Transcript 09 Physiological anatomical peculiarities of the heart

Physiologic anatomical
peculiarities of the heart and
blood vessels in children.
Percussion of theDoc.
heart.
Nykytyuk S.O.
Timeline for development of the heart
Paired endocardial
tubes form in
cardiogenic region of
splanchnic
mesoderm
Fuse to form a single
heart tube
Ectoderm - blue
Mesoderm - red
Endoderm - yellow
Four layers contribute to the wall of the heart tube
Lumen of
heart
Constrictions & expansions foreshadow adult heart
Development of the septae of the heart
• The single heart tube is divided into four
definitive chambers by internal partitioning
during weeks 4-7
1. Interatrial
2. Atrioventricular
3. Interventricular
4. Ventricular outflow tract
• Many congenital heart defects arise during
septation
Fetus
Neonate
Fetal and neonatal circulatory systems:
shunts and changes at birth
1. Fetal foramen ovale shunts blood from right to
left atrium
•Adult remnant is fossa ovalis
2. Fetal ductus arteriosus shunts 90% of blood from
pulmonary trunk to aorta
•Adult remnant is ligamentum arteriosum
3. Fetal ductus venosus shunts 50% of blood from
umbilical vein to inferior vena cava by passing liver
•Adult remnant is ligamentum venosum
Differences in circulatory systems
Prenatal:
•
•
•
•
Little pulmonary blood flow
Gas exchange via placenta
Nutrient delivery to fetus through placenta
Right to left shunting of blood in heart
Postnatal:
• Functional pulmonary respiration and gas
exchange
• Loss of placental circulation
• Occlusion of right to left shunt in heart and
fetal anastomoses
Congenital heart defects
• Most common type of congenital malformations
• Incidence of nearly 1% of live births
• Causes elusive, multifactoral: single gene &
chromosome defects, environmental factors,
viruses, toxins, alcohol, drugs
• Specific etiology unknown in many cases but most
arise during critical period of heart dev. 20-50
days after fertilization
• Well tolerated before birth because of fetal shunts
• Most produce symptoms postnatally
DIAGNOSTIC EVALUATION


