Chapter 17: Physiological Transition of the Newborn Flashcards
1
Q
Fetal Breathing Movements
A
first initiated in utero as the fetus spends months practicing coordinated inhalation and exhalation movements
-fetal breathing movements can be observed by ultrasonography as early as 11 weeks of gestation
>breathing movements= helps develop the muscles of the chest wall and the diaphragm
2
Q
Surfactant
A
slippery, detergent-like lipoprotein
- lung expansion after birth stimulates the release
- causes a decreased surface tension within the alveoli, which allows for alveolar re-expansion after each exhalation
- maintains alveolar stability
- surfactant is produced in sufficient amounts by the 34th to 36th week of gestation
3
Q
What can interfere with Surfactant metabolism?
A
-acidemia
-hypoxia
-shock
-mechanical ventilation
-hypercapnia (increased level of CO2)
>production is decreased in infants of diabetic mothers, infants with hemolytic disorders, and in multiple gestations
4
Q
Intrapulmonary Fluid
A
- decrease in the secretion as the fetus approaches term
- the fluid shift assists in reducing the pulmonary resistance to blood flow (necessary while in utero) and facilitates the initiation of air breathing
5
Q
Four Factors that Influence the initiation of the newborns first breath
A
- chemical changes
- sensory factors
- thermal factors
- mechanical factors
6
Q
Chemical Changes: Initiate Respirations
A
chemical factors that initiate respirations are hypercarbia, acidosis, and hypoxia
>these, brought about by the stress of labor and birth, stimulate the respiratory receptor in the brain to initiate breathing
-hypoxia causes blood oxygen levels (PO2) and pH to drop; blood carbon dioxide levels (PCO2) begin to rise and prompt the respiratory center within the medulla to initiate breathing
-asphyxia occurs in all newborns during the birth process; prolonged asphyxia = abnormal and may cause CNS-mediated respiratory depression
7
Q
Asphyxia
A
a condition arising when the body is deprived of oxygen, causing unconsciousness or death; suffocation
- occurs in all newborns during the birth process
- prolonged asphyxia is abnormal and can cause respiratory depression in the newborn
8
Q
Sensory Factors: Initiate respirations
A
newborn experiences a major amount of stimuli when leaving a familiar, comfortable, warm environment to a sensory-overloaded one; this aids in the initiation of respirations
9
Q
Thermal Factors: Initiate Respirations
A
after months of development in a warm (98.6 Degrees F) fluid-filled environment, the newborn enters into an environment that ranges from 70 to 75 Degrees F
>this change in temperature helps in the initiation of respirations
>sensors in the skin respond to the temperature changes and send signals to the respiratory system in the brain
-the baby’s physiological temperature may change, but if he stays in the normal range (97.7 to 98.6 Degrees F), there should be no problems r/t the thermal environment
>to prevent cold stress and respiratory depression; the nurse should immediately dry and place the infant skin-to-skin with the mother or in a radiant warmer
10
Q
Mechanical Factors: Initiate Respirations
A
removal of fluid from the lungs with the replacement of air constitutes the mechanical factors involved with the initiation of respirations for the infant (the infant has been living in the amniotic fluid that’s where the fluid comes into play)
- the fetal chest compression that occurs during a vaginal birth increases the intrathoracic pressure and helps to push fluid out of the lungs
- recoil of the chest wall after delivery of the neonate’s trunk creates a negative intrathoracic pressure; this facilitates a small, passive inspiration of air, which replaces the fluid that has been squeezed out
11
Q
Recognizing Normal Neonatal Lung Sounds During EARLY Auscultation
A
continuation of respirations occurs when the pressure within the neonate’s lungs increases and pushes the remaining fetal lung fluid into the lymphatic and circulatory system
- most of the fluid is absorbed within the first few hours but may take up to 24 hours
- lungs may sound moist during early auscultation but should become clear as the fluid is absorbed
12
Q
The Process of Absorption of Fetal Lung Fluid once Breathing has Been Initiated After Birth
A
- Before Labor, alveolar fluid fills the lungs and circulates with amniotic fluid
- During Labor, air sacs and airways remain filled with fluid
- During Vaginal Birth, the fetal thorax is compressed (thoracic squeeze) and approximately one-third of the lung fluid is expelled
- After Vaginal Birth, the neonate’s first breath expands the lungs and fluid is displaced
>spontaneous respirations happen over the next 24 hours; air displaces the remaining fluid, which is removed by the capillaries and lymphatics
13
Q
Factors That May Interfere with the Neonate’s Ability to Initiate Respirations
A
prematurity or birth asphyxia can affect lung compliance (elasticity) and surfactant production
-childbirth events such as trauma, maternal medications, and the mode of delivery can interfere with normal pulmonary transition
