Chapter 19: Normal Newborn: Processes Of Adaptation Flashcards
1
Q
What is the purpose of fetal lung fluid?
A
- The aveoli produce fetal lung fluid that expands the alveoli and is essential for normal development of the lungs.
- Some of the fluid empties from the lungs into the amniotic fluid.
2
Q
In preparation for birth, what happens to fetal lung fluid?
A
-Production of lung fluid decreases in preparation for birth. (Fluid must be cleared for the infant to breathe air)
3
Q
When does absorption of fetal lung fluid begin?
A
During early labor.
By the time of birth, only about 35% of the original amount remains.
4
Q
Absorption of fetal lung fluid is accelerated by
A
Secretion of fetal epinephrine and corticosteroids.
5
Q
Absorption of fetal lung fluid may be delayed by
A
- Cesarean birth without labor.
- C/S baby may be born with more fluid still in lungs (need to get fluid out)
6
Q
The removal of fetal lung fluid reduces
A
pulmonary resistance to blood flow that is present before birth and enhances the advent of air breathing.
7
Q
Surfactant is detectable by what weeks of gestation?
A
24-25 weeks of gestation. *
8
Q
By what weeks is there a sufficient amount of surfactant produced to prevent respiratory distress syndrome?
A
By 34 to 36 weeks. *
9
Q
Accelerated fetal lung maturation occurs in
A
- A fetus who has intrauterine growth restriction.
- A fetus who is stressed by conditions such as chronic maternal HTN, preeclampsia, and prolonged rupture of membranes (PROM).
10
Q
Slow fetal lung maturation occurs in
A
Infants of mothers with diabetes.
11
Q
Infant breathing is initiated by what 3 factors?
A
- Mechanical factors
- Chemical factors
- Thermal factors
12
Q
Why is surfactant important in infants as they begin to breathe at birth?
A
- Surfactant lines the inside of the alveoli and reduces surface tension within alveoli, allowing the alveoli to remain partially open when the infant begins to breathe at birth.
- Without surfactant the alveoli collapse as the infant exhales.
13
Q
Absorption of Fetal Lung Fluid
A
- During labor, the fluid begins to move into the interstitial spaces, where it is absorbed.
- At birth the infant’s first breath must force remaining fetal lung fluid out of the alveoli and into the interstitial spaces around the alveoli to allow air to enter the lungs.
14
Q
Mechanical Factors
A
- During a vaginal birth, the fetal chest is compressed by the narrow birth canal.
- The fluid passes out of the mouth or nose or is suctioned as the head emerges from the vagina
- When the pressure against the chest is released at birth, recoil of the chest draws a small amount of air into the lungs and helps remove some of the viscous fluid in the airways
- This reduces the amount of negative pressure needed for the first breath after birth
15
Q
Approximately how much fetal lung fluid is forced out of the lungs into the upper air passages during birth?
A
1/3 *
16
Q
The first breath of a baby is referred to as the
A
Inspiratory gasp
17
Q
Chemical Factors
A
- Inspiratory gasp is triggered by an increase in PCO2 and decrease in pH and PO2 levels.
- This triggers the aortic and carotid chemoreceptors to stimulate the respiratory center in the medulla.
- A forceful contraction of the diaphragm results, causing air to enter the lungs.
18
Q
Chemical Factors: Stimulation of the respiratory center and breathing do NOT occur if
A
Prolonged hypoxia causes CNS depression.
19
Q
Thermal Factors
A
- After birth, infant moves from warm, fluid-filled uterus into an environment where the temperature may be much cooler.
- The cold stimulates the skin nerve endings, sending impulses to the brain that stimulate the respiratory center and breathing.
- The newborn begins to respond with a rhythmic respiration.
20
Q
Excessive cooling of the infant can lead to
A
Cold stress.
21
Q
Hazards of Cold Stress include
A
- Increased oxygen need (d/t increased metabolic rate and metabolism of brown fat)
- Decreases surfactant production
- Respiratory distress (d/t increase oxygen need)
- Hypoglycemia (d/t metabolism of glucose to produce heat)
- Metabolic acidosis
- Jaundice (d/t increased fatty acids)
22
Q
How much air remains in the lungs after the first breaths are drawn?
A
20-30 ml
23
Q
How can crying help with absorption of fetal lung fluid?
A
- Crying increases the pressure within the lungs.
