What is different in children vs adults regarding the tongue?
Tongue:
- larger in proportion to oral cavity than in adult
What is different in children vs adults regarding the epiglottis?
Epiglottis
- narrower, shorter at level of 1st vertebrae and overlaps soft palate
- Ω shaped
What is different in children vs adults regarding the larynx?
Larynx:
- higher in the neck, C2 in neonate
- C 3-4 in children (C5-6 in adults)
- angle between base of tongue and glottis opening is more acute
What is different in children vs adults regarding the cricoid?
Cricoid:
- conically shaped, narrowest portion is at cricoid ring (adults is vocal cords)
What is different in children vs adults regarding the trachea?
- Deviated posteriorly and downward
- Is similar to adult around 8-10 years
—> length of trachea (vocal cords to carina) in neonates and children up to 1 year is 5-9 cm or 2-2.5 inches
** do not bury ETT once through the vocal cords **
What is different in children vs adults regarding the head?
- Occipital is larger
- optimal incubating position is with a shoulder roll to prevent neck flexion while supine
—> extreme neck extension causes obstruction- want head parallel with the ceiling
What implications does the small airway size have?
A small decrease in airway size (edema/trauma) results in a huge increase in resistance to flow
T/F Infants are obligate nasal breathers until 3-5 months because major source of resistance to airflow is in the lower airways.
True
Overcoming resistance of nares takes only 25% of work of breathing in infants (60% in adults)
Occluding an infants nares = ____________ airway obstruction.
Complete
1 mm edema decreases crossectional area by ____, and increases resistance ______ in laminar flow.
75%
16 times
(Will increase resistance 32 times in turbulent flow)
Under 6 months of age the primarily rely on what type of breathing?
Diaphragmatic
Intercostals contribute 20-40% to ventilation
Under 6 months, the thorax is weak and unstable with a smaller % of which type of diaphragmatic fibers?
Type I fatigue resistant
In infants FRC is small but ______ __________.
Not functional
How do you calculate the ETT size for a child?
(Age in years + 16)/4= internal diameter in mm
- if newborn use 3.0 tube
- if <6 months use 3.5 tube
- if 1 year use 4.0
What is important regarding ETT size?
- should have audible air leak @ 15-25 cmH2O pressure
- excessive tube size causes post op croup more than any other factor
- always prepare calculated tube size and 1/2 size smaller **
What is important in obtaining a pre-op history?
- current complaint: how it affects resp system
- past resp. History- neonate and family hx
- review of systems- assess functional state of pt’s lungs
- ** this is more useful than lab data ***
What is important in obtaining a pre-op physical exam?
- exam of a calm child provides much more info
- character of respirations- depth, rate
- work of breathing- nasal flaring, retractions
- URI- bilateral breath sounds
- if URI within past 2-6 weeks —> significant risk of bronchospasm
What is a laryngospasm?
- sustained tight closure of the vocal cords during light plane of anesthesia (creates central disinhibition)
- caused by stimulation to the SLN—> contracts adductor muscles of larynx
- lateral cricoarytenoids, thyroarytenoids and cricoarytenoids
What causes laryngospasm?
- inhaling volatile agents
- excessive airway secretions
- presence of URI (hyper-irritable)
- manipulation of airway (intubation/extubation)
- stimulating of visceral nerve endings in pelvis, abdomen, and thorax
How is laryngospasm treated?
- remove stimulus and debris—> suction
- deepen anesthesia
- 100% O2 via tight fitting mask
- sustained positive pressure ~ 30-40 cmH2O
- manual forward displacement of mandible
- if airway maneuvers fail—> atropine, succinylcholine and consider intubating
- succinylcholine 0.4mg/kg IV, or 4mg/kg IM
What are some facts about post laryngeal edema?
- greatest incidence in kids 1-4 years, but can occur in all ages
- caused by:
- mechanical trauma to airway during intubation
- placement of ETT that is too big (no leak at 40cmH2O)
How is post intubation laryngeal edema treated?
- humidify inspired gases
- racemic epi—> vasoconstricts capillaries in subglottic mucosa
- reintubate/tracheostomy
What is epiglottitis?
- a rare cause of infectious upper airway obstruction in kids
—> caused by influenza B - occurs in 3-6 year olds mainly
What are the pathology and S/S of epiglottitis?
Patho—> septicemia (systemic) with local erythema and edema- worse in the epiglottis, aryepiglotic folds and supraglottic connective tissue
S/S:
- rapid progression <24 hours
- dysphasia, dysphasia, drooling, inspiratory strider, distress, high fever >39ËšC
How is epiglottitis treated?
O2, urgent intubation (under GA in the OR)
- abx
- antipyretics
- fluids
What kind of anesthetic management must be done with epiglottitis?
- transfer to OR
- do not upset or agitate the child
- ENT MUST BE PRESENT ***
- smooth, controlled inhalation induction with SEVO—> keep child in sitting position—> add CPAP to circuit
- obtain IV—> give atropine
- achieve stage 3
- use small ETT
- maintain spontaneous ventilation
- dx is confirmed by ENT surgeon via direct laryngoscopy
What are anesthetic implications with epiglottitis?
