Ped. Respiratory Anatomy And Physiology Flashcards Preview

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Flashcards in Ped. Respiratory Anatomy And Physiology Deck (47)
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1
Q

What is different in children vs adults regarding the tongue?

A

Tongue:

- larger in proportion to oral cavity than in adult

2
Q

What is different in children vs adults regarding the epiglottis?

A

Epiglottis

  • narrower, shorter at level of 1st vertebrae and overlaps soft palate
  • Ω shaped
3
Q

What is different in children vs adults regarding the larynx?

A

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
4
Q

What is different in children vs adults regarding the cricoid?

A

Cricoid:

- conically shaped, narrowest portion is at cricoid ring (adults is vocal cords)

5
Q

What is different in children vs adults regarding the trachea?

A
  • 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 **
6
Q

What is different in children vs adults regarding the head?

A
  • 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
7
Q

What implications does the small airway size have?

A

A small decrease in airway size (edema/trauma) results in a huge increase in resistance to flow

8
Q

T/F Infants are obligate nasal breathers until 3-5 months because major source of resistance to airflow is in the lower airways.

A

True

Overcoming resistance of nares takes only 25% of work of breathing in infants (60% in adults)

9
Q

Occluding an infants nares = ____________ airway obstruction.

A

Complete

10
Q

1 mm edema decreases crossectional area by ____, and increases resistance ______ in laminar flow.

A

75%
16 times
(Will increase resistance 32 times in turbulent flow)

11
Q

Under 6 months of age the primarily rely on what type of breathing?

A

Diaphragmatic

Intercostals contribute 20-40% to ventilation

12
Q

Under 6 months, the thorax is weak and unstable with a smaller % of which type of diaphragmatic fibers?

A

Type I fatigue resistant

13
Q

In infants FRC is small but ______ __________.

A

Not functional

14
Q

How do you calculate the ETT size for a child?

A

(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
15
Q

What is important regarding ETT size?

A
  • 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 **
16
Q

What is important in obtaining a pre-op history?

A
  • 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 ***
17
Q

What is important in obtaining a pre-op physical exam?

A
  • 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
18
Q

What is a laryngospasm?

A
  • 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
19
Q

What causes laryngospasm?

A
  • 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
20
Q

How is laryngospasm treated?

A
  • 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
21
Q

What are some facts about post laryngeal edema?

A
  • 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)
22
Q

How is post intubation laryngeal edema treated?

A
  • humidify inspired gases
  • racemic epi—> vasoconstricts capillaries in subglottic mucosa
  • reintubate/tracheostomy
23
Q

What is epiglottitis?

A
  • a rare cause of infectious upper airway obstruction in kids
    —> caused by influenza B
  • occurs in 3-6 year olds mainly
24
Q

What are the pathology and S/S of epiglottitis?

A

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

25
Q

How is epiglottitis treated?

A

O2, urgent intubation (under GA in the OR)

  • abx
  • antipyretics
  • fluids
26
Q

What kind of anesthetic management must be done with epiglottitis?

A
  • 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
27
Q

What are anesthetic implications with epiglottitis?

A

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
28
Q

In a child with epiglottitis, when would you consider extubating?

A
  • 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
29
Q

What is laryngotracheobronchitis?

A

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

30
Q

What is laryngotracheobronchitis caused by?

A

Parainfluenza type 1 and 2
Influenza A
Respiratory syctitial virus
—> occurs in kids <2 years

31
Q

How is laryngotracheobronchitis treated?

A
  • O2 with cool mist
  • racemic epi (Ăź blocker effect)
  • albuterol
  • corticosteroids
  • antipyretics
  • intubation is rare unless exhaustion occurs
32
Q

What are s/s of foreign body aspiration and where is it most likely to occur?

A
* most likely to occur right mainstem bronchus
S/S:
- coughing
- wheezing 
- decreased air entry into affected lung
- URI
- PNA
33
Q

What is the treatment for foreign body aspiration?

A
  • laryngoscopy or endoscopic removal
  • best if removed within 24 hours
    if FB left, risk of:
  • migration of aspirated material
  • PNA, residual pulmonary disease
34
Q

Anesthetic management for foreign body aspiration?

A

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
35
Q

What are complications of foreign body aspiration?

A
  • airway obstruction
  • fragmentation of FB
  • hypoxemia
  • hypercarbia
    • subglottic edema from trauma to tracheobronchial tree (from FB instrumentation)
36
Q

What are clinical applications for a tonsillectomy and andenoidectomy?

A
  • upper airway obstruction
  • massive hypertrophy
  • chronic URI
  • OSA
37
Q

Anesthetic management for a T and A?

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 **
38
Q

How is post- tonsillectomy bleeding characterized?

A
  • 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)
39
Q

Which populations are at greatest risk for post-tonsillectomy bleeding?

A
  • older patients
  • presence of inflammation or infection (hx of strep)
  • pre-op aspirin, NSAIDS
  • platelet inhibition
  • coagulopathy
40
Q

How is post-tonsillectomy bleeding prevented?

A
  • careful direction in tonsillar capsule
  • meticulous hemostasis
  • avoid surgery during/immediately after acute inflammation/infection
  • avoid blind, vigorous suctioning
  • avoid use of NSAIDS
41
Q

What are s/s of post-tonsillectomy bleeding and how does it present clinically?

A
S/S:
- frequent swallowing
- throwing up blood
Clinical presentation:
- hypovolemia 
- anemia
- agitation
- shock 
- stomach full of blood
- active bleeding—>poor visualization of glottis
42
Q

What is important to include in your pre-op eval for a tonsillectomy?

A
  • 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 **
43
Q

Anesthetic management for a tonsillectomy?

A
  • 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
44
Q

What is choanal atresia?

A

Occlusion of one or both posterior nares

  • partially or totally bony in 90% of cases
  • frequently associated with craniosynostosis
45
Q

What is so dangerous about choanal atresia?

A
  • 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
46
Q

What is true regarding unilateral choanal atresia?

A

May go undiagnosed for years—> eventual diagnosis d/t presence of intractable unilateral nasal drainage

47
Q

Anesthetic management in choanal atresia?

A
  • 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