- This leads to absorption of fetal lung fluid into interstitial spaces and absorption into pulmonary and lymphatic systems.
24
Q
How long does it take for complete absorption of fetal lung fluid to occur?
A
- Takes several hours.
- Some lungs sound moist when first auscultated but become clear in a short time.
25
How much can an infant’s temperature drop if not kept warm at birth?
Can drop 0.2 degrees to 1 degree C (0.5 to 1.7 degrees F) per minute. *
26
What are newborn characteristics that can lead to heat loss?
1. Skin is thin and blood vessels are close to the surface.
2. Little SQ or white fat is present
3. Heat is readily transferred from the warmer internal areas of body to cooler surfaces and surrounding air
4. Newborns lose heat at a rate 4x greater than that of adults.
27
Why do healthy full term infants remain in a position of flexion?
-This decreases the amount of skin surface exposed to surrounding temperature and decreases heat loss.
28
Why are premature infants not able to maintain flexion?
They have decreased muscle tone to remain flexion.
29
What are the methods of heat loss in an infant?
1. Evaporation
2. Conduction
3. Convection
4. Radiation
30
Evaporation
Occurs when wet surfaces are exposed to air.
| As the surface dries, heat is lost.
31
How do infants lose heat through evaporation?
1. At birth, when amniotic fluid on the skin evaporates.
2. During bathing.
3. Insensible water loss from the skin and respiratory tract increases heat loss from evaporation.
32
How can you prevent heat loss through evaporation in an infant?
Drying the infant, especially the head, as quickly as possible after birth and after bathing helps prevent heat loss by evaporation.
33
Conduction
Movement of heat away from the body occurs when newborns have direct contact with objects that are cooler than their skin.
34
How can infants lose heat through conduction?
- Placing infants on cold surfaces or touching them with cool objects.
- The reverse is also true, contact with warm objects increases body heat by conduction.
35
How can you prevent conductive heat loss in an infant?
- Warming objects that will touch the infant.
| - Placing the unclothed infant against the mother’s skin (“skin to skin”).
36
Convection
Convection occurs when heat is transferred to air surrounding the infant.
37
What can cause heat loss in an infant through convection?
Air currents from air conditioning or the movement of people.
38
How can you prevent heat loss through convection in an infant?
- Keeping the newborn away from drafts
- Maintaining warm environmental temperatures (i.e incubator)
- Warming oxygen before prolonged administration
39
Radiation
The transfer of heat to cooler objects that are not in direct contact with the infant.
40
How can an infant lose heat through radiation?
- Placed near cold windows.
| - Placed in an incubator with cold walls (infant is cooled despite the warm temperature inside of the incubator)
41
How can you prevent heat loss from radiation in an infant?
- Incubators with double walls
- Placing cribs and incubators away from windows and outside walls.
- Use radiant warmer to transfer heat from the warmer to the cooler infant.
42
Shivering in a newborn
- Newborns rarely shiver except during prolonged exposure to low temperatures.
- Shivering is not an important method of thermogenesis in a newborn.
43
When infants are cold, instead of shivering, what do they do?
-They cry and become restless*
(This increased activity and flexion help generate some warmth and reduce the loss of heat from exposed surface areas of the body)
44
Why are premature infants at an increased risk for cold stress?
- Have decreased muscle tone and are unable to maintain a flexed position.
- Have thinner skin and even less white SQ fat than full-term infants
45
In infants, exposure to cool temperature can cause
Vasoconstriction, preventing heat loss from the skin and causes the skin to feel cool to the touch.
46
Acrocyanosis
- Bluish discoloration of the hands and feet.
| - Occurs when infant is exposed to cool temperatures and peripheral vasoconstriction occurs.
47
How can a drop in temperature affect metabolic rate and respiratory functions?
A drop in temperature increases the metabolic rate as much as 100%, causing above-normal oxygen and glucose use.
48
What is the primary method of heat production in infants?
Nonshivering Thermogenesis
49
Nonshivering Thermogenesis
The metabolism of brown fat to produce heat.
50
What causes the brown color of brown fat?
It’s abundant supply of blood vessels.
51
Where is brown fat primarily located?
- Back of the neck
- In the axillae
- Around the kidneys
- Adrenals
- Sternum
- Between the scapulae
- Along the abdominal aorta
52
Metabolism of Brown Fat
-Generates more heat than white SQ fat
53
Blood passing through brown fat
is warmed and carries heat to the rest of the body.
