Fnk 201 Physiology Neonate

8/6/2019 Fnk 201 Physiology Neonate

1/21

FNK 201

NORMAL NEONATES

OBJECTIVES:

1.DESCRIBE the PHYSIOLOGY of theNEWBORN

2.EXPLAIN the MECHANISM of the FIRST

BREATH of a NEWBORN

3.DEFINE APGAR SCORING


2/21

PHYSIOLOGY of the NEWBORN

At birth the Newborn must undergo rapid,profound physiologic changes to adapt to extrauterine life.

Understanding these physiologic changes isimportant for the nurse who must assess,whether or not the Newborn is making asuccessful transition


3/21

IMPORTANCE of TRANSITIONAL EVENTS

The day of birth is a momentous day , perhaps

the most important day in an individuals life.

It is important not only because it is temporally

first, and all subsequent days and years of life

are dependent upon its having gone well, but ,

more importantly, because greater

physiological adjustments are required in thefirst hours after birth that will be necessary for

the remainder of ones lifetime.


4/21

PHYSIOLOGICAL ADJUSTMENTS

A Newborns survival depends on making

the correct physiological adjustments.

Some babies make the transition

smoothly, while for others the process is

complicated. The risk of dying in those

first few hours is greater than on any day

( or week or even a year after).Likewise ,the risk of being damaged in the process

of birth and transition -

is also very high.


5/21

TO ACHIEVE PHYSIOLOGICALADJUSTMENTS.-the adaptations

necessary for the transition toextrauterine life ,the Newborn

must:

1. Initiate breathing and quickly maintainregular respirations of the proper depth

to meet metabolic needs for Oxygenuptake and Co2 excretion


6/21

2.Go from a fluid filled to a gas filled lungs.

This involves generating enough opening pressure

to overcome frictional resistance of the airways

and elasticity of the chest - wall, lung tissues and

curved surfaces of the millions of alveoli.

3.Redirect deoxygenated blood from the rightheart that previously bypassed the lungs, sothat

it all flows through the lungs.

4.Close the foetal shunts (represented byForamen Ovale,Ductus Arteriosus, and Ductus

Venosus


7/21

5.Provide Energy to maintain body temperatures

and support metabolic processes.

6.Dispose of waste products produced by food

absorption metabolic processes and tissue

breakdown.

7.Ward off infection ( usually for the first time).


8/21

In the first two issues listed above ,

Rearrangements of mechanical forces within the

thorax will have to take place.

The second two issues involve equally profound

rearrangements of flow, pressure, and resistancewithin the Pulmonary and Systemic Circulation

Last three adjustments require a tremendousmobilisation of energy reserves and outpouring

of hormones and a stimulation of enzymes


9/21

A nurse needs to understand clearly all theseprocesses of transition in order to ;

(i) Nurture and support those infants who are notmaking the proper adjustments, intervening tohelp them complete their tasks or re-right the

balance as it begins to tip in the wrong

direction.

(ii) Appreciate how excessive birth stress,congenital defects and peri-natal diseases can

interfere with these processes and(iii)Know what new problems can arise simply as a

result of the babys failure to properly makethe transition.


10/21

As you study the various physiologic

adjustments or adaptations made by the

neonate in transition, it is important toremember that some of the functional

adaptations occur at a faster rate than others,

but proper timing or order of succession is

still crucial.

A nurse should know how fast each of the

steps should go, how one follows the other

,and how this succession is dependent upon

each steps going well in order for the

adaptation to reach completion.


11/21

There are crucial interrelationships betweenthe various processes, as one is accomplished,

the others are automatically assisted in theirprocess. So when one transitional or adaptiveprocess is delayed, the other processes arealso likely to be adversely affected . Having

previously gone well, if things start to slowdown in their normal progress, they mightreverse direction altogether, and then spiraldownward to a potentially damaging or fataloutcome. In addition , such a downward trendbecomes progressively more difficult to turnback into the right direction with passing time.


12/21

The quicker one identifies a slowing down of

transition from its normal course, or a

reversing of the trend in a wrong direction,the quicker one can intervene; and the quicker

one intervenes, the more likely one is to

achieve success thus avoiding sequelae(lasting damage) or death in this most crucial

period of life.