1.
2.
3.
4.
Anamnestic
Physical examination:
inspection
palpation
percussion
auscultation( although the latter is the
most significant)
FIGURE 26–1 Fetal circulation. Blood leaves the placenta and enters the fetus through the umbilical vein. The ductus venosus, the
foramen ovale, and the ductus arteriosus allow the blood to bypass the fetal liver and lungs. After circulating through the fetus, the blood
returns to the placenta through the umbilical arteries. From Ladewig, P. W., London, M. L., Moberly, S., & Olds, S. B. (2002).
Contemporary Maternal-Child Nursing Care (8th ed,. p. 51 ). Upper Saddle River, NJ: Prentice Hall.
Jane W. Ball and Ruth C. Bindler
Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc.
Upper Saddle River, New Jersey 07458
All rights reserved.
FIGURE 26–2 A, Fetal (prenatal) circulation. B, Pulmonary (postnatal) circulation. LA, left atrium; LV, left ventricle; RA, right atrium;
RV, right ventricle.
Jane W. Ball and Ruth C. Bindler
Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc.
Upper Saddle River, New Jersey 07458
All rights reserved.
Normal pressure gradients and oxygen saturation levels in the heart chambers and great
vessels. The ventricle on the right side of the heart has a lower pressure during systole than the left
ventricle because less pressure is needed to pump blood to the lungs than to the rest of the body.
FIGURE 26–3
Jane W. Ball and Ruth C. Bindler
Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc.
Upper Saddle River, New Jersey 07458
All rights reserved.
THE PECULIARITIES
OF INTRAUTERINE CIRCULATION.
Superior
vena
cava
Pulmonai
artery
Plumonary
vein
Descending
aorta
Inferior vena cava
Postnatal circulation.
Spumoni
artery
Pulmonary
vein
Ligamentum
teres
Transitional circulation in the newborn.
1.
2.
3.
4.
5.
• The mechanism of transition of the cardiovascular system to the
extrauterine functioning is as follows.
The infant's first breath raises p02, which causes dilatation of the
pulmonary arterial blood vessels and allow blood to flow freely to
the lungs. Now the pulmonary blood pressure is decreased.
The umbilical arteries constrict in response to higher p02 levels,
and the cord is cut. The umbilical arteries turn into the lateral
umbilical ligaments.
Circulation through the umbilical vein ends. Later, the umbilical
vein becomes the round ligament.
As the venous duct closes, the systemic blood pressure rises. Later
the venous duct turns into the venous ligament.
These changes in pressures cause blood flow through the arterial
duct to reverse its direction, thus changing one of the "righttoleft" shunts. The arterial duct then constricts (also in response to
higher pC«2 levels), preventing blood flow through it by the end of
the first day. It will later become the arterial ligament.
1. Since there is now an increased blood flow to the lungs, there must
be an increased flow from the lungs through the pulmonary veins
and to the left atrium.
2. The increased pressure of this blood against the oval foramen
forces it to close against the interatrial septum. This reverses the
other "right-to-left" shunt (the site of the old oval foramen will
later become the oval fossa).
3. The above changes make it possible for blood to flow to the
newborn lungs for gas exchange and return to the heart for
distribution to the body. All foetal vessels (umbilical arteries and
veins, venous and arterial ducts) first functionally and then
anatomically adapt to adult circulation by obliteration.
The results of the normal transition are
as follows.
1.Decrease
in
pulmonary
blood
pressure
with
2.Resultant
increase
in
pulmonary
blood
flow.
3.Closure of the oval foramen.
4.Constriction of the arterial duct.
5.End of flow through the umbilical vein.
• Failures of this transition are such life-threatening disorders
• as persistent foetal circulation or persistent pulmonary
hypertension.
The heart and blood vessels
• Blood vessels.
• The arteries of the child are relatively wider than in adults.
• The capillaries are particularly wide in infancy.
• Contrarily, the veins of young children are relatively narrow.
• (In adults the diameter of the veins are twice as wide as the
diameter of the arteries).
The heart.
• The mass of the heart is relatively greater in children than in
adults.
• In the newborn the weight of the heart is 0.9 % of the body
weight,
• while in adults it is only 0.5 %.
• The initial weight of the heart (17-24 g)
• doubles to 6-7 months,
• triples between one and two years
• , increases fourfold in the fifth year of life,
• six fold in the tenth year,
• and eleven fold by 16 years of age
an increase in the heart weight
• lags behind an increase in the body weight. The energy of
cardiac growth is higher in the first year of life, between 7 and 14
years it slows down, and again increases at puberty, it means,
cardiac growth keeps to the general laws of the bodily growth.
• The mass of heart is bigger in boys than in girls.
• The right and left ventricles have approximately the equal size
in newborn, thickness of their wall is about 5 mm. The atria and
main vessels have a relatively larger size in comparison with the
ventricles than those in adults.
• The growth of the left part of the heart, especially the left
ventricle, is more intensive after birth, than the right part. It is
caused by an increase of vascular resistance and arterial pressure.
• The growth of the heart is accompanied with tissue
differentiation.
The histological features of the cardiac muscle of children are as
follows.
1. Slenderness of muscular fibres, their closer congregation.
