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Pediatric Airway Management: An Update. HANY EL-ZAHABY, MD Anesthesia, Ain Shams University. Five Cardinal Anatomical Features of Infant’s Larynx. 1- Higher Larynx - PowerPoint PPT Presentation
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Pediatric Airway Management:An Update
HANY EL-ZAHABY, MD
Anesthesia, Ain Shams University
Five Cardinal Anatomical Featuresof Infant’s Larynx
1- Higher LarynxAcute angulation between plane of tongue & plane of glottis makes exposure difficult ►straight blade ►exaggerated by mandibular hypoplasia (Pierre Robin syndrome).
2- Relatively Larger Tongue:Obstructs airwayObligate nasal breathersDifficult to manipulate & stabilize with laryngoscopic blades
3- Anteriorly Angulated Vocal Cords:
The anterior attachment of vocal cords are lower than posterior attachment ► difficulty in nasal intubations where “blindly” placed ETT lodges in the anterior commissure rather than in the trachea.
4- Differently Shaped Epiglottis
Infant epiglottis ohmega (Ώ) shaped and angled away from axis of trachea
More difficult to lift an infant’s epiglottis with laryngoscopic blade
5 -Funnel shaped larynx
Narrowest part of infant’s larynx is the cricoid cartilage :Tight fitting ETT may cause edema.Uncuffed ETT preferred for patients < 8 years old
The only complete ring
Respiratory PhysiologyObligate nasal breathers
Immaturity of coordination between respiratory efforts and oropharyngeal motor/sensory input.
During quiet respiration, the tongue rests against the roof of the mouth.
Respiratory PhysiologyRespiratory Parameters
High metabolic rate (5-8 ml/kg/min)
Tidal volume (6-7 ml/kg/min)
High respiratory rate (40-60 breaths/min)
High alveolar ventilation (130 ml/kg/min)
Lung compliance is less while chest wall compliance is more than those in adults {reduced FRC and atelectasis} ►PEEP.
Respiratory PhysiologyTracheal and Bronchial Function
Infant's larynx, trachea, and bronchi are highly compliant and hence more subject to distention and compression forces
The intrathoracic trachea is subject to stresses that are different from those in the extrathoracic portion
Respiratory PhysiologyDynamic Airway Obstruction
Normal inspiratorystretch/collapse
(crying)
Dynamic collapseat inlet
Bronchiolitis/asthma
Respiratory PhysiologyWork of Breathing
• The work of breathing is needed to overcome the chest wall compliance and the resistance of the airways.
• The WOB per kilogram is similar to adults. • The nasal passages account for 25% of the total
resistance to airflow in a neonate, compared with 60% in an adult. In infants, most resistance to airflow occurs in the bronchial and small airways ► respiratory failure with bronchiolitis.
• Long, small ETT, obstructed ETT, narrowed airway ► increased WOB ► increased oxygen consumption ► increases oxygen demand.
Change in work of breathing after placement of an appropriate endotracheal tube in extremely low birth weight infants (<1000 g), premature infants (1500 g), full-term infants, children, and adults
Respiratory Physiology Effect of Edema on WOB
Respiratory PhysiologyType I Muscle Fibers
Unable to sustain increased WOB for long periods
Evaluation of the Upper Airway (History)
URTI Snoring (adenoidal hypertrophy, obstructive sleep
apnea) Croupy cough (subglottic stenosis, TEF repair,
F.B.aspiration) Inspiratory stridor (subglottic stenosis or web,
laryngomalacia, macroglossia, extrathoracic F.B. or extrathoracic tracheal compression)
Hoarse voice (laryngitis, vocal cord palsy, papillomatosis, granuloma)
Asthma Repeated pneumonias Previous anesthetic problem
Evaluation of the Upper Airway (Physical Examination)
Facial expression Nasal flaring Mouth breathing Color of mucous membranes Retractions (suprasternal, intercostal, subcostal) Respiratory rate Voice change Mouth opening Size of mouth Size of tongue and its relationship to other pharyngeal
structures (Mallampati)?
Loose or missing teeth. Size and configuration of palate. Size and configuration of mandible (side view). Location of larynx in relation to the mandible. Presence of inspiratory stridor :epiglottitis, croup,
extrathoracic foreign body. Both inspiratory and expiratory stridor: aspirated foreign
body, vascular ring, or large esophageal foreign body. Prolonged expiration: lower airway disease? Baseline oxygen saturation in room air.
Bilateral microtia (ear deformity easily notable) is associated with mandibular hypoplasia & difficulty in visualizing the laryngeal inlet (42%) & with unilateral microtia (2.5%).
Are there congenital anomalies that may fit a recognizable syndrome? The finding of one anomaly mandates a search for others.
Evaluation of the Upper Airway (Diagnostic Testing)
X-ray, MRI and CT.
Radiologic airway examination in a child with a compromised airway must be undertaken only when
there is no immediate threat to the child's safety and only in the presence of skilled and appropriately equipped
personnel able to manage the airway . Endoscopic evaluation (flexible fiberoptic endoscopy) Arterial blood gas analysis (chronic airway obstruction
with respiratory acidosis)
Causes of Difficult Airway
Congenital AnomaliesTumorsInfectionMusculoskeletal Problems
Encephalocele Pierre Robin S.
Down S.Bilateral Cleft Palate Achondroplasia
Hallermann-Streiff S.
Crouzon S. Seckel S. Treacher Collins S.
Apert S. Nager S.
Goldenhar S.