14
Q
Respiratory Distress Syndrome (RDS)
A
developmental disorder of the respiratory system that begins at birth or very soon afterward
-occurs most frequently in infants born with immature lungs
-preterm infants more likely to develop this because of the low surfactant levels that are present in infants less than 36 weeks gestation
>lack of surfactant leads to the sequelae associated with RDS: progressive atelectasis, loss of functional residual capacity, alterations in the ventilation perfusion ratio, and poor lung compliance
15
Q
What Medications Will be Administered if there is a strong likelihood that a Preterm delivery will occur
A
-tocolytic medications (inhibit uterine contractions) to postpone birth; this delay allows for administration of glucocorticoids (e.g. betamethasone) to boost fetal lung maturity
16
Q
Betamethasone
A
glucocorticoid
- boost fetal lung maturity
- given to a woman at least 24 hours before birth if possible to prompt the production of fetal surfactant and hopefully improve respiratory functioning in the neonate
17
Q
Cardiopulmonary Transition of The Neonate At Birth
A
As air enters the lungs, the PO2, rises in the alveoli; causes pulmonary artery relaxation and a decrease in pulmonary vascular resistance
- as the vascular resistance decreases, the blood flow increases, reaching 100% by the first 24 hours of life
- once the pulmonary circulation has been functionally established, blood is distributed throughout the lungs
18
Q
Assessment of Neonates Cardiopulmonary System
A
must occur immediately after birth
- skin color= most important indicator of how well the neonate is making the transition to extrauterine life
- respiratory rate
19
Q
Assessment of Cardiopulmonary System: Skin color
A
typically exhibit central pink hue with acrocyanosis (bluish coloration of the hands and feet)
-in darker-skinned infants, mucus membranes provide a better indication of cyanosis
20
Q
Acrocyanosis
A
bluish discoloration of the hands and feet
-may persist up to 24 hours until peripheral circulation improves
21
Q
Assessment of Cardiopulmonary System: Respirations
A
30 to 60 breaths/min
- breathing pattern often shallow, diaphragmatic, and irregular
- abdominal movements should be in sync with the chest movements
- may experience “periodic breathing”
- apnea is a normal finding
22
Q
Periodic Breathing
A
breathing pattern may include brief pauses that last 5 to 15 seconds
- not usually associated with any change in skin color or heart rate
- no prognostic significance
23
Q
Apnea
A
cessation of breathing that lasts more than 20 seconds
-abnormal in the term neonate and may or may not be accompanied by changes in skin color or a decrease
in the heart rate less than 100 beats per minute
-reported immediately
24
Q
Indicators of Respiratory Difficulties
A
- expiratory grunting and retractions when the neonate is at rest
- breathing rate that is outside the normal range (30-60 breaths/min)
25
Closure of the Foramen Ovale
the foramen ovale is a flap in the septum of the fetal heart that allows blood flow between the left and right atria
-oxygen rich blood returning to the heart from the inferior vena cava crosses from the right atria to the left atria across the foramen ovale; this pathway allows most of the oxygenated blood to bypass the nonfunctioning lungs and supply the aorta and vessels of the heart and head with oxygen
>the right-to-left shunting stops once the umbilical cord has been clamped
-the ventricular and aortic pressures in the left side of the heart rise; the systemic vascular resistance increases while pressure in the right side decreases
-the pulmonary blood vessels respond to the increase in PO2 during lung expansion and introduction of air with vasodilation and a decrease in pulmonary vascular resistance
>these changes cause an increase in blood flow through the pulmonary veins to the left atrium and lead to an increased left atrial pressure that results in closure of the foramen ovale ; because the foramen ovale is capable only of shunting right-to-left, this event closes the shunt; because of the unequal pressures, the foramen ovale, which becomes the fossa ovalis, closes within 1 to 2 hours
-deposits of fibrin and cells seal the shunt, and close by 1 month of age; permanent closure at 6 months
26
What happens to the Foramen Ovale if the infant experiences difficulties such as asphyxia, acidosis, or cold stress during the physiological transition period
the shunt may reopen and allow for continued right to left shunting because of the increased pressure in the right atria
27
Closure of the Ductus Arteriosus
in utero, most of the fetal blood flow occurs across the ductus arteriosus
-functions as the pathway between the pulmonary artery and the descending aorta
-blood flow occurs in a right-to-left direction
>once the umbilical cord is clamped, placental blood flow is stopped and there is an increase in the systemic blood pressure and vascular resistance
