Pediatrics I Flashcards Preview

AS - N935 Advanced Patho II > Pediatrics I > Flashcards

Flashcards in Pediatrics I Deck (70)
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1
Q

Premature

A

< 37 weeks gestation

2
Q

Low Birth Weight

A

< 2,500g

3
Q

Very-Low Birth Weight

A

< 1,500g

4
Q

Extremely-Low Birth Weight

A

< 1,000g

5
Q

Pediatric Airway Differences

A

Larger tongue in proportion to oral cavity → easy obstruction
Narrow nasal passages
↑salivary secretions
Large tonsils & adenoids
Larynx
- Higher, more cephalad (neonates to 2yo)
- Anterior
- C3-C4
- Oblong/football shaped
Epiglottis narrow omega shaped & angled away (more difficult to lift)
Vocal cords lower, more caudad attachment anterior → difficult to pass ETT twist
Trachea shorter 4-5cm (infant)
Subglottic = narrowest portion
- Funnel shaped

6
Q

Subglottic Stenosis

A

90% acquired results from ETT & prolonged intubation

Often requires smaller ETT placement

7
Q

Tracheal Stenosis

A

Often occurs at carina

Creates additional resistance to ETT

8
Q

Tracheobronchomalacia

A

Intrathoracic airway collapses during exhalation

PEEP or CPAP helpful to stent airway open

9
Q

Surfactant Production

A

Begins b/w 23-34 weeks

Inadequate concentration until 36 weeks post-conception

10
Q

Type 1 Muscle Fibers

A

Low numbers 10-25%

  • Marathon muscles
  • Slow twitch muscles
  • Used for prolonged activity
  • Do not develop adequate type 1 fibers until >6-8 mos

↓muscle strength → fatigue
Apnea risk

11
Q

Chest Wall

A

Horizontal & pliable

Minimal vertical movement ↓lung expansion room

12
Q

Vaginal Squeeze

A

Approximately 90mL or 30mL/kg fluid forced from lungs
Compression relieved after delivery & air sucked into lungs
C-section infants more residual fluid in lungs

13
Q

Oxygen Consumption

A

↑2-3x

6-10mL/kg/min

14
Q

Respiratory System

A

↓FRC ↑closing capacity
Immature hypoxia & hypercapnia drive
↑metabolic rate ↑CO2 ↑RR

15
Q

Premature infant response to hypoxia?

A

Initially ↑ventilation
After several minutes (fatigue)
↓minute ventilation → bradycardia or apnea
Decreased ventilatory response to hypothermia & carbon dioxide

16
Q

What are increased risks associated with premature infants in the postop period?

A

↑hypoxia, hypercapnia, & apnea risks

17
Q

What factors contribute to premature infants risks?

A

Immature respiratory control system

Immature intercostal & diaphragmatic muscles

18
Q

BPD

A

Bronchopulmonary Dysplasia

Chronic lung disease that occurs in neonates who survive severe lung disease

19
Q

BPD Cause

A

Uncertain
Potentially r/t ↑end-inspiratory lung volumes & frequent collapse & re-opening alveoli
Oxygen toxicity, barotrauma (PPV), inflammation, ETT intubation, premature lungs

20
Q

BPD S/S

A
Hypoxia
Lower airway obstruction
Air trapping
CO2 retention
Atelectasis
Bronchiolitis
Bronchopneumonia
21
Q

BPD Treatment

A
4-6mL/kg TV
↑RR
PEEP
Minimize FiO2
ICU therapy ↑calories to meet energy demand d/t WOB, respiratory support, diuretics, bronchodilation, & alternative ventilation support (ECMO or HFOV)
22
Q

RDS

A

Respiratory distress syndrome
Breathing disorder that affects newborns
Common in premature infants born < 34 weeks (6 weeks early)

23
Q

Apnea inversely r/t _____

A

Post-conceptual age
= conceptual age + post-natal age
= 23&6 + dol 138
= 45 weeks corrected

24
Q

RDS Cause

A

2° lack surfactant production

Results in airway collapse w/ hypoxia

25
Q

RDS Complications

A
Treatment → BPD
Anemia
Apnea history
Residual chronic respiratory disease
Impaired gas exchange
Prolonged ventilation history
Residual subglottic stenosis d/t long-term ETT
26
Q

Apneic Episodes

A

> 15 seconds

→ bradycardia & desaturations

27
Q

Central Apnea

A

Failure to breath

28
Q

Obstructive Apnea

A

Failure to maintain patent airway

29
Q

Apnea Risk Factors

A
Low birth weight
Anemia
Hypothermia
Sepsis*
Neurological abnormalities
Surgical procedure (even w/ regional)
30
Q

When does apnea & periodic breathing risk decrease?

