Exam 3: Extrauterine adaptations Flashcards
Surfactant
Effect on FRC
Made in T2 alveolar cells, stored as lamellar bodies 90% lipid Monolayer with non-polar tails Upon collapse, tail repulsion No FRC without surfactant
Hyaline membrane disease
Premie/delay maturity
Increased WoB (retractions, grunting)
Cyanosis on RA
Microatelectasis
Tx of surfactant deficency
Oxygen
CPAP
Ventilation
Surfactant replacement
Important of FRC
The perfect amount needed
Too little FRC -> increased work to expand
Too much FRC -> overexpanded, too near capacity
In utero lung fluid
Secreted by lung epithelial cells (Cl- secretion)
Forms amniotic fluid
Clearance of fluid at birth
Na channels for reabsorption (upreg by catecholamines/stress of labor)
Physical contractions squeeze fluid faster than produced
(therefore more fluid in C section)
Breathing results in stepwise increase in FRC
Transient tachypnea of the newborn
Causes
Mech
Rapid labor, C-section
Ineffective initial breaths (premie, poor tone etc)
Fluid takes much longer to be absorbed by lymph (retained lung fluid)
3 reasons for failure to breathe
1˚ apnea: stimulation/rubbing solves (HR/BP maintain)
2˚ apnea: PPV to stimulate initial breaths (HR/BP drop)
NM impairment: primary neuro or maternal sedation/MgSO4
APGAR categories
HR (>< 100) Respiration (cry) Tone Response to suction Color
Persistent pulmonary HTN of the newborn
PVR remains high, SVR doesn’t increase
Ovale maintains flow
Ductus maintains flow bypassing lungs
Two tone bebe
Preductual blood flow (head/R arm) well oxygenated
Postductual blood flow not -> pale
PVR modulation
Increased: low O2/high CO2 states and constrictors
Decreased: high O2/low CO2 states and dilators
Other important transitioning factors
Glucose
Temperature
Calcium (fetal PTH suppressed, calcitonin high)
Hypocalcemia looks like hypoglycemia but with BG wnl
Risk for neonatal hypoglycemia
IUGR
Maternal DM
Premature
Polycythemia