2. Poor development of connective tissue.
• 3. Muscular cells in newborns and infants are shorter and much
thinner than those of adults.
4. Muscle cell nuclei have an elongated oval configuration.
5. The total amount of nuclei is greater than in adults.
• The elastic tissue is poorly developed, abundant
Automatism
Phases of active potential
•
•
•
•
•
0 – depolarization
1 – beginning rapid repolarization
2 – slowly repolarization or plateau
3 – ending rapid repolarization
4 – rest period.
Conductive system of heart
2 – SA node;
3 – Bachman tract;
4 – tracts of Bachman,
Venkebach,
Torel
6 – AV node
7 – Hiss bungle
8 – right leg of Hiss bungle
9 – anterior brunch of left leg of
Hiss bungle
10 – posterior brunch of left leg of
Hiss bungle
11 - Kent bungle
12 – Jams bungle
Cardiac cycle
Systole
• 1. period of tension
•
asynchrony contraction
•
isometric contraction
•
(all valves are closed)
• 2. period of ejection
•
protosphigmic interval
(opening of semilunear valves)
•
fast ejection
•
slow ejection
Cardiac cycle
Diastole
• 1. Period of relaxation
•
protodiastolic interval (closing of
semilunear valves)
•
phase of isometric relaxation
(opening of AV-valves is end of this phase)
• 2. Period of filling
•
phase of rapid filling
•
phase of slow filling
•
phase of filling by help of atrium
systole
Hypoxemia in the infant
• below 95% pulse oximetry.
• cyanosis results from hypoxemia
• perioral cyanosis indicates central
hypoxemia
• acrocyanosis does not.
Response to Hypoxemia
• acute: HR increases
• chronic: bone marrow produces
more RBC to increase the amount of
Hgb available for oxygen transport.
• Hct>50 is called polycythemia.
• increased blood viscosity increases
risk of thromboembolism.
Cardiac Functioning
• 02 requirements are high the first few
weeks of life
• normally, HR increases to provide
adequate oxygen transport
• infant has little cardiac output
reserve capacity
• cardiac output depends almost
completely on HR until the heart is
fully developed (age 5 yr).
Compliance in the infant
• in infancy, muscle fibers are less
developed and organized
• results in less functional capacity or
less compliance
• less compliance means the infant is
unable or less able to distend or
expand the ventricles to achieve an
increase stroke volume in order to
compensate for increased demands.
Severe Hypoxemia
• children respond with bradycardia
• cardiac arrest generally results from
prolonged hypoxemia related to
respiratory failure or shock
• in adults, hypoxemia usually results
from direct insult to the heart.
• therefore, in children, bradycardia is
a significant warning sign of cardiac
arrest.
GATHERING COMPLAINT
• The child of older age can present his/her complaints by
himself/herself:
• Pain on the area of heart . In this case it is necessary to
specify:
• character of pain – sharp, blunt, burning, stabbing.
• Time when it appears – at night, in the afternoon, constant,
after
• neuro-psychological stress or physical exercises or in a
state of
• Rest.
• connection of pain with position of the patient – change in
pain
•
•
•
•
•
•
•
•
•
•
•
While getting up, in position on the left or right side.
. Irradiation of the pain – especially to the left hand.
. probable change after taking medicines , ect.
Cardiac dyspnea which leads to take deep breath, stop
during
climbing ,sometimes with groaning.
Perceptible heartbeat ( in a state of rest or during physical
Excertion.
Complaints of general character: rise in temperature,
fatigue, weakness,
Headache, loss of memory, loss of appetite , loss of body
weight,ect.
When younger cnugren and especially cnugren of the
breast feeding
Are ill, gathered complaints are less informative as parents
usually notice
• Attentive relatives can specify certain Is orders such as:
• Sudden shout ,anxiety of child , which atternates with long
periods of
• Flaccidity , flabbiness and pallor.
• Improper sucking:
•
. A child starts sucking breast , but after short time baby
stops.
•
. Signs of weariness and dyspnea.
•
. after resting for a while child again starts sucking, but
for a
•
Short time.
•
The anamnesis of disease
• while gathering anamnesis of disease it is necessary to ask
the parents in dletails about the dynamics of disease from
the moment it started: when and which symptoms appeared
first , how they changed (for example if the parents
• know about presence of noise , it is necessary to ascertain
its features- time of appearance, what noise , its changes,
ect.), what are the additional symptoms.
•
•
•
•
•
The anamnesis of life
• Gathering anamnesis of life has special significance for
cardiovascular
• Diseases, in childhood the cardiac pathology can be of
congenital genesis or
• May develop as complications after various diseases which
results to destruction of the myocardium.
•
Obstetric anamnesis should be carried out very
attentively: toxicosis
•
Of pregnancy, nephropathy, toxoplasmosis, infectious
diseases of mother ,
•
Professional exposure to harmful conditions – all this
can cause CHD.
•
• .
•
•
•
•
•
•
•
As complication of severe and chronic infections, allergic
diseases. The most common cause of heart diseases in
school children is rheumatic fever.
Assuming the probability of rheumatic fever. It is
necessary to clarify the following questions :
. presence of chronic infection or frequent acute
diseases in the upper
Respiratory tract ( chronic tonsillitis, qulnsy).
. family anamnesis , possibility of hereditary
rheumatic fever
. if rheumatic fever is repeated, it is necessary to
ask in details about its
Time , course and previous treatment
Inspection