A

After 44 weeks corrected

Neonates < 2,500g 25% risk
< 1,000g 85% risk

31
Q

Apnea Management Post-Anesthesia

A

Common up to 48 hours postop
Admit all premature infants < 60wks
Continuous apnea & bradycardia monitoring
IV caffeine 5-10mg/kg
Nasal CPAP or tracheal intubation w/ mechanical ventilation

Defer elective surgery until > 44-50 weeks corrected

32
Q

Cardiovascular System

A

Immaturity & ↓myofibrils #
↓contractility ↓relaxation
↑risk CV collapse during anesthesia & surgery
Fetal heart ↑connective tissues, less organized contractile elements, & ↑dependence on extracellular Ca2+
Less compliant tissues
↓catecholamine sensitivity
Autoregulation not well-developed
HR unable to compensate hypovolemia → impaired blood flow & cerebral oxygen delivery
R & L ventricle are equal size

33
Q

Micropreemie EBV

A

110mL/kg

34
Q

Preemie EBV

A

100mL/kg

35
Q

Full-Term Neonate EBV

A

90mL/kg

36
Q

Infant EBV

A

80mL/kg

37
Q

Child EBV

A

70mL/kg

38
Q

How do neonates tolerate fluid shifts?

A
POORLY
↓contractility & relaxation
↑afterload poorly tolerated
↓preload poorly tolerated
Dependent on serum ionized Ca2+
Immature Frank-Starling curve
↓volume load response
39
Q

_____ innervation well-developed

A

Parasympathetic
Vagus → bradycardia

Sympathetic innervation = poorly developed

40
Q

PDA Failure to Close

A

↑CV collapse risk during major surgery

PDA promotes pulmonary HTN & CHF

41
Q

R → L Shunt

A

Blue or cyanotic lesions
Occurs w/ ↑PVR
Venous blood ejected systemically ↓pulmonary blood flow
→ hypoxia, hypercarbia, & acidosis

ASD or VSD w/ pulmonary HTN
Tetralogy of Fallot during Tet spell

42
Q

L → R Shunt

A

Pink or acyanotic lesions
Occurs w/ ↑SVR
↑pulmonary blood flow
→ hypotension & pulmonary volume overload

PDA, ASD, & VSD

43
Q

Normal Fetal Circulation

A

AVA
Umbilical arteries x2 originate from fetal internal iliac arteries & deliver fetal blood to the placenta
Umbilical vein x1 carries oxygenated blood from the placenta to the fetus
1° umbilical vein blood supply bypasses the liver via the ductus venous & empties into the IVC where mixes w/ less oxygenated blood from LE
IVC blood enters R atrium via Eustachian valve across foramen ovale into the L atrium
L ventricle pumps blood to UE via aortic arch great vessels
Deoxygenated SVC blood enter R atrium & crosses tricuspid valve into R ventricle
↑PVR → R ventricular output → systemic circulation via ductus arteriosus

44
Q

Ductus Arteriosus

A

Originates from pulmonary artery & inserts into the aorta at point distal to L subclavian artery origin

45
Q

Fetal Circulation Characterizations

A

↑PVR
↓SVR
Oxygenated blood from umbilical vein → perfuse brain & heart via ductus venosus shunt across the liver
Foramen ovale connects R & L atrium

46
Q

Umbilical Vein PaO2

A

30-35mmHg

47
Q

Fetal Hemoglobin

A

LEFT SHIFT
P50 = 19mmHg
↑Hgb (polycythemia) levels in utero ↑CaO2

48
Q

When do neonates transition from fetal to adult circulation?

A

Umbilical cord clamping & lung inflation

49
Q

What happens when the lungs inflate w/ air?

A

↑PaO2 ↓PVR
Vasomotor tone relaxation
↑pulmonary blood flow ↑L atrium blood flow via the pulmonary vein
↑L atrium pressure > R atrium → closes atrial septum over the foramen ovale

50
Q

What happens when the OB places the umbilical cord clamp?

