Pediatric Airway Management Final

Report
Pediatric Airway Management:
An Update
HANY EL-ZAHABY, MD
Anesthesia, Ain Shams University
Five Cardinal Anatomical Features
of Infant’s Larynx
1- Higher Larynx
Acute 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 airway
Obligate nasal breathers
Difficult 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
The only complete ring
Narrowest part of infant’s larynx is the cricoid cartilage:
Tight fitting ETT may cause edema.
Uncuffed ETT preferred for patients < 8 years old
Respiratory Physiology
Obligate 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 Physiology
Respiratory 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 Physiology
Tracheal 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 Physiology
Dynamic Airway Obstruction
Normal inspiratory
stretch/collapse
(crying)
Dynamic collapse
at inlet
Bronchiolitis/asthma
Respiratory Physiology
Work 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 Physiology
Type 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 Anomalies
Tumors
Infection
Musculoskeletal Problems
Encephalocele
Bilateral Cleft Palate
Hallermann-Streiff S.
Achondroplasia
Pierre Robin S.
Down S.
Crouzon S.
Seckel S.
Treacher Collins S.
Goldenhar S.
Apert S.
Nager S.
Mucopolysaccaridosis
Type IH (Hurler)
Type 1 H/S (Hurler-Scheie)
Type II Hunter
Type III (Sanfilippo)
Tumors
Cystic hygroma
Hemangioma of tongue, pharynx
Teratoma
Infection
Retropharyngeal abscess
Epiglottitis
Laryngotracheobronchitis
(subglottic croup)
Ludwig’s angina
Adenotonsillitis, abscess, hypertrophy
( obstructive sleep apnea)
Scleroderma
Laryngeal 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 Airway
Head tilt- Chin lift - Jaw Thrust – Oropharyngeal Airway
Techniques to open the Airway
Nasopharyngeal Airway
Size
Hazards: 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
Age
Miller
Macintoch
Preterm
0
-
Neonate
0
-
Neonate-2 Yrs
1
-
2-6 Yrs
-
2
6-12 Yrs
2
2
>12 Yrs
3
3
Tracheal Tube Sizes
Insufflation Pressure ?
Muscle Relaxants?
Age
Size (mm ID)
Insertion length
(Alveolar ridge)
Preterm 1000g
Preterm 1000-2500g
2.5
3.0
6-9 cm
Neonate-6 Month
3.0-3.5
10 cm
6 Month – 1 Yr
3.5-4.0
11 cm
1-2 Yrs
4.0-5.0
12 cm
Beyond 2 Yrs
age (yrs)/4 + 4
age (yrs)/2 + 12
Micro-cuff ETT
More anatomical fit
Sealing at low pressures
More distal position
Greater 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
Silicone
Softer,
deeper mask
bowl, bite
block,
improves
stability
PVC
Silicone
LMA sizes
Mask size
Patient’s weight
Maximum cuff
volume (ml)
(Least effective
volume)
Largest TT (mm
ID)
1
1-5 kg
4
3.5
1.5
5-10 kg
7
4.0
2
10-20 kg
10
4.5
2.5
20-30 kg
14
5.0
3
> 30 kg
20
6.0, non-cuffed
Special Techniques for Intubation
Rigid 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 Stylet
Light 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 airways
Laryngosopic blades
TT
Stylets
LMA
Fiberoptic laryngoscope
PC cricothyrotomy kit
Jet ventilation eq.
TT exchangers
Exhaled CO2 detectors
Experienced assistance
IV access
Incomplete Airway Obstruction
Apply gentle positive pressure
No improvement
Improved
Eliminate noxious stimulus,
+ concentration of volatile anesthetic
Improved
IV thiopentone/propofol, stabilize &
resume anesthetic
No improvement
Stabilize + resume anesthetic
IV succinylcholine + atropine
Ventilate with 100% oxygen + ETT
Roy WL, Lerman J, Anaesthesia 1988:35, 93
51
No improvement
Complete Airway Obstruction
Jaw thrust, ventilate with 100% oxygen
Improvement
Eliminate noxious stimulus,
+ concentration of
volatile anestheticNo improvement +
IV access
Ventilation 100%
oxygen
Succinylcholine +
atropine +
intubate
Ventilate + intubate
52
No improvement +
no IV access
Intubate immediately without
relaxant
Call for help
spray cords with lidocaine,
intubate
Start CPR, cricothyrotomy
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

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