-at this point, the lungs oxygenate the blood and the increased PaO2 stimulates the closure of the Ductus Arteriosus
>during pregnancy, the placenta produces prostaglandin E2 (PGE2), a hormone-like substance, that causes vasodilation of the ductus arteriosus; after birth, declining PGE2 levels contribute to the closure of the ductus arteriosus
-in the neonate, a small amount of blood flowing through the ductus arteriosus may produce a small murmur; when present, it can be heard at the left sternal border, 2nd intercostal space; considered innocent, this functional murmur occurs in the absence of any cardiac anomalies and is generally asymptomatic
>closure occurs within first 72 hours of life; permanent closure= 3 to 4 weeks and termed ligamentum arteriosum; permanent closure results from endothelial destruction, connective tissue formation, and subintimal proliferation
28
Closure of the Ductus Arteriosus: If the infants birth transition has been complicated by factors such as asphyxia or prematurity
risk of a return of fetal circulation
- results from continued blood flow through the partially opened ductus arteriosus
- low levels of oxygenated blood flowing through the shunt cause it to dilate, creating a serious transitional complication
29
Closure of the Ductus Venosus
links the inferior vena cava with the umbilical vein
-the umbilical vein delivers 50% of placental blood flow through the ductus venosus into the inferior vena cava and then mixes with the systemic venous drainage from the lower body; blood flow through the left hepatic vein mixes with blood in the inferior vena cava and flows toward the foramen ovale
-oxygenated blood traveling through the umbilical vein enters the left ventricle and supplies the carotid arteries with oxygen
>once the umbilical cord is clamped, cessation of umbilical venous blood return, along with mechanical pressure changes, leads to closure of the ductus venosus
-closure of the bypass route forces enhanced blood flow to the liver
>fibrosis (scarring) occurs in the nonfunctional ductus venosus and termed ligamentum venosum
-closes by the end of the first week
30
Assessing the Cardiovascular Transition
-immediately after birth, the pulse may reach 160 to 180 bpm
-during the first 30 minutes of life, the rate should decline to 120 to 160 bpm
>exhibits a brisk capillary refill (less than 3 seconds is adequate) and a stable blood pressure
31
Neonatal Thermoregulation
newborns ability to maintain a normal body temperature after birth is dependent on factors in the external environment as well as internal physiological processes
-newborns are homeothermic- attempt to regulate and maintain their internal core temperature regardless of varying external environmental temperatures
32
The Neutral Thermal Environment (NTE)
the range of temperature in which the newborn's body temperature can be maintained with minimal metabolic demands and oxygen consumption
-body size and gestational age affect ability to maintain NTE
>normal position of flexion facilitates maintenance of body heat; preterm infants are born with very little adipose tissue and lack muscle development needed to maintain a flexed position for heat conservation
>as the newborn transitions to extrauterine life, the core body temperature decreases in response to the environmental temperature; can fall 0.5 degrees F per minute up to a total of 5.4 Degrees F; most term newborns are able to restore and stabilize at a normal temperature (axillary; 97.7 to 98.6 Degrees F) within 2 to 3 hours after birth
33
Factors Related to Cold Stress
exposure to low environmental temperatures, for a long period of time, cause an increase in oxygen consumption and increased rate of metabolism; leads to cold stress
>high risk for cold stress and ineffective thermal regulation:
-large body area in relation to body mass
-limited subcutaneous fat
-limited ability to shiver
-skin is thin and their blood vessels are close to body surface
34
When the infant is exposed to a cold environment, several physiological adaptations help him to increase heat production:
- increasing the basal metabolic rate and muscle activity to generate heat
- peripheral vasoconstriction to conserve heat
- non-shivering (or chemical) thermogenesis (NST) (heat production)
35
Non-shivering thermogenesis (NST)
newborns are unable to shiver to generate heat
>the sympathetic nervous system responds to skin receptors programmed to recognize a drop in the environmental temperature; once low temp is detected, the receptors alert the SNS
-non-shivering thermogenesis uses the newborn's stores of brown adipose tissue (BAT) to provide heat
>formation of BAT begins around 26 to 30 weeks of gestation; the deposits of BAT increase until 2 to 5 weeks after birth unless they have been depleted by cold stress
36
Brown Adipose Tissue (BAT)
"brown fat"
-highly vascular fat found only in newborns
-gets its name form the rich abundance of blood vessels, cells, and nerve endings that cause it to appear dark in color
-accelerate triglyceride metabolism, triggering a process that produces heat