Mucopolysaccaridosis
Type IH (Hurler)
Type III (Sanfilippo)
Type 1 H/S (Hurler-Scheie)
Type II Hunter
Tumors
Cystic hygroma Hemangioma of tongue, pharynx
Teratoma
Infection
Retropharyngeal abscess Epiglottitis
Laryngotracheobronchitis )subglottic croup( Ludwig’s angina
Adenotonsillitis, abscess, hypertrophy ( obstructive sleep apnea)SclerodermaLaryngeal web
Musculoskeletal Problems
Ankylosis of jaw, cervical spine
Unstable or dislocated cervical vertebrae
Wired jaw
Cervical cord tumor
Halo traction apparatus
Facial trauma, fractures, laceration, burns
Techniques to Open the AirwayHead tilt- Chin lift - Jaw Thrust – Oropharyngeal Airway
Techniques to open the AirwayNasopharyngeal AirwayTechniques to open the AirwayNasopharyngeal Airway
SizeSize
Hazards: long, bleeding 30%, intracranial placementHazards: long, bleeding 30%, intracranial placement
Aligning of the Upper Airway Axes ( More than 6 Years Old)
Three-axes theory?
Ventilation Techniques Multi-handed Mask Ventilation
Tracheal Intubation Laryngoscopic Blade Sizes
AgeMillerMacintoch
Preterm0-
Neonate0-
Neonate-2 Yrs1-
2-6 Yrs-2
6-12 Yrs22
<12 Yrs33
Tracheal Tube Sizes Insufflation Pressure ?Muscle Relaxants?
AgeSize (mm ID)Insertion length
)Alveolar ridge(
Preterm 1000g
Preterm 1000-2500g
2.5
3.0
6-9 cm
Neonate-6 Month3.0-3.510 cm
6 Month – 1 Yr3.5-4.011 cm
1-2 Yrs4.0-5.012 cm
Beyond 2 Yrsage (yrs)/4 + 4 age (yrs)/2 + 12
Micro-cuff ETT
More anatomical fit Sealing at low pressuresMore distal positionGreater permeability for nitrous oxide
For neonates ≤3 kg and infants ≤1 year, ID 3.0-mm
For children 1 to 2 years of age, ID 3.5-mm
For children ≥2 years, ID (mm) = age/4 + 3.5
Post-intubation croup was 0.4% (2/500 children)
LMA: Reusable Classic, Disposable Unique, ProSeal
SiliconePVCSiliconeSofter, deeper mask bowl, bite block, improves stability
LMA sizes
Mask sizePatient’s weightMaximum cuff volume (ml)
)Least effective volume(
Largest TT (mm ID)
11-5 kg43.5
1.55-10 kg74.0
210-20 kg104.5
2.520-30 kg145.0
3 <30 kg206.0 ,non-cuffed
Special Techniques for IntubationRigid Laryngoscopy The retromolar, paraglossal, or lateral approach to rigid laryngoscopy utilizing a straight blade.
Optimal External Laryngeal Manipulation (OELM)OELM is particularly helpful for infants & children with immobile or
shortened necks.
Either by an assistant or the laryngoscopist.
Intubation Guides
Lighted StyletLight Wand
Glidescope Video Laryngoscope
Intubation through LMA (Blind)
Fibreoptic Intubation through LMA
Fibreoptic Assisted Intubation
Percutaneous Cricothyrotomy
Percutaneous needle cricothyrotomy provides only a mean for oxygen insufflation and does not reliably provide adequate ventilation.
If glottic or subglottic pathology is not suspected, LMA placement to establish ventilation may be appropriately attempted first.
Retrograde Intubation
• Awake approach? • Sedation?• General anesthesia (inhalation/IV)?
“Assisted spontaneous ventilation during inhaled anesthesia is the preferred technique when
abnormal airway anatomy is present”.
Rules
“To avoid trouble one must be prepared for trouble”
“Have an IV access & experienced assistant”
“Do what you masters”
“Have definitive plan A, but have plan B & C”
Rules
“Use your common sense”
“ Do not continue to do the same thing and expect different results’’
“Easier comes first”
“Each difficult intubation is a different”
Difficult Airway Cart
Oropharyngeal/nasopharyngeal airwaysLaryngosopic bladesTTStyletsLMAFiberoptic laryngoscopePC cricothyrotomy kitJet ventilation eq.TT exchangersExhaled CO2 detectorsExperienced assistanceIV access
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Incomplete Airway Obstruction
Apply gentle positive pressure
Eliminate noxious stimulus ,+ concentration of volatile anesthetic
IV thiopentone/propofol, stabilize& resume anesthetic
Stabilize + resume anesthetic IV succinylcholine + atropineVentilate with 100% oxygen + ETT
No improvementImproved
Improved No improvementNo improvement
Roy WL, Lerman J, Anaesthesia 1988:35, 93
Complete Airway Obstruction
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Jaw thrust, ventilate with 100% oxygen
Intubate immediately without relaxant
Eliminate noxious stimulus , + concentration of
volatile anesthetic
Call for help spray cords with lidocaine,
intubate
Start CPR, cricothyrotomy
Succinylcholine + atropine +
intubate
Ventilation 100% oxygen
Ventilate + intubate
No improvement+ no IV access
Improvement
No improvement+ IV access
Extubation of Difficult Intubation Patient
Facial Grimacing
Documentation
1.Whether or not mask ventilation was attempted and, if there was a special maneuver needed?
2.Any difficulty with intubation?
3.What Special technique that was required for successful intubation?
4.What special technique that was not helpful for intubation?
5. What grade of laryngoscopic view of laryngeal structures during rigid laryngoscopy?
Conclusion
Successful management of the difficult airway depends on prediction, preparation, maintenance of good oxygenation and ventilation, and the use of familiar tools by experienced physician.
THANK YOU