Date post: | 07-Apr-2018 |
Category: |
Documents |
Upload: | josateki-qioniwasa |
View: | 219 times |
Download: | 0 times |
of 21
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
8/6/2019 Fnk 201 Physiology Neonate
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
8/6/2019 Fnk 201 Physiology Neonate
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.
8/6/2019 Fnk 201 Physiology Neonate
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.
8/6/2019 Fnk 201 Physiology Neonate
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
8/6/2019 Fnk 201 Physiology Neonate
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
8/6/2019 Fnk 201 Physiology Neonate
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).
8/6/2019 Fnk 201 Physiology Neonate
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
8/6/2019 Fnk 201 Physiology Neonate
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.
8/6/2019 Fnk 201 Physiology Neonate
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.
8/6/2019 Fnk 201 Physiology Neonate
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.
8/6/2019 Fnk 201 Physiology Neonate
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.
8/6/2019 Fnk 201 Physiology Neonate
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.
8/6/2019 Fnk 201 Physiology Neonate
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.
8/6/2019 Fnk 201 Physiology Neonate
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.
8/6/2019 Fnk 201 Physiology Neonate
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.
8/6/2019 Fnk 201 Physiology Neonate
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 .
8/6/2019 Fnk 201 Physiology Neonate
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
8/6/2019 Fnk 201 Physiology Neonate
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
8/6/2019 Fnk 201 Physiology Neonate
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
8/6/2019 Fnk 201 Physiology Neonate
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