>rapid metabolism, along with generation of heat, quickly sends heat to the peripheral circulation
>fatty acids are released from metabolized BAT and can cause life-threatening metabolic acidosis
>when elevated fatty acids are released into the blood stream, the infant is at risk for jaundice caused by interference with the transport of bilirubin to the liver
37
4 Mechanisms by which Heat is Lost After Birth
- Evaporation
- Conduction
- Convection
- Radiation
38
Heat Lost: Evaporation
loss of heat that occurs when water is converted into vapor
>if not dried after birth, the neonate loses heat through the evaporation of amniotic fluid on the skin (Insensible water loss (IWL))
-Nursing Interventions: drying neonate after birth, removing wet linens, and immediately placing a hat on the head to prevent evaporation through the scalp
39
Heat Loss: Conduction
the loss of heat to cooler surface via direct skin contact
-occurs when the infant is placed on a cold surface, such as a cold scale, mattress, or examining table
>Nursing Interventions: placing infant on a prewarmed radiant warmer, using warmed blankets, covering scales with blankets prior to weighing, and avoiding the use of cold instruments (e.g. stethoscope)
>can also place skin-to-skin with mother
40
Heat Loss: Convection
loss of heat from the warm body surface to the cooler air currents
-occurs when neonate is exposed to drafts and cool circulating air
>Nursing Interventions: prevent drafts in the birth area (e.g. no ceiling fans), and placing newborn away from doors or windows
-warmly clothed or swaddled
41
Heat Loss: Radiation
heat loss occurs when there is a transfer of heat between objects that are not in direct contact with each other
-walls of the nursery or incubator can be a source
>Nursing Interventions: have a prewarmed radiant warmer present at the birth, avoid placement of crib or incubator by a cold window, and keep cold objects away from neonate
42
Hematopoietic Adaptation: Blood Volume
average blood volume: 80 to 90 mL/kg of body weight
- determined by the timing of umbilical cord clamping
- holding the neonate below the level of the placenta and delaying clamping of the cord may allow up to a 100 mL/kg increase in total blood volume; facilitates a improved transition because of enhanced pulmonary perfusion and the gain of additional iron stores
43
Hematopoietic Adaptation: Erythrocytes and Hemoglobin
at birth, the neonate has a greater number of erythrocytes and higher hemoglobin and hematocrit levels than those found in an adult
>During early fetal development, erythropoiesis (formation of red blood cells) occurs in the liver; at 6 months gestation, the bone marrow becomes the site for hematopoiesis (formation of blood cells); During the later stages, fetal hemoglobin (HbF) is slowly replaced by adult hemoglobin (HbA) (Fetal hemoglobin carries 20 to 50% more oxygen than adult)
44
Neonate: Process of Erythropoiesis
is stimulated by the renal hormone erythropoietin
-RBC production increases in response to a rise in erythropoietin after low fetal oxygen saturation; facilitates adequate tissue perfusion and oxygenation
>After the initiation of respirations at birth, the neonates oxygen saturation rises, causing inhibition in the secretion of erythropoietin; which inhibits production of RBCs
-the neonates erythrocytes (fetal RBCs) have a shorter life span (90) days than do adult RBCs (120) days
-as the neonates RBC count decreases, physiological anemia of infancy may develop and persist for 2 to 3 months
>in the event of hemolysis, the hemoglobin is broken down, and bilirubin is released into the systemic circulation; if large numbers of RBCs are involved, blood levels of bilirubin rise and the newborn becomes jaundiced
45
Hematopoietic Adaptation: Hematocrit
percentage of RBCs within a certain unit volume of blood
-hematocrit levels are higher in peripheral blood samples because of peripheral vasoconstriction and the stasis of blood cells
>Hematocrit for peripheral site: 46 to 68%
>If a hematocrit drawn from a central site is > 65%, they are considered polycythemic
46
Polycythemia
abnormally high RBC count (> 65%)
- places infant at risk for jaundice and organ damage caused by increased viscosity of the blood cells
- at risk for hypoglycemia and respiratory distress
47
Hematopoietic Adaptation: Leukocytes (WBC)
serve as major defense against infection in neonate
-neutrophils, eosinophils, basophils, lymphocytes, and monocytes
>During the first 12 hours after birth, usually remains elevated
>Average: 18,000/ mm3, Normal range: 9,000 to 30,000/ mm3
-infection associated with a decrease in leukocyte count
-sepsis accompanied by increased number of immature leukocytes along with a decrease in total number of platelet count
48
Leukocytes: Neutrophils
act as phagocytes that ingest and destroy small particles of bacteria and cellular debris
49
Leukocytes: Eosinophils
same action of neutrophils but survive for longer periods of time
-important mediators in allergic and anaphylactic responses
50
Leukocytes: Basophils
responders to allergic and inflammatory reactions
