Difficult airway- congenital abnormalites Flashcards
What level is the larynx in the infant?
C3-C4
Where is the larynx in the adult?
C5-C6
infants are obligate nasal breathers until around when?
5 months
What are the features of the pediatric airway?
-large epiglottis
-short trachea and neck
-prominent adenoids and tonsils
-rigid cricoid ring is functionally the narrowest portion of the larynx
-tongue is larger in proportion to mouth
-pharynx is smaller
-epiglottis is larger and floppier
-larynx is more anterior and superior
-trachea is narrow and less rigid
What physiologic lung values are increased in the neonate/infant/ped?
Increased O2 consumption (6 vs 3)
increased alveolar ventilation (130 vs 60)
Increased Co2 production (6 vs 3)
What physiologic lung values are decreased?
Vital capacity (35 vs 70)
FRC (25 vs 40)
PaO2 (65-85 vs 85-95)
What are peds prone to when apneic?
atelectasis and hypoxemia
During apnea, how does paco2 rise?
6 mmHg during the first minutes, the 3-4mmHg each min after
What percentage of type 1 slow twitch muscle fibers in the diaphragm does the ped have?
25%
-promotes chest wall collapse during inspiration and low residual lung volumes during expiration
What respiratory drives are not well developed in the ped?
hypercapnic and hypoxic
Which conditions have a large tongue?
-Beckwith syndrome
-Trisomy 21
“Big tongue”
Which conditions have a small mandible (micrognathia/mandibular hypoplasia)
-Pierre Robin
-Goldenhar
-Treacher Collins
-Cri du chat
“Please Get That Chin”
Which conditions have spine anomalies?
Klippel-Feil
Trisomy 21
Goldenhar
“Kids Try Gold”
The larger the tongue the more likely the ______
obstruction
What does an anterior larynx mean?
Larynx sits high under the base of the tongue: no space to displace the tongue; the larynx will remain anterior
What does the TMJ do?
opens the upper airway and translocates the lower jaw forward.
What are some syndromes with soft tissue abnormalities?
Freeman-Sheldon syndrome
Beckwith- Wiedeman Syndrome
Down syndrome
Sturge Weber
Dwarfism
-limits movement of the airways
-affects mouth opening
What are some syndromes with craniosynostosis?
Apert syndrome
Crouzon syndrome
Pfeiffer syndrome
What are the features of Crouzon disease?
-Hypertelorism (increased distance btwn eyes)
-craniostenosis
-shallow orbits
-proptosis (abnormal protrusion of eyes)
-midface hypoplasia
What are the features of Apert disease
-Hypertelorism (increased distance btwn eyes)
-craniostenosis
-shallow orbits
-proptosis (abnormal protrusion of eyes)
-midface hypoplasia
-Syndactyly of extremities (webbing)
-cardiac and renal problems: dydronephrosis/polycystic kidney disease
-possible esophageal atresia
What are the anesthesia implications for craniosynosis?
OSA- may require trach
-need smaller ETT
-Difficult mask
-don’t close mouth or will obstruct
-topical lidocaine before oral airway
-ETT not difficult unless neck mobility issues
With what cleft abnormality will you see obstruction?
Cleft palate
What are the features of bilateral clefts?
Premaxilla angled anteriorly (makes blade insertion difficult)
If younger than 6 months- intubation won’t be as difficult
What are other associated diseases with cleft lip and palate?
-associated w congenital heart disease
-pulm aspiration
- anemia (d/t poor nutrition)
What is usually placed pre-op for a cleft palate and lip?
Tongue stitch before waking up bc correction can narrow the airway making it more likely for the tongue to obstruct the airway
What meds should be used for cleft lip and palate?
non-respiratory depressants
-tylenol
-dexmedetomidine
-ketorolac
What age are cleft lips corrected?
3 months
What age are cleft palates repaired?
6 months
What happens in micrognathia?
Glossoptosis (downward displacement or retraction of the tongue)
resp obstruction
usually isolated but can be a part of stickler syndrome or velocardial syndrome
Describe Pierre Robin Sequence
Resp compromise:
-hypoxia
-arrest
-pulm HTN
-failure to thrive
-25% have feeding problems
-rapid facial growth btwn 3-12 months
What can be done at birth to relive obstruction for Pierre robin?
place oral airway and place prone
extreme cases: tracheostomy
What are the intraoperative considerations for Pierre robins?
do not give muscle relaxants while attempting intubation
keep pt breathing
-fiberoptic
What is the OMENS classification?