Expect slow induction d/t partially obstructed airway
- inflamed airway increases potential for coughing, breath holding and laryngospasm
- CV depressant effect of IA are magnified d/t hypovolemia
- have rigid ventilating bronchoscope available and surgical airway equipment
- identifying structures may be difficult with severe swelling
- may need to replace oral ETT with nasal tube for 48-96 hours
In a child with epiglottitis, when would you consider extubating?
- when temperature and WBC decrease
- an audible air leak is heard around ETT
- extubate only after direct laryngoscopy in OR under GA to confirm swelling is resolved
What is laryngotracheobronchitis?
Croup, subglottic infection
(Accounts for 99% of infectious upper airway obstruction in kids)
- mucosal/submucosal edema within cricoid ring- decreases luminal size
- gradual onset/progression - 24-72 hours
- hx of URI progressing to hoarse cry or barking cough
- low grade fever <39ËšC
What is laryngotracheobronchitis caused by?
Parainfluenza type 1 and 2
Influenza A
Respiratory syctitial virus
—> occurs in kids <2 years
How is laryngotracheobronchitis treated?
- O2 with cool mist
- racemic epi (Ăź blocker effect)
- albuterol
- corticosteroids
- antipyretics
- intubation is rare unless exhaustion occurs
What are s/s of foreign body aspiration and where is it most likely to occur?
* most likely to occur right mainstem bronchus S/S: - coughing - wheezing - decreased air entry into affected lung - URI - PNA
What is the treatment for foreign body aspiration?
- laryngoscopy or endoscopic removal
- best if removed within 24 hours
if FB left, risk of: - migration of aspirated material
- PNA, residual pulmonary disease
Anesthetic management for foreign body aspiration?
Induction technique depends on severity of airway obstruction
** with airway obstruction **
—> inhalation of volatile agent in O2, maintaining spontaneous ventilation
- avoid NDNMBs
- without obstruction—> standard IV induction
- positive pressure may migrate FB
- direct laryngoscopy: anesthetize the vocal cords to prevent laryngospasm—> 1% lidocaine, 1-2 mg/kg
POST OP
- Racemic epi
- corticosteroids
What are complications of foreign body aspiration?
- airway obstruction
- fragmentation of FB
- hypoxemia
- hypercarbia
- subglottic edema from trauma to tracheobronchial tree (from FB instrumentation)
What are clinical applications for a tonsillectomy and andenoidectomy?
- upper airway obstruction
- massive hypertrophy
- chronic URI
- OSA
Anesthetic management for a T and A?
- premeditate with P.O. or intranasal midazolam
- IH induction with Sevo
- intubate deep: sevo + propofol + short acting NDNMBs
- analgesia: morphine or fentanyl
- steroids: dexamethasone
- EXTUBATE WHEN FULLY AWAKE **
How is post- tonsillectomy bleeding characterized?
- early: within 1st 24 hours (90% occurs within the 1st 6 hours)
- secondary delayed: 24 hours to 3 weeks—> peak on POD 7
(On day 7 people get daring and try to eat Doritos)
Which populations are at greatest risk for post-tonsillectomy bleeding?
- older patients
- presence of inflammation or infection (hx of strep)
- pre-op aspirin, NSAIDS
- platelet inhibition
- coagulopathy
How is post-tonsillectomy bleeding prevented?
- careful direction in tonsillar capsule
- meticulous hemostasis
- avoid surgery during/immediately after acute inflammation/infection
- avoid blind, vigorous suctioning
- avoid use of NSAIDS
What are s/s of post-tonsillectomy bleeding and how does it present clinically?
S/S: - frequent swallowing - throwing up blood Clinical presentation: - hypovolemia - anemia - agitation - shock - stomach full of blood - active bleeding—>poor visualization of glottis
What is important to include in your pre-op eval for a tonsillectomy?
- assess volume status: BP, HR, UOP, mucous membranes, skin turbot, sensorium
Labs: H/H, urine SG/osmolality - establish IV access - for IVF or immediate transfusion
** SEND FOR BLOOD **
Anesthetic management for a tonsillectomy?
- full stomach—> RSI, cricoid pressure
- maintain O2, IH, opioids
- 2 suctions, 2 blades/handles, multi-styletted cuffed ETTs
- atropine, propofol, Etomidate, ketamine, rocuronium, succinylcholine
Emergence—> suction stomach, awake extubation
What is choanal atresia?
Occlusion of one or both posterior nares
- partially or totally bony in 90% of cases
- frequently associated with craniosynostosis
What is so dangerous about choanal atresia?
- infants are obligate nose breathers—> bilateral choanal atresia causes suffocation
—> must keep mouth open with OPA or large rubber nipple
** surgical correction with tracheostomy must be performed within the 1st few days of life
What is true regarding unilateral choanal atresia?
May go undiagnosed for years—> eventual diagnosis d/t presence of intractable unilateral nasal drainage
Anesthetic management in choanal atresia?
- awake intubation with oral rae
- maintain O2/N2O/IH, NDNMBs, opioids
Post-op: - intermittent airway obstruction may persist for some time—> must monitor until patency assured
- stents are placed - transfer baby to ICU