13/21

ONSET OF BREATHING

How is it that NEWBORN BABIES NORMALLY KNOWJUST WHEN TO START BREATHING?

A premature onset of gasping respirations while a baby

is still in the mother would produce AspirationSyndrome, whereas delayed onset of breathing afterdelivery would lead quickly to Asphyxia Neonatorum.

The normal term Newborn takes his first breath withinseconds after being delivered and not before by30seconds he is breathing regularly; for a preterm,initial breath and time till regular breathing, maybedelayed 15 to 30 seconds.


14/21

RESPIRATION

Initiation of respiration is the most urgentphysiological adjustment for a Newborn.

Achieved in response to:

Stimulation of the Respiratory centre in theMedulla oblongata by a high level of CO2

Chest wall .previously compressed by the birth

canal, suddenly expands, allowing the air torush in.

Temperature change or the shock of beinghandled may cause baby to gasp.


15/21

CIRCULATION

Temporary structures of foetal circulation

must close to provide effective circulation for

extrauterine existence.

Closure of the structures depends upon the

beginning of respiration.

The lungs expand with the onset of

respiration, which opens up the Pulmonary

capillary bed- creating a negative pressure.


16/21

Cont. Blood now flows from the Pulmonary

Artery through to the Lungs (to balance

pressure ) for Oxygenation. The ductus

arteriosus contracts as the lungs expand

eventually becomes a supporting ligament in

the thorax.The increased blood flow to the Lungs reduces

pressure on the Right side of the Heart and

increases pressure on Left side of the heartWith the equal pressure in the heart the

valve-like Foramen ovale is no longer being

forced open, so it closes.


17/21

Umbilical vessels contract at birth

Blood clots in the;Umbilical Vein and Arteries

and in the Ductus Venosus and Hypogastric

Arteries these structures remain as fibrousbands .


18/21

HEAT REGULATION

The Newborn has a limited ability to regulatebody temperature in relation to theenvironment in danger ofHypothermiaunless preventive measures are taken.

Important Factors to consider;Poor production of heat low metabolic rate

Temperature change environmentconditioned for the comfort of the labouringmother and the Accoucher.

Vasoconstriction of skin vessels occurs topreserve body heat


19/21

Cont.

Baby is born wet , and so loses heat by

Evaporation

Has a large body surface in proportion to weight

His hypothalmic temperature-regulating

centre is not fully mature, so processes ofShivering and Sweating are poorly developed.

The Newborn is dried as soon as it is practical todo so, and the time of his exposure to cooler

environment is minimised


20/21

DIGESTION/ELIMINATION

In utero , the foetus received adequate nourishment inthe simplest form.

After birth, babys digestive system must be able to

digest and absorb food as well as eliminates wastes. The food designed by nature to introduce the babys

digestive system to the process of digestion is calledColostrum.

Colostrum: highly nutritive,easily digested (its proteinin the form of lactoglobulin),contains vitamins andimmune bodies,and functions as a laxative.

The process of taking in and digesting food stimulatesperistalsis of bowels and results in the passage of

Meconium


21/21

IMMUNITY

The mature baby has received antigens and passive immunity tocertain infections from the mother in last 6 or so weeks beforebirth. Leaving a sterile environment he may encounter micro-organisms and other antigens suddenly. To develop activeimmunity, may take some weeks.

Maternal Immunoglobulin G crosses the placenta to give the

foetus passive immunity The process of birth itself exposes the newborn to new organisms.

Candida albicans (thrush ), the gonococcus and herpesvirus maybeencountered in the vagina.Hospital delivery, likely to encounterStaphylococcus aureus, an organism to which baby may have littleresistance.

To compensate for poorly-developed immunological status ofNewborn; careful antenatal supervision and exclusion or treatmentof all possible Infections, aseptic delivery techniques and extremecare exercised in all aspects of the Newborns management, arevital

Fnk 201 Physiology Neonate

Documents

Transcript of Fnk 201 Physiology Neonate