Transitional Task Of The Newborn App 1

Front 1

When does the most significant part of transition occur from fetal to extrauterine life

Back 1

24-72 hours.

Front 2

Adaptive changes that occur

Back 2

Establish FRC

Convert Circulation

Recovery from Birth asphyxia

Maintain core temperature

Front 3

Fetal Respiration

Back 3

Gas exchange occurs in placenta

O2 transport via Fetal Hgb

Fetal Hgb shifts curve to the left

Hgb of full term neonate 18-20g/dl

Front 4

Fetal Lung devleopment

Back 4

4 weeks - primitive lung buds develop from foregut

16 weeks - breaching of bronchial tree complete to 28 divisions, no further formation of cartilaginous airways

Front 5

Fetal lung development 24 weeks and 28-30 weeks

Back 5

24- primitive alveoli (saccules) and type 2 cells present, surfactant detectable. Survival possible with mechanical ventilation.

28-30 weeks - capillary network surround saccades; unsupported survival possible

Front 6

Fetal lung development 36-40 weeks

Back 6

True alveoli present, roughly 20 million at birth

Front 7

Birth to 3 months in fetal lung development

then to 6 years

Back 7

birth to 3 monthsPaO2 rises as R to L mechanical shunts close

6 years- rapid increase in alveoli, 350 million at age 6

Front 8

Development of resp function -(air breathing)

Back 8

Fetus makes resp movements in utero.

from 30 weeks gestation - present 30% of the time at a rate of 60 breaths/min

Does respond to chemical stimuli

Prenatal practice.

Front 9

Adaptation of breathing

Back 9

Rhythmic breathing occurs with clamping of the umbilical cord and increasing O2 tensions from air breathing

Front 10

Primary event of the respiratory system transition is

Back 10

Initiation of ventilation**

changes the alveoli from fluid-filled to an air-filled state.

Front 11

Pressure must infant generate to inflate lungs

Back 11

Infant must generate high negative pressure -70 cm H2O to inflate lung.

Front 12

With onset of ventilation what happens

Back 12

PVR decreases dramatically and PBF increases allowing gas exchange to occur.

Changes in PO2, PCO2, and pH are responsible for decrease in PVR

Front 13

Resp System Transition

Back 13

FRC 25-30 ml/kg is established acts as a buffer against cyclical alterations in PO2 and PCO2 between breaths

Neonates/infant lungs prone to collapse , weak elastic recoli, weak intercostal muscles, intrathoracic airways collapse during exhalation

Front 14

Resp System Transition continued

Back 14

High closing volume encroaches upon FRC small airway closure beings at volumes at or above FRC leading to lung collapse and QV mismatch

Front 15

Why doesn't infants have lung collapse all of the time?

Back 15

Infant terminate the exp phase of breathing before reaching their true FRC which results in intrinsic PEEP and a higher FRC.

when anesthetized infants need 5 of PEEP helps maintain lung inflation/FRC

Front 16

Control of ventilation in neonates

Back 16

system is normal by 3-4 weeks, but before resp control is poorly developed.

Chemoreceptor control is present at birth

Front 17

Newborns and Hypercarbia

Back 17

Newborns respond to hypercarbia by increasing ventilation, but the slope of the response curve is decreased

Hypoxia depresses the neonate's response to CO2

Front 18

Response to Hypoxia in infants

Back 18

Biphasic - initial hyperpnea followed by depression of respiration in about 2 minutes.

Initial hyperpneic response is abolished by hypothermia and low levels of anesthetic gases

Apnea most common response in real danger.

by 3 wks of age hypoxia produces sustained hyperventilation

Front 19

Apnea of infancy

Back 19

Resp. pauses exceeding 20 sec or those accompanied by bradycardia or cyanosis

Front 20

Apnea of infancy factors

Back 20

increase work of breathing = fatigue**

very compliant upper airway structures and ribcage which tend to collapse during inspiration

25% of muscle fibers in diaphragm are type 1 fatigue resistant compared to adults 55%

Front 21

Apnea O2 consumption, FRC, closing volume

Back 21

O2 consumption 6ml/kg = twice adult

decrease FRC= non functional

increased closing volume

apnea occurs much quicker due to these factors

Front 22

CV system fetal vs newborn

Back 22

gas exchanges occur in placenta in fetal system

Lungs require only nutrient flow (5-10% of CO)

Front 23

Why do we have Shunts in CV system

Back 23

fetal intracardiac and extracardiac shunts exist to minimize blood flow to the lungs while maximizing the blood flow/O2 delivery to organ systems

Ductus venosus(extra), Foramen ovale, and Ductus Arteriosus

Front 24

Fetal Circulation is what

Back 24

Parallel

Deoxygenated blood travels the descending aorta to the umbilical arteries to the placenta (very low resistance)

oxygenated blood returns via the umbilical vein (PO2 35)

Front 25

Ductus Venosus

Back 25

Diverts approx 50% of blood away from the liver into the IVC then to the RA

Front 26

Preferential streaming?

