ngd week 3 objectives

7/28/2019 NGD Week 3 Objectives

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NGDWeek3 Fetal NeonatalTransition

1. Explainthe physiologicaltransitionsthat occurat birth andexplainhowalterationsin theseprocessescan causedisease. Transitionsincludemoving

fromplacentaldependenceto independentfunctionfor gas exchange,nutritionalneeds,metabolicfunctionsandimmunologicalprotection.

NEWBORN WITH RESPIRATORY DISTRESS

**SYMPTOMS OF NEONATAL RESPIRATORY DISTRESS Dusky in room air Tachypnic

Nasal flaring/intercostal indrawing/grunting

DIFFERENTIAL DIAGNOSIS FOR NEONATAL RESPIRATORYDISTRESS

TTB

HD/RDS Meconium Aspiration syndrome Non-pulmonary causes

o Anemia, Medication, Pneumothoraxo Congenital heart disease or malformationo Upper airway obstructiono Persistent pulmonary HTN

Cause/ Effects Prevalence andpopulation

Diagnosis Treatment

TransientTachypnea ofNewbor

n

wetlung

Failure of fluid to leavelungs fully at birth

Normally increasedcatecholamines in laborincreased Nareabsorption+Vaginal delivery canalso squeeze fluid out oflungs

Failure of this failureto clear lungs of fluid

More likely in term ornear term infants

More likely in infantsdelivered by C-section

Most common causeof neonatalrespiratory distress

CXR: hyperinflation of lung,(hyperaeration) flat domes ofdiaphragm, vascular markings in lungs,prominent interlobular fissures

Tachypnea

Intercostal retractions, grunting, nasalflaringindicate difficulty breathing(increased force and effort in breathing)and low gas exchange

Hypoxia without hypercapnia

Cyanotic, dusky color

Self resolves in1-3 days (extralittle time forreabsorption offluid)

Respiratoryfailure is unlikelyusually mild-moderaterespiratorydistrress

RespiratoryDistress

Decreased surfactant inimmature lungs

Premie babies,immediate onset

CXR: ground glass, loss of cardiacsilhouette, loss of diaphragmaticsilhouette, small lung volume

Surfactant withsupportive care


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Syndrome(HyalineMembraneDisease)

Increased surfacetension in alveolus increased effortrequired to inflate airspaces

Will dissipate whenbabe begins makingsurfactant

May see atelectasis (collapsed lung)

Histology: hyaline membranes andcollapsed airspaces

Tachypnea

Intercostal retractions, grunting, nasalflaringindicate difficulty breathing

(increased force and effort in breathing)and low gas exchange

Hypoxia with hypercapnia



Varying needs ofrespiratorysupport and O2

MeconiumAspiration

Aspiration of meconiumcaused by stress duringdelivery

Obstruction of smallairways and alveoli

Presents asPneumonitis, disruptssurfactant, mechanicaldisruption of airway

Most likely in cases offetal distress, difficultlabor

Usually stainedamniotic fluid too

Usually full terminfants >34 weeks

CXR: atelectasis, consolidation,hyperinflation of lungs, air trapping,spontaneous pneumothorax

Audible grunting, severe retractions(subcostal, intercostal, sternal)

Pneumothorax(air inthepleuralspace)

Idiopathic, or 2 tomechanical ventilation(ie too much air or toomuch force ofventilation, leading togas escaping intopleural space)

Primarily occurs inbabies with lungdiseaselike RDS,aspiration syndromes,ventilation, CPAP

Forces air out intopleural space via lunglesion/laceration

ACUTE increase in respiratory distressand O2 requirements

Transillumination of chest cavity

CXR: hyperaeration of lungs

If severe need 1way valve chesttube (moderateto largepneumothoraxrequiresdrainage)

Diaphra Developmental defect CXR- hypolastic lungs and obvious Surgery


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gmaticHernia

(bowel loops, liver,spleen) in chest cavity

defects


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2. Review thermoregulation, with special emphasis on the neonate(continuation from PRIN)

Fetus has a 0.5OC higher temperature than that mother with heat transfer viaplacenta and suppression of thermogenesis

After birth, it is exposed to cooler environment with all kinds of heat transferremove heat from the baby Conduction, Convetcion, Evaporation, Radiation

Babies have brown fat which are mitochondria rich to hydrolyze fat resulting inheat production

3. Explain the basis for unique congenital, transplacental and neonatalinfections and the responses to and sequelae of these infections

Innate immunity

Complement (C)o NO placental transfer all made by infanto At birth, 2/3 adult levels of C does not gain full function until 2 wkso Increased risk of infection with extracellular bugs in first 2 weeks

(neonatal premature and term infant)o eg. E coli sepsis (frequently from mother GI tract)

Neutrophilso Neonate has lower BM storage pool, and lower expression of migration

receptorso Lower phagocytic activity; tendency to deplete neutrophils neutropeniao Increased risk of infection with extracellular bugs in first 2 months

(premature and term infant)

Adaptive immunity

B cellso Complete lack of anti-polysaccharide Abo Lower levels of IgG, A (and M, if premature infant) than adulto Only IgG transported across placenta (passive fetal Abs), but most of

them transferred in the last trimester, so only term neonates have similarlevels to mother

o Slower and decreased response, especially to encapsulatedbacteria (Group B Strep!)