examining the chest
point of maximum impulse, or apical pulse,
respiratory function
general physical growth and development
presence of all pulses (especially the femoral
pulses),
distended neck veins,
peripheral cyanosis,
edema
ASSESSMENT OF HEART
DISORDERS IN CHILDREN


History
Physical
assessment
general
appearance
 pulse, blood
pressure, &
respirations

Hypoxemia in the infant




below 95% pulse oximetry.
cyanosis results from hypoxemia
perioral cyanosis indicates central hypoxemia
acrocyanosis does not.
Response to Hypoxemia




acute: HR increases
chronic: bone marrow produces more RBC to
increase the amount of Hgb available for oxygen
transport.
Hct>50 is called polycythemia.
increased blood viscosity increases risk of
thromboembolism.
Compliance in the infant



in infancy, muscle fibers are less developed and
organized
results in less functional capacity or less
compliance
less compliance means the infant is unable or
less able to distend or expand the ventricles to
achieve an increase stroke volume in order to
compensate for increased demands.
clinical symptoms

Generalised moderate
peripheral cyanosis in
a shocked new
born with vasomotor
instability and poor
lung expansion.
clinical symptoms
A‘ blue baby' There is
severe peripheral and
central cyanosis.
Post-mortem revealed
Fallot's tetralogy. Note
the malformed low-set
ear.
clinical symptoms
Severe peripheral and
central cyanosis
Convulsion
was produced by
increased hypoxia after
prolonged crying. Postmortem revealed atresia
of the pulmonary artery
and a single ventricle.
clinical symptoms
“pitting” edema
Main clinical symptoms in patient with cardiovascular
disorders











Cardialgies,
tachycardia,
dyspnea,
abdominal pains,
heart enlargement,
decrease of tones' sonority,
rigidity of cardiac rhythm,
rhythm of gallop,
apical systolic murmur,
considerable cardiomegaly,
mitral or aortic configuration of
the heart at X-ray of the chest,





blood circulation's insufficiency,
stability or slow progress of heart
disturbances,
combined ECG-disorders (the
disorders of automatism,
conductivity, excitability, processes
of de-and repolarization),
echocardiographic disorders,
decreased of myocardium
contractive ability, objectively
confirmed by the instrumental
investigations.
Palpation



point of maximum impulse (presence of vibratory thrills
and pericardial friction rubs)
Assessing the quality and symmetry of all pulses (rate,
rhythm, volume, and character (alternative, large, swift,
dicrotic, intermittent, labile, small, slow, soft, tense,
rhythmic, rapid, pulse deficit, pulse flutter, tension of
the pulse, full (weak) pulse ) )
Determine blood pressure.
Pulse


Tachycardia is a puls rate more than 160 bpm in
an infant and more than 100 bpm at 3 years of
age.Tachycardia is particulary significant if it
persist during sleep, when the possibility of
exitement is removed.
Abnormal pulse pattent that tend to occur in
children with heart disorders are shown in Table
1.
Abnormal Pulse patterns
Pulse patterns
Water hammer
Description
Very forceful and bounding pulse
(Corrigan's pulse)and capillary
pulsation may be apparent even in
the fingernails suggest cardial
insufficiency, as in patient ductus
arteriosus
Pulsus alternant
Dicrotic
Adouble radial pulse for every
apical beat, symptomatic of aortic
stenosis
Average pulse rates at rest (beats per minute)
Newborn
6 months
1 year
2 years
3 years
140-160
130-135
120-125
110
105
4 years
5 years
6-7 years
10 years
12 years
100
98-100
90-85
78-85
70-75
The normal rate is not
more then 10 % of
average
Blood pressure, mmHg
Upper extremity
Newborn
systolic: 70-76
diastolic: 35
For children younger
12 months
systolic: 76 + 2 x n (n is
age in months)
diastolic: 1/2-1/3 of
systolic
Lower extremity
Newborn
systolic: 70-76
diastolic:35
For children younger 9
months
systolic: 76 + 2 x n (n is
age in months)
diastolic: 1/2-1/3 of
systolic
Blood pressure, mmHg
Upper extremity
1 year
systolic:90-100
diastolic: 60
For children older 1 year
systolic: min. 90 + 2 x n (n is
age in years)
max. 100 + 2 x n (n is
age in years)
diastolic: 1/2-1/3 of systolic
Lower extremity
In children older 9-10
months
the blood pressure is 5-20 mm
Hg more than upper
extremity
Shock vs. Hypotension

Shock


State of insufficient perfusion to meet the metabolic
demands of tissues
Hypotension


Physical sign characterized by a fall in systolic blood
pressure (BP below normal values)
Hypotension is a late sign of shock in children and it’s
presence in children implies profound cardiovascular
compromise
Hypotension