54
When does nonshivering thermogenesis begin?
begins when thermal receptors in the skin detect a skin temperature of 35° to 36° C (95° to 96.8° F) *
55
What happens during nonshivering thermogenesis?
1. Thermal receptor stimulation is transmitted to the hypothalamus thermal center.
2. As a result, NE is released in brown fat, initiating its metabolism.
56
NST goes into effect even before
A change occurs in skin temperature or in core body temperature.
(Therefore, NST may begin in an infant when skin temperature has been cooled, even though the core and skin temperature measurements show normal readings)
57
Activating thermogenesis before core temperature decreases allows
The body to maintain an internal heat at an even level.
58
A decreased core temperature will not occur until
NST is no longer effect
59
What infants are likely to have inadequate brown fat stores?
- Preterm infants
- Infants with intrauterine growth restriction (may deplete brown fat stores before birth)
- Infants with hypoxia,hypoglycemia and acidosis
60
Why may preterm infants have inadequate brown fat stores?
Because it is accumulated mainly during the third trimester.
61
Why may hypoxia, acidosis and hypoglycemia cause inadequate brown fat stores in an infant?
Because it may interfere with the infants ability to use brown fat to generate heat.
62
What can happen in infants with inadequate brown fat stores?
They are not able to raise their body temperature if they are subjected to cold stress and may have serious complications.
63
What causes metabolic acidosis during cold stress?
- Metabolism of glucose + presence of insufficient oxygen = increased production of acids.
- Metabolism of brown fat also releases fatty acids.
64
How can cold stress lead to jaundice?
Increase in fatty acids from metabolism can interfere with the transport of bilirubin to the liver = increased risk of jaundice.
65
Decreased oxygen concentrations in the blood may also cause?
Vasoconstriction of the pulmonary vessels, leading to further respiratory distress.
66
What are the functions of the hepatic system?
1. Maintenance of blood glucose levels
2. Conjugation of bilirubin
3. Production of factors necessary for blood coagulation
4. Storage of Fe+
5. Metabolism of drugs
67
During the third trimester, glucose is
Stored as glycogen in fetal liver and skeletal muscles for use after birth.
68
Fetal glucose stores are completely depleted within
12 hours after birth.
69
Glucose stored in the third trimester is used for energy during
1. Stress of delivery
2. Breathing
3. Heat production
4. Movement
5. Activation of all functions neonate must assume at birth
70
Until newborns are having regular feedings and intake is adequate to meet energy requirements, what happens to glucose?
Glucose present in the body will continue to be used
71
Glucose concentration falls to the lowest levels by
60-90 minutes after birth but rises and stabilizes 2-3 hours after birth.
72
Term Infant Glucose Levels: On first day
40-90 mg/dL
73
Glucose levels < 40 indicate
Hypoglycemia
74
Term Infant Normal Glucose Levels: After the first day
50-90 mg/dL
75
What kind of infants may have inadequate glycogen or fat stores for metabolism?
- Preterm
- Post-term infant
- Small for gestational age infants
- Large for gestation age infants with diabetic mothers
- Asphyxia or infection (exhaustion of glycogen stores)
- Cold stress infant (depletion of glycogen stores)
76
What may cause the post-term infant to have an inadequate store of glycogen and fat for metabolism?
Stores may be used up before birth d/t poor intrauterine nourishment from a deteriorating placenta.
77
What may cause inadequate stores of glycogen or fat for metabolism in large for gestation age infants w/ diabetic mothers?
Produce excessive insulin that consumes glucose quickly
78
Jaundice is caused by
Hyperbilirubinemia
79
Bilirubin
Is the product of RBC hemolysis
80
In order for bilirubin to be eliminated from the body, it must be
Conjugated into a water soluble form
81
Unconjugated bilirubin
- Is fat soluble.
| - Allows it to be absorbed in the SQ = yellow discoloration of skin.
82
If increased unconjugated bilirubin accumulate in the blood, it can cause
Staining of the tissues in the brain.
| May cause acute bilirubin encephalopathy
83
Acute Bilirubin Encephalopathy
Neurological condition from bilirubin toxicity.
| If it becomes chronic -> Kernicterus (permanent neurological injury)
84
Normal Conjugation of Bilirubin
- Unconjugated bilirubin attach to bindings sites of albumin in plasma -> transfer to liver -> becomes conjugated bilirubin -> bile -> duodenum
- Normal floral acts to reduce bilirubin to be excreted in stools
85
Decrease albumin levels can be d/t
- Medications
- Free fatty acids (bind to albumin, blocking attachment of bilirubin)
- Acidosis
- Infection
86
Beta-glucuronidase
Is an intestinal enzyme that can deconjugate bilirubin.
