Newborn Physiologic Adjustments (Cardiovascular System) Flashcards
(42 cards)
What causes a functional closure of the foramen ovale?
Increased pulmonary blood flow from the left side of the heart increases pressure in the left atrium.
During the first few days of life, what may crying do to the foramen ovale?
May temporarily reverse the flow through the foramen ovale and lead to mild cyanosis.
What is an important role for circulating hormone prostaglandin E (PGE2)?
Closure of the ductus arteriosus.
When does the closure of the ductus arteriosus occur in term infants?
Functionally class within the first hours after birth; permanent closure usually occurs within 3 to 4 wks.
What happens to the ductus arteriosus after permanent closure?
Becomes ligaments
Upon auscultation of the chest, ductus arteries can be detected as a…
Heart murmur.
What can the ductus arteriosus open in response to?
Low O2 levels in association with hypoxia, asphyxia, or prematurity.
Why do the umbilical vein and arteries constrict rapidly within the first 2 minutes after birth?
Exposure of the cord to the cooler extrauterine environment and to increased oxygenation as the infant begins to breathe.
What happens to the umbilical arteries, vein and ductus venosus when the cord is clamped or severed?
They are functionally closed and convert to ligaments within 2 to 3 months.
What is the normal HR range for a term newborn?
110 to 160 beats/min
What is the normal HR range for a sleep term newborn?
85 to 100 beats/min
What is the normal HR range for a crying term newborn?
Can increase to 180 beats/min or higher
A HR that is either >160 or <100 should be?
Reevaluated within 30 mins to 1 hr or when the activity of the infant changes.
When can the HR be palpated using the umbilical cord?
Immediately after birth
Where is the apical impulse (point of maximal impulse [PMI]) located on a newborn?
At the fourth intercostal space and to the left of the midclavicular line.
The PMI is often visible and easily palpable because of the thin chest wall; this is also known as…
Precordial activity
How long should a nurse auscultate an infants heart rhythm and for how long?
Apical pulse rates should be determined in all infants for 1 whole min. Preferable when the infant is asleep.
When is a abnormal HR not uncommon for an infant?
First few hours of life.
Heart sounds during the neonatal period are of…
Higher Pitch
Shorter Duration
Greater intensity than during adult life.
Are the 3rd and 4th heart sounds auscultated in a normal newborn?
No.
When do half the murmurs of newborns disappear?
After 6 months.
A murmur combined with what characteristics should be investigated?
Presence of a murmur and accompanying signs such as poor feeding, apnea, cyanosis, or pallor are considered abnormal.
What is the average term newborn’s systolic BP?
60 to 80
What is the average term newborn’s diastolic BP?
40 to 50