Blood Pressure

Lowest acceptable systolic blood pressure
Birth – 1 month: 60 mmhg
 1 month – 1 year: 70 mmhg
 1 year – 10 year: 70 + (2 X age in years)
 >10 years : 90 mmhg


Normal systolic
80 + (2 x age in years)
 or fiftieth percentile

Percussion
Percussion is used mainly to determine the
size of the heart by outlining its borders.
Dullness is normally heard over the left
area of the heart and partially over the
right.
Deviation from the expected finding may
indicate cardiac enlargement or
displacement and warrants further study.
Border's of heart relative
dullness
Border
Right
Upper
Left
until 2 years
•right parasternal line
•the II rib
•2 cm outward from left
midclavicular line
Transvers
•6-9 cm
Border
Right
Upper
Border
Right
Border
Right
Upper
Left
older 12 years
•the right sternal line
•the III intercostals space
•0.5 cm medially from left
midclavicular line
Transversal
size
•9-14 cm
al size
7-12 years
•Between the right parasternal line and the right sternal
line
Upper
Left
Transversa
l size
•the III rib
•0.5 cm outward from left
midclavicular line
•9-14 cm
Left
Transversal
size
2-7 years
•right parasternal line
•the II intercostals
space
•1 cm outward from left
midclavicular line
•8-12 cm
Border's of heart absolute
dullness
Border
Right
Upper
Left
until 2 years
•left sternal line
•the II intercostal space
•1.0-0.5 cm outward from
left midclavicular line
Transvers •2-3 cm
al size
Border
Right
Upper
Left
Transversa
l size
7-12 years
•left sternal line
•the III intercostal space
•Between the left
midclavicular line and left
parasternal line
•5-5.5 cm
Border
Right
Upper
Left
2-7 years
•left sternal line
•the III rib
•left midclavicular line
Transversal
size
•4 cm
Border
Right
Upper
Left
Transversal
size
older 12 years
•left sternal line
•the IV rib
•left parasternal line
•5-5.5 cm
Clinical symptoms


Tachycardia
Bradycardia
Pulsus alternans

Pulsus bigeminus





Increased rate
Decreased rate
Strong beat followed by
weak beat
Coupled rhythm in
which beat is felt in pairs
FIGURE 26–13 Clubbing of the fingers is one manifestation of a cyanotic defect in an older child. What neurologic signs may be
associated with such a defect?
Jane W. Ball and Ruth C. Bindler
Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc.
Upper Saddle River, New Jersey 07458
All rights reserved.
Blue-or-tet-spells
FIGURE 26–12
Place the infant who has a hypercyanotic spell in the knee–chest
position. This position increases systemic vascular resistance in the lower extremities.
Jane W. Ball and Ruth C. Bindler
Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc.
Upper Saddle River, New Jersey 07458
All rights reserved.
FIGURE 26–10
A child with a cyanotic heart defect squats (assumes a knee–chest
position) to relieve cyanotic spells.
Jane W. Ball and Ruth C. Bindler
Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc.
Upper Saddle River, New Jersey 07458
All rights reserved.
Tests
1.
What is the term of formation of the
4-chamber heart in the foetus?
a) At 3 weeks of gestation;
b) at 5 weeks of gestation;
c)at 7 weeks of gestation;
d)at 10 weeks of gestation;
e)at 18 weeks of gestation.
2.
In which of the following foetal
vascular structures is oxygen content the
lowest?
a)The umbilical vein;
b)the inferior vena cava;
c)the left atrium;
b) the umbilical arteries; e) the arterial duct;
3.
The change from the foetal to
newborn
circulation
is
primarily
accomplished by:
a)clamping the umbilical cord;
b)closure of the arterial duct;
c)expansion of the lungs;
e) closure of the umbilical arteries;
4.
The heart's position in the chest and
its relative dullness borders can be
influenced by the following factors, except
for:
a)shape of the chest;
b)level of the diaphragm;
c)size of the spleen;
d)size of the liver;
e)meteorism;
5.
Tachycardia can be noticed in all the
conditions below, but:
a)intoxication;
b)hyperthermia;
c)diseases of the cardiovascular system;
d)hyperthyroidism;
Answers: 1 - a; 2 - d; 3 - c; 4 - c; 5 - e; 6 - d,
Thank you for attention