T cellso Total numbers and TCR diversity in term neonates essentially the same as

mother; however, they are nave in phenotype and function higheractivation threshold slower to respond

o

Increased susceptibility to rapidly spreading intracellular infection(eg. CMV)

Barrier Skin (chemical and physical barrier and immune organ)

Stratum corneum only develops >32 to 34th gestational weeko Rapidly develops within 2 weeks of birth

Premature infants: initially decreased physical barrier Increased susceptibility to infections with skin flora for premature


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infants and briefly around birth (eg. Coagulase negative staphylococci)

Exposure Pregnant = sexually active

STDs (Treponema pallidum, HSV, HBV, HIV etc) Placental/fetal tropism : Listeria, Malaria Increased susceptibility to infections with STI bugs

Note: congenital syphilis can be prevented with one simple test and one simpleshot of penicillin, if indicated. If untreated, intrauterine death, perinatalmortality, or overt symptoms result.

Exposure Vaginal Colonization during pregnancy

Lactobacilli consistently high GBS typically rises in the last 3-4 weeks of pregnancy (~36wks GA)

o Tests for GBS therefore done at 36 weeks gestation, not earlier

Exposure postnatal colonization = increased exposure to all kinds of bugs

Highest risk of infection is at birth!

4. Explain how the unique characteristics of newborn infants affectpharmacokinetics, drug efficacy and drug toxicology

Particularly in the first year of life, dramatic developmental changes in the physiologicaland biochemical processes that govern drug pharmacokinetics take place. Thesechanges have significant consequences for the way that infants respond to and dealwith drugs. The major differences relate to body composition and the ADME processesof Pharmacokinetics (Absorption, distribution, metabolism, excretion).

Absorption

Oral delivery:increased gastric pH Transdermal delivery:stratum corneum is thinner

Distribution

Babies are born weto Increased proportion of total body water compared with adults

o Increases the volume of distribution of hydrophilic drugs

Neonates have fewer plasma proteins

o reduced overall protein content since it takes time for the proteins to befully synthesized

o lower binding capacities of those proteins that are presento Increases the free fraction of drugs that are normally extensively protein

bound With less protein binding thereis a higher overall fraction of free

(active) drug compared to the adult (protein bound) situation, againraising the risk of adverse effects.

the blood-brain barrier is also not fully developed at birth, and this results in anincreased susceptibility to CNS drugs and related side effects.

Metabolism


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Both the Phase I and II enzyme systems are incompletely developed in theneonate, and it takes at least 6 months to reach near adult levels

o Especially the case with P450 enzymeso impairment in the capacity for drug elimination

Excretion

Renal function is incompletely developed, and in fact for the first year of life

GFR and renal tubular secretion only function at ~20% that of an adult. Thismarkedly impairs the capacity for drug elimination in the urine and results inincreased drug half lives and decreased clearance

This is even more critical in babies who are born prematurely, where thesedifferences are more dramatic yet.

5. Describe infant development (birth to 2 years) in cognitive, communication,fine and gross motor, adaptive/activities of daily living and social/emotionalterms

CognitiveThe best measure of cognitive development in infancy and childhood is communication

0 4 Mo: Out of sight, out of mind 4 8 Mo: Infant will look for fallen object or reach for partially hidden object

o Infant has learned that if an object is out of sight, it may still exist andhave fallen on the ground.

8 12 Mo: Infant will search for a completely hidden object 12 18 Mo: Infant will search for an object after seeing it being moved 18 24 Mo: Infant will look puzzled and continue to search for missing object

o The early understanding that objects continue to exist no matter wherethey were last seen

Communication Components of communication include receptive and expressive languageo Literacy development included here

Early language development requires interaction with RESPONSIVE sources, notTV.

Expressive Language Pre-linguistic phase:

o 1 4 Mo: Cooingo 4 8 Mo: Babbling and non-specific da-da/ma-mao 8 12 Mo: Specific da-da/ma-ma, then first true word at approx. 1 year

Linguistic Phase

o 12 18 Mo: Single words (Minimum 10 different words by 18 months)o 18 24 Mo: 2 word sentences by 2 years of age (Minimum)

Receptive Languageo 1 4 Mo: Orientates to voiceo 4 8 Mo: Responds to own name and tones of voiceo 8 12 Mo: Understands Noo 12 18 Mo: Follows 1 step commands; points to body parts when askedo 18 24 Mo: Follows 2 to 3 step commands; points to pictures when asked


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Literacy Development Early literacy development is a predictor of academic success and other outcome

measureso By 6 months: Infant will look at a booko 12 18 Mo: Infant will point to pictures; brings book to parent to reado 18 36 Mo: Infant will carry books with him/her; wants same story over

and over

MotorMotor skill attainment DOES NOT predict cognitive development; however, early motordelay may be the first indicator of a range of developmental problems such as cerebralpalsy