A

Removes the low resistance placenta
↑SVR
↓IVC blood flow & R atrium pressure
Reverse flow via ductus arteriosus
↑O2 concentration ↓PGEs → ductus arteriosus closure
Closures prevent blood from bypassing pulmonary circulation
Neonatal blood able to become oxygenation in newly operational lungs

51
Q

Foramen Ovale

A

Functional closure quick

Anatomic closure usually requires weeks

52
Q

Ductus Arteriosus

A

Remains open d/t hypoxia, mild acidosis, & placental PGEs
Functional closure when these factors are removed
Reverse flow pressure & ↑PaO2 >50-60mmHg causes muscular wall to constrict

53
Q

When does permanent PDA anatomic closure complete?

A

5-7 days

Potential to persist until 3 weeks

54
Q

What physiological stressors cause the newborn to revert to fetal circulation?

A
Hypothermia
Hypercarbia
Acidosis
Hypoxia
Sepsis
↑PVR

Delayed PDA closure common in premature infants < 34wks

55
Q

PDA S/S

A

Low diastolic pressure
Congestive heart failure
Pulmonary edema → pulmonary HTN

56
Q

Central Nervous System

A

Incomplete myelination
Cerebral cortex less developed
Immature blood-brain barrier (more vulnerable to drugs or toxins)
Neural pathways present
Impaired cerebral autoregulation → blood flow = pressure dependent

57
Q

IVH

A

Fragile cerebral vessels susceptible to rupture → intra-cerebral hemorrhage & intraventricular hemorrhage
Spontaneous bleeding into & around lateral ventricles

58
Q

IVH Predisposing Factors

A

Small birth weight & preterm (1/3 micropreemies)

RDS - hypoxia, hypercarbia
Acute BP fluctuations
Acidosis
Hypernatremia
↓Hct
Over transfusion
Stress/trauma
Rapid admin hypertonic fluids (NaHCO3 or dextrose)
59
Q

IVH S/S

A
Hypotonia
Apnea
Seizures
Loss sucking reflex
Bulging anterior fontanelle
60
Q

ROP

A

Retinopathy of prematurity
Normal retinal vascular development stops
Neovascularization & fibrous tissue formation in the retina → retinal detachment, fibrosis, & blindness

61
Q

ROP Associated w/

A
Low birth weight < 1,000g
Prematurity
Oxygen exposure
Apnea
Blood transfusions
Sepsis
CO2

*Fluctuating oxygen levels or rapid swings

62
Q

Anesthesia Goal Saturation

A

90-94%

Titrate based on pre-ductal saturation

63
Q

Why are pediatric patients more susceptible to hypothermia?

A

↑surface are per kg
Thin skin
↓fat content

↑heat loss risk
Radiation > convection > evaporation > conduction

64
Q

Heat Production Mechanisms

A
Non-shivering thermogenesis (up to 3mos)
Brown fat metabolism
Volatile anesthetics inhibit thermogenesis 
Crying
Movement
Stress → poor weight gain
65
Q

Volatile Anesthetics Impact on Temperature

A

Depress the hypothalamus
- Reduction in already impaired ability to maintain body temperature
Cutaneous vasodilation

66
Q

Pediatric hypothermia results in…

A
Delayed awakening from volatile anesthetics
Cardiac instability
Respiratory depression
↑PVR
Altered drug response
67
Q

How to prevent hypothermia?

A
Transport isolette and/or heating pad
Room temp 70-80°F
Fluid warmer
Limit skin exposure
Cover infant head
Forced air warmer
Heat lamps
68
Q

Renal System

A

↓ability to compensate volume swings
Glomeruli continue to develop until 40 days postnatal
Prolonged duration/half-life drugs dependent on GFR excretion
↓proximal tubular Na+/H2O reabsorption
Monitor Na+ & electrolytes
Impaired glucose production

69
Q

Hepatic System

A

Immature
CYP450 phase 1 metabolism 50% adult values at birth
Phase 2 impaired until 1yo
Limited glycogen stores & ability to handle large protein loads
↓albumin synthesis ↑unbound drug available
Bilirubin & ABO incompatibility

70
Q

Calcium

A

Infant dependent on extracellular Ca2+ & reserves
Parathyroid function not fully established
Vitamin D stores inadequate
Anticipate hypocalcemia especially in preterm, severe neonatal illness, & after blood transfusions
Calcium gluconate or chloride infusions to treat symptomatic hypocalcemia
Central line preferred