Back 26

Causes O2 rich blood to be directed across the Foramen oval which connects the right and left atrium

O2 rich blood fed to the LV and ejected into the aorta, thereby feeding the coronary and cerebral circulations

Front 27

SVC and hepatic venous flow delivered to the

Back 27

RV.. pulmonary vascular resistance is high

Front 28

RV output is delivered across the what?

Back 28

Ductus Ateriosus - which connects the PA to the descending aorta.

Blood entering the descending aorta returns to the placenta and feeds lower body (PO2 22)

Front 29

Transitional Circulation series

Back 29

At birth placental vessels are clamped, SVR increases dramatically

initiation of ventilation increase arterial and alveolar Po2 which dilates pulm vasculature - which decreases PVR dramatically and increased PBF by 450%.

Front 30

Ductus arteriosus closure

Back 30

constricts within several minutes due to increase PO2 and decrease in circulating prostaglandins.

Physiologic closure in 10-15 hours, anatomic closure 2-3 weeks.

Ductus venosus closes

Front 31

What is Persistent pulmonary HTN of the newborn

Back 31

fetal shunting beyond the normal transition period.

Front 32

Cause of Persistent Pulmonary Hypertension of the newborn

Back 32

Hypoxia and Acidosis

Front 33

Consequences of PPHN

Back 33

increase PVR, pulm htn, decrease PBF, RAP>LAP, and increase in ductal flow

Front 34

PPHN signs and symptoms

Back 34

Marked cyanosis, tachypnea, acidosis, and right to left shunt across FO and DA

Front 35

What can cause transient right to left shunting in normal neonates

Back 35

Coughing, bucking, or straining during anesthetic induction or emergence can cause shunting prior to anatomic close of fetal shunts

Front 36

PPHN treatment

Back 36

Adequate ventilation and oxygenation is key*

hyperventilate (maintain alkalosis)

Prostagladin, minimal handling, avoid stress

Front 37

Renal systen

Back 37

Major function - passive production of urine which contributes to the formation of amniotic fluid

Amniotic fluid important for normal development of the fetal lung and acts as a shock absorber for the fetus.

Front 38

Characteristics of the fetal kidney

Back 38

Low renal blood flow and glomerular filtration rate

Front 39

Transitional changes in the newborn renal system

Back 39

increase in arterial pressure

decrease in vascular resistance

increase in size and function occur through maturity

Front 40

Renal system depends on what age

Back 40

Post-conceptual age, by 34 weeks all nephrons are developed, so a premature baby has incomplete renal development

Front 41

Renal system at birth

Back 41

first several day in full term infant - diminished ability to concentrate urine from low GFR at birth.

urine osmo 700-800 and Cr 0.8-1.2

Front 42

Renal system and Na at birth

Back 42

Neonates have a normal renin-angiotension aldosterone system. they have immature neonatal tubules do not completely resorb Na under the stimulus of aldosterone.

Front 43

Neonate and Na

Back 43

The neonate will continue to excrete Na even in the presence of a severe Na deficit

The neonate is therefore considered an obligate sodium loser ***

Front 44

Na filter 1week, 2week, adult

Back 44

1week =70%

2 week = 84%

adult = 99.5%

urine Na 5-10 adult and 20-25 in neonate

Front 45

IV fluid neonate

Back 45

must contain Na because they can't conserve it.

Front 46

Increased RBF and decreased RVR result in what

Back 46

rapid improvement of renal function within the first 3-4 days of life.

Front 47

Best way to conserve heat

Back 47

Warming the room.

heat lamps are helpful.

Front 48

Thermal regulation - major component in the neonate is what

Back 48

Nonshivering thermogenesis.

metabolism of brown fat. develops between 26-30weeks.