51
Leukocytes: Lymphocytes
respond to graft versus host allergic diseases and allergic reactions
52
Leukocytes: Monocytes
clean up old blood cells and cellular debris and remove activated clotting factors from the circulation
53
Hematopoietic Adaptations: Platelets
because of the absence of vitamin k at birth, the neonate is at risk for developing a blood-clotting deficiency during the first few days of life
-Blood factors present to facilitate clotting: factor II (prothrombin), and factors VII, IX, and X
>Range: 150,000 to 350,000/ mm3
>circulating platelets are hypoactive during first few days of life
>given IM injection of Vitamin K1 phytonadione (AquaMEPHYTON) during the initial care to prevent hemorrhagic disease of the newborn
54
Vitamin K
given IM to prevent hemorrhagic disease of newborn
| -helps in blood-clotting
55
Hepatic Adaptation
liver: regulation of blood glucose, iron storage, bilirubin conjugation, and coagulation of the blood
56
Glycogen and Blood Glucose Maintenance
Throughout pregnancy, the fetus receives glucose by way of the placenta
-During the last 4 to 8 weeks of gestation, the glucose is stored as glycogen in the fetal liver and skeletal system for use after birth
-the stressful events associated with the birth process prompt the conversion of fats and glycogen to glucose
>After delivery, an increase in circulating catecholamines triggers the release of glycogen from the neonates liver; glycogen provides a ready source of glucose to the brain and other vital organs
>During the first 3 hours of life, a healthy term newborn may use up to 90% of his livers glycogen stores; it can also use ketones, lactic acid, fatty acids, and glycerol if necessary to maintain adequate supply of energy
>The blood glucose of a term infant should be 70 to 80% of the maternal blood glucose level
>During the first 4 to 6 hours of life, the newborns main source of energy is glucose; the serum blood glucose level drops during first 3 hours and then gradually rises over the next 3 to 4 hours to 40 to 60 mg/dL
-Glycogenolysis (breakdown of glycogen into glucose) can occur if newborn does not receive any exogenous glucose before the initial hepatic and skeletal glycogen stores have been depleted
57
Neonatal Hypoglycemia
can occur after any stressful events (e.g. hypothermia or hypoxia) that increase metabolic demands
-neonates after any stress , rapidly use their glucose stores to assist with the transition process
58
Risk Factors for Hypoglycemia in the Neonate
-prematurity
-postmaturity
-intrauterine growth restriction (IUR)
-large or small for gestational age (LGA or SGA)
-asphyxia
-difficult transition at birth
-cold stress
-maternal diabetes mellitus or preeclampsia
-maternal intake of terbutaline (Brethine)
-infection
-congenital malformations
>because the neonate needs to use its glycogen stores for energy to help in the transition if it is having difficulties or went through a difficult event/ stress
59
Signs and Symptoms of Hypoglycemia in the Neonate
jitteriness, diaphoresis, poor muscle tone, poor sucking reflex, temperature instability (low temperature), respiratory distress, tachycardia, dyspnea, apnea, high-pitched cry, irritability, lethargy, seizures, or coma
>(cold and clammy, need some candy)
60
Neonatal Blood Glucose Assessment
capillary blood obtained from the neonates heel
- when available, heel warmer is used to increase blood flow to the sample site
- area is cleansed with a sterile alcohol pad, and the heel is gently punctured, taking care to avoid the middle area where there is a risk of nerve damage or puncture of plantar artery
- large drop of blood is placed on the test strip, and a sterile bandage is sued to apply pressure on sample site
61
Hepatic Adaptation: Iron Storage
During the last few weeks of pregnancy, iron is stored in the fetal liver
-At birth, the iron store is proportional to the total hemoglobin and length of gestation
-as RBCs are destroyed after birth, the neonatal liver stores additional iron until needed for the production of new RBCs
>At term= 270 mg of iron, 140 to 170 mg of the iron is contained in the hemoglobin
-term infants who are breastfeed do not need additional iron until at least 6 months of age
-if formula fed, given an iron-fortified formula
>at beginning of 6 months, all infants should receive iron supplements or iron-rich foods to prevent anemia
62
Hepatic Adaptations: Conjugation of Bilirubin
```
function of the liver
-conjugation is a process that converts the yellow lipid-soluble (non-excretable) bilirubin pigment (present in bile) into a water soluble (excretable) pigment
>jaundice= results from the accumulation of bile pigments associated with excessive amount of bilirubin in the blood (hyperbilirubinemia)
>in normal conjugation, bilirubin attaches the the blood albumin and is transported to the liver; in the liver, the unbound bilirubin detaches from the albumin and is conjugated with glucuronide, this process produces water soluble direct bilirubin which is excreted into the common duct and duodenum; normal intestinal flora reduce the direct bilirubin into urobilinogen and stercobilinogen which is then excreted as a yellow-brown pigment in the stools, and a small amount excreted through the kidneys
