, pallor

Impending respiratory arrest Reduced GCSApnoeic epsiodesSilent chestBradycardia

Assessment

• Mobilise help early– Senior anaesthetist– ENT– Theatre staff

Viral Croup

Viral Croup

• Laryngotracheobronchitis• 80% of stridor cases (2% admitted)• Parainfluenza virus– Also: ’Flu A+B, RSV, rhinovirus

• 6m – 3y (peak 2y)

Viral Croup

• Symptoms– 2-3 of URTI symptoms– Barking cough– Low-grade pyrexia– Inspiratory stridor

• Assessed by Croup score

Croup ScoreScore 0 1 2

Breath sounds Normal Harsh, wheeze Delayed

Stridor None Inspiratory Biphasic

Cough None Hoarse cry Bark

Recession None Flaring, suprasternal

Flaring, suprasternal and intercostal

Cyanosis None In air In O2 40%

Croup Score

• Mild– 0-3

• Moderate– 4-6 (requires HDU)

• Severe– 7+ (requires intubation)

Anaesthetic Management Plan

• Remember ABC…• Assessment and resuscitation• Help and mobilisation of services

• Serial assessments• Treatment– Humidified gases– Steroids– Adr. Nebs. (0.5mL.kg-1 1:1000, max. 5mL)– Heliox

Anaesthetic Management Plan• AIRWAY

– Assess obstruction; is intubation warranted immediately?• BREATHING

– Assess degree of respiratory distress– O2, SpO2

• CIRCULATION

• Avoid upsetting child• Transfer to theatres• Inhalational induction with child sat upright• O2 and sevoflurane• Low-level CPAP can aid obstruction

Anaesthetic Management Plan

• Slow induction time (alveolar ventilation is restricted)• Ensure adequate depth of anaesthesia prior to IV access

and airway manipulation• ENT team on standby for emergency tracheostomy• Swap ETT for nasal tube if possible (PICU transfer)• Once stable:

– CXR– NG– Sedate and IPPV– IV fluids– Blood and laryngeal cultures, and antibiotics.

Epiglottitis

Epiglottitis

• Life-threatening emergency• H. influenzae (type B) – now rare due to Hib

vaccine (1992)• 2-6y (peak at 3y)• Fulminant onset and toxic appearance of child• Rapid and high fever, dysphagia and stridor,

drooling.• Child will often lean forward with jaw and

tongue hanging down.

Epiglottitis

• Inhalational induction, as per croup• ENT surgeon on standby• Sitting position• Follow the bubbles• 1.0mm ID smaller ETT

Epiglottitis

Bacterial Tracheitis

Tracheitis

• S. aureus, H. influenzae, streptococci, Neisseria• Mild 2-3d URTI, followed by rapid deterioration

– high fever and respiratory distress• Copious tracheal secretions• Hoarse voice, and stridor• Obstruction can occur secondary to oedema or

due to debris

Tracheitis

• Similar assessment and management to epiglottitis.

• Bronchoscopy often required to remove debris from airway.

Abscess

Abscesses

• Retropharyngeal– Form in space between post. pharyngeal wall and pre-

vertebral fascia• Tonsillar• Organisms

– Staphylococci and streptococci.• Unwell child; limited neck movements, drooling, trismus• Oedema and swelling upper airway obstruction• Care must be taken to avoid rupture and subsequent

pus aspiration during intubation.

Foreign Body

Foreign Body

• Commonest between ages 1-2y• Often of sudden onset with choking, but

unwitnessed events can mimic asthma• Partial obstruction of lower airways can cause

ball and valve effect pneumothorax and surgical emphysema.

Foreign Body

• Timing weighing up urgency against fasting.• Rigid bronchoscopy• Dexamethasone and Adr. nebs will help

reduce post-op. swelling

MCQs

1. Which of the following have been shown to be effective in the treatment of moderate to severe viral croup in children?

a) Nebulised adrenaline 1:1000.b) Oral dexamethasone.c) Nebulised dexamethasone.d) Nebulised budesonide. e) Inhaled Heliox.

MCQs

2. The presentation of bacterial tracheitis differs from epiglottis in that:

a) Stridor is inspiratory. b) There is dysphagia and drooling. c) The patient can lie flat. d) There is an antecedent history of an upper respiratory

tract infection. e) Paroxysms of coughing produce copious tenacious

secretions.

MCQs

3. In the management of a child with epiglottitis:

a) A lateral X-ray of the neck is needed to confirm the diagnosis.

b) Direct inspection of the epiglottitis using a tongue depressor will show a swollen, red epiglottis.

c) The child should be anaesthetised with a rapid sequence induction.

d) Nebulised adrenaline will help ease respiratory distress. e) Peak incidence is at 3 years of age.

MCQs

4. When securing the airway of a child with upper airway obstruction:

a) Inhalational induction of anaesthesia is rapid.b) Anaesthesia should be induced with a volatile agent

in an oxygen-nitrous oxide mixture.c) Sevoflurane may be used safely.d) It is best to exclude parents to avoid distress.e) It essential to have intravenous access before

induction.

SAQs

• You are called to assess a 2-year-old girl in the ED whose mother describes a 4-day history of malaise, low-grade pyrexia and worsening cough. She has now developed stidor and is becoming increasingly agitated.

(a) List the differential diagnoses of acute stridor in this child (20%)

(b) What would be the indications for airway intervention in this child? (10%)

(c) Following diagnosis, describe your management plan for this child. (70%)

Reference

• Maloney E, Meakin G. Acute Stridor in Children, CEACCP. 2007 7(6) 183-6

• Maloney E, Meakin G. Acute Stridor in Children - MCQs, CEACCP. 2007 7(6) 215

• Shorthouse J, Barker G, Waldmann. SAQs for the Final FRCA, 2011 Oxford University Press, Oxford.