87
Why is beta-glucuronidase important in fetal life?
Because only unconjugated bilirubin can be cleared by the placenta for conjugation by the mother’s liver.
88
What can cause an increase in bilirubin?
- Hemolysis of excessive erythrocytes
- Short red blood cell life span
- Lack of albumin-binding sites
- Liver immaturity
- Preterm or late preterm birth
- Lack of intestinal flora
- Delayed or inadequate feedings
- Trauma resulting in bruising or cephalhematoma
- Fatty acids from cold stress or asphyxia
89
What are factors necessary for blood coagulation?
- Prothrombin & coagulation factors are produced by the liver and activated by vitamin K.
- Vitamin K is deficient in newborns.
90
Storage of Fe+ in the fetus
Stored in fetal liver and spleen during the last weeks of pregnancy
91
Fe+ needs in infants
- Termed infants who are breast feeding don’t need added Fe+ until 6 months age.
- Infants not breast feeding should be given Fe+ fortified formula
92
Metabolism of drugs in newborns
Newborns liver inefficiency metabolizes drugs.
93
Hyperbilirubinemia: Be sure to note
Yellowing skin and sclera.
94
Potential causes of hyperbilirubinemia
- Forceps or vacuum extraction can create more bilirubin to be handled by the liver.
- Rh negative or ABO incompatibility (mom type O)
95
What is the treatment for hyperbilirubinemia?
1. Increase supplementation of formula to promote elimination in bowel
2. Phototherapy
96
Phototherapy
- Involves placing infant under special fluorescent lights.
- Bilirubin in the skin absorbs the light and changes into water-soluble products, the most important of which is lumirubin.
- Doesn’t require conjugation by liver and can be excreted in the bile and urine.
97
Because preterm infants are more vulnerable to bilirubin toxicity,
Phototherapy is begun a lower TSB levels than for full-term infants.
98
What are side effects of phototherapy?
- Frequent loose, green, stools from increased bile flow and peristalsis. (results in fluid loss)
- Erythematous, macular skin rash.
- (Bronzing baby syndrome) Grayish-brown discoloration of skin and urine in infant with cholesterol jaundice.
99
After phototherapy is completed, what happens?
- color changes and rashes disappear gradually
| - rebound TSB level increase of 1-2 mg/dL is normal.
100
What are complications of hyperbilirubinemia?
- Nonphysiologic jaundice
| - Kernicterus
101
Kernicterus
Staining of brain tissue caused by accumulation of unconjugated bilirubin in the brain.
Bilirubin encephalopathy is the brain damage that results from these deposits.
102
Physiologic jaundice
- Nonpathologic or developmental jaundice. Is a transient hyperbilirubinemia.
- Considered normal*
103
When does physiologic jaundice present itself?
- NOT presented during first 24 hours of life.
| - Appears on the second or third day after birth.
104
Physiologic jaundice becomes visible at what levels?
When bilirubin levels reach 5-7 mg/dL
105
The rate at which bilirubin level in the blood rises and falls is important because..
It helps determine whether the rate for a particular infant is following the expected curve for age and birth weight.
106
Bilirubin levels between the second and fourth days of life
Rises rapidly, peaking at 6-7 mg/dL between the second and fourth days of life.
107
Bilirubin levels by days 5-7
The bilirubin level then begins to fall.
| Declines to <2 mg/dL by 5-7 days
108
Bilirubin levels by days 10-14
Declining to adults levels of 1 mg/dL by 10-14 days of age.
109
Bilirubin levels in Asian infants
Bilirubin levels rise higher and falls more slowly in Asian infants**
110
Non-physiologic jaundice
May occur within first 24 hours.
111
What can cause non-physiologic jaundice?
- Abnormalities causing excessive RBC destruction
- Problems with conjugation
- Incompatibility between mother and infant blood types
- Infection
- Metabolic disorders
112
Example: A termed infant with no complications who is 24 hours old is considered low risk if TSB is
5 mg/dL or less**
113
Example: A termed infant with no complications who is 24 hours old is considered high risk if TSB is
> 8 mg/dL**
114
Infants have a low tolerance for changes in fluid d/t
1. Location of water within the newborns body
2. Inability of the kidney’s to adapt to large changes in fluid volume
3. Fluid turnover rate is > than adults
115
Water distribution in infants
- More water is found in extracellular areas.
| - Therefore, extracellular water is easily lost from the body.