Fine Motor (visual and fine motor tasks)o Less than 1 Mo: Visual fixationo 3 Mo: Can bring hands to midlineo 6 Mo: Puts toys in moutho 8 Mo: Pincer graspo 9 Mo: Grasp and figures out how to ring a bell

Gross Motoro Gross motor development is dependent on several factors

Balance of extensor and flexor tone Evolution of protective and equilibrium responses Decline of obligatory primitive reflexes

Moro reflex persists until 4 mo. Asymmetric tonic neck reflex persists until 6 mo. Postural reflexes

o Neonates tone is predominately flexoro Lower extremity hyperreflexia is common in infants under 4 monthso Extensor plantar response is seen under 12 months

o Gross motor milestones 4 Mo: Rolls prone to supine 5 Mo: Rolls supping to prone 6 Mo: Sits unsupported 8 Mo: Crawls 9-10 Mo: Cruises 12 Mo: Walks 15 Mo: Runs 18 Mo: Stairs with alternating feet

Adaptive/activities of daily living Involves the integration of all developmental domains into daily life

o E.g. dressing, feeding, self-care, getting along in daily life Should develop at the same rate as intellectual development

Social/Emotional Attachment - Specific bi-directional bond that develops between children and

caregivers.o Caregiver must be emotionally available, perceptive, and able to meet the

childs needs


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o Infant helps in the process by being aware, alert and reactive to caregiver Process starts in utero and continues to develop overtime

o Secure attachment leads to better coping with stress, better performanceat school and lays the foundation for relationships over the life of the child

It allows you to go out on a limb and take risks more sense ofsecurity

Social/Emotional Milestones

o By 3 Mo: reciprocal interactions between infant and caregiver; empathy isrecognizedo 3-5 Mo: Infant demonstrates a clear preference for their primary

caretakerso 9 Mo: Stranger anxiety developso 18 Mo: Empathy is demonstrated


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Developmental Milestones Summary Table

Age Cognition Literacy GrossMotor

FineMotor

Receptivelanguage

Expressivelanguage

Social/emotional

Play

Birth-1month

Turns tovoice

Range ofcries

1-4months

Roll tosupine

Bringshands tomidline

Searches forspeaker witheyes

Babbling,cooing

Preference forprimarycaregivers

Thumbsucking

4-8

months

Visually

follows anobject beingdropped

Looks at a

book, likesstorytime

Roll supine

to proneand can situnsupported

Toys in

mouthPincergrasp

Responds to

own nameand tones ofvoice

Babbling, da-

da

Bangs toys

and putsthem inmouth

8-12months

Finds anobject afterwatching itbeinghidden(1 towel)

CrawlCruiseWalk

GraspsFigures outhow to ringa bell

Understandsno

Jargonspeech,mama, dada,specificwords(single)

Stranger anxiety Peek a boo

12-18months

Infantsearches ofobject afterseeing itmoved (2towels)

Points topictures ina book.Brings bookto parents

Run 1 stepcommands,points tobody parts

10 words by18 months

Empathy Symbolicplay

18-24months

Knows

object existseven whenthey aregone(missesobject whenabsent)

Carries

books.Wants thesame storyover andover

Stairs 2-3 step

commands,points topictureswhen asked

2 word

sentences(2 words by2)

Imaginative

play


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Case Objectives

1. Describe the cardiorespiratory adaptations at birth (the transition from fetalto neonatal life)Source: Kliegman

Birth:o Rapid decrease inpulmonary vascular resistance due to

Mechanical expansion of lungs: increase in arterial Po2 ***continually remodelling over first few weeks further decrease

pulmonary resistance- e.g. thinning of vascular smooth muscle,recruitment of new vessels.

o increase in systemic vascular resistance due to removal of low resistance placental circulation

Result:o Output from right ventricle follows the path of least resistancepulmonary

circulation Shunt through ductus arteriosus reverses, becomes left to right,

because pulmonary vascular resistance now lower than systemicvascular resistance

Ductus arteriosus will eventually close due to high arterial PO2(functional closure usually by 10-15hr), becomes theligamentum arteriosum.

o Increased volume of pulmonary blood flow returning to left atrium from thelungs increases left atrial volume and pressure, closes foramen ovale(usually functionally closed by 3 mo, may remain probe patent for severalyears)

o Removal of placenta results in closure ofductus venosus.o Left ventricle coupled to high resistance systemic circulation, wall thickness

and mas will nstart to increase.

2. Discuss how infection alters this adaptationSource: Kliegman

As mentioned in the objective above, the cardiopulmonary transition relies on thedecrease in pulmonary vascular resistance. This decrease is due to vasodilation ofpulmonary vessels secondary to filling of lungs with gas, rise in PaO2, reduction inPaCO2, increased pH, and release of vasoactive substances.

Infection will alter these changes. For example pulmonary edema secondary topulmonary infection will interfere with filling of lung with gas, and will decreasePaO2 and increase PaCO2.

The result is vasoconstricted pulmonary vessels pulmonary resistance does notdecreasepersistent pulmonary hypertension of the newborn. In our PBL case, GBS infection can cause this.

ngd week 3 objectives

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