>term infant produces 6 to 10 mg of bilirubin/kg
```
63
Bilirubin
is a highly neurotoxic substance
-produced from the hemolysis (breakdown) of RBC's
-normal= 3 mg/dL or less
-elevated blood levels of unconjugated bilirubin ("indirect") can result in kernicterus ("yellow nucleus")
>the newborns liver must be able to convert the fat-soluble (non-excretable) bilirubin into a water-soluble (excretable) for by way of conjugation
64
Kernicterus
"yellow nucleus"
the deposition of unconjugated bilirubin in the basal ganglia of the brain and to the permanent neurological sequelae of untreated hyperbilirubinemia
65
Jaundice
characterized by a yellow coloration of the skin, sclera, and oral mucus membranes
-first noticed in the head, and progresses to the thorax, abdomen, and extremities
>results from accumulation of bile pigments associated with an excessive amount of bilirubin in the blood (hyperbilirubinemia)
-neonatal jaundice occurs during first week of life from excessive levels of unconjugated bilirubin; first noted on the face and sclera when the serum bilirubin levels reach 4 to 6 mg/dL, then progresses as the total serum bilirubin (TSB) rises to 6 to 7 mg/dL
66
Factors that May Influence Bilirubin Levels in the Neonate
- cultural background: Chinese, Japanese, Korean, Alaska Native, and Native American
- perinatal events (e.g. delayed cord cutting, breech presentation, the use of Pitocin)
- prematurity
- maternal diabetes
- excess bilirubin production (e.g. hemolytic disease such as Rh(D) isoimmunization and ABO incompatibility; sepsis; metabolic disorders)
- delayed feedings
- liver immaturity
- birth trauma
- family hx of jaundice
- neonatal complications (e.g. asphyxia neonatorum, cold stress, and hypoglycemia)
67
Development of Pathological Jaundice
occurs within the first 24 hours of life
-may exhibit TSB that increases by 0.5 mg/dL per hour or 5 mg/dL per day
>diagnosis: when TSB climbs greater than 12.9 mg/dL in term and 15 mg/dL in preterm
>pathological jaundice results from disorders that cause excessive hemolysis of RBCs, leading to an increased production of Bilirubin
-excessive blood cell break down may result from polycythemia (high RBC count) or increased bruising after a traumatic delivery; infections, metabolic disorders, and incompatibilities between the mothers and newborns blood (Rh incompatibility)
68
Breastfeeding-Associated Jaundice (Early-Onset Jaundice)
occurs when there is a decreased intake of breast milk and a decreased passage of meconium
-occurs between the 2nd and 4th days of life
-the total serum bilirubin (TSB) levels peak at 15 to 19 mg/dL by 72 hours of life
>associated with poor feeding practices and is not related to the composition of the milk
>Interventions: early and frequent feedings (10-12 times/day) with avoidance of formula and glucose supplementation
69
Breast Milk Jaundice (Late-Onset Jaundice)
occurs in the full-term infant
-later onset than breastfeeding jaundice and appears after the first week of life and peaks around day 10
>bilirubin levels continue to rise and peak at 2 to 3 weeks of life
>may be related to factors in human milk that inhibit the conjugation or decrease the excretion of bilirubin
-no intervention is necessary; if continues to breastfeed the TSB gradually declines over course of few weeks; some recommend temporarily halting breastfeeding for 48 hours to allow serum bilirubin levels to decline
70
Gastrointestinal Adaptation: Stomach and Digestive Enzymes
neonates stomach capacity is 6 mg/kg at birth, and by the end of the first week of life, its increased to 90mL
>in utero, the GI system reaches maturity around 36 to 38 weeks of gestation where there is sufficient enzymatic activity for digestion and the transport of nutrients throughout the body
-to nutritionally thrive, newborns must be able to digest essential carbohydrate disaccharides (lactose, maltose, and sucrose)
>Lactose, primary carbohydrate in breast milk, is easily digested and readily absorbed
-pancreatic amylase, lacking at birth and during few months of life, makes it difficult to digest fats
-decreased production of lipase and bile acids, limit further ability to absorb fats; usually increases during first few weeks of life
71
Gastrointestinal Adaptation: Intestinal Peristalsis
Immediately after birth, air enters the stomach and reaches the small intestine within 2 to 12 hours
- Bowel sounds present within first 15 to 30 minutes of life because air has entered the stomach and small intestines
- stomach empties intermittently, at beginning of the feeding and up to 2 to 4 hours after
- salivary glands are immature, little saliva is produced for the first 3 months
- cardiac sphincter (between esophagus and stomach) is immature, not unusual for newborn to regurgitate small amounts following feedings
- pass first meconium within 8 to 24 hours of life; if absence by 72 hours = obstructive bowel problem