116
Infants have increased insensible water d/t
- Large surface area and rapid RR
- Increase fluid loss when infant is placed under radiant warmers or phototherapy lights (evaporation)
- Low humidity in air
117
What is a normal urine output of an infant?
2-5 mL/kg/hr
118
Normal Specific Gravity in infants
1.002-1.01
119
The infants decreased ability to localize infection can lead to
Sepsis
120
Infant WBCs
- Respond slowly and inefficiently when the body is invaded by organisms.
- The infants decreased ability to localize infection can lead to sepsis.
121
Why doesn’t fever and leukocytosis present itself during an infection of a newborn?
Because the hypothalamus and inflammatory responses are immature.
122
What are signs that can indicate sepsis in a newborn?
Nonspecific signs such as changes in activity, color, tone or feeding may be the only signs of sepsis.
123
What may be a sign of infection in a newborn?
Hypothermia
124
When do full-term newborns receive antibodies from their mothers?
- During the last trimester of pregnancy.
| - Continues to receive antibodies through the mother’s milk during breast feeding.
125
IgG
- Only one to cross the placenta
| - Begins within first trimester
126
Why do preterm infants have less IgG?
Because transfer is greatest during 3rd trimester.
127
What is the function of IgG?
Passive temporary immunity to bacteria, bacterial toxins and viruses to which the mother developed immunity.
128
Full term infants: IgG levels
Are as high or higher than those of mom.
129
Production of IgG in infants is delayed until
After 6 months of age
130
Passive immunity given by IgG gradually disappears in the infant reaching its lowest level at what age?
2-4 months of age
131
IgM
- First immunoglobulin produced by the body when newborn is challenged.
- Too large to cross placenta
132
What is the function of IgM?
-Protects against gram- bacteria
133
Production of IgM in infants begins when?
A few days after birth from exposure to environmental antigens.
134
If IgM is found in umbilical cord blood, this indicates what?
EXPOSURE to infection in utero has occurred
135
What is the function of IgA?
-Protects GI and respiratory systems
136
IgA can be found in
Colostrum and breast milk. (Therefore breastfeeders have more protection than those who don’t)
137
Increased numbers of immature leukocytes in a neonate
are a sign of infection or sepsis in the neonate.
138
During the first and second periods of reactivity in a newborn, what happens?
- Newborns are active and alert.
- May be interested in feeding.
- May have a low temperature, elevated pulse and respiratory rates and excessive secretions.
139
Newborn kidneys
filter, reabsorb, and maintain fluid and electrolyte balance less efficiently than the adult's kidneys.
140
Breastfeeding jaundice is often associated with
Insufficient intake
141
True breast milk jaundice
begins later than physiologic jaundice and may be caused by substances in the milk.
142
Laboratory values for erythrocytes, hemoglobin, and hematocrit are
higher for newborns than for adults because less oxygen was available in fetal life than after birth.
143
When does the first period of reactivity occur in neonates?
Begins at birth and lasts for 30 minutes.
144
First period of reactivity Characteristics
- Wide awake, alert and interested in surroundings.
- Infants moves arms and legs energetically.
- RR may be as high as 80 breaths per minute
- HR may be elevated to 180 bpm
- These gradually slow and infant becomes sleepy.
145
Second period of reactivity characteristics
- Lasts 4-6 hours
- Infants have alert periods
- May be interested in feeding.
- May pass meconium.
- May be tachycardia and rapid respirations.
- Mucous secretions increase and infants may gag or regurgitate.
146
The underlying cause of newborn regurgitation is
a relaxed cardiac sphincter
147
In healthy, unclothed, full-term newborns, what temperatures provide a thermoneutral zone?
an environmental temperature of 32 to 33.5 C (89.6 to 92.3 F) provides a thermoneutral zone.
148
In healthy, dressed, full-term newborns, what temperatures provide a thermoneutral zone?
the thermoneutral range is 24 to 27 C (75.2 to 80.6 F).
149
During the first few minutes after birth, which physiologic change occurs in the newborn as a response to vascular pressure changes in increased oxygen levels?
Dilation of pulmonary vessels
