Pediatrics Flashcards
Neonatal period:
age
PGA calculation
What is considered low birth rate?
Extremely low gestational age?
- Neonate is birth to 30 days old
- PGA =(# weeks gestation at birth) + (current age in weeks)
- post-op admission for pts <60 weeks PGA
- Pre-term <37 weeks
- Low birth rate <2500 grams
- ELGAN = 23-27 weeks
All pre-term patients have potential for what problems?
(8)
- respiratory distress
- apnea
- hypoglycemia
- electrolyte disturbances (low mg and Ca)
- infection
- hyperbilirubinemia
- polycythemia
- thrombocytopenia
What are the risks for babies of normal gestation?
postmature?
former premature up to 60 weeks PGA?
- Normal gestation: 37-40 weeks
- congenital anomalies
- viral infections
- perinatal depression
- fetal alcohol
- thrombocytopenia
- Postmature: >42 weeks (the above risks +…)
- meconium aspiration
- birth trauma if LGA
- hypoglycemia (esp if mother is diabetic)
- hyperbilirubinemia
- Up to 60 weeks PGA
- post-op apnea and bradycardia (often require 12 hour admission)
Describe fetal circulation
- oxygenated blood leaves placenta via umbilical vein
- blood bypasses the liver via the ductus venosus to go straight to the IVC
- Portion of this blood “Jet streams” straight across Right atrium through Foramen ovale into left atrium to then be pumped through ventricle and aorta
- *Remaining blood goes normal route to right ventricle and PA. High pulmonary vascular resistance forces most of this blood through the Ductus arteriosus from PA to Aorta
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What are the primary changes that occur to fetal circulation at birth?
(6)
- ductus venosus closes
- blood is now oxygenated via lungs
- ductus arteriosus closes (d/t increased arterial O2 concentration)
- pulmonary vascular resistance decreases
- peripheral vascular resistance increases
- foramen ovale closes
- true closure is weeks later and 25-30% of adults have patent foramen ovale
What is transitional circulation and what causes it?
How can it be prevented?
- occurs at birth and first several weeks of life
- hypoxia, hypercapnia, or hypothermia can lead to increased pulmonary artery pressure, reversal of flow through the foramen ovale, re-opening of ductus arteriosus and shunting
- hypoxia is #1 cause
- Prevention with optimal oxygenation, correct acidosis, keep pt warm
How does the neonatal cardiovascular system differ?
- Heart:
- structurally immature
- fewer myofibrils
- sarcoplasmic reticulum immature
- cardiac calcium stores reduced
- Ventricles less compliant
- CO is HR dependent
- increased preload does not increase SV as much as in an older child
- Baroreceptor reflex immature in the neonate causing inability to compensate for hypotension with reflex tachycardia
- Parasympathetic dominance- tendency to brady
What is the resting CO for a neonate at birth?
infant?
adolescent?
- neonate at birth: 400 ml/kg/min
- infant: 200 ml/kg/min
- adolescent:100 ml/kg/min
Neonates are vulnerable to problems caused by citrated blood products because __________.
__________ is the preferred treatment of badycardia and decreased cardiac output in pediatric patients.
they are dependent on ionized calcium
Epi
How does the neonatal pulmonary system differ?
- Fewer and smaller alveoli- they increase in number and size up until 8 yo
- Infants have a small airway diameter and increased resistance
- Highly compliant airway and chest wall - easy to see retractions
- Closing capacity is greater than FRC in very young and very old
- airway closure can occure before end exhalation–leads to shunting and dead space
- Early fatigue and diaphragmatic and intercostal muscles until age 2 b/c type 1 muscle fibers are not mature
- neonates have 10%, 2 yr and greater have 55%
- O2 consumption is 2-3x an adult
Describe the airway anatomy of an infant
(10)
- larger tongue in smaller submental space
- higher larynx (C2-C4)
- short stubby (omega shaped) epiglottis
- angles vocal cords (caudal slant)
- funnel shaped larynx with narrowest region @ cricoid ring
- obligate nasal breathers
- large occiputs that affect sniffing position (use shoulder roll)
- edentulous
- short trachea (4-5 cm)
- angulation of right mainstem bronchus
Airway differences comparing infant to adult
(table)
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Compare between an adult and neonate: (table)
Oxygen consumption
alveolar ventilation
respiratory rate
TV
![](https://s3.amazonaws.com/brainscape-prod/system/cm/264/390/534/a_image_thumb.png?1547078979)
How does the pediatric airway affect gas flow?
A 50% reduction in radius increases the pressure ___-fold
- young children have elevated airway resistance at baseline
- swelling can have huge impact by increasing resistance
- Turbulant airflow is present to 5th bronchial division
- 32-fold
How does the pediatric neurological system differ?
O2 consumption
CBF
growth
other things…
- Oxygen consumption and CBF is about 50% greatr in children than adults
- adults: 3.5 ml blood flow/100 g brain mass
- neonates: 5.5 ml/100g
- Myelinization and synaptic connections not complete until age 3-4 years
- Rapid brain growth in first 2 years
- Conus medullaris at L3 at birth, migrates to L1 or L2 by 3 yo
- Fontanels: anterior closed by 18 months, posterior closed by 2 mo
What does recent research say about anesthesia-induced developmental neurotoxicity?
- Increased and accelerated neuroapoptosis occurs with virtually all anesthetics
- Single exposures of short duration are usually of no consequence
- Repeated and/or prolonged exposures at a young age (<3-4 years) may be associated with later behavioral and learning difficulties
- ***evidence is inconclusive
What are differences you should consider with neuraxial in pediatrics?
- The conus medullaris ends at L1 in adults and at the L2-L3 in neonates and infants
- Iliac crest is even with L4-L5 or L5-S1 interspace (similar to adults) so it is still well below the conus medullaris
- Dural sac terminates more caudally (S3) in neonates and infants than in adults (S1)
- Infants have less lumbar lordosis leading to increased risk of high spinal with changes in positioning
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