72
Meconium
consists of particles found in the amniotic fluid such as vernix, skin cells, hair, and cells that have been shed by the intestinal tract
- greenish-black and viscous; gradually change to transitional stools that are thinner and greenish brown to yellowish-brown
- newborn may pass stools from one to ten times a day over a 24- hours period
73
Genitourinary Adaptation: Kidney Function
kidneys not mature and fully functional until after birth when the newborn becomes responsible for elimination of waste products
>the neonates elevated hematocrit and low blood pressure may lead to a decreased GFR; kidneys are then unable to dispose of fluid rapidly and tend to reabsorb excess sodium
-as kidneys mature and enlarge, the GFR rapidly increases during first 4 months of life
-urine specific gravity ranges from 1.002 to 1.010; term newborns unable to concentrate urine (reabsorb water back into the blood) because kidney tubules are short and narrow; lead to losses of substances (amino acid and glucose)
>Bladder capacity: 6 to 44 mL of urine
-usually void 2 to 6 times in a 24-hour period; total output of 15 to 60 mL of urine/kg/day; by 4th day void up to 6 times or more in a 24-hour period
>because the kidneys have difficulty concentrating urine and removing waste products from the blood immediately after birth, small amounts of protein and glucose frequently present in urine; Urate crystals, which are pink-red in color, are excreted in the urine and can be mistaken for blood; the crystals ("brisk dust spots") disappear after the first few days of life as kidneys mature
74
Three Factors enable the kidneys to maintain bodily fluids and excrete urine in the term newborn
- the nephrons are fully functional by 34 to 36 weeks of gestations
- the glomerular filtration rate is lower than that of the adult
- there is a limited capacity for the reabsorption of HCO3 and H+
75
Urate Crystals
"brick dust spots"
because the kidneys have difficulty concentrating urine and removing waste products from the blood immediately after birth, small amounts of protein and glucose frequently present in the urine
-urate crystals, which are pink-red in color, are excreted in the urine and can be mistaken for blood
-disappear after the first few days of life as kidney function matures
76
Newborns and Fluid
during first 24 to 48 hours, full-term newborns need 60 to 80 mL/kg of fluid to maintain adequate fluid balance
-increases to 100 to 150 mL/kg per day after the first few days and a urine output of 1 to 3 mL/kg/hour
>careful monitoring of fluid is essential
77
Assessment of Appearance of Newborns Urine
is essential
- after first voiding, urine may be cloudy (from mucus) and contain urate crystals
- be odorless and straw colored to clear and the fluid intake increases
78
Immunological Adaptation
remains immature after birth and may not adequately react to an infectious process
-newborn receives immunity through active acquired immunity and passive-acquired immunity
>three primary immunoglobulins (humoral antibodies): IgG, IgA, and IgM; important in protecting the newborn against bacterial and viral infections
79
Active Acquired Immunity
pregnant woman's exposure to illness and immunizations prompts the development of antibodies in active acquired immunity
-this is how infant continues to develop antibodies; either by direct exposure to an infection or through immunization schedule recommended by American Academy of Pediatrics (AAP)
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Passive-Acquired Immunity
infant receives through antibodies that have been passed through the placenta by way of IgG immunoglobulins
>disappears by 6 months of age
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IgG Immunoglobulin
only immunoglobulin able to pass through the placenta before birth
-occurs in third trimester
-at birth, full-term infants already acquired immunity for tetanus, diphtheria, smallpox, measles, mumps, poliomyelitis, and a host of other bacterial and viral diseases
>preterm infants born before 34 weeks at higher risk
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IgA Immunoglobulin
important in protecting the infant against gastrointestinal and respiratory infections
-Sources of IgA: Colostrum and Breast Milk
>IgA not detectable in system until 2 to 3 weeks of life; unless elevated levels are present from a viral infection
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IgM Immunoglobulin
produced in response to blood group antigens, gram-negative enteric pathogens, and certain maternal viruses
-early in utero, 10 to 15 weeks gestation
-detectable levels reached by 30 weeks gestation
-levels increase rapidly after birth
>elevated levels at birth may result from placental leaks, or from antigenic stimulation that occurred in utero, thus an increased IgM titer = exposure to an intrauterine infection such as syphillis of one of the TORCH infections (toxoplasmosis, rubella, cytomegalovirus, and herpes virus)
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The First Period of Reactivity