-orbital distortion
-mandibular hypolasia
-ear anomaly
-nerve involvement
-soft tissue deficiency
What happens in hemifacial microsomia?
- varying degree of mandibular hypoplasia
-auricular abnormalities
-overlying soft tissue loss
-facial nerve weakness
-unilateral defects in 90% of cases
normally right sided
Variant of Goldenhar syndrome
Mandibular abnormalities: Pruzansky classifies 3 types:
- Mild hypoplasia of the ramus with little abnormality of the mandibular body
- Mandible has a small condylar head and ramus. Condyle is flat, glenoid fossa is poorly developed or absent, infratemporal surface assumes a flat contour
- Mandible abnormality
TMJ joint fails to form
Ramus may exist as a thin bony lamina or may be completely absent
the degree of mandibular hypoplasia is associated with increased difficulty of ET intubation
What is Goldenhar syndrome?
associated w abnormality on chromosome 5p15
defect in development of the 1st and 2nd branchial arches
Main feature: macrostomia (failure of fusion of maxillary and mandibular process
- vertebral abnormalities
-limited neck extension
-10% cardiac defects w outflow tract/septum issues
-hydrocephalus
-TEF
if abnormality is bilateral- similar to Pierre robin
What is Treacher Collin syndrome?
Disorder or the 1st and 2nd pharyngeal arches
-autosomal dominant mandibularfacial dysostosis (development of the bone)
hypoplasia of maxillary, zygomatic, and mandibular
- -laterally sloping palpebral fissures
-notched lower eyelids
-coloboma of eye (lens, retina, iris)
-small mouth
-high arched palate
-hearing loss (atresia of auditiory canal)
-absence of the medial lower eyelashes
secondary problems: cleft palate, velopharyngeal incompetence
Anesthetic considerations for treacher collins syndrome:
mask ventilation and intubation difficult
keep pt spontaneously breathing
sedated fiberoptic intubation
LMA or fiberoptic
Trach
Craniofacial abnormality management
sevo
prop
ketamine
precedex
nebulized lido
alfentanil
nasal trumpet or nasal ray to deliver volatile anesthetics
What are the noncraniofacial abnormalities?
Mucopolysaccharidoses
Beckwith-Wiedemann
Down syndrome
What is Mucopolysaccharidoses
Lysosomal storage disorder: deficiency in the enzymes required for the stepwise breakdown of glycosaminoglycans (GAGs)
Components of ground substance of bone and cartilage, lubricant for joint fluid, and the surface coating that initially binds growth factors to cells
How does Mucopolysaccharidoses affect the airway?
Airways: infiltration of GAG deposits leads to tongue enlargement, thickening and redundancy of the soft-tissue mucosa of the oropharynx, and blockage of nasal passages
Progressive airway obstruction leads to severe respiratory compromise
Mask ventilation and tracheal intubation become impossible
What are the features of MPS 1: Hurler syndrome?
Appear normal at birth
During first year: course facial features, wide nasal bridge, flattened midface
Hepatosplenomegaly, umbilical or inguinal hernias
Skeletal abnormalities: dysostosis multiplex
Typically present at 6 months to 2 yrs. with developmental delay, recurrent respiratory infections with chronic nasal discharge
Rapidly enlarging head size, heart failure, hernias, lower spine deformities
Age:2-3: joint stiffness and contractures, multiword sentences and walking: declines
MPS 1: Hurler syndrome continued
High pressure communicating hydrocephalus
Craniosynostosis
Loss of vision: corneal clouding early on
Soft tissue thickening of the nose and pharynx, storage within the tonsils, adenoids, and abnormalities in tracheal cartilage cause progressive airway obstruction and sleep apnea
Sleep apnea: hypoxemia at night, pulmonary HTN, cor pulmonale
Cardiac abnormalities: age 5
Cardiomyopathy, endocardial fibroelastosis, valvular regurgitation
Abnormal storage of GAG in coronary vessels cause narrowing
Odontoid Dysplasia and anterior C1-C2 subluxation: can cause cord compression and sudden death.
What is the management for MPS?
