Transition to Extrauterine Life Flashcards
What characterizes adult circulation?
High systemic vascular resistance and low pulmonary vascular resistance.
What events cause a fall in pulmonary vascular resistance (PVR)?
- Gas-filled lungs
- Increased pO2
- Decreased pCO2
What events cause a rise in systemic vascular resistance (SVR)?
- Loss of placenta
- Peripheral vasoconstriction
- Increased pulmonary return
What is required for initial lung inflation?
High pressures to displace lung fluid.
What is the primary work of inspiration in newborns?
Overcoming the surface tension of the terminal lung units at the gas/tissue interface.
What assists in the replacement of fluid with air in newborns?
- Vaginal/thoracic squeeze
- Chest recoil
What is surfactant’s role in lung aeration?
Stabilizes the alveoli and prevents collapse.
What type of stimuli assist in lung aeration?
- Proprioceptive
- Tactile
- Thermal
- Auditory
- Visual
How does the ductus venosus functionally close?
When blood flow through the umbilical vein ceases.
What causes the foramen ovale to functionally close?
In response to increased SVR and decreased PVR.
What leads to the functional closure of the ductus arteriosus?
Increased SVR and decreased PVR allowing flow of highly oxygenated blood.
What are the normal cardiovascular indicators in a newborn?
- Heart rate 80-140 bpm
- Good perfusion
- BP > 35-40 mmHg systolic
- Pulses 2+ bilaterally
- No central cyanosis
What are the signs of abnormal cardiovascular adaptation in newborns?
- Congenital Heart Disease
- Supraventricular Tachycardia
- Shock (Hypovolemic, Neurogenic, Cardiogenic, Septic)
What is the significance of the first 6-10 hours of life for newborns?
Most dramatic changes occur in the first minute of life.
What characterizes fetal circulation?
Low resistance of the systemic and placental circulations and high resistance of the pulmonary circulation.
How much fetal lung fluid is produced daily during the canalicular stage?
Approximately 250 cc/day.
What are the characteristics of fetal lungs?
- Decreased blood flow
- Thick muscular layer in pulmonary arteries
- High pulmonary vascular resistance
What is the main goal of fetal circulation?
To bring oxygen-enriched blood from the placenta to vital fetal organs.
What is the normal urinary output for a newborn within the first 24 hours?
100% void.
What are the normal gastrointestinal indicators in a newborn?
- 98.5% stool in the first 24 hours
- Active bowel sounds
- No distention
What defines the first period of reactivity in newborns?
Lasts for the first 15-30 minutes.
What are the components of the APGAR score?
- Activity (Muscle Tone)
- Pulse
- Grimace (Reflex Irritability)
- Appearance (Skin Color)
- Respiration
What are common signs of illness in a newborn?
- Poor skin perfusion
- Irritability
- Lethargy
- Poor feeding
- Temperature instability
What are the methods of heat loss in newborns?
- Evaporation
- Radiation
- Convection
- Conduction