- this stage is the first period of active, alert wakefulness that the infant displays immediately after birth
- quiet, alert state
- lasts 30 minutes; time to get to know the baby
- newborn very alert and moves around energetically while taking in new surroundings
- heart rate and respirations are rapid, infant may exhibit occasional nasal flaring and grunting that can last up to 15 minutes
- muscle tone and motor activity increased
- body temperature decreased
- bowel sounds absent and minimal saliva production
- best time to initiate breastfeeding
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The Period of Inactivity and Sleep
after the first period of reactivity, the neonate settles into the sleep phase
- displays decreased muscle activity, and is difficult to awaken, resting quietly and recovering from the stress of birth
- heart rate and respirations return to a normal range
- central perfusion and general coloring should be excellent (can still show acrocyanosis)
- sleep period may last from a few minutes to 2 to 4 hours
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The Second Period of Reactivity
newborn awakens and becomes alert once again
-most show signs for feeding readiness (e.g. sucking and rooting) and are eager to begin feeding if not previously fed
-becomes increasingly more responsive to exogenous and endogenous stimulation, which can cause the heart rate to become easily altered; may experience brief periods of tachycardia, tachypnea, and rapid changes in color and muscle tone
>nurse be aware of newborn behaviors
-bowel sounds usually present, and may have increased oral mucus, causing episodes of gagging and vomiting
>monitor airway, and have suctioning available
>patients taught how to use a bulb syringe
>GI system becomes more active; not unusual for newborns to pass their first meconium stool or void if they have not already done so
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Newborn Behavioral States: Sleep states
- Deep sleep: infants eyes are closed, no eye movements occur, and breathing is regular and even; jerky motions are common although behavioral responses to external stimuli are delayed; heart rate ranges from 100 to 120 bpm
- REM sleep: infants respirations are irregular, the eyes are closed with REMs visible through the lids, and irregular sucking motions are common; minimal activity; environmental and internal stimuli may prompt a startle reaction and a change of state
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Newborn Behavioral States: Alert State
the quiet alert state, occurs during the first 30 minutes after birth = first period of reactivity and an excellent time for parents to enjoy bonding
-periods of alertness are brief during first 2 days of life as the infant recovers from events associated with birth
-then infants alert states are from choice or necessity; hunger, cold, and heat
>4 phases: drowsy or semi dozing, quiet alert or wide-awake, active alert, and crying state
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Drowsy or Semi-dozing State
open or closed eyes; fluttering eyelids; semi-dozing appearance; and slow, regular movement of extremities
-is a delayed response to external stimuli
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Quiet Alert or Wide-awake State
infant is alert and follows and fixates on attractive objects, faces, or auditory stimuli
- minimal motor activity
- delayed response to external stimuli
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Active Alert State
eyes are open
- motor activity intense
- displays thrusting movements of the extremities
- environmental stimuli increase the motor activity
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Crying State
jerky movements accompany intense crying
- crying serves as a distraction from unpleasant stimuli such as hunger and pain
- allows infant to discharge energy and elicits a helpful response from the parents
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Summary Points
- Surfactant, a lipoprotein that reduces surface tension, is essential in keeping the lungs expanded during expiration
- initiation of the neonate's first breath is influenced by chemical, sensory, thermal, and mechanical factors
- successful cardiopulmonary adaptation in the neonate is dependent on 5 major changes r/t aortic, venous, and pulmonary pressures and closure of the foramen ovale, ductus arteriosus, and ductus venosus
- a number of factors, including body size and gestational age, affect the neonate's ability to maintain a neutral thermal environment
- heat loss may occur through the process of evaporation, conduction, convection, and radiation
- the neonate's liver has essential roles in iron storage, carbohydrate metabolism, bilirubin conjugation, and blood coagulation
- the neonate receives immunity through active acquired immunity and passive acquired immunity
- the newborn exhibits two periods of reactivity and two behavioral states that may be divided into sleep states and alert states