FIRST CHOICE: AWAKE FOI
Preop evaluation of upper airway, lungs, cervical spine, heart, and neurologic evaluation
Periop morbidity and mortality most often related to difficult airway management and tracheal intubation
Awake FOI first choice
Spontaneous ventilating FOI
Be aware of co-existing cardiac and liver disease and choose drugs accordingly
Cautious use of narcotics as depressant effects could worsen pre-existing restrictive/obstructive ventilation defects
Delayed awakening in Hunter’s Syndrome has been described
What is Beckwith-Wiedemann syndrome
Omphalocele, macroglossia, gigantism
Hyperplasia of the kidneys and pancreas
prone to hypoglycemia**
Hepatosplenomegaly
Eventration of diaphragm (higher than usual in anatomic position)
Large protuberant tongue: can lead to airway obstruction
microcephaly, macroglossia, umbilical hernia
Management of Beckwith-Wiedemann syndrome:
-keep spontaneously breathing
-mask difficult d/t large tongue
-have someone gold tongue
-immediate post op s/p partial glossectomy- tongue may be bigger
-Keep pt intubated nasally
Down syndrome
Smaller than normal for age
Craniofacial: microbrachycephaly (small head)
Short neck, oblique palpebral fissure
Epicanthal folds, Brushfield’s spots (small white or greyish/brown spots on the periphery of the iris)
Small low set ears
Macroglossia
Microdontia with fused teeth
Mandibular hypoplasia
Narrow nasopharynx with hypertrophic lymphatic tissue: tonsils and adenoids
Generalized hypotonia
pulm HTN
atlantoaxial instability
subglottic stenosis
Smaller ETT
Most common heart abnormalities in down syndrome
Atrioventricular septal defect
VSD
TOF
PDA
strong underlying vagal tone: bradycardia common during induction
What is Klippel-Feil syndrome?
Severe limitation of flexion/extension of the neck as a result of fusion of cervical vertebrae and atlanto-occipital abnormalities
Spinal canal stenosis
Scoliosis
Easy mask ventilation usually
Intubation very difficult due to l
imitation of neck movement
Care must be taken in manipulation of neck as neurological injury can occur
FOI vs LMA
What syndromes had the highest rate of tracheotomy?
Crouzon
Apert
Pfeiffer
Next highest: Treacher Collins
what reduced risk of tracheotomy?
cleft palate
CAEC 8:
ett 3.5-4.5
CAEC 11:
ett 5.0-6.0
CAEC 14:
ett 6.5-7.0
indications for spinal anesthesia
hernia repair
orchiopexy
hypospadias
circumcision
exploratory lap
muscle biopsy
LE surgery
Where is the infant clonus medularis located?
L3
Where is the infant dural sac located?
S3
What is the volume of csf in neonates?
> 10mL/kg
what is the volume of csf in infants?
4mL/kg (<15kg)
what is the volume of csf in children?
3mL/kg
What is the volume of csf in adults and adolescents?
1.5-2ml/Kg
What size needle do you use for an infant and neonate spinal?
1.5 inch
Where should the spinal needle be placed?
L4-L5 interspace (iliac crests)
what is the most commonly used regional block in pediatric anesthesia?
caudal block
-lower extremities, lower abdomen, lower thoracic dermatomes
what are contraindications to a caudal block?
pilonidal cyst
abnormal superficial landmarks
myelomeningocele
hydrocephalus or intracranial htn
neuropathies
parental nonconsent
caudal anatomy: sacral hiatus
Results from the lack of dorsal fusion of the 5th and often 4th sacral vertebral arches
V-shaped aperture
Limited laterally the sacral cornua
Covered by the sacrococcygeal membrane (sacral continuation of the ligamenta flava)
in a caudal block where is the needle placed?
sacral canal
22G/20G angio-catheter or tuohy needle
what is the positioning for a caudal block?
lateral- into fetal position
prone
sacral level
0.5-0.75 mL/kg
Lumbar level
1-1.2 ml/kg
low thoracic
1.2-1.5ml/kg
max volume/max dose
25ml / 3mg/kg
toxicity treatment
20% intralipid
bolus 1.5 ml/kg repeat 1-2 times if needed
infusion 0.25ml/kg/min for 30-60 mins
what are signs of intravascular injection?
HR increase of 10 bpm
BP increase of 15 mm Hg
T wave ampitude increase of >25% of baseline or bradycardia are all signs of intravascular injection.
Children are at an increased risk because of increased C.O. and increased systemic uptake of the agent.
signs of neurotoxicity
Neurotoxicity: HA, somnolence, vertigo, perioral or lingual parathesias, tremors, twitching, shivering or convulsions.
signs of cardiac toxicity
Cardiac toxicity: LA prevents the fast inward sodium channels in the myocardium from opening.
Dysrhythmias, conduction block, widening QRS, torsades de pointes, VT, or